Annual Shields Research Day

38th Research in Progress Meeting Friday, April 28, 2017 Department of Anesthesia Arcadian Court, 401 Bay Street University of Toronto Simpson Tower, 8th Floor

Toronto, Ontario 07:15 Breakfast, Registration Location: Arcadian Court – Ballroom, 8th Floor 08:00 Welcome Location: Arcadian Court – Ballroom, 8th Floor Brian Kavanagh, Chair, Anesthesia Trevor L. Young, Dean, Faculty of Medicine Zeev Friedman, Chair, Annual Shields Research Day 2017 08:30 Session A – Oral Presentations Location: Arcadian Court – Ballroom, 8th Floor Chairs: Dr. Chung, Dr. Hare A1 Diaphragm atrophy and clinical outcomes in

mechanically ventilated adults Michael Sklar – Resident St. Michael's Hospital

A2 Virtual Reality for educating and reducing preoperative anxiety in children – Phase 1: Design, face validity and acceptability by healthcare professionals Ben O’Sullivan – Fellow Hospital for Sick Children

A3 Impact of lung microenvironment on the protective vs. detrimental effects of MSC administration in experimental acute lung injury Diana Islam – Fellow St. Michael’s Hospital

A4 A systematic review and meta-analysis of erythropoietin and intravenous iron therapy to reduce red blood cell transfusion in patients undergoing surgery Tiffanie Kei – Graduate Student St. Michael's Hospital

A5 Intraoperative handover: What are we missing? Sophia Lane – Resident Sinai Health System

A6 The effect of anesthetic technique on mortality and major morbidity following hip fracture fixation. A retrospective, propensity-matched cohort study Laith Malhas – Fellow UHN-Toronto Western Hospital

A7 Deflation injury following release of sustained PEEP Bhushan Katira – Fellow Hospital for Sick Children

09:15 Session B - Poster Session Location: Gallery Level, 9th Floor B1 A multidisciplinary team consensus on the

allocation of resources, roles and responsibilities at emergency crash cesarean deliveries Ibukun Adedugbe – Fellow Sinai Health System

B2 Does the presence of an Anesthesiologist improve the outcome after endovascular treatment for acute ischemic stroke? Gabriela Alcaraz García-Tejedor – Fellow UHN-Toronto Western Hospital

B3 Hippocampal volume determines the quality of emergence from anesthesia Sujoy Banik – Fellow UHN-Toronto Western Hospital

B4 Pediatric regional Anesthesia workshops for faculty development: Curriculum design, implementation and evaluation Abhijit Biswas – Fellow Hospital for Sick Children

B5 Programmed intermittent epidural bolus for labor analgesia during first stage of labor: A biased-coin up and down sequential allocation trial to determine the optimum interval time between boluses of a fixed volume of 5ml of bupivacaine 0.125% plus fentanyl 2 cg/ml. Ricardo Bittencourt – Fellow Sinai Health System

B6 Complex airway management of symptomatic cricoid tumor Jaclyn DesRoches – Resident UHN-Toronto Western Hospital

B7 Maximizing efficacy of simulation-based anesthesiology training: Rapid cycle deliberate practice versus traditional medical simulation Danelle Dower – Fellow Hospital for Sick Children

B8 Thoracic epidural placement in a preoperative block area improves OR efficiency and decreases epidural failure rate Josh Gleicher – Fellow Sunnybrook Health Sciences Centre

B9 Comparison of forces generated by direct and indirect laryngoscopy using the GlideScope® T-MAC blade in a manikin Joanna Gordon – Fellow UHN-Toronto General Hospital

B10 Preoperative predictors of severe postoperative pain in women undergoing cesarean deliveries under spinal anesthesia Jennifer Guevara Velandia – Fellow Sinai Health System

B11 Sleep-disordered breathing and delirium Enoch Lam – Graduate Student UHN-Toronto Western Hospital

B12 Recovery of oxytocin responsiveness in pregnant human myometrial explants after oxytocin-induced desensitization: An in-vitro analysis of oxytocin receptor expression and signalling Alice Luca – Graduate Student Sinai Health System

B13 A propensity-matched comparison of the analgesic effects of superficial versus deep serratus fascial plane block for ambulatory breast cancer surgery David MacLean – Resident UHN-Toronto Western Hospital

10:00 Session C – Oral Presentations Location: Arcadian Court – Ballroom, 8th Floor Chairs: Dr. Karkouti, Dr. Cuthbertson C1 Surface echocardiography in the assessment of

left ventricular function during ex vivo heart perfusion: Comparison of 2D and 3D echocardiography Giulia Maria Ruggeri – Fellow UHN-Toronto General Hospital

C2 Cost of inpatient craniotomy is double that of outpatient craniotomy for brain tumors Elyana Wohl – Fellow UHN-Toronto Western Hospital

C3 The effects of pre-operative cannabis use on opioid consumption following elective Inflammatory Bowel Disease surgery Noreen Jamal – Graduate Student Sinai Health System

C4 Pharmacologically inhibiting GABA-A receptors reverses impaired synaptic plasticity and memory loss after traumatic brain injury Shahin Khodaei – Graduate Student Sunnybrook Health Sciences Centre

C5 The effect of analgesics on cancer growth and metabolism Doorsa Tarazi – Graduate Student Hospital for Sick Children

C6 The influence of anesthesia on intraoperative neuromonitoring changes in high-risk spinal surgery Nathan Royan – Fellow UHN-Toronto Western Hospital

C7 Analgesic effect of adductor canal block after knee surgery: a systematic review and meta-analysis David Goodick – Fellow Hospital for Sick Children

10:45 Session D – Poster Session Location: Gallery Level, 9th Floor D1 Selective cannabinoids for chronic neuropathic

pain: a systematic review and meta-analysis Howard Meng – Resident UHN-Toronto Western Hospital

D2 Increased cerebrovascular reactivity during anemia: a potential novel indicator of anemia-induced brain hypoxia? Nikhil Mistry – Graduate Student St. Michael's Hospital

D3 Anesthetic challenges during interventional management of extra-cranial vascular malformations Bahadur Niazi – Fellow UHN-Toronto Western Hospital

D4 Assessment of dexmedetomidine and scalp block to facilitate intraoperative brain mapping for awake craniotomy Stuart Nicholson – Fellow St. Michael's Hospital

D5 A survey of Canadian anesthesiologists and residency program directors and department chiefs assessing current environmentally sustainable anesthesiology practice Maria-Alexandra Petre – Resident St. Michael's Hospital

D6 Cardiac toxicity of bupivacaine is mediated via altered calcium dynamics in stem cell-derived cardiomyocytes Julia Plakhotnik – Graduate Student Hospital for Sick Children

D7 Role of screening questionnaires and quantitative sensory testing in detecting neuropathic pain in osteoarthritis: a scoping review Rajendra Kumar Sahoo – Fellow UHN-Toronto Western Hospital

D8 Beyond masks and syringes: Early ideas of Anesthesiology in Canada - A critical historical analysis Richa Sharma – Resident

D9 Choice of intraoperative resuscitation fluid during cardiac bypass surgery: A cost effectiveness analysis Lavarnan Sivanathan – Resident Sunnybrook Health Sciences Centre

D10 Discharge opioid prescription practices in a Pediatric teaching hospital Naiyi Sun – Fellow Hospital for Sick Children

D11 Rapid cycle deliberate practice in simulation-based medical education: A systematic review Jillian Taras – Resident Hospital for Sick Children

D12 Risk factors for failure of patient-controlled oral Analgesia after total hip and knee arthroplasty: A retrospective cohort study Leon Vorobeichik – Resident UHN-Toronto Western Hospital

D13 Esophageal manometry in Acute Respiratory Distress Syndrome (ARDS): Safer expiration, safer inspiration Takeshi Yoshida – Fellow Hospital for Sick Children

11:30 Session E – Oral Presentations Location: Arcadian Court – Ballroom, 8th Floor Chairs: Dr. Orser, Dr. Wijeysundera

E1 The universal definition of perioperative bleeding (UDPB) in cardiac surgery: Validation of a consensus-based bleeding endpoint for use in clinical trials Justyna Bartoszko – Resident UHN-Toronto General Hospital

E2 Blood brain barrier integrity after moderate traumatic brain injury is improved with human umbilical cord perivascular cell therapy Tanya A. Barretto – Graduate Student St. Michael's Hospital

E3 Ketamine reverses postanesthetic increase in extrasynaptic GABA-A receptor function in hippocampal neurons Kirusanthy Kaneshwaran – Graduate Student Sunnybrook Health Sciences Centre

E4 Opioid prescription following discharge in patients undergoing total knee arthroplasty Hawn Trinh – Fellow Sunnybrook Health Sciences Centre

E5 A novel brain stress test: Combined controlled end-tidal CO2 and MRI imaging to assess stroke risk Jay Shou Han – Resident UHN-Toronto Western Hospital

E6 A population-based study evaluating the association between pediatric surgical activity at the weekend and perioperative adverse outcomes Asad Siddiqui – Resident Hospital for Sick Children

E7 MicroRNA-200b protects neuronal cells from reactive oxygen species (ROS) Joshua Bell – Resident

12:15 Lunch Break and Poster Viewing 13:00 Anesthesia in the News: Dr. Brian Kavanagh: “Academic Anesthesia in Toronto 2050” 13:30 Annual Shields Lecture: Dr. Hugh C. Hemmings: “The synaptic pharmacology of general anesthesia” 14:15 Shields Day Award Presentation Session

Bateman, Hammell, Rothbart, Byrick, Bryan, Orser, Best Poster at Shields Day, Awards for Clinical Excellence, Residents and Fellows Tuition Awards, Laws Travel Awards

14:45 Departure

This event is an Accredited Group Learning Activity (Section 1) as defined by the Maintenance of Certification

Program of the Royal College of Physicians and Surgeons of Canada, approved by Continuing Professional Development, Faculty of Medicine, and University of Toronto up to a maximum of 4.5 Hours

Annual Shields Lecture – Dr. Hugh C. Hemmings

“The synaptic pharmacology of general anesthesia”

Hugh C. Hemmings Jr., MD, PhD, FRCA is the Joseph F. Artusio Jr. Professor and Chair of Anesthesiology and Professor of Pharmacology at Weill Cornell Medical College, and Anesthesiologist-in-Chief at NewYork-Presbyterian Hospital/Weill Cornell Medical Center. Dr. Hemmings earned a BS in Biochemistry from Yale College, a PhD in pharmacology from Yale Graduate School, and an MD from Yale Medical School. His graduate work in the laboratory of Paul Greengard, PhD was cited in his 2000 Nobel Prize in Physiology and Medicine. He completed postdoctoral work at The Rockefeller University, a residency in anaesthesia at the Massachusetts General Hospital, and a fellowship in cardiac anesthesia at NewYork-Presbyterian Hospital/Weill Cornell Medical Center, where he has been a faculty member for 25 years.

An internationally recognized neuropharmacologist, Dr. Hemmings is an expert in the synaptic effects of general anesthetics and mechanisms of neuronal signal transduction. His research in these areas is supported by grants from the National Institutes of Health. He is active in several national and international societies for anesthesiology and neuroscience, and serves as Editor-in-Chief of the British Journal of Anaesthesia. He has been elected Fellow of the Royal College of Anaesthetists and is a member of the Association of University Anesthesiologists. Dr. Hemmings has authored more than 110 articles in anesthesiology and neuroscience, and has edited four books, including Pharmacology & Physiology for Anesthesia: Foundations and Clinical Application published in 2013.

The Awards

Dr. Evelyn Bateman Award

Named in honor of Dr. Evelyn Bateman, Chief of Anesthesia at the Women’s College Hospital from 1956-1972, this award recognizes excellence in anesthesia at the undergraduate level.

Dr. David Bevan Award

The Dr. David Bevan Award is awarded to the presenter of the best overall research poster at the Annual Shields Research Day

Dr. A.C. Bryan Award

The A.C. Bryan Award is Awarded to a graduate student judged to have presented the best research project at the Annual Shields Research Day.

Dr. Thomas Donald Hammell Award

The Thomas Donald Hammell Memorial Award in Anesthesia recognizes outstanding contributions to the Residency Program (as chosen by other residents).

Dr. Alan K. Laws Travel Fellowship Award

The Laws Travel Fellowship Award one of two awards given by the Department of Anesthesia in honor and memory of Dr. Alan Laws. This award provides travel support for senior residents or fellows to advance their research programs in anesthesia.

The Marion and Earl Orser Prize in Anesthesia and Sleep Medicine

The Marion and Earl Orser Prize in Anesthesia and Sleep Medicine is awarded to residents,

Dr. R.J. Byrick Award

The R.J. Byrick Award recognizes the best fellow’s research paper presented at the Annual Shields research Day. Dr. Byrick was the Department’s 6th Chair of Anesthesia, serving from 1993-2003. He was then Vice-Dean of Clinical Affairs for the Faculty of Medicine, University of Toronto, until 2007. Dr. Byrick is currently a clinician at St. Michael’s Hospital.

Awards for Clinical Excellence For excellent clinical skills (Anesthesia and Critical Care Medicine) and consistent demonstration of exemplary patient service.

clinical fellows, post-doctoral fellows or graduate students in support of research in clinical sciences as well as basic/translational sciences.

Dr. Hynek Rothbart Award

The Dr. Hynek Rothbart Award is awarded to the best paper presented by a resident at the Annual Shields Research Day.

UT Anesthesia Resident and Fellows Tuition Awards

Awarded to meritorious Anesthesia residents and/or fellows who are engaged in graduate studies that are clearly integrated into their existing residency/fellowship program, and are linked with their overall career plan.

Abstracts A1 ● Diaphragm atrophy and clinical outcomes in mechanically ventilated adults Michael Sklar – Resident St. Michael's Hospital Background Prolonged mechanical ventilation is associated with poor long-term outcomes and substantial healthcare costs. Studies demonstrate that ventilation can cause diaphragm atrophy and dysfunction, but it is unknown whether this substantially impacts clinical outcomes. Methods In adult patients requiring invasive mechanical ventilation, diaphragm thickness was measured daily by ultrasound. Diaphragm atrophy was defined as a decrease in thickness exceeding 10% of baseline. The primary outcome was time to liberation from ventilation. Secondary outcomes included complications of acute respiratory failure (composite of at least one of reintubation, tracheostomy, ventilation longer than 14 days, or death in hospital). The association between diaphragm atrophy and the daily probability of liberation from ventilation was assessed using Cox proportional hazards modelling with time-varying covariates adjusting for severity of illness, sepsis, sedation, neuromuscular blockade, baseline thickness, and comorbidity. Findings A total of 211 patients were enrolled. By median day 4 of ventilation, thickness decreased by more than 10% in 78 patients (41%) and increased by more than 10% in 47 (25%). In the primary analysis, diaphragm atrophy was associated with a lower probability of liberation from ventilation on any given day (adjusted hazard ratio 0.67, 95% CI 0.53-0.85, per 10% decrease in thickness from baseline). The development of diaphragm atrophy was also associated with prolonged ICU admission (adjusted duration ratio 1.71, 95% CI 1.29-2.27), and an increased risk of complications (adjusted odds ratio 3.00, 95% CI 1.34-6.72). Increased diaphragm thickness during ventilation was associated with prolonged ventilation (adjusted relative duration 1.38, 95% CI 1.00-1.90) but this association was not significant in the primary model (adjusted hazard ratio 0.79, 95% CI 0.60-1.03, per 10% increase in thickness from baseline). Interpretation Diaphragm atrophy during ventilation is associated with markedly prolonged ventilation and an increased risk of complications.

Figure 1. Diaphragm atrophy during mechanical ventilation delays liberation from mechanical ventilation. Left: the adjusted relative hazard of liberation from mechanical ventilation at any given time is reduced with progressively greater decreases in diaphragm thickness (Tdi) (adjusted hazard ratio 0·67, 95% CI 0·53-0·85, per 10% decrease in Tdi below baseline). The association between increases in Tdi above baseline and the adjusted relative hazard of liberation from ventilation did not reach significance (adjusted HR 0·79, 95% CI 0·60-1·03, per 10% increase in Tdi above baseline). Grey shaded areas represent 95% confidence intervals for estimated hazards computed by Cox proportional hazards regression. Right: to evaluate the effect of diaphragm atrophy on the duration of ventilation, estimated hazards for liberation derived from the Cox proportional hazards model were employed to predict the probability of remaining on mechanical ventilation over time for varying degrees of diaphragm atrophy.

A2 ● Virtual reality for educating and reducing preoperative anxiety in Children – Phase 1: Design, face validity and acceptability by healthcare professionals

Ben O’Sullivan – Fellow Hospital for Sick Children Introduction Child pre-operative anxiety reduction techniques have been extensively researched and can be categorized into preoperative preparation, distraction techniques and parental presence. Children above the age of 6 have started to develop logical thinking, have a better understanding for reasons for the therapies required and may benefit from tours and preparation programmes. Virtual Reality offers an immersive experience that may assist with reduction of anxiety in children. Having previously demonstrated healthcare workers’ acceptance of our virtual experience as a valid, acceptable and potentially beneficial form of preparing children for their perioperative journey, phase 2 of our study was to investigate the usability and acceptability of our virtual experience by children and their parents. Methodology Following Institutional Approval and written consent, we recruited children between the ages of 6 and 18 to use our novel immersive virtual reality 1st person experience prior to anesthesia. This allowed children to prepare for the operating room by enabling them to ‘experience’ the process of receiving and recovering from an anaesthetic, thereby improving their understanding of upcoming events and maybe assisting with the reduction of pre-operative anxiety and postoperative behavioural disorders. Participants completed questionnaires evaluating the immersive VR experience on ease of use (System Usability Score - SUS), level of realism, acceptability, impact on their anxiety and preference over the standard PPT method. Results We recruited 93 children and their parents. 95.5% of children evaluated the immersive virtual reality as preparing them well for anesthesia and 90% would wish to use it again in the future. Children with previous anaesthetics rated the experience highly. 98% (95% CI, 92-100) of children rated the system as easy to use & required no further training. 93.3% (95%CI, 86-98) of children chose the immersive virtual reality experience over the PowerPoint slideshow for future anesthesia preparation. 2 (2.15%; 95% CI, 0.5 to 7) of the children experienced motion sickness / dizziness. 3 (3.2%; 95%; 2 to 10) children found the video blurry and in 1 (1.08%) this caused a headache. All symptoms were mild, resolved as soon as the headset was removed and did not prevent completion of the experience. Children & parents reported high SUS scores of 85.6 and 86.5 respectively indicating excellent usability. Comments from children included ‘this would help with anxiety’ & ‘so cool’. Discussion We have demonstrated that both children and their parents evaluate our immersive virtual experience as a valid, acceptable and fun form of preparing for the operating room. Children self-reported the benefits of this in reducing their anxiety. The incidence of side effects is low among our participants. We will continue evaluating immersive virtual reality in prospective RCTs.

A3 ● Impact of lung microenvironment on the protective vs. detrimental effects of MSC administration in experimental acute lung injury

Diana Islam – Fellow St. Michael’s Hospital Introduction Acute respiratory distress syndrome (ARDS) is a complex disorder with high mortality among critically ill patients. Most ARDS non-survivors had complications of pulmonary fibrosis. Mesenchymal stromal cells (MSC) are considered good candidates for therapy due to their ability to home into injury sites and provide paracrine support to injured cells. However, some evidence suggests that MSC may contribute to pulmonary fibrosis. Thus one needs to understand how MSC behave in ARDS conditions before clinical application. Here we used a mouse model of ARDS induced by Hydrochloric acid (HCl) aspiration and mechanical ventilation (MV) to investigate whether MSC administration can modulate outcome of ARDS. Hypothesis Lung microenvironment modulates the protective vs detrimental effects of MSC administration in ARDS Methods HCl or normal saline (control) was used to induce ARDS in 14 week old C57BL/6 mice, followed 48h later by MV with low or high pressure MV. Mouse bone marrow MSC were delivered via intra-tracheal and intravenous routes 48h after HCl instillation prior to MV; Non-MV served as control groups. Bronchoalveolar lavage fluids (BALF) were collected before and 48h after MSC delivery for proteomic analysis of lung microenvironment. Outcomes of MSC therapy were evaluated for up to 14 days. Key proteins identified in the BALF were further verified in plasma of ARDS patients, and served as therapeutic targets in phase 2 and 3 studies. Correction of lung microenvironment before MSC delivery. Antioxidant depletion was most affected profile in HCl model. lentiviruses carrying glutathione peroxidase-1 (LVGPx-1) were delivered intratracheally 4h after HCl-induced lung injury followed 48 h later by MSC delivery. Modification of MSC targeting inflammation and fibrosis. MSCs were transduced with LVs carrying the anti-inflammatory interleukin-10 (MSCIL-10) and the anti-fibrotic hepatocyte growth factor (MSCHGF), respectively were delivered 48h after ARDS. Results HCl instillation resulted in depletion of antioxidant capacity and upregulation of pro-coagulant, pro-fibrotic and pro-inflammatory mediators at 48h. This pattern of proteomic profiles was also observed in the plasma of patients with ARDS at ICU admission. These injury indexes became even worse after MSC delivery leading to development of lung fibrosis seen at 14 days. On the contrary, in the mild lung injury conditions of the saline control and MV alone groups, the MSC delivery reduced inflammation and injury and prevented fibrosis development. Correction of the lung microenvironment by enhancing antioxidant capacity using the LVGPx-1 prior to MSC delivery or treatment with MSCIL-10 and MSCHGF after the HCl-induced lung injury was able to reduce the injury and attenuated lung fibrosis. Conclusion MSC therapy can be beneficial and detrimental depending on the microenvironment at the time of administration, thus identification of microenvironment profiles is critical for guiding MSC therapy in ARDS.

A4 ● A systematic review and meta-analysis of erythropoietin and intravenous iron therapy to reduce red blood cell transfusion in patients undergoing surgery

Tiffanie Kei – Graduate Student St. Michael's Hospital Background Pre-operative anemia affects up to 50% of surgical patients and increases the risk of red blood cell (RBC) transfusion. Both pre-operative anemia and perioperative RBC transfusion are associated with an increased risk of adverse outcomes following surgery. Pre-operative treatment of anemia includes oral and intravenous (i.v.) iron and erythroid stimulating agents (ESA) such as erythropoietin (EPO); however, the optimal treatment strategy for pre-operative anemia remains to be established. Our objectives were to evaluate the efficacy and safety of ESA and iron therapy based on their effects on the risk for RBC transfusions and adverse thrombotic events. We hypothesized that ESA therapy would be more effective than iron therapy at reducing RBC transfusions. Methods We searched the Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE from inception to July 2016. We included randomized controlled trials in which adult patients undergoing surgery received either an ESA and/or i.v iron before surgery, versus iron or no intervention. Two authors independently reviewed the studies and extracted data from included trials. Risk of bias was assessed for all included studies. Our primary outcome was the number of patients transfused with red blood cells. Secondary outcomes included risk of mortality and other thrombovascular events (stroke, myocardial infarction, deep vein thrombosis, and pulmonary embolism). Results A total of 79 randomized controlled trials (8,137 participants) were included. Patients that received ESAs in addition to oral or i.v. iron had a reduction in their risk for transfusion (risk ratio [RR], 0.50; 95% CI, 0.46-0.53), relative to those that only received oral or i.v. iron or no intervention. Treatment with i.v iron alone, relative to oral iron or no treatment, also reduced the risk of RBC transfusion (RR, 0.80 [95% CI, 0.63-1.01]. No clear increased risk of adverse events was observed with EPO use: mortality (RR, 1.03 [95% CI, 0.68-1.57]), myocardial infarction (RR, 1.14 [95% CI, 0.60-2.14]), deep vein thrombosis (RR, 1.43 [95% CI, 0.92-2.21]), stroke (RR, 1.49 [95% CI, 0.62-3.59]) or pulmonary embolism (RR, 0.50 [95% CI, 0.12-2.06]). Conclusion Amongst patients undergoing surgery, the administration of an ESA in addition to oral or i.v. iron was associated with a reduction in patients requiring RBC transfusion. Intravenous iron was less effective at reducing RBC transfusion. Neither treatment was associated with any clear increase in risk of adverse thrombotic events. Additional large prospective randomized controlled trials are required to determine the optimal management strategy for patients undergoing surgery with anemia. Collaborator(s): G. Curley, K. Pavenski, N. Shehata, R. Tanzini, M.F. Gauthier, N. Mistry, C.D. Mazer, G.M.T. Hare

A5 ● Intraoperative handover: What are we missing? Sophia Lane – Resident Sinai Health System Introduction Effective handover is crucial to the provision of safe patient care [1,2]. Permanent intraoperative transfers of care between anesthesia providers are common. Unfortunately, intraoperative handovers are also associated with increased patient morbidity and mortality [3,4]. Currently, defined handover strategies in anesthesia are typically absent [5]. We studied how utilizing a checklist to structure intraoperative handover affected the number of data items handed over, as compared to ‘typical handover.’ Secondary outcomes included handover duration and the handover recipients' satisfaction with the quality of handover. Methods An intraoperative handover checklist (IHC) was devised after reviewing the related existing literature [6, 7] and then constructed through a Delphi process (Fig. 1). We obtained REB approval before commencing our study. 'Typical' handovers between anesthesia providers were observed and videotaped for future analysis. Data from corresponding anesthetic records were extracted to serve as a comparison to the verbal handovers. Next, we introduced the IHC and observed handovers done with the checklist. Videos of all handovers were independently analyzed by two separate researchers (SL, MG) to increase reliability. Discrepancies were resolved by re-watching the video to assess the discordant data extractions. Once data collection was completed, study participants were surveyed on their perceived utility of the IHC. Results A total of 65 anesthesia staff, fellows and residents participated in the study and 53 handovers from the pre-checklist phase, and 51 handovers from the checklist phase were analyzed. Use of the IHC increased the frequency of certain data being handed over, including: patient's age and weight, ease of mask ventilation, endotracheal tube depth, use of anti-emetics and post-operative analgesic plan (Tables 1-4). Importantly, use of the IHC did not significantly increase handover duration. Half (46%) of study participants completed the post-study survey. Most (77%) perceived that the IHC improved the quality of handover they received and 85% perceived it improved the quality of handover they gave. Furthermore, 85% were amenable to incorporating the checklist into their regular practice, with 11% being neutral and only 4% disagreeing with its incorporation. Conclusion Checklists are a proven tool for transferring information [1,2,8] and intraoperative handover of patient care is associated with increased patient morbidity and mortality [3,4]. Our study shows the IHC significantly increased the frequency of delivering data about both patient demographics and anesthetic care, without increasing handover duration. We believe an institution specific structured handover tool should be a part of standard practice. Further work is required to delineate whether standardizing handover decreases patient morbidity and mortality.

Table 1: Patient demographics

Handover

Pre-intervention n=53

Post-intervention n=51 p-v

name 62.26 84.31 0.01

Age 94.23 (n=52) 94.12 0.98

Sex 100 100 ns weight/BMI 41.51 62.75 0.03 ASA 5.66 5.88 0.96

Procedure 94.23 (n=52) 94.12 0.98

Positioning 22.64 15.69 0.37 Past Medical Hx 100 98.04 0.31 Contact Precaut 1.89 3.92 0.53 Past Anesth Hx 58.49 72.55 0.13 Medications 81.13 90.2 0.19 Allergies 71.70 86.27 0.07

Values are percentage within group. P-value based on Two-sample test of proportions. Table 2. Airway

Handover

Pre-intervention n=53

Post-intervention n=51 p-value

Mask ventilation 22.64 43.14 0.03 Airway grade/ease 81.13 80.39 0.92 Airway size 43.4 58.82 0.12 Airway depth 18.87 37.25 0.04 Mechanical ventilation 3.77 11.76 0.13

Values are percentage within group. P-value based on Two-sample test of proportions Collaborator(s): Marketa Gross, Cristian Arzola, Archana Malavade, Zeev Friedman

A6 ● The effect of anesthetic technique on mortality and major morbidity following hip fracture fixation. A retrospective, propensity-matched cohort study

Laith Malhas – Fellow UHN-Toronto Western Hospital Background Spinal anesthesia is associated with improved morbidity following hip fracture surgery but there is limited evidence regarding mortality benefit. Randomised control trials have been underpowered for this outcome and existing meta-analyses that rely on historical studies have reported a weak correlations at best. Observational studies on large databases have insufficient clinical information to draw meaningful conclusions. To address these limitations, we performed a retrospective propensity-score matched cohort study to evaluate the association of anesthetic technique and mortality in patients undergoing hip fracture fixation at UHN over a 13 year period. Methods After receiving research ethics board approval, the University Health Network Electronic Data Warehouse was used to identify patients who underwent hip fracture fixation over a 13-year period and clinical, laboratory and outcome data were extracted. Mortality data were obtained from the hospital discharge database. Principal exposure was spinal versus general anaesthetic and the primary outcome was 90-day in hospital mortality. Secondary outcomes were 1) length of stay, 2) pulmonary embolism, 3) major blood loss (>2 units), 4) major acute cardiac events. A propensity score-matched-pair analysis was performed using non-parsimonious logistic regression model of spinal anesthetic use. Results Two thousand five hundred and ninety one patients were identified. Of these, 883 patients in the spinal anesthesia group (SA) were matched to patients in the general anesthesia group (GA) who were similar in all other characteristics and the matched cohort’s outcomes analysed. The GA group was found to have a greater 90-day mortality (8.6% (n=76)) compared to the RA group (6.3% (n=56), p=<.001), and higher frequency of pulmonary embolism (2.3% vs 0.5%, p=<.001) and major blood loss (7.7% vs 4.8% , p=<.001). There was no difference on length of stay or major cardiac events. Discussion The results of this observational, propensity score-matched cohort study suggest a strong association between spinal anesthesia and lower 90-day mortality, as well as reduced rates of pulmonary embolism and major blood loss.

A7 ● Deflation injury following release of sustained PEEP Bhushan Katira – Fellow Hospital for Sick Children Introduction ARDS continues to be a significant problem with high mortality. Sustained inflation of lungs is routinely used to recruit the alveoli in ARDS but multiple RCTs of sustained inflation have been negative despite the physiological benefits. This, we think is because of a hidden form of injury offsetting the positive effects of lung inflation – injury induced by lung deflation. Aim To determine if sudden deflation of normal lungs after sustained inflation causes lung injury, its nature, timing, ultrastructural impact, and the possible hemodynamic mechanisms responsible for this injury. Methods Healthy Sprague Dawley rats were anaesthetised, ventilated (tidal volume 6 mL/kg), and randomized to Intervention or Control. Intervention was incremental increases in PEEP (3 to 11 cmH2O (over 70 min), abrupt deflation to ZEEP and ventilation for 30 min; Control was ventilation for 100 min (PEEP 3cmH2O) [Fig 1]. Lungs analysed for wet-to-dry ratio, BAL protein, static compliance, SpO2 and histology. To detect the timing of injury, rats received Evans Blue dye (EBD-30 mg/kg IV) at the initiation and were euthanized immediately before lung deflation or at 2, 5, 10 or 20 min afterwards (4/group). Terminal BAL analysed for EBD absorbance. Ultrastructure was studied by electron microscopy on lungs sampled from rats euthanized before deflation, and at 1 and 5 min after deflation. Hemodynamic data was obtained by ECHO performed at baseline (PEEP 3 cmH2O), immediately before and after deflation, and at 30 mins after deflation. RV pressure was measured with a Millar catheter. Results Wet-to-dry ratio (6.1±0.6 vs 4.6±0.4; P=0.00) and BAL protein (3.9±4.0 vs 1.5±0.7; P=0.18) was higher; and static compliance (0.48±0.97 vs 0.82±0.2; P=0.00) and SpO2 (67±23.5 vs 91±4.4; P=0.04) were lower in Intervention vs Control. Histology revealed collapse, hemorrhage and neutrophil accumulation in the intervention group. BAL Evans Blue demonstrated that microvascular leak was absent before deflation and was maximal by 10 min of deflation [Fig 2]. Ultrastructural analysis showed that sustained inflation caused minimal swelling of epithelium and endothelium before deflation; deflation resulted in major cellular and interstitial edema, and endothelial injury. Hemodynamic data showed that RV and LV were under-filled during inflation. Upon deflation, RV output, pulmonary vascular resistance, RV systolic transmural and diastolic pressures increased precipitously. RV/LV ratio increased progressively [Fig3]. Conclusion Sudden deflation after sustained inflation with PEEP causes protein leak, inflammation, hypoxemia, reduced compliance, endothelial injury and RV failure. The mechanism appears to be endothelial injury resulting in microvascular leakage, pulmonary hypertension and RV failure. Significance Deflation injury may be an important entity to prevent when using sustained inflation manoeuvres and may explain -in part- why several important RCTs in ARDS have been negative.

Collaborator(s): D. Engelberts, R.E. Giesinger, C. Ackerley, T. Yoshid, D. Zabini, G. Otulakowski, M. Post, W.M. Kubler, B Kavanagh

B1 ● A multidisciplinary team consensus on the allocation of resources, roles and responsibilities at emergency crash cesarean deliveries

Ibukun Adedugbe – Fellow Sinai Health System Introduction Emergency crash cesarean deliveries are usually performed in a sporadic manner and are often chaotic moments on the Labor and Delivery floor (1). The necessary tasks are completed in a haphazard manner that risks patient safety and is often stressful for the health care professionals involved(2-4). The aims of this study are: 1) to identify the current barriers that limit the ability of the multidisciplinary team to perform emergency crash cesarean deliveries in an organized, co-ordinated and timely manner; 2) to generate a protocol to perform these tasks in an organized fashion. Methods This is an ongoing study where a modified Delphi technique(5)is being used as a consensus building tool to obtain the opinions of an expert panel of anesthesiologists, obstetricians, obstetric nurses, respiratory therapists/anesthesia assistants and neonatologists. The study is being conducted in four rounds. An open-ended questionnaire was sent out in Round 1 to gather opinions on the current challenges in performing an emergency crash cesarean delivery and the possible suggested solutions. The level of agreement with the opinions stated in Round 1 was then sought in Round 2. Ideas that reached an agreement >70% were considered to have achieved consensus. These ideas will be used in Round 3 to build a list of resources, roles and tasks required for an emergency crash cesarean delivery, based on a face-to-face multidisciplinary discussion with 1-2 representative (s) of each stakeholder. We will then build a practical guideline/algorithm that details resource and task allocations as well as communication. Agreement on such document will be sought in Round 4. Results We invited 35 subjects representing the five stakeholder groups; 25 consented to the study. In Round 1, communication across the multi-disciplinary teams and human resource allocation were the main themes of the current challenges experienced by the team. In Round 2, there was consensus within the stakeholders about the following 1) need for an agreed definition of emergency crash cesarean delivery; 2) need for an agreed criteria for urgency based on standard benchmark timings from decision to delivery ; 3) need to improve handover of patient information across the specialities; 4) need to improve assistance available to anesthetists to provide general anesthesia; 5) need to improve the inefficiency of the process due to inadequate number of nurses to carry out tasks; 6) need to define a leader for the emergency situation. Conclusion Major deficiencies in our current system have been identified. The results of this study will provide a tool for education of the multidisciplinary team involved in emergency crash cesarean deliveries. References 1) J Obstet Gynaecol Can 2015;37:1116–7; 2) J Obstet Gynaecol Can 2013;35:82–83; 3) Acta Anaesthesiol Scand 2015;59:1287–95;

4) Curr Opin Anesthesiol 2009;22:352 – 356; 5) Can J Anesth 2015;62:271-7

B2 ● Does the presence of an Anesthesiologist improve the outcome after endovascular treatment for acute ischemic stroke?

Gabriela Alcaraz García-Tejedor – Fellow UHN-Toronto Western Hospital Background: Recently, there has been a growing interest on the impact of the type of anesthesia1,2 and the blood pressure control3,4 during endovascular treatment for acute ischemic stroke (AIS). In many centers, anesthesiologists might not routinely get involved except for patients who are unstable or require general anesthesia (GA)3,5. The aim of our study was to determine if the presence of an anesthesiologist improves the outcomes of patients undergoing endovascular treatment of AIS. Materials and Methods: After Institutional ERB approval, we conducted a retrospective cohort study on patients undergoing endovascular treatment for AIS of the anterior circulation between 2012 and 2016. Clinical and procedural variables during the intervention were collected. Multivariate analysis was performed to identify the predictors of hemodynamic intervention, failed hemodynamic control (systolic blood pressure, SBP, < 140 and/or >180 mmHg), in-hospital death and favorable neurological outcomes (Modified Rankin Scale < 2) at discharge. Results: A total of 143 patients were analyzed, 43% male and 57% female. Median age was 74 years (Interquartile Range, IQR, 63-83). The majority of cases had a thrombotic origin (98%), and intravenous thrombolysis prior to endovascular treatment was performed 69.3% cases. The location of the occlusion was: Middle Cerebral Artery (79.3%), Internal Carotid Artery (6.9%), Tandem (6.9%) and multiple (6.9%). The mean (±SD) NIHSS and ASPECTS scores were 17.26 (± 6.84) and 8.21 (± 1.6) respectively. Anesthesiologists were present in 98.6% of the procedures. The majority of patients received monitored anesthesia care (MAC), with or without sedation (88.1%). Nine patients received GA and 8 had intraoperative conversion to GA. Hemodynamic intervention was needed in 46.9% of the patients; 23% required intervention for hypotension and 23.8% for hypertension. The need for hemodynamic intervention was significantly associated with GA (OR 5.88; p=0.01) and SBP at hospital admission (OR 1.02; p=0.019). Hemodynamic control failed in 47 patients, and the main predictor for hypotension (OR 0.92, p=0.001) and hypertension (OR 1.08, p=0.001) were baseline SBP. Successful revascularization and favorable neurological status were achieved in 68.5% and 27.9% of patients respectively. In-hospital mortality was 16.3%. This was significantly higher among patients converted to GA (50%) compared to elective GA (25%), sedation (12.7%) and MAC (20%), p 0.019. Conclusion: This cohort represented one of the highest involvement rates of anesthesiologist during the endovascular therapy of AIS. In our study, the involvement of anesthesiologists resulted in a low rate of GA, a tighter hemodynamic control and better outcomes. The presence of an anesthesiologist during endovascular treatment should be routine practice to provide appropriate anesthetic care and better hemodynamic control. Collaborator(s): Jason Chui, M, Pirjo Manninen, MD, Andreu Porta, MD, Vitor Pereira, MD, Lashmi Venkatraghavan, MD

B3 ● Hippocampal volume determines the quality of emergence from anesthesia Sujoy Banik – Fellow UHN-Toronto Western Hospital Background: Emergence agitation is common following surgery for temporal lobe epilepsy and can lead to catastrophic complications in the immediate postoperative period. It has been shown that the process of emergence from anesthesia starts from the limbic structures (mesial temporal lobe, amygdala and hippocampus) and then spreads outwards to brainstem, reticular activating systems and then to the cortex. Preoperative neuropsychological assessment quantifies the expected loss of higher mental functions and thus may help predict postoperative behavioral changes. We hypothesised that a correlation existed between preoperative neuropsychological scores and the quality of emergence from anesthesia in patients undergoing surgery for temporal lobe epilepsy. Methods: After IRB approval, 36 consecutive adults (>18years) undergoing anterior temporal lobectomy and amygdalohippocampectomy for epilepsy were enrolled into the study. As a part of surgical planning, all patients had standard neuropsychologic testing ( handedeness, education, verbal and non verbal IQ, language and memory dominance and the volumes of limbic sructures). Anesthesia management was standardized in all patients and they were allowed to wake up with “no touch” technique. Time of emergence, and quality of emergence (Riker sedation-agitation scale) were noted. Emergence characteristics were classified as either smooth emergence (Riker scale 3-4) or agitated emergence (Riker scale >4). Data were analysed using Chi square test, unpaired t-tests and Pearson correlations. Results: 28 patients completed the study ( mean age of 35 years, 13 Female). Seven patients ( 25%) demonstrated agitated emergence (Group A), while 21 had smooth emergence (Group S). Among the agitated emergence, 2 patients had Riker scale of 7 indicating violet emergence. Patient demographics, handedness, language and meory dominance, anesthethetic used and the emergence times were similar between the groups. There were no differences between the groups with verbal, visuo-spatial and total IQ values (p= 0.82, 0.93 and 0.84). However, hippocampal volume was significantly smaller in patients with agitated emergence when compared to smooth emergence ( 3578 ± 344 mm3 vs 3903 ± 516 mm3 , p= 0.05, Pearson correlation coefficient -0.16) Conclusion: Our pilot data showed that hippocampal volume may be a significant factor in emergence from anaesthesia in patients undergoing epilepsy surgery. Further studies are required to elucidate the role of hippocampus in anesthetic emergence and to study different anesthtics on patient outcomes. Collaborator(s): Pirjo Manninen, Suparna Bharadwaj, MaryPat McAndrews,Taufik Valiante

B4 ● Pediatric Regional Anesthesia workshops for faculty development: Curriculum design, implementation and evaluation

Abhijit Biswas – Fellow Hospital for Sick Children Introduction The Pediatric Regional Anesthesia Network (PRAN) describes the applications of regional anesthesia in pediatric surgery. To offer the full range of ultrasound-guided regional anesthetic blocks in children, established faculty benefit from continuing professional development. Conference workshops are limited in scope, costly and require time away from work. With significant expertise among local faculty, we sought to design and implement a longitudinal education series. Method Data from PRAN formed the general needs assessment by providing benchmark data from similar institutions. Our local learners’ needs assessment comprised an online survey aiming to identify current gaps (among faculty and fellows). Our initial survey was designed by an educator with expertise in this field and refined based on feedback from a pilot phase. Learners opinions were sought on their current self-assessed competence in selected techniques and their preferred content, format and timing of a workshop series. On the basis of this we described specific and measurable objectives that would permit rigorous course evaluation and refinement. We elected to use a multi-modal educational strategy (below), continuously modified in light of solicited learner evaluations. Results Response rate to learners’ needs assessment was moderate (24/48, 50%). We constructed a 14 workshop series including ultrasound equipment updates, phantoms for needling, simulated patients, live models, and innovative needle-localization task trainers. We invited external speakers to deliver specialized sessions. We have sought Royal College Section 3 accreditation for this activity. Early learner evaluation data has been positive with respect to relevance, applicability to clinical practice and satisfaction with format and delivery. Anecdotally, faculty are increasing their application of regional anesthesia on the basis of confidence imparted by the education initiative. Conclusion While postgraduate training in regional anesthesia is exceptional at resident level, we identified a gap in faculty development. Since beginning a drive to actively increase use of regional anesthesia at our hospital we have increased the annual block volume by over 20%. Our faculty development program will continue to evolve to support this increase in case volume. Furthermore, we are collecting data to demonstrate an impact beyond learner reactions and perceptions to investigate translation to practice and patient care. Collaborator(s): Dr. Joost DeRuiter; Dr. Tobius Everett

B5 ● Programmed intermittent epidural bolus for labor analgesia during first stage of labor: A biased-coin up and down sequential allocation trial to determine the optimum interval time between boluses of a fixed volume of 5ml of bupivacaine 0.125% plus fentanyl 2 cg/ml

Ricardo Bittencourt – Fellow Sinai Health System Background: Programmed Intermittent Epidural Bolus (PIEB) analgesia has been shown to be superior to Continuous Epidural Analgesia (CEI) (1). PIEB regimens with bupivacaine 0.0625% with fentanyl produce highly effective analgesia, sensory block levels may be unnecessarily high (2). It is unknown whether regimens administering higher concentration and smaller volume of bupivacaine will result in lower levels of sensory block while maintaining the same quality of analgesia. We conducted a study to establish the optimal interval of boluses of 5ml of bupivacaine 0.125% plus fentanyl 2mcg/ml that would produce analgesia in 90% of women during first stage of labor without breakthrough pain. Methods: This was a double-blind sequential allocation trial with a biased-coin up and down design to determine the effective interval 90% (EI90) for the PIEB regimen. We recruited nulliparous women requesting epidural analgesia. Epidural catheter placement was performed with the assistance of ultrasound at L2/L3 or L3/L4. A multi-orifice epidural catheter was inserted 5 cm into the epidural space. A 3mL test dose of bupivacaine 0.125% plus fentanyl 3.3 mcg/ml was followed by a loading dose of 12ml of the same solution. the PIEB regimen was set to start one hour later, fixed at 5 ml of bupivacaine 0.125% plus fentanyl 2mcg/ml. The PIEB interval for the first patient was 60 minutes. The PIEB interval for subsequent patients was set at varying time intervals (60, 50, 40 and 30 minutes) according to the biased-coin design. The primary outcome was effective analgesia, defined as no requirement for PCEA or MD administered bolus for 6 hours after the initiation of PIEB, or until the patient presented full cervical dilatation, whichever occurred first. Pain scores, sensory block level, degree of motor block and non-invasive blood pressure were recorded every hour. Results: We studied 40 patients. The estimated EI90 with the truncated Dixon and Mood method was 36.5 minutes (95%CI 34.0, 39.0). The estimated EI90 by the isotonic regression method was 34.2 minutes (95%CI 30.8, 41.5). Overall, sensory block was above T6 in 20/40 women when assessed by ice and in 10/34 women when assessed by pinprick. 34/40 women exhibited no motor block. No patient required treatment for hypotension. Discussion: The optimal time interval between programmed intermittent boluses of 5 mL of bupivacaine 0.125% with fentanyl 2 mcg/mL is approximately 35 minutes. A significant number will exhibit sensory block above T6 to ice. Results suggest no advantage of this regimen over current bupivacaine 0.0625% regimens. References: 1) Anesth Analg 2013; 116:133-44; 2) Anesth Analg 2017; 124: 537-541 Collaborator(s): Paul Zakus, Cristian Arzola, Kristy Downey, Jose Carvalho

B6 ● Complex airway management of symptomatic cricoid tumor Jaclyn DesRoches – Resident UHN-Toronto Western Hospital Purpose: Chondrosarcoma is a rare tumor of the airway often involving the cricoid cartilage. Although it is a slow growing tumor, it can become symptomatic and cause airway compromise. This case describes the anesthetic management of a female patient undergoing elective laminoplasty for spinal stenosis in the prone position with known symptomatic chondrosarcoma. Clinical Features: Patient consent to publish was obtained. An 82-year-old female with chondrosarcoma involving the left cricoid cartilage was booked for an elective laminoplasty L2-L5 due to severe spinal stenosis. She presented to ENT 3 years’ prior with hoarseness, and nasopharyngoscopy revealed left side vocal cord paralysis. CT scan demonstrated a left posterior mass 1.4 cm in size, involving the cricoid cartilage. She was followed regularly by ENT and given the stability of tumor size and symptoms she declined surgical management. Following the difficult airway guidelines we planned for awake fibreoptic intubation. If any difficulty was encountered, we would abandon airway manipulation and cancel the case. We pre-treated with steroids and began a dexmetetomidine infusion while topicalizing the airway with Lidocaine 4% gargle plus pledgets. Standard CAS monitors as well as entropy and awake arterial line were applied. A pediatric bronchoscope was used and the glottic opening was visualized. Some distortion of the anatomy was noted due to a firm, white, nonfriable mass compressing the left arytenoid and obstructing 60% of the tracheal lumen. At this time a CMAC blade 3 was inserted to visualize the passage of the endotracheal tube cuff and a size #5 microlaryngoscopy tube (low pressure cuff) was passed atraumatically into the trachea. After confirmation of tube placement, the patient was anesthetized and placed in the prone position and the surgery was completed uneventfully. Limited flexion of the head, fluid restriction and reverse trendelenburg were applied during surgery in order to prevent postoperative airway edema. Prior to extubation the patient was given a second dose of steroid and the airway was compared under direct visualization with the CMAC. Some mild edema was noted; however, there was patency visualized on the right side of glottic opening and a cuff leak was detected. She was extubated smoothly and uneventfully and remained stable in the post-operative period. Conclusion: Most of the existing literature regarding airway management for cricoid chondrosarcomas includes definitive tracheal resection. This case is unique as it was an elective spinal surgery in the prone position and the location of the tumor necessitated careful preoperative planning and complex airway manipulation for delivery of safe care. Collaborator(s): Raja Rampersaud, Marco Garavaglia

B7 ● Maximizing efficacy of simulation-based anesthesiology training: Rapid cycle deliberate practice versus traditional medical simulation

Danelle Dower – Fellow Hospital for Sick Children Background Simulation based medical education (SBME) is an effective educational tool in a range of medical disciplines. Elements of feedback and repetitive practice have been shown to be features of SBME that lead to effective learning. Rapid cycle deliberate practice (RCDP) is a novel strategy that combines these essential features thus may be superior to traditional SBME. In this work-in-progress we are exposing anesthesiologists to simulated operating room emergencies and we are seeking to describe and compare the performance enhancement conferred by RCDP versus traditional SBME. As secondary outcomes we are studying retention and transferability of the two techniques. Methods Anesthesiology trainees at a university-affiliated teaching hospital are offered pediatric anesthesia emergency SBME as part of their regular curriculum. With REB approval, during the study period learners are randomized to receive that teaching in one of two formats: RCDP or traditional (where a scenario is conducted uninterrupted and debriefed at the end). Based on our previous work in this field our sample size is 80 simulation encounters. We conduct knowledge transfer scenarios immediately after the teaching and retention and transferability scenarios at six months. These performances are videoed and scored by trained expert raters using scoring instruments for which we have previously published validity evidence in this context. We are also collecting Kirkpatrick level one data on learner acceptability and perception if impact, given that this is a novel teaching strategy. Results In this work-in-progress we have implemented the RCDP program and collected preliminary data from learners, 100% of whom have rated the teaching method as effective or highly effective. Further quantitative data regarding impact on performance will be available for presentation at Shields Day. Conclusions RCDP is a novel form of SBME that offers potential advantages to traditional methods by combining essential components of feedback and repetitive practice. In this pilot study we have demonstrated that RCDP is an acceptable alternative to traditional SBME and further will be able to describe it’s impact on performance and knowledge retention. Further research is needed to investigate if RCDP compared to traditional SBME leads to improved objective measures of trainee performance.

B8 ● Thoracic epidural placement in a preoperative block area improves OR efficiency and decreases epidural failure rate

Josh Gleicher – Fellow Sunnybrook Health Sciences Centre Background Thoracic epidural analgesia (TEA) offers effective perioperative analgesia, with a low incidence of side effects for major abdominal surgical procedures. Furthermore, they have been shown to reduce perioperative cardiopulmonary complications and even mortality. TEA placement takes time and resources. At most centres they are inserted in the operating room prior to anesthetic induction and this consumes valuable operating room time. The pressure for a punctual start may also add to stress burden of the anaesthetist during this busy time. Following the addition of a regional anesthesia block room at our centre, we transitioned to inserting TEA before the patient arrives in the operating room. We set out to evaluate the impact of this intervention. Methods A retrospective quality improvement chart review for all elective major abdominal surgery cases receiving TEA over a twelve-month period. The review included 6 months of data prior to implementation of the regional anesthesia block room and 6 months of data following implementation. Collected data included: age, gender, body mass index (BMI), American Society of Anesthesiologists Physical Status (ASA-PS), procedure type, anesthesia-related OR time, and epidural failure rate (defined as inability to locate the epidural space or lack of any surgical site sensory block following epidural bolus). Local ethics board approval was not required as per our institution’s guidelines for quality improvement studies of this nature. Results A total of 254 thoracic epidural cases were reviewed: 112 pre-block room TEAs; 142 post-block room implementation TEAs. There were no statistical differences for patient age, gender, BMI, ASA-PS, or procedure type. Insertion of TEAs in the block room reduced anesthesia-related OR time by an average 22.9 minutes per patient (95% CI: 19.3 - 26.3, P < 0.0001). TEA failure rates decreased from 16.0 %(18/112) to 5.6 % (8/142) for an absolute reduction of 10.4% (P=0.0058). Conclusions Results suggest that insertion of TEA in a preoperative block room setting can save valuable operating room time. This study demonstrates the savings a preoperative block room can have on operating room flow and efficiency. An unanticipated finding in our study was the reduction of TEA failure rate from 16.0% to 5.6%. Potential explanations for this include increased time available for patient positioning and anatomical landmark identification, epidural placement by personnel who perform a higher volume of these procedures, and closer supervision for epidurals inserted by trainees. Collaborator(s): Oskar Singer, Steven Choi, Paul McHardy

B9 ● Comparison of forces generated by direct and indirect laryngoscopy using the GlideScope® T-MAC blade in a manikin

Joanna Gordon – Fellow UHN-Toronto General Hospital Background During laryngoscopy force is applied to oropharyngeal structures, often causing cardiovascular changes that may pose risk to the patient. Oropharyngeal trauma contributes to postoperative sore throat and can make bag mask ventilation and further laryngoscopy difficult. Direct laryngoscopy requires displacement of oropharyngeal tissues to achieve a line-of-sight straight towards the larynx. Indirect (video) laryngoscopy allows a laryngeal view without requiring this extent of oropharyngeal structure compression. This study investigates whether more force is required to achieve the same view on a manikin with direct laryngoscopy versus video laryngoscopy using the Glidescope T-MAC®. Methods Following REB approval, Staff and Fellow Anesthesiologists performed laryngoscopy and intubation on the Ambu® Airway Man Manikin. We analysed 25 complete data sets. Three FlexiForce® Sensors were fitted to the blade of the Glidescope T-MAC®. The sensors were calibrated and connected to the Tekscan Economical Load and Force (ELFTM) measurement system. Participants were asked to perform 4 laryngoscopies and intubations. Each participant aimed to achieve a POGO (Percentage Of Glottic Opening) score of 50% and > 80% with both direct and indirect laryngoscopy. Computer randomization allocated the sequence of POGO views and direct versus indirect attempts. Forces were measured throughout laryngoscopy. For each laryngoscopy, we calculated Peak Force, Average Force and Impulse Force (integral of total force over time for laryngoscopy). The forces were compared using the Mann Whitney U Test and the Kruskal-Wallis with Dunn's post-test. Statistical analysis was performed using Prism 5.0a. Results The peak, average and impulse forces were similar for direct and indirect laryngoscopy for both 50% and 80% POGO views. Where differences were noted, these were small and not statistically significant. Peak forces ranged from 2.9N to 38.4N. Impulse forces ranged from 16.9N to 208.4N. The greatest force recorded was from direct laryngoscopy for 80% POGO view. The smallest force was recorded during indirect laryngoscopy to achieve 50% POGO view. While the forces generated in the manikin may not reflect forces in clinical practice, it is interesting that some anesthesiologists used a laryngoscopy technique that enabled them to create the same laryngeal view with far less force than others. Conclusions We found no significant differences between forces generated by direct and indirect laryngoscopy. The results demonstrated that each individual’s technique may be a more important determinant of force than direct versus indirect laryngoscopy. Forceful laryngoscopy can cause harm and some participants applied over ten times the peak and impulse force of others for the same POGO score. There may be a role for force analysis in laryngoscopy training for anesthesiologists to adjust their technique. Collaborator(s): Vaughan Bertram, Sangwoo Leem, Matteo Parotto, Richard Cooper

B10 ● Preoperative predictors of severe postoperative pain in women undergoing cesarean deliveries under spinal anesthesia

Jennifer Guevara Velandia – Fellow Sinai Health System Background: Postoperative pain after cesarean delivery (CD) remains a challenge despite advances in pain management. Up to 10.9% of women report severe pain 36 hours after delivery and 9.2% report persistent pain after 8 weeks (1). Pain is a unique experience influenced by multiple factors; therefore, the ability to predict women at risk of developing severe pain would allow physicians to tailor specific strategies. A 3-item questionnaire has been shown to predict women experiencing evoked pain intensity after CD above 80th percentile with a sensitivity of 0.68 and specificity of 0.67 (2). Pain modulation theories propose that individuals exhibiting a facilitated pain response and/or reduced descending pain-modulatory capacities, which can be assessed by psychophysical pain tests (PPT) (3), may express a higher pain phenotype. We hypothesized that the addition of two PPT (pressure algometry and temporal summation) to the existing 3-item questionnaire would improve the ability to predict women at risk of experiencing severe pain after CD. Methods: This is an REB approved, ongoing prospective, descriptive study on women undergoing elective CD under spinal anesthesia. Women are assessed preoperatively using the 3-item questionnaire, pressure algometry (magnitude) and mechanical temporal summation (either positive or negative response, positive response being defined as a difference ≥1cm on a VAS 0-10cm between the 1st and 11th stimulus). All women receive standard institutional perioperative care and are assessed 24 and 48h after surgery for severity of pain at rest and on movement using a 0-100mm VAS. Patient satisfaction and opioid consumption are also recorded. A follow-up call is carried out 8 weeks after CD to enquire about residual pain. Based on power analysis we will require 215 subjects to detect a 20% increase in the ability to predict women presenting pain on movement at 24h > 80th percentile. Receiver operator curves will be used to determine sensitivity and specificity of predictors. Results: We have recruited 20% of our sample. The median [IQR] VAS pain scores at rest and on movement at 24 h were 14mm[39] and 52mm[42], respectively; 19.4% of women exhibited VAS above 80th percentile at rest (49.6mm) and on movement (77.2mm). Responses from the 3-item questionnaire correlated moderately with pain at 24 h (r=0.39–0.41; p=0.01-0.02). The mean (SD) pressure threshold (algometry) was 7.7 (2.6) kg/cm2 and 13.9% had a positive response to temporal summation. Conclusion: We plan to determine whether adding psychophysical pain tests to the 3-item questionnaire improves our ability to predict women at risk of experiencing severe pain after CD. References: (1)Pain 2008;140:87;(2)Anesthesiology 2013;118:1170;(3)Pain 2014;155:663 Collaborator(s): Jose Carvalho, Kristi Downey, Xiang Y. Ye, Cristian Arzola

B11 ● Sleep-disordered breathing and delirium Enoch Lam – Graduate Student UHN-Toronto Western Hospital Background: Sleep-disordered breathing (SDB) is highly prevalent and has been associated with cognitive impairment in older individuals. Delirium is an acute change in mental function and attention that fluctuates throughout the day and often occurs after surgery. Several studies suggest a relationship between SDB and postoperative delirium. The aim of this systematic review is to evaluate the literature on SDB, delirium, and cognitive impairment, and discuss the pathophysiology and perioperative considerations. Method: A literature search was performed of Medline (1946 - 2016), Medline In-Process (June 2016), Embase (1947-2016), Cochrane Central Register of Controlled Trials (May 2016), Cochrane Database of Systematic Reviews (2005 - June 2016). Inclusion criteria for studies were: a) SDB confirmed by polysomnography, b) cognitive impairment confirmed by a validated diagnostic tool, and c) publications in the English language. Results: The literature search identified 2 studies and eleven case reports on SDB and delirium, fifteen studies on SDB and cognitive impairment, and 5 studies on the effect of continuous positive airway pressure (CPAP) on cognitive impairment in elderly patients. The studies found a correlation between SDB and delirium. Roggenbach et al.1 found that an AHI > 19 event/h was associated with a six-fold increase of postoperative delirium while Flink et al.2 reported patients with OSA had 2.5 times greater chance of delirium. In all case reports, SDB was associated with delirium, and delirium resolved when CPAP was utilized.3 The fifteen studies on SDB and cognitive impairment show that SDB is strongly correlated to cognitive impairment. The five studies on CPAP therapy in elderly patients showed an improvement in cognitive function and memory when patients used CPAP for >4hrs/day. Discussion: This systematic review showed that patients with SDB may have a greater risk of postoperative delirium. The pathophysiology of SDB and postoperative delirium is unclear, but SDB is thought to affect the brain by causing repetitive nocturnal hypoxia, reducing cerebral blood flow, increasing cortisol levels, and causing systemic inflammation. Preliminary evidence suggests that CPAP therapy may lower the risk of delirium and maintain or improve cognitive function. Health care professionals need to be aware that undiagnosed SDB may contribute to postoperative delirium and they should consider preoperatively screening patients for SDB. Collaborator(s): Frances Chung, Jean Wong

B12 ● Recovery of oxytocin responsiveness in pregnant human myometrial explants after oxytocin-induced desensitization: An in-vitro analysis of oxytocin receptor expression and signalling

Alice Luca – Graduate Student Sinai Health System Introduction Postpartum hemorrhage (PPH) is a leading cause of maternal mortality and morbidity worldwide, caused most commonly by poor uterine tone. Oxytocin is the first line drug in the treatment of PPH and is also used for the augmentation of labor. Clinically, women with augmented labor are at increased risk of atonic PPH due to their exposure to high amounts of oxytocin, presumably mediated by oxytocin receptor (OTR) desensitization [1]. It is possible that discontinuation of oxytocin (recovery period) may reverse the desensitization phenomenon and restore myometrial contractility. However, this was not observed in an in-vitro study done by our group when the recovery time ranged from 30 to 90 min [2]. On the contrary, a clinical study showed that there is an inverse relationship between the recovery interval and blood loss at cesarean delivery (CD) in women with oxytocin-augmented labor [3]. Given these seemingly contradictory results, the objective of our study was to investigate the signalling pathways governing contractility in human myometrium, to gain a better understanding of OTR desensitization and resensitization. Methods The in-vitro study was conducted after REB approval and written informed consent from women undergoing elective CD. Myometrial tissue obtained from the uterine incision was dissected into 8 strips, mounted in individual organ baths and allowed to contract in physiological salt solution (PSS). To investigate the signalling pathways governing desensitization and resensitization, the strips were pretreated with oxytocin 10-5M (desensitization model) or left in PSS for 2 hours (control). This was followed by a 0, 30 or 60 min recovery period in PSS. The myometrial strips were then flash frozen and used for western blot experiments. The primary outcomes were total OTR protein expression and its localization within the plasma membrane, cytoplasmic and nuclear cell fractions. Results So far we have performed 10 experiments. We found no changes in total OTR protein levels with increasing recovery time post-desensitization. When looking at its distribution within the cell, we observed that there was an increase in the level of OTR protein within the cytoplasmic fraction of the cell with increasing recovery time post-desensitization. We will also be looking at the phosphorylation levels of the OTR and downstream proteins to confirm our findings. Final results will be presented at Shield’s day, following recruitment of 10 more patients. Conclusions Our results suggest that although recovery time post-desensitization may not alter total OTR protein expression levels, changes in the distribution of the OTR within the cell may be responsible for the changes in contractility and clinical effects observed in desensitized myometrium. References: 1) Phaneuf, Hum Reprod Update 1998;4:625-33; 2) Balki, Anesth Analg 2016;122:1508-15; 3)Tran, Can J Anaesth 2017 (in press). Collaborator(s): Dora Baczyk , John Kingdom and Mrinalini Balki

B13 ●

A propensity-matched comparison of the analgesic effects of superficial versus deep serratus fascial plane block for ambulatory breast cancer surgery

David MacLean – Resident UHN-Toronto Western Hospital Background: The serratus block is a recently described technique for postoperative analgesia in breast surgery. Analgesia is achieved primarily through blockade of intercostal sensory branches, yet the question of whether to inject superficial or deep to the serratus muscle has not been addressed. This cohort study compared the analgesic benefit of superficial versus deep serratus plane blocks in ambulatory breast cancer surgery patients at Women’s College Hospital between February 2014 and December 2016. We tested the joint hypothesis that a deep serratus block is noninferior to superficial serratus block for both postoperative in-hospital (pre-discharge) opioid consumption and pain severity. Methods: Seventy patients were propensity-matched among two groups (35 per group): superficial versus deep serratus blocks. The cohorts were used to evaluate the effect of blocks on postoperative oral morphine equivalent (OME) consumption and area under the curve (AUC) for rest pain scores. Deep serratus block was considered to be noninferior to superficial block if it were noninferior for both outcomes, within noninferiority margins (∆) of 15 mg OME and 4 AUC units. Secondary outcomes included intraoperative fentanyl consumption, time-to-first analgesic request, duration of recovery room stay, and incidence of postoperative nausea and vomiting (PONV). Results: Deep serratus block was associated with postoperative morphine consumption and rest pain AUC that were noninferior to superficial serratus block (Table 1, Figure 1). Intraoperative fentanyl consumption, time-to-first analgesic request, recovery room discharge, and PONV were not different between blocks. Conclusions: The postoperative in-hospital analgesia associated with the deep serratus block is as effective as the superficial serratus block following ambulatory breast cancer surgery. These new findings are important to inform both current clinical practices and future prospective studies. Collaborator(s): Brull, R; Abdallah, F.W. Table: Oral morphine equivalent (OME) consumption and pain scores for superficial versus deep serratus blocked patients. AUC, area under the curve. Figure: Area under the curve (AUC) for rest pain scores in superficial versus deep serratus blocked patients. There was no difference in pain scores between superficial versus deep serratus block locations at any time during the postoperative recovery in first and second postanesthesia care unit (PACU).

Table:

Primary outcome

Superficial serratus block

(n=35)

Deep serratus block (n=35)

p-value (versus ∆)

Cumulative in-hospital postoperative OME consumption (mg) 19.6 [17.6, 21.6] 21.9 [19.8, 24.0] <0.001

AUC for in-hospital pain severity VAS scores at rest 18.8 [16.5, 21.1] 21.6 [18.9, 24.3] <0.001

Figure:

C1 ●

Surface echocardiography in the assessment of left ventricular function during ex vivo heart perfusion: Comparison of 2D and 3D echocardiography

Giulia Maria Ruggeri – Fellow UHN-Toronto General Hospital Background: Transthoracic and transesophageal echocardiography are a non-invasive, established method to evaluate and monitor cardiac function in various clinical contexts. 3D echocardiography is superior in the assessment of cardiac chamber volumes and mass evaluation [1] and recently recommended over the use of 2D for Left Ventricular (LV) volumes and Ejection Fraction (EF) measurements [2]. The aim of our pilot study is to evaluate LV function by means of epicardial echocardiography comparing different echo technique (2D and 3D) with the actual gold standard Pressure-Volume (PV) loop conductance catheter, during isolated beating heart in Ex Vivo Heart Perfusion (EVHP). Methods: After ethical board approval, 12 Yorkshire pigs underwent general anesthesia for heart harvesting. The hearts were placed on an ex vivo circuit and a custom made 3D printed set-up was used to maintain a transesophageal probe adherent to the heart. The echocardiographic evaluation was performed in vivo, after chest opening to establish a baseline and during loading of the left ventricle at the first (T1) and the fourth (T4) hour of extracorporeal circulation. EF was calculated off-line from 2D and 3D images and compared with PV loop catheter measurements. Results: 2D and 3D echocardiographic EF evaluation show very similar results but with smaller standard deviation for what concerning 3D measurements (2D: In Vivo 51±9, T1 44±16, T4 36±9 % p=0.007. 3D: In Vivo 50±7, T1 41±4, T4 37±6 % p=0.012; RM One Way Anova. Figure 1). The absolute numbers recorded by the PV loop catheter are significantly lower, however shared a very similar trend. Conclusions: During EVHP, echocardiographic evaluation of LV EF is feasible with both 2D and 3D analysis but the absolute numbers are significantly higher than PV loop catheter results. Additional studies using an independent gold standard method are needed to confirm these findings. References: [1] Hung J et al; 3D echocardiography: a review of the current status and future directions. J Am Soc Echocardiogr 2007; 20:213-33 [2] Lang MR et al; EAE/ASE Recommendations for Image Acquisition and Display Using Three-Dimensional Echocardiography. J Am Soc Echocardiogr 2012; 25:(1)3-36 Collaborator(s): Flavia Ballocca, Liming Xin, Bryan Gellner, Roberto Vanin Pinto Ribeiro, Mitesh V. Badiwala, Massimiliano Meineri

C2 ● Cost of inpatient craniotomy is double that of outpatient craniotomy for brain tumours

Elyana Wohl – Fellow UHN-Toronto Western Hospital Background The advantages of outpatient surgery to patients and healthcare providers are well established. Traditionally, neurosurgery is considered a resource-intense specialty, many patients needing admission before surgery, and a long post-operative stay including intensive care unit (ICU) admission. Outpatient craniotomy has been shown to be safe for some neurosurgical procedures. The economic implications of outpatient neurosurgery have not been studied. Our study aimed to determine the cost implications of outpatient compared to in-patient craniotomy for brain tumour. Methods After ethical approval, we conducted this single-centre study over eighteen months, on patients who underwent either outpatient or in-patient craniotomy for tumour. We included awake craniotomies performed by a single surgeon. All cases were less than 4 hours in duration without post-operative ICU admission. The hospital costs were gathered using data from the Ontario Case Cost Initiative (OCCI). Direct, indirect and total costs were compared between the groups. We used student’s t-test, ANOVA and chi-squared tests for data analysis. Results Patient characteristics were similar. The results on costs of the two groups are shown in table 1. Four patients were excluded as the length of stay (LOS) extended to 10 days or more. The costs were significantly lower for patients who underwent ambulatory surgery. Breakdown showed significant reduction in expenses incurred in pharmacy, general ward and investigations, but not in operating room or anesthetic expenses. The total cost reductions became statistically significant when LOS extended to 2 days or more. Conclusions This was the first study examining the cost implications of outpatient versus in-patient craniotomy. Our results show that LOS of 2 days nearly doubles the cost of outpatient surgery. It is unclear whether this saving could be extrapolated to other surgical specialties or other neurosurgical procedures. Collaborator(s): Dr. Lawrence LM Li, Dr. Lashmi Venkatraghavan, Dr. Rebecca Moga, Dr. Mark Bernstein Table 1. Main results on cost analysis

Out-patient In-patient P value Costs

Direct 3695 (± 666) 7636 (± 4054) < 0.01 Indirect 1547 (± 277) 3013 (± 1522) <0.01 Total 5242 (± 931) 10649 (± 5570) <0.01

Direct Costs ($ CAD) Theatre 2299 (± 430) 2312 (± 623) 0.94 Anaesthetics 276 (± 51) 259 (± 54) 0.25

Investigations 531 (± 406) 834 (± 517) 0.02 Pharmacy 18 (± 20) 372 (± 638) 0.004 Food NA 190 (± 172) Unit (ward costs)

570 (± 248) 3000 (± 2534) < 0.01

Costs according to LOS Mean (± 95% CI)

Out-Patient 1 Day 2 Days > 2 Days

Direct 3695 (± 877) * # 5443 (± 1670) 7683 (± 1785) * 10506 (± 1928) # Indirect 1547 (± 331) * # 2187 (± 629) 3031 (± 673) * 4094 (± 727) # Total 5242 (± 1205) * # 7630 (± 2295) 10714 (± 2453) * 14600 (± 2650) #

CAD – Canadian Dollars; LOS – Length of Stay. All values are means (± standard deviation) unless otherwise stated. * # denote statistical significance.

C3 ●

The effects of pre-operative cannabis use on opioid consumption following elective inflammatory bowel disease surgery

Noreen Jamal – Graduate Student Sinai Health System Background: Minimizing opioid use for post-operative pain control is an essential part of the enhanced recovery protocol and the attempt to reduce the length of stay for surgical patients. Anecdotally, health care professionals on the Acute Pain Service have observed that individuals consuming cannabis pre-operatively have higher opioid requirements in the post-operative period. The aim of this study was to examine whether pre-operative cannabis use has an impact on opioid consumption in the first 24 hours post-operatively in individuals undergoing surgery for Inflammatory Bowel Disease (IBD). Methods: Following REB approval, we conducted a retrospective chart review of patients who underwent surgery for IBD at Mount Sinai Hospital between January 1, 2014 and December 31, 2015. Patients were excluded if they received neuraxial anesthesia or if pre-operatively they were taking methadone or any synthetic or extracted forms of delta-9-tetrahydrocannabinol. Demographic data, cannabis use, as well as data on pre-operative, intra-operative and post-operative opioid consumption was collected. All opioid amounts were converted to morphine IV equivalents (ME). Results: Of the 355 charts included in the study, 42 (11.8%) were cannabis users (C) and 313 (88.2%) were cannabis non-users (NC). The C group was significantly (p<0.05) younger, with a higher percentage of males but did not differ with respect to type of surgery, length of surgery, pre-op opioid use or intra-op opioid use compared with the NC group. After accounting for the effects of age, pre-operative daily ME use, intra-operative ME use and length of surgery using applied regression analysis, we found that post-operative opioid consumption was proportional to the amount of cannabis consumed. The cannabis group required an additional 0.35 mg (95% CI 0.05, 0.63) ME per mg daily cannabis used, in the first 24 hours after surgery, compared with the non-users group (p=0.015). Conclusions: Our results demonstrate that cannabis use increased the post-operative opioid consumption in patients undergoing IBD surgery, which could impede adequate pain management and increase the risk of opioid side effects. Future prospective studies should expand beyond the IBD population and look at the role of synthetic cannabinoids as adjuncts for pain management. Studies should also extend beyond the first 24 hours post-operatively to gain a better understanding of how to optimize pain control in this patient population. Collaborator(s): Archana Malavade, May Musing, Jennifer Korman, Brenda Coleman and Zeev Friedman

C4 ●

Pharmacologically inhibiting GABA-A receptors reverses impaired synaptic plasticity and memory loss after traumatic brain injury

Shahin Khodaei – Graduate Student Sunnybrook Health Sciences Centre Abstract text removed at author's request. Collaborator(s): Nathan Chan, Alejandro Fernandez-Escobar, Dian-shi Wang, Beverley A Orser, Sinziana Avramescu

C5 ● The effect of analgesics on cancer growth and metabolism Doorsa Tarazi – Graduate Student Hospital for Sick Children Background Morphine is the gold standard and first therapeutic option for cancer pain treatment, however its effects on tumor growth and patient outcome are still unresolved. After screening several anesthetic/analgesic agents, we found that morphine and no other opiate inhibits isocitrate dehydrogenase 1 (IDH1) in vitro. IDH1 is the most commonly mutated metabolic enzyme found in cancers. The IDH1 mutant enzyme produces 2-hydroxyglutarate (2HG), an oncometabolite, instead of alpha-ketoglutarate (⍺KG). Given this novel relationship between morphine and cellular metabolism, we aimed to determine the effects of morphine and hydromorphone on glioma oncogenesis by examining cell proliferation and metabolic state. Methods The U87 glioma cell line was treated with clinically relevant concentrations of morphine (10µM and 50µM) and hydromorphone (5µM, and 25µM) for one week. Resultant changes in 86 metabolites were quantified by targeted mass spectrometry. Oncogenesis was approximated by measuring cell proliferation of U87 cells treated with morphine (0.1-50µM) or hydromorphone (0.1-25µM) for one week, via the xCELLigence RTCA platform Results Compared to vehicle, 43 metabolites changed following analgesic treatment: 20 exclusively by morphine, and 3 exclusively by hydromorphone. Specifically, 10µM morphine increased 5 pentose phosphate pathway metabolites, and varied 8 glycolytic metabolites. Furthermore, morphine decreased ⍺KG levels by 44% and increased 2HG by 38% (p-value < 0.01), suggesting morphine inhibits IDH1 in cellulo. The pentose phosphate pathway is involved in DNA synthesis and NADPH production. Metabolite increases in both the aforementioned pathways correlates to the observed increase of cell proliferation by 20-40% (p-value < 0.05) in all morphine treated samples. Hydromorphone at 0.1 and 1µM caused no change in proliferation rate, while 5 and 25µM treatment decreased growth rate by 25% (p-value < 0.05). Conclusion We show that morphine, but not hydromorphone, alters the glycolytic state in U87 glioma cells. Increased 2HG and decreased ⍺KG in morphine samples may suggest that the interaction between morphine and IDH1 promote a similar metabolic profile to IDH1 mutant cancers but with the added advantage of amplified proliferation rates of up to 40%. This challenges the misconception of risk-free cancer pain management, suggesting a need for adjustments to the current pain treatment paradigm.

C6 ●

The influence of anaesthesia on intraoperative neuromonitoring changes in high-risk spinal surgery

Nathan Royan – Fellow UHN-Toronto Western Hospital Background: The use of intraoperative neuro-monitoring is a well-established method of detecting neurologic injuries during spine surgery. Anaesthesia, especially inhalational agents, influence motor evoked potential (MEP) monitoring. The aim of our study was to compare the effect of balanced anaesthesia (BA) (intravenous plus inhalational anaesthesia) and total intravenous anaesthesia (TIVA) on the incidence of intraoperative neuro-monitoring changes, interventions performed and neurological outcomes of patients following high-risk spinal surgery. Methods: After REB Approval, a retrospective review of 155 patients who underwent spinal surgery with MEP was performed. Data was collected on changes in MEP and/or somatosensory evoked potential (SSEP), interventions performed, and neurological outcomes. Patients were divided into BA and TIVA groups and data was analysed. Results: 152 patients were eligible for the study (mean age 54 ±17, M:F 45:55). A BA technique was used in 62% and TIVA in 38%. Desflurane (<0.5MAC) was used in 85% BA cases. Intraoperative neuro-monitoring changes occurred in 11.8% (18/152) of cases. There was no statistical difference in incidence of monitoring changes between BA (78%) and TIVA (22%) groups. (p=0.197). Anaesthetic or surgical interventions were performed in 12 patients, with resolution of changes in 50%. (p=0.455). All 5 patients with persistent MEP changes had worsening of existing neurological deficits post operatively; 8 had transient MEP changes and 2 experienced worsening of existing neurological deficits. Conclusion: We found that intraoperative neurophysiological monitoring can be performed with both BA (MAC<0.5) and TIVA in high-risk spinal surgery with no statistical difference in incidence of intraoperative monitoring changes. Collaborator(s): Nancy Lu, Pirjo Manninen, Lashmi Venkatraghavan

C7 ●

Analgesic effect of adductor canal block after knee surgery: a systematic review and meta-analysis

David Goodick – Fellow Hospital for Sick Children Background: Adductor canal block (ACB) is increasingly used in lieu of femoral nerve block for knee arthroscopy and arthroplasty due to its quadricep sparing and equivalent analgesia, thus improving patient’s functional outcome and early recovery (1). No reviews have yet been conducted to compare the effect of adductor canal block to placebo for both knee arthroscopy and arthroplasty. Methods: We conducted a systematic review and meta-analysis of randomised trials comparing ACB to placebo. Four databases (inception to December 2016) were searched for relevant articles. We evaluated risk of bias using the Cochrane Risk of Bias instrument and certainty in effect estimates using the GRADE approach. Data extracted from each study included consumption of postoperative opioid medications and pain scores at rest and during movement at 8 ± 4 h and 24 ± 4 h after surgery. Results: The systematic review included 10 studies (n = 525 patients), of which 8 were eligible for meta-analysis. Arthroscopy studies (n = 168) investigated single-shot ACB, whereas arthroplasty studies (n = 258) used a catheter technique for multiple dosing or continuous infusion of local anaesthetic. ACB significantly decreased initial 24 h opioid consumption (SMD, -0.61; 95% CI, -0.98 to -0.25, P = 0.001) and pain scores at rest at 8 ± 4 h (WMD, -4.27; 95% CI, -8.14 to -0.39, P = 0.03) after knee arthroscopy. After arthroplasty, ACB significantly decreased initial 24 h opioid consumption (SMD, -0.51; 95% CI, -0.81 to -0.21, P = 0.0008) and pain scores at rest at 24 ± 4 h (WMD, -13.06; 95% CI, -18.37 to -7.74, P < 0.00001), and during movement at 8 ± 4 h (WMD, -9.17; 95% CI, -17.00 to -1.33, P = 0.02) and 24 ± 4 h (WMD, -15.91; 95% CI, -26.67 to -5.15, P = 0.004). No analysis could be performed for adverse events due to inadequate reported data in the studies. Conclusions: ACB is associated with significant reductions in opioid consumption and pain score in the first 24 h after knee arthroscopy and arthroplasty, although the effect size is moderate. Reference: 1. Faraj et al. Anesthesiology 2016; 124: 1053-64. Collaborator(s): Abhijit Biswas; Monica Caldeira-Kulbakas; Bradley C. Johnston; Jason Hayes; Clyde Matava; Conor McDonnell; Maisie Tsang

D1 ● Selective cannabinoids for chronic neuropathic pain: a systematic review and meta-analysis Howard Meng – Resident UHN-Toronto Western Hospital Background: There is a lack of consensus on the role of selective cannabinoids for the treatment of neuropathic pain (NP). Guidelines from national and international pain societies have provided contradictory recommendations. The primary objective of this systematic review and meta-analysis (SR-MA) was to determine the analgesic efficacy and safety of selective cannabinoids compared to conventional management or placebo for chronic neuropathic pain. Methods: We reviewed randomized controlled trials (RCT) that compared selective cannabinoids (dronabinol, nabilone, nabiximols) with conventional treatments (e.g. pharmacotherapy, physical therapy or a combination of these) or placebo in patients with chronic neuropathic pain because patients with NP may be on any of these therapies or none if all standard treatments have failed to provide analgesia and or if these treatments have been associated with adverse effects. MEDLINE, EMBASE and other major databases up to March 11, 2016 were searched. Data on scores of numerical rating scale for neuropathic pain and its subtypes, central and peripheral, were meta-analyzed. The certainty of evidence was classified using the Grade of Recommendations Assessment, Development and Evaluation (GRADE) approach. Results: Eleven RCTs including 1219 patients (614 in selective cannabinoid and 605 in comparator groups) were included in this SR-MA. There was variability in the studies in quality of reporting, etiology of neuropathic pain, type and dose of selective cannabinoids. Patients who received selective cannabinoids reported a significant, but clinically small, reduction in mean numerical rating scale pain scores (0-10 scale) compared with comparator groups (-0.65 points; 95% confidence interval, -1.06 to -0.23 points; p=0.002, I2=60%; GRADE: weak recommendation and moderate-quality evidence). Use of selective cannabinoids was also associated with improvements in quality of life and sleep with no major adverse effects. Conclusions: Selective cannabinoids provide a small analgesic benefit in patients with chronic neuropathic pain. There was a high degree of heterogeneity among publications included in this SR-MA. Well-designed, large, randomized studies are required to better evaluate specific dosage, duration of intervention, and the effect of this intervention on physical and psychological function. Collaborator(s): Bradley Johnston, Marina Englesakis, Dwight E Moulin, Anuj Bhatia

D2 ●

Increased cerebrovascular reactivity during anemia: A potential novel indicator of anemia-induced brain hypoxia?

Nikhil Mistry – Graduate Student St. Michael's Hospital Background: Preoperative anemia affects up to 40% of non-cardiac surgery patients (1), and is associated with increased risk of postoperative kidney injury, stroke, and mortality (2). It is suggested that moderate anemia-induced tissue hypoxia may contribute to organ injury and mortality in surgical patients. To assess this, an immune mediated model of moderate anemia in transgenic hypoxia-inducible factor-1α (HIF-1α)-oxygen-dependent degradation domain (ODD) luciferase mice was utilized to measure cardiovascular adaptation and hypoxic cellular responses. Methods: With institutional animal care committee approval, hemoglobin concentration (Hb; co-oximetry), peripheral arterial oxygen saturation (pulse oximetry), blood flow (Doppler ultrasound), tissue PO2 (G4 oxyphor), in vivo bioluminescence (HIF-luciferase), HIF-dependent gene transcription (qPCR) and cerebrovascular reactivity to CO2 was assessed. Results: Red blood cell (RBC)-specific antibody induced moderate anemia (Hb=94±11 g/L), primarily clearing RBCs via splenic sequestration. Cardiovascular adaptations during anemia included increased peripheral arterial oxygen saturation (97.8±0.4 vs. 97.0±0.8%, p=0.013), increased cardiac output (12.38±1.98 vs. 10.21±2.41ml/min, p=0.011), and increased internal carotid (0.60±0.13 vs. 0.35±0.09 ml/min, p<0.001) but not renal blood flow (1.05±0.30 vs. 1.03±0.29ml/min, p=0.239). This was associated with maintained brain tissue PO2 (22.7±5.2 vs. 23.4±9.8mmHg PO2, p=0.935) and a reduction in kidney tissue PO2 (13.1±4.3 vs. 20.8±3.7 mmHg PO2, p<0.001). We observed increased expression of HIF-luciferase in vivo in the renal (p=0.034) and splanchnic (p=0.017) regions during anemia. Consistent with this finding, there was a ~20 fold increase in renal EPO mRNA expression (p<0.05). Despite the relative maintenance of brain tissue PO2, we observed a ~2 fold increase in brain EPO mRNA expression (p<0.05); suggesting that subtle degrees of tissue hypoxia were present in the brain. Anemia was also associated with an increase in internal carotid, but not common carotid, cerebrovascular reactivity (p=0.006), a potential novel indicator of mild brain tissue hypoxia. Conclusions: We demonstrated evidence of organ-specific tissue hypoxia during moderate anemia. Enhanced cerebrovascular reactivity may represent a novel response to mild anemia-induced brain tissue hypoxia. These results may help define the mechanism of anemia-induced organ injury and mortality in surgical patients. References: 1) Anesthesiology. 2009 Mar;110(3):574-81. 2) Lancet. 2011 Oct 15;378(9800):1396-407. Collaborator(s): Mistry N, Mazer CD, Sled JG, Lazarus AH, Cahill L, Solish M, Zhou Y, Hare AG, Doctor A, Fisher JA, Brunt KR, Simpson JA, Hare G

D3 ●

Anesthetic challenges during interventional management of extra-cranial vascular malformations

Bahadur Niazi – Fellow UHN-Toronto Western Hospital Introduction Arteriovenous malformations (AVMs) are vascular anomalies characterized by shunting of blood from arterial to venous circulation by one or more fistulae. Advances in interventional techniques have rendered them more amenable to treatment. Anesthesia care of these patients are challenging due to high cardiac output states warranting invasive monitoring, the need for complex airway management, difficult pain management and special concerns with sclerosing agents. Aim of this study is to review the anesthetic management of patients undergoing radiological intervention of extracranial AVMs, to determine challenges and perioperative complications. Methods After institutional ethics board approval we conducted a retrospective study on elective patients who underwent interventional treatment for extracranial vascular malformations (head and neck, peripheral regions) at our institution during the 6-year period (2010-2016). Data collected included patient demographics, anesthetic techniques, airway management, invasive monitoring, sclerosing agents used and perioperative complications. Descriptive statistics were used for analysing the data. Results Total of 142 patients underwent 182 procedures (mean age 41.73 years, 65 female). (Table1). General anesthesia was the commonly used technique. Thirteen patients needed complex airway management [nasal intubation (4), tracheostomy (3), video-laryngoscope (6)]. Six patients in the peripheral group presented with high output cardiac failure needing invasive cardiac output monitoring. Bleomycin was the sclerosing agent in all head and neck AVMs and alcohol was commonly used for peripheral AVMs. Most complications were minor except for unexpected ICU admission (n=2) with exacerbation of cardiac failure with the use of alcohol and severe postoperative pain needing hospitalization (n=4). Discussion/Conclusions Extracranial vascular anomalies are rare and but complex lesions. Anesthetic management of these patients can be challenging; main issues being airway management, underlying high cardiac output states and the pain from ischemia. Incidence of complications is low, however better understanding of their presentation and their management is important. Collaborator(s): Najia Hasan

Table 1 (Anesthetic challenges during interventional management of extra-cranial vascular malformations)

Head and neck (N= 100) Peripheral (N = 42)

Location Tongue (24), Lips (25), Neck (13), Others (38)

Lower limb (18), Upper limb (12), Pelvis (6), Others (3)

Anesthesia GA (85); Sedation (15) GA (74); Sedation (2); Regional (6)

Airway management

Oral airway (5), LMA (55) Oral intubation (17), Nasal intubation (5), Tracheostomy (3)

LMA (17), Endotracheal intubation (57)

Sclerosing agents used

Bleomycin (100) Alcohol (48), Onyx and other Glue (20), Coils (2), Foam (6)

Complications Skin reaction with adhesives tapes (15), Intraoperative Laryngospasm (1), Difficult intubation (1)

Cardiogenic shock (1) Failed extubation (1) Severe Pain (4)

Postoperative disposition

Day surgery (100) Day surgery (76) Ward (2) ICU/HDU (4)

D4 ●

Assessment of dexmedetomidine and scalp block to facilitate intraoperative brain mapping for awake craniotomy

Stuart Nicholson – Fellow St. Michael's Hospital Background: Important anesthetic goals for awake craniotomy are to ensure: airway patency, stable hemodynamics, patient comfort, and optimal conditions for real-time brain mapping. In 2012, we instituted a standardized anesthetic technique using dexmedetomidine and scalp blocks in patients selected for awake craniotomy due to the anatomic characteristics of brain tumour pathology. We hypothesized that dexmedetomidine in conjunction with scalp blocks is a safe and effective anesthetic in patients undergoing awake craniotomy for brain tumour resection. Methods: With Research Ethics Board approval, we conducted a retrospective cohort study describing perioperative outcomes for all patients who underwent awake craniotomy from 2012 to 2016. We assessed the incidence of critical perioperative airway outcomes, perioperative complications, and successful intraoperative mapping for all patients. The primary anesthesia outcome was the incidence of perioperative airway complications. Secondary outcomes were duration of surgery and the incidence of perioperative complications (significant hemodynamic instability, nausea and vomiting, new onset neurological deficits or seizure activity, and protocol failure requiring conversion to general anesthesia). A primary surgical outcome was the correlation between functional MRI analysis and intraoperative brain mapping, as well as the incidence of altered surgical management due to information acquired at the time of real-time brain mapping. Results: We identified 39 eligible patients who completed the awake craniotomy protocol and successful tumour resection. The median length of an awake craniotomy procedure was 200 min (IQR±50 min). Characteristics and intraoperative data for all patients are summarized in Table 1. There were no critical events that involved rescue of an obstructed airway and no patients required airway instrumentation or conversion to a full general anesthetic. No significant hemodynamic instability was observed. Conditions for intraoperative mapping were deemed excellent in all cases and allowed for multimodal motor, sensory and language assessment. In most cases, intraoperative mapping provided additional functional and anatomical information that was not provided by preoperative fMRI. In many cases, information provided by intraoperative mapping influenced surgical decisions regarding the degree of tumour resection, enhancing the ability to preserve eloquent brain function or safely increase the degree of tumour resection. Individual cases will be explained in full text/during presentation. Conclusion: Safe and effective anesthesia for awake craniotomy was provided using dexmedetomidine with scalp blocks. The lack of airway manipulation, and titratable levels of sedation, provided excellent conditions for intraoperative mapping and patient cooperation. Consequently, surgical conditions were ideal, which minimized the risk of neurological deficit and increased the ability to provide maximal surgical resection. Ongoing assessment of such an approach could include the development of a formalized prospective trial to assess important clinical outcomes, including duration of disease-free survival, time to tumour recurrence, and the overall quality of patient experience. Collaborator(s): McAuliffe N,Garavaglia M, Pshonyak I, Hare GMT, Das S, Rigamonti A.

D5 ●

A survey of Canadian anesthesiologists and residency program directors and department chiefs assessing current environmentally sustainable anesthesiology practice

Maria-Alexandra Petre – Resident St. Michael's Hospital Introduction: Anesthesia related waste represents 25% of all operating room waste and anesthesiology practice is a known major contributor to environmental waste and global warming. The aim of this study is 1) to ascertain the current state of environmentally sustainable practice among anesthesiologists and 2) to delineate barriers to improvement in this practice at the residency and departmental leadership levels. Methods: With REB approval, Canadian Anesthesiology Society (CAS) members, Canadian anesthesiology residency program directors, and ACUDA-affiliated anesthesiology department chiefs were invited to complete group-specific electronic surveys ascertaining current environmentally sustainable practices in anesthesiology. Results: The CAS survey response rate was 16% (426/2695). Despite a willingness to recycle at work among most anesthesiologists (95%), only 30% did so. Respondents identified lack of support from hospital/OR leadership (64%) and inadequate information/education (63%) as major barriers to recycling and sustainability efforts in the OR. The response rate for the program directors’ survey was 41% (7/17). Of these, only 2 programs (29%) had a sustainability curriculum. The identified barriers to the implementation of such a curriculum included a lack of faculty expertise, time within structured curriculum, and institutional support. The response rate for the chiefs’ survey was 24% (27/113). Many site chiefs indicated that their departments participate in sustainability efforts such as recycling (58%), using reusable alternatives for commonly-used anesthesia equipment (58%) and choosing anesthetic gases based on their environmental footprints (58%). Furthermore, many chiefs indicated their departments had plans to introduce or expand efforts in environmental sustainability, particularly in recycling (82%) but identified inadequate funding (72%), lack of a mandate from hospital leadership (64%) and inadequate knowledge on sustainability topics (60%) as barriers to the implementation of environmental sustainability programs. Conclusion: Our results provide a cross-sectional view of the current attitudes, gaps and barriers to environmentally sustainable anaesthesiology practice in Canada. This study may help inform the development of a cross-Canada collaborative residency curriculum in this field and identifies opportunities for leadership capacity building. Collaborator(s): A. van Rensburg, L. Bahrey, M. Crawford, M. Levine, C. Matava

D6 ●

Cardiac toxicity of bupivacaine is mediated via altered calcium dynamics in stem cell-derived cardiomyocytes

Julia Plakhotnik – Graduate Student Hospital for Sick Children Background Local anesthetics (LA) can cause lethal cardiac toxicity, limiting the clinically safe dose for patients. Investigating possible mechanisms, previous studies showed differential blockade of cardiac sodium and potassium channels between more toxic (bupivacaine, BUP) and less toxic (ropivacaine, ROP) LA, but did not fully explain the extent of observed BUP cardiac toxicity. We aimed to determine the effects of BUP and ROP on contractile function and channel activity of human cardiomyocytes, to avoid and better explain LA cardiotoxicity. Methods Human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM) were treated with sub-cardiotoxic and cardiotoxic concentrations (3 and 6 mcg/ml, respectively) of BUP and ROP, or co-treated with calcium chloride (0.5 mM). Real-time continuous recordings of electrical impedance (contractility) and field potential were acquired with the xCELLigence RTCA Cardio ECR system (Acea Biosciences). Intracellular calcium cycling was quantified with the FLIPR5 cytosolic calcium dye (Molecular Devices) via epifluorescence microscopy in live, beating cells, using standard techniques. P-values were calculated using one-way ANOVA compared to control cells. Results 5h post treatment, BUP reduced spontaneous beat rate by 60% (p-value<0.001), and delayed excitation-contraction coupling by 25% (p-value<0.001). This was normalized by co-treatment with calcium chloride (p-values 0.97 and 0.99). ROP reduced beat rate by 40%, which was further reduced another 30% by calcium chloride (p-values<0.001). ROP delayed excitation-contraction coupling by 15%, which was further extended another 15% by calcium chloride (p-values 0.02 and <0.001). Cells treated with subtoxic concentrations of both LA were similarly affected, although to a lesser extent. Investigation of the electric field potential signal revealed BUP-specific defects in the calcium wave (20% increase in duration, but a 60% decrease in overall flux; p-values <0.001), which were mitigated by calcium chloride co-treatment (p-values 0.99). Quantification of intracellular calcium by the FLIPR5 dye confirmed that BUP prolonged time and slowed the rate (p-value<0.001) of calcium re-absorption into the sarcoplasmic reticulum, signifying a more severe diastolic dysfunction than in ROP-treated cells. Furthermore, calcium co-treatment normalized the BUP-induced inhibition of the sodium current, however, did not improve ROP-exposed cells, suggesting that basal differences of the sodium channel block between BUP and ROP are, in part, due to the compromised calcium dynamics caused by BUP. Conclusions Our results implicate that calcium-mediated dysfunction is specific to bupivacaine and may account for the higher cardiac toxicity associated with this local anesthetic. Collaborator(s): PA Lonnqvist and JT Maynes

D7 ●

Role of screening questionnaires and quantitative sensory testing in detecting neuropathic pain in osteoarthritis: a scoping review

Rajendra Kumar Sahoo – Fellow UHN-Toronto Western Hospital Objective: To perform a scoping review of role of screening questionnaires for neuropathic pain and quantitative sensory testing (QST) in detecting neuropathic pain in subjects with osteoarthritis (OA). Design: A comprehensive search for relevant literature published in January 2000 or later in Embase, Medline, Medline In-Process, Cochrane Database of Systematic Reviews and Google Scholar was performed. A highly sensitive search strategy was used. Data on type of screening questionnaires and QST protocols and main results of the studies were extracted. Results: The literature search yielded 24 articles that met the inclusion criteria. All the studies had a cross-sectional design. painDETECT was the most frequent questionnaire used to screen for neuropathic pain in OA. QST measures confirmed to recommended protocols with pressure pain thresholds being the commonest measure used to detect central or peripheral sensitization in OA. Prevalence of neuropathic pain was around 20% in subjects with OA but it varied depending on the modality used for detection. There was strong evidence of discordance between radiologic features of OA and presence of neuropathic pain, especially in subjects with early grades of OA with high reported levels of pain. Conclusions: Screening questionnaires for neuropathic pain and QST can help in qualifying and quantifying neuropathic pain in subjects with OA. Use of both modalities may increase yield and confidence for diagnosing neuropathic pain in OA but there are knowledge gaps in their application. Further research is required on role of these tools in detecting neuropathic pain.

D8 ●

Beyond masks and syringes: Early ideas of Anesthesiology in Canada - A critical historical analysis

Richa Sharma – Resident Background Anesthesia was not always a component of the surgical experience. By questioning how and why our specialty came to exist, we can identify taken-for-granted assumptions embedded in current definitions of our work. We applied a critical historical lens to the early beginnings of anesthesia in Canada. Methods We took as our starting point the following question: how did societal norms go from burning a woman at the stake for requesting labour analgesia in 1591 to the last reported surgical procedure without anesthesia in Toronto in 1868? Informed by the work of Michel Foucault, we addressed this question using textual critical historical analysis. Our archive began with the first public demonstration of ether by Dr. William Morton in Boston, Massachusetts in October 1846. Using the British American Journal of Medical and Physical Sciences (BAJMPS), the only English-language medical publication of that time period, we examined the social, economic and political context of doctors in Canada. The last surgery performed in Toronto without anesthesia occurred in 1868, marking a defining moment for Canadian anesthesia, and the limit of the archive. We analyzed all articles published in BAJMPS from six months before the first public demonstration of ether (March 1846) until eighteen months after (February 1848) to understand who spoke, what they thought, and what actions they engaged in. All articles published in the BAJMPS from March 1846 until January 1848 that included terms or themes relating to, ‘anesthesia’ were analyzed for discursive elements. Next, Canadian medical journal publications from 1868 were searched for the same themes. The archive was investigated for language about anesthesia in five-year intervals, moving back in time from 1868 to 1863 to 1858 and so on until 1848. If a change in language occurred in a given year, that five-year section of papers was searched in one-year sections. This rigorous methodology has been used previously in critical historical analysis to manage a large volume of data. Results Analysis of papers published from 1846 to 1848 revealed three dominant conversations about anesthesia. Firstly, practitioners questioned whether ‘rendering insensible’ during surgery was safe and necessary for patients. Skepticism surrounded the notion of dentists as anesthetic providers, and fears about patenting anesthetics for economic gain. By 1868, specific powerful voices inform publications, resulting in a shift from fear to ‘saving suffering humanity’. Secondly, the concept of ‘insensibility’, and its associated agents and practices, were subject to ordering, categorization and classification via text. Foucauldian thinking posits that different ordering systems co-exist and transform based on their historical and social context. Physicians sought tirelessly to explain ‘insensibility’ and often used their own physical bodies to do so. Thirdly, early discussions about anesthesia, in particular the parturient experience, empowered the first patient-centred discourses in the language of surgery. A series of papers discussing the Biblical interpretation of labour analgesia marks an intersection between medicine and society. Conclusions We analyzed the Canadian medical literature between 1846 and 1868 in order to understand the

emergence of the specialty of anesthesia. Using a critical historical approach, we gain a greater breadth and depth about our collective identity as anesthesiologists. Collaborator(s): Dr. Cynthia Whitehead, Dr. Ayelet Kuper

D9 ●

Choice of intraoperative resuscitation fluid during cardiac bypass surgery: A cost effectiveness analysis

Lavarnan Sivanathan – Resident Sunnybrook Health Sciences Centre Introduction: Major surgery can be associated with physiological intraoperative instability, which results in increased morbidity, mortality, and health-care costs. Perioperative intravenous fluids used to treat hypotension and tissue hypoperfusion can influence patient outcomes. However, the optimal choice of intravenous fluid for patients undergoing coronary artery bypass graft (CBG) surgery remains controversial. Previous research has compared clinical outcomes after infusion of Crystalloids (CRYS), human albumin (HA), and hydroxyethyl starches (HS); however, the cost-effectiveness(CE) of these fluid choices has not been studied. We constructed a decision analysis model comparing the CE of CRYS, HA and HS in a base case that involved a 65 year-old patient undergoing a CBG procedure who develops intraoperative hypotension. Methods: We constructed a Markov-model decision tree, in which the initial decision was whether to choose CRYS, HA or HS as the resuscitation fluid for a patient experiencing intraoperative hypotension. The outcomes were calculated as US dollars per quality adjusted life years (QALY). The complications modeled included reoperation, transfusion, congestive heart failure (CHF), other cardiopulmonary complications, and renal failure requiring replacement therapy (RRT). The rates, relative risks, costs and utilities data were obtained from previously conducted randomized control trials, systematic reviews and reports from the Canadian Institute of Health Information and the Tufts University’s CE Database. Results: The most cost-effective fluid choice was CRYS at $2,225/QALY, followed by HA at $2,263/QALY, and then HS at $2,311/QALY. CRYS and HA also had the best lifetime clinical benefit at 16.89 QALY, followed by HS at 16.87 QALY. CRYS dominated the cost-effectiveness evaluations across most sensitivity analyses, even when transfusion rates and RRT among all three fluid choices were equalized. HA became the most cost-effective fluid choice when the odds of developing CHF after CRYS infusions surpassed 1.46. Conclusions: Our model shows that CRYS was the most CE fluid and is also associated with the highest number of QALYs. HA had similar clinical outcomes, but is associated with higher total costs. However, HA may represent an alternate fluid choice in patients who are at increased risk of CHF, due to the high volumes of CRYS required for intraoperative hypotension. HS is the least CE fluid across all sensitivity analyses. Collaborator(s): Joseph Corkum MD, John De Almeida MD Msc, Damon C. Scales MD PHD

D10 ●

Discharge opioid prescription practices in a Pediatric teaching hospital

Naiyi Sun – Fellow Hospital for Sick Children Introduction: Opioid analgesics are the cornerstone of treatment for moderate to severe pain in children as hospital inpatients. At the time of discharge, physicians frequently continue to prescribe opioids for pain management in the outpatient setting. However, the use of opioids at high doses can be associated with potential harm (1). The use of a transitional pain service has been described for discharge management of adult patients on opioids(2). The discharge opioid prescribing practices in the pediatric population have not been well-studied. The first objective of this study is to characterize the dosing and formulation of opioids prescribed at time of discharge across all the services from a single academic pediatric hospital. The second objective is to compare the characteristics between patients who received high and lower doses of opioid prescriptions. Methods: In this cross-sectional study, we identified all the patients who were discharged from the inpatient unit with a prescription for opioid analgesics over a 1-year period in a large pediatric teaching hospital. For each prescription, we collected data on the type of opioid, formulation, amount dispensed, associated diagnosis and prescribing service. Demographics data including age, gender and weight were also collected. Results: During the 1-year period, we identified 2,538 patients who received 2,658 discharge opioid prescriptions. The average age of this population was 8.6 years (range: 0-24 years) and the percentage of males was 54.9%. The most commonly prescribed opioid medication was morphine (86.2%) followed by hydromorphone (10.2%) and oxycodone (3.3%). The most common prescribing services were Orthopedics (42.9%), followed by Plastic Surgery (20.4%) and Otolaryngology (20.1%). Within the subgroup of patients given a high dose opioid (> 2 mg/kg/24h oral morphine equivalent) prescription, the top 2 prescribing service were Orthopedics (44.9%) and Plastic Surgery (29.3%) with spinal surgeries and burns as the most common reasons for admission, respectively. Conclusions: In this study, we identified specific subgroups of patients who were more likely to be discharged with high dose opioid prescriptions. A transitional pain service can be utilized to focus efforts on this high risk group to enable close follow up and effective opioid weaning following inpatient care in the pediatric setting. References: 1. Opioid dose and drug-related mortality in patients with non malignant pain and overdose: a cohort study. Ann Intern Med 2010; 152: 85-92. 2. Chronic postsurgical pain and persistent opioid use following surgery: the need for a transitional pain service.Pain Manag. 2016 Oct;6(5):435-43 Collaborator(s): Jacqueline Hanley, Lisa Isaac

D11 ●

Rapid cycle deliberate practice in simulation-based medical education: A systematic review

Jillian Taras – Resident Hospital for Sick Children Background: Rapid Cycle Deliberate Practice (RCDP) is a novel simulation-based education model that is currently attracting interest, implementation, exploration and research in medical education. The objective of this systematic review is to examine the literature and summarize existing knowledge on RCDP in simulation-based medical education. Methods: We included published and non-published resources. Authors independently screened references identified by the search strategy. Both authors independently assessed the resources for eligibility and one author performed the data extraction. Results: Fifteen resources met inclusion criteria; they were diverse and heterogeneous, such that we did not perform a quantitative synthesis or meta-analysis, but rather a narrative review on RCDP. All resources described RCDP in a similar manner: maximizing time in deliberate practice, providing multiple opportunities to practice the right way, using directed feedback within the scenario rather than lengthy debriefing after the scenario and aiming to achieve mastery. Implementation strategies common to the resources were: splitting traditional simulation cases into smaller segments, microdebriefing in the form of ‘pause, debrief, rewind and try again’ and providing progressively more challenging cases. A variety of outcome measures were used and results were inconsistent. Four studies used qualitative evaluations in which learners reported improved confidence and resuscitation skills after RCDP. Five studies used scoring tools to measure participant’s technical and non-technical skills. Two studies used procedural assessments using checklists or video review. Three studies used time-to active skills, such as time to defibrillation or time to epinephrine. One study used clinical reports after RCDP training. Conclusions: All resources split traditional simulation cases into smaller segments, used microdebriefing within the scenario and provided progressively more challenging cases. Limited and variable outcome measures were used by the studies identified and results were inconsistent. There is an absence of data on retention after RCDP teaching, on RCDP with learners from specialties other than pediatrics, on RCDP for adult resuscitation scenarios and if RCDP teaching translates into practice change in the clinical realm. We have identified important avenues for future research on RCDP.

D12 ●

Risk factors for failure of patient-controlled oral Analgesia after total hip and knee arthroplasty: A retrospective cohort study

Leon Vorobeichik – Resident UHN-Toronto Western Hospital Introduction: Intravenous patient-controlled analgesia (IVPCA) is commonly used for pain management following total hip or knee arthroplasty2 (THA/TKA) but requires trained staff, specialized equipment, and is associated with adverse effects.3 Patient-controlled oral analgesia (PCOA) is a novel method of oral opioid administration practiced at our institution for postoperative pain following THA and TKA, whereby breakthrough pain is treated with a set dose of a short-acting oral opioid that is available at all times to the patient (with a minimum “lock-out” period).4 We reviewed the success rates of PCOA and risk factors for failure of PCOA, defined as severe pain necessitating conversion to IVPCA in the first 24 postoperative hours following THA and TKA. Methods: Following institutional review board approval, we performed a retrospective cohort study of all patients who underwent THA/ TKA between April 1, 2015 and September 30, 2016 at Toronto Western Hospital. Patients were divided into two cohorts based on the primary analgesic modality used in the first 24 postoperative hours, i.e. PCOA or PCOA replaced by IVPCA. Data was extracted from our in-house database, Networked Online Processing of Acute Pain Information (NOPAIn), that captures data in real-time on multiple variables, including patient demographics, premorbid conditions, preoperative medications, regional anesthesia techniques, surgical variables, postoperative pain and analgesics. Data was analyzed using univariable and multivariable analysis techniques. Results: Out of the 1772 consecutive patients who underwent THA or TKA, 1574 patients were successfully managed with PCOA and 148 patients required IVPCA because of failure of PCOA, representing a PCOA success rate of 91.4%. Variables associated with PCOA failure on univariable analysis (Table 1) included younger age, female, bilateral surgery, non-smoker, underlying chronic pain syndrome, preoperative short- and long-acting opioid use, use of antidepressants, gabapentinoids, and cannabinoids. Lack of intrathecal morphine in the perioperative subarachnoid block, higher cumulative opioid consumption, and higher rest and dynamic pain scores in the first 24 postoperative hours were also associated with failure of PCOA.. Multivariate logistic regression was performed and predictor variables that had a significant impact on failure of PCOA were analyzed (Table 2). Female patients were 2.6 times more likely to have inadequate pain relief with PCOA (and require IVPCA) than male patients and not using intrathecal morphine doubled the likelihood of having inadequate pain relief with PCOA in the first 24 postoperative hours following THA or TKA. Discussion: This is the first study to investigate feasibility of PCOA and risk factors for failure of PCOA in the first 24 hours following THA and TKA. Our findings support the practice of routinely administering PCOA while identifying high-risk patients who may benefit from IVPCA. Collaborator(s): Anuj Bhatia, Arlene Buzon-Tan, Susan Walker, Kyle Kirkham, Dharini Ilangomaran, Lashmi Venkatraghavan

D13 ●

Esophageal manometry in Acute Respiratory Distress Syndrome (ARDS): Safer expiration, safer inspiration

Takeshi Yoshida – Fellow Hospital for Sick Children Background: Ventilator-induced lung injury in ARDS occurs mostly in ventilated, non-dependent lung regions. Esophageal manometry (esophageal-pressure, Pes) is a classical technique that estimates pleural pressure (Ppl) enabling calculation of the transpulmonary pressure (PL), the difference between airway and Ppl, that distends the lung. However, its validity has been questioned. Ppl differs with lung region (higher in dorsal and lower in ventral when supine); thus, it is uncertain in which lung regions esophageal manometry reflects PL. We addressed this issue using two approaches: human cadavers, and anesthetized pigs. We compared Pes with directly measured Ppl in dependent and non-dependent lung, and determined in which regions PL is reflected by esophageal manometry. Methods: Human cadavers with preserved elasticity (n=3; Thiel, CER-14-201-08-03.17) and anesthetized pigs with surfactant depletion (n=6; Yorkshire, 40.1±2.9 Kg) were monitored by standard esophageal balloons, while regional Ppl was directly measured by surgically inserted pleural sensors (wafer-type, flat-balloon) in non-dependent and dependent pleural spaces. Across a range of PEEP values, regional expiratory PL was calculated (airway pressure - local Ppl; dependent or non-dependent), or by using absolute Pes. Regional inspiratory PL were similarly calculated, and were also estimated using tidal changes in Pes. Results: In human cadavers and pigs, expiratory or inspiratory PL using absolute Pes were close to values estimated from dependent pleural sensors, or were intermediate between dependent and non-dependent sensors (adjacent to the esophageal balloon) (Figure 1-A, B). However, inspiratory PL calculated from tidal changes in Pes closely reflected the estimates derived from non-dependent sensors (Figure 2-A, B). Conclusions: Absolute Pes in expiration accurately reflects Ppl in the dependent to middle lung regions where atelectasis usually predominates. Thus, setting PEEP using expiratory Pes to prevent atelectasis makes sense. The inspiratory change (not absolute value) in Pes enables estimation of the local Ppl in the non-dependent lung where is the most susceptible to stress during inspiration, and its local PL may be a more specific marker of risk from ventilation-induced injury than global parameters such as plateau pressure, tidal volume or driving pressure. Collaborator(s): Marcelo B.P. Amato, Jean-Christophe Richard, Domenico Luca Greco, Cristhiano Lima, Laurent Brochard, Brian P. Kavanagh

E1 ●

The universal definition of perioperative bleeding (UDPB) in cardiac surgery: Validation of a consensus-based bleeding endpoint for use in clinical trials

Justyna Bartoszko – Resident UHN-Toronto General Hospital Introduction: Significant bleeding is a clinically and prognostically important complication of cardiac surgery. Research into perioperative bleeding has been hampered by lack of a standardized definition for this outcome. The consensus-based Universal Definition of Perioperative Bleeding (UDPB) was developed to address this, but has undergone minimal validation to-date. We conducted a substudy of the Transfusion Avoidance in Cardiac Surgery (TACS) randomized trial to help assess the validity of the UDPB definition across multiple domains. Methods: The TACS Study included 7402 consecutive patients who underwent cardiac surgery at 12 Canadian hospitals from 2014-15. Substudy institutional REB approval was obtained. To assess construct validity of the UDPB definition, its association with redo and complex procedures was compared. To assess its criterion validity, multivariable logistic regression models were used to determine the unadjusted and adjusted association between UDPB classes and 28-day mortality. Three models were constructed: (1) Model 1 incorporated prognostically important factors from the literature; (2) Model 2 incorporated Model 1 factors plus UDPB; (3) Model 3 incorporated factors from Model 1, UDPB, and other major postoperative complications. Results: 190 (2.6%) patients died with 28 days after surgery . Higher UDPB classes were observed in redo and complex procedures (p<0.0001). Increasing UDPB severity was associated with increases in mortality in unadjusted and adjusted analyses (Table). Model 1: Preoperative variables had good discrimination (c-index 0.83) and good calibration (Hosmer-Lemeshow p=0.76). Model 2: Addition of UDPB to Model 1 resulted in significantly higher discrimination [c-index 0.91, p<0.001] and good calibration (Hosmer-Lemeshow p=0.78). UDPB had the largest odds for the prediction of mortality. Model 3: The addition of other major complications improved discrimination by a statistically significant albeit small amount [c-statistic 0.94, p<0.001] with good calibration (Hosmer Lemeshow p=0.74). UDPB remained the strongest predictor of mortality despite accounting for other complications including acute kidney injury, myocardial infarction, stroke, and sepsis. Conclusions: The UDPB definition of bleeding in cardiac surgery can be feasibly applied in a large randomized trial. It demonstrates construct and criterion validity. Consistent with prior research, it is a predictor of short-term mortality after cardiac surgery even when accounting for comorbidities, operative procedure, and other complications. Our findings support the use of UDPB as a clinical trial endpoint. Collaborator(s): Duminda N. Wijeysundera

Table: Adjusted odds ratios and logistic model statistics for the outcome of 28-day postoperative mortality. Models are adjusted for site.

MODEL 1: PREOPERATIVE and OPERATIVE FACTORS Model c-statistic (95% CI): 0.83 (0.80-0.86) Hosmer-Lemeshow: p=0.76 Predictor Adjusted OR 95% CI Wald Chi-Square Value Overall P-Value Age (per each 10 year increase) 1.15 0.98-1.34 2.88 0.09 Procedure Urgency Elective Urgent Emergent

Reference 1.33 4.55

0.87-2.04 2.79-7.42

1.79 36.78

<0.001

Preoperative Comorbidities Abnormal Renal Function Extracardiac arteriopathy Liver Disease Congestive Heart Failure

2.20 1.72 3.48 2.05

1.50-3.23 1.19-2.48 1.69-7.16 1.41-2.97

16.26 8.47 11.42 14.15

<0.001 0.003 <0.001 <0.001

Preoperative Hemoglobin (per each 10 g/L increase)

0.84 0.77-0.92 15.28 <0.001

Redo Procedure 1.26 1.03-2.73 0.72 0.39

Complex Procedure 2.46 1.69-3.59 21.77 <0.001

Preoperative IABP 4.01 2.03-7.91 15.28 <0.001

MODEL 2: PREOPERATIVE and OPERATIVE FACTORS + UDPB Model c-statistic (95% CI): 0.91 (0.89-0.93) Hosmer-Lemeshow: p=0.78 Predictor Adjusted OR 95% CI Wald Chi-Square Value Overall P-Value Age (per each 10 year increase) 1.18 1.01-1.38 4.20 0.04 Procedure Urgency Elective Urgent Emergent

Reference 0.96 2.65

0.62-1.50 1.58-4.43

0.03 13.73

<0.001

Preoperative Comorbidities Abnormal Renal Function Extracardiac arteriopathy Liver Disease Congestive Heart Failure

1.86 1.74 2.97 1.77

1.25-2.78 1.18-2.57 1.43-6.18 1.20-2.63

9.24 7.75 8.48 8.18

0.002 0.005 0.004 0.004

Preoperative Hemoglobin (per each 10 g/L increase)

0.92 0.84-1.00 3.28 0.07

Redo Procedure 0.99 0.57-1.74 0.001 0.98 Complex Procedure 1.44 0.97-2.14 3.20 0.07 Preoperative IABP 3.50 1.70-7.21 11.61 <0.001 UDPB Class 0 Class 1 Class 2 Class 3

Reference 6.52 6.08 35.84

1.38-30.86 1.39-26.55 8.63-148.80

5.59 5.76 24.28

<0.001

Class 4 131.48 30.88-559.84 43.56 MODEL 3: PREOPERATIVE and OPERATIVE FACTORS + UDPB + POSTOPERATIVE COMPLICATIONS Model c-statistic (95% CI): 0.94 (0.93-0.96) Hosmer-Lemeshow: p=0.74 Predictor Adjusted OR 95% CI Wald Chi-Square Value Overall P-Value Age (per each 10 year increase) 1.27 1.07-1.51 7.30 0.007 Procedure Urgency Elective Urgent Emergent

Reference 0.78 2.43

0.48-1.26 1.40-4.21

1.05 9.96

<0.001

Redo Procedure 0.94 0.52-1.72 0.04 0.85 Complex Procedure 1.29 0.85-1.98 1.41 0.23 Preoperative IABP 3.93 1.87-8.29 12.96 <0.001 Preoperative Hemoglobin (per each 10 g/L increase)

0.93 0.84-1.02 2.36 0.12

Preoperative Comorbidities Abnormal Renal Function Extracardiac arteriopathy Liver Disease Congestive Heart Failure

1.66 1.42 3.33 1.88

1.08-2.55 0.93-2.16 1.54-7.17 1.23-2.86

5.29 2.66 9.40 8.61

0.02 0.10 0.002 0.003

UDPB Class 0 Class 1 Class 2 Class 3 Class 4

Reference 6.17 5.63 27.53 96.30

1.29-29.58 1.28-24.77 6.56-115.47 22.29-416.02

5.18 5.22 20.54 37.43

<0.001

Postoperative Complications AKI Stroke MI Sepsis Sternal Infection

2.21 8.36 12.13 6.91 0.96

0.81-6.05 4.78-14.64 4.45-33.01 3.77-12.67 0.40-2.34

2.39 55.27 23.85 39.04 0.01

0.12 <0.001 <0.001 <0.001 0.93

E2 ●

Blood brain barrier integrity after moderate traumatic brain injury is improved with human umbilical cord perivascular cell therapy

Tanya A. Barretto – Graduate Student St. Michael's Hospital Background: Traumatic Brain Injury (TBI) is the leading cause of morbidity and life-years lost in North America. There are currently no clinical therapeutic treatments for TBI. As such, advancement in this area is an urgent issue. TBI is composed of a primary injury, which results from the direct impact to the skull and a secondary injury follows. The latter is composed of cellular and molecular mechanisms that result in the breakdown of the blood brain barrier (BBB) and white matter among other events and spans from minutes to months following insult. This prolonged time frame of secondary injury suggests a window of opportunity for intervention. The BBB is composed of the neurovascular unit (NVU), which is integral for regulated transport of nutrients and gases between the blood and brain. Following injury, the NVU is damaged therefore disrupting controlled gas and nutrient transport. This disruption contributes to edema formation and associated increases in inter-cranial pressure which adversely affects outcome. Human umbilical cord derived perivascular cells (HUCPVCs) isolated from full term cords have been shown to express mesenchymal, neurotrophic and vascular factors, making them a potential candidate to rescue BBB breakdown. The pleiotropic activity of these factors may potentially protect the neurovascular unit and rescue white matter damage after TBI. Methods: A moderate traumatic brain injury was modeled using a rat fluid percussion injury (FPI) device. A weighted pendulum was used to deliver a calibrated force via an impacted water column to induce an extradural fluid impact to the brain. Rats were systemically infused with 1.5 x 106 cells either 1 hour pre-injury or 1.5 hours post injury, and survived for 24h, 48h or 7 days. Vascular leakage was assessed using 4% Evan’s blue dye systemically injected and allowed to circulate for 30 minutes prior to sacrifice. Brains were extracted and the injured hemisphere was assessed for vascular leakage and edema formation. Immunohistochemistry (IHC) for RECA-1 at 24h and 48h was performed to assess vascular density in brain sections. Cortical and hippocampal tissue at the injury site was extracted at 24h and 48h for Western blot analysis to examine the expression of tight junction proteins and white matter breakdown following injury and treatment. Results: Vascular leakage was expressed in mg of Evans Blue per gram of tissue. At 24h and 48h vascular leakage was 6.4 mg and 15.5 mg vs. 1.7 mg in sham rats. Pre-injury HUCPVC treated rats had Evan’s blue levels at 4.0 mg and 5.6 mg at 24 and 48 hours, respectively. Post-injury leakage values were 5.5 mg and 3.3 mg at 24 and 48 hours, respectively. At 7 days post-injury, FPI rats demonstrated leakage values similar to sham rats. Interestingly, post-injury treated rats demonstrated less Evan’s blue leakage compared to sham rats at 0.4 mg. Edema formation was not significantly different across treatment groups. IHC and western blot analysis is currently being assessed. Conclusions: This model demonstrated quantifiable outcome of vascular leakage. The infusion of HUCPVCs both prior to and following injury was associated with less vascular leakage. Post-traumatic vascular permeability may represent an important component of secondary injury contributing to worse outcome. HUCPVC

cell therapy is a potential therapeutic strategy to address neurovascular injury after TBI. Further clarification of the mechanisms involved in the neurovascular pathology phenomena reported here may provide insights into both the pathophysiology of secondary injury as well as potential therapeutic targets.

E3 ●

Ketamine reverses postanesthetic increase in extrasynaptic GABA-A receptor function in hippocampal neurons

Kirusanthy Kaneshwaran – Graduate Student Sunnybrook Health Sciences Centre Abstract text removed at author's request.

E4 ●

Opioid prescription following discharge in patients undergoing total knee arthroplasty

Hawn Trinh – Fellow Sunnybrook Health Sciences Centre Background: Total knee arthroplasty (TKA) may result in significant and sustained post-operative pain necessitating the use of opioids for analgesia. Our hypothesis is that post-discharge opioids are being prescribed following TKA in a uniform, potentially suboptimal pattern that could under or over-estimate postoperative patient requirements. We conducted a retrospective review study to determine the amount of amount opioid prescribed post discharge from the hospital and examined the correlation with in-hospital use. Methods: Following Research Ethics Board approval, we performed a chart review of randomly selected, opioid naive patients aged >18 years who underwent TKA between January 2013 and April 2014. Any patients who were on preoperative opioids of greater than or equal to 30mg/day oral morphine equivalent, or transferred to an extended rehabilitation facility were excluded. Demographic data and clinical information were collected including age, sex, body mass index, surgical procedure, anesthetic modality, analgesic adjuncts, in-hospital opioid consumption up to 48 hours after surgery, and discharge opioid prescription. The primary outcome was to determine the mean oral morphine equivalent prescribed post discharge from hospital. The secondary outcome was to determine if there was any correlation between the total opioids prescribed and the in-hospital use at 48 hours. Results: A total of 902 patients were randomly selected, of which 888 were analyzed. Demographic and clinical characteristics are presented in Table 1. Total mean in-hospital opioid consumption in oral morphine equivalents at 48 hours was 176mg (SD 138.6) and discharge opioid prescription was 668mg (SD 332.7). Regression analysis showed a correlation coefficient of 0.14919 between in-hospital use and discharge prescription. Conclusions: Based on our findings, the opioids for discharge are prescribed in a manner that does not reflect patient needs for usage. There appears to be no correlation between in-hospital opioid consumption and discharge opioid prescription. Future prospective studies are needed to determine how to best optimize discharge opioid prescribing following total knee arthroplasty.

E5 ●

A novel brain stress test: Combined controlled end-tidal CO2 and MRI imaging to assess stroke risk

Jay Shou Han – Resident UHN-Toronto Western Hospital Background: In patients with occlusive cerebrovascular disease (OCVD), the risk of stroke depends on the ability of the territory at risk to recruit collateral blood flow. Currently the ability to perform a “stress test” on the brain for the purpose of assessing stroke risk does not exist. We have developed a novel brain stress test using precise control of PETCO2 and Blood Oxygen Level Dependent (BOLD) MRI - to measure cerebrovascular reserve (CVR) which is indicative of the adequacy of collateral blood flow. Impaired CVR is associated with increased risk of acute and chronic cerebral ischemia. The aim of our study was to determine the efficacy of this preoperative brain stress test to identify patients with poor cerebrovascular reserve and to determine their risk of stroke with or without intervention at 1 year. Methods: After IRB approval 109 patients with OCVD were enrolled for this prospective observational study. Each patient then underwent end-tidal controlled CO2 hypercapnia and BOLD MRI CVR imaging. Images were then analyzed to yield whole brain CVR maps. CVR values were expressed as % BOLD MR signal change per mmHg change in PETCO2. Patients who demonstrated abnormal CVR imaging and electing to under go surgical revascularization had repeat CVR imaging at three months. All patients were then followed clinically for one year. Results: 100 patients completed the study (mean age of 56 years, M: F 32:68). 24 patients showed normal CVR and 76 patients had impaired CVR indicating poor cerebrovascular reserve. Fifty nine (59/76) patients underwent surgical revascularization with 86% (51/59) of patients demonstrating improvement in the CVR post-surgery. The Incidence of stroke in the entire cohort with impaired CVR at 1 year was 4% (4/100). However, the incidence was higher in the no-intervention group compared to intervention group (13 % vs 3 % P <0.05) Conclusion: Our study showed that the precise targeting of CO2 in combination with BOLD-MRI, provide a feasible, non-invasive and reproducible measure of CVR. This combined technique may be complementary in identifying patients with poor cerebrovascular reserve at risk for stroke and thus constitute a “Brain Stress test”. This technique can now be used for routine clinical testing in the diagnosis, treatment and prognostication of patients who are at risk of hemodynamic stroke and other suspected cerebral blood flow abnormalities.

E6 ●

A population-based study evaluating the association between pediatric surgical activity at the weekend and perioperative adverse outcomes

Asad Siddiqui – Resident Hospital for Sick Children Background: Surgery is often performed at the weekend for risk to life or limb, when timing is mandated by clinical guidelines, or administrative reasons. Whether higher rates of adverse outcomes observed for healthcare interventions at weekends truly represent the effect of altered medical staffing or are a function of data artefact and confounding by severity has generated recent controversy(1-3). The aim of this study was to evaluate whether pediatric surgical activity (i.e., surgical admissions and/or operating room procedures) at the weekend is associated with increased risk of perioperative adverse outcomes compared with children who are admitted and undergo surgery on weekdays. Methods: With research ethics board approval, we conducted a matched cohort study of children (age ≤17 yr) who underwent noncardiac surgery in Ontario, Canada, between 2003 and 2014. Individuals in exposure and reference groups were directly matched (1:3) on five variables (age, median neighbourhood household income, resource utilization band, rurality, and year of index event). The primary outcome was the composite rate of perioperative (30-day) complications; secondary outcome was 30-day all-cause mortality. Generalized estimating equation-based multivariable logistic regression models were used to estimate the association between weekend i) surgery and ii) surgical admission only and outcomes. Covariates adjusted in models included admission category (elective, newborn, and urgent), major comorbidities, sex, and teaching hospital status. Results are presented as odds ratios (OR) and 95% confidence intervals (CI); statistical significance was defined as two-tailed P<0.05. Results: Children who were admitted and underwent surgery at the weekend (n = 16,070) had a small increase in the odds of having a perioperative complication (adjusted OR 1.14, 95%CI 1.03-1.26; P=0.01) but not mortality (adjusted OR 0.95, 95%CI 0.49-1.84; P=0.9) compared with reference children who were admitted and underwent surgery on a weekday. Children who were admitted at the weekend but whose surgery was performed on a later weekday (n = 4,763) had a higher odds of a perioperative complication (adjusted OR 1.45, 95%CI 1.24-1.70; P<0.001) but not mortality (adjusted OR 2.04, 95%CI 0.97-4.29; P=0.06) compared with reference children. Conclusions: After mitigating for important covariates, this study found a small increase in the odds of perioperative adverse outcomes for children who undergo surgery or are admitted under surgical services at the weekend. These findings will help guide the scheduling of non-urgent pediatric surgery. References: 1. J Health Serv Res Policy 2017;22:12-19 2. BMJ 2016;353:i2648 3. BMJ 2016;353:i2750

E7 ●

MicroRNA-200b protects neuronal cells from reactive oxygen species (ROS)

Joshua Bell – Resident Background: Oxidative stress mediated by reactive oxygen species (ROS) is an important final common pathway in cerebral ischemia, trauma, surgical stress, and anesthetic-induced injury. Excitotoxicity in brain ischemia and trauma is the primary mechanism responsible for ROS generation, which leads to DNA fragmentation, calcium influx, oxidation of protein targets, and initiation of apoptosis. Modulation of the cellular response to ROS has widespread implication for neuroprotection across modalities. MicroRNAs are short non-coding RNA molecules which bind to the 3' untranslated region (UTR) of target mRNA strands and inhibit their translation to protein. Epigenetic modulation of the ROS-response, by microRNAs, may inhibit death-effector proteins activated by oxidative stress, and is a novel approach to anti-oxidant therapy. The ROS species H2O2 is generated in vivo, and can be used to investigate cellular responses and therapies for oxidative stress. H2O2 is known to induce lethal calcium influx, in particular, coming from the transient receptor potential melanocortin 2 (TRPM2) channel. MicroRNA-200b (miR-200b) in silico targets Poly ADP Ribose Polymerase (PARP) as well as protein kinase C alpha (PKCa), two important mediators of TRPM2-dependent calcium influx in response to H2O2. Here, we examined the effects of miR-200b on neuroprotection against ROS and ischemic injury in neuronal cells. Methods: N2a neuroblastoma cells were differentiated into neurons. Cell death was assayed via propidium iodide uptake and read via multiwell plate fluorescence scanning. Following RNA extraction, RT-qPCR was performed to validate microRNA upregulation in response to miR transfection. Fura-2AM loading was used to examine ROS-induced intracellular calcium rises. Lastly, oxygen-glucose deprivation modeled cerebral ischemia in vitro. Results: We describe a dose response of miR-200b upregulation, verified by RT-qPCR, in response to varying concentrations of transfected miR-200b mimic. In an injury model of one-hour exposure to H2O2 and serum deprivation, miR-200b afforded significant neuroprotective effects at 24 hours post injury. H2O2 induced a delayed, but pronounced rise in cytosolic calcium, attenuated in cells transfected with miR-200b. miR-200b also attenuated secondary excitotoxicity in neuronal cells exposed to oxygen/glucose deprivation (OGD). However, miR-200b did not protect glial cells from ischemic injury or H2O2 exposure. Accordingly, we confirm TRPM2 expression only in neuronal cells, and the association of PKCa and TRPM2 following ROS exposure. Conclusion: Taken together, these results describe a novel method of cellular neuroprotection against ROS-induced injury by modulating protein intermediaries which gate lethal calcium channels. These findings have potential implication for a number of acute CNS insults involving oxidative stress.

Save the Date!

Faculty Development Day 2017 Monday, November 13, 2017

89 Chestnut Residence and Conference Centre University of Toronto

This event is an Accredited Group Learning Activity (Section 1) as defined by the Maintenance of Certification Program of the Royal College of Physicians and Surgeons of Canada, approved by

Continuing Professional Development, Faculty of Medicine, University of Toronto up to a maximum of 5.0 hours.

The Department of Anesthesia, University of Toronto would like to acknowledge the generous, unrestricted education grants provided by our sponsors: