Best Practice:ACLS: Physiology and Review of

Current Literature

Jacob Imber, MDWednesday, Aug 12, 2015

Objectives

• Describe the epidemiology of cardiac arrest• Review 3-phase cardiac arrest theory

– Discuss impact on resuscitation efforts

• Discuss physiologic goals of CPR– Review evidence to support current guidelines

• Examine use of IV medications in CPR

Motivation• Cardiac arrest is becoming less frequent (importance

of practice and review)– Decreasing incidence of CAD– Increased recognition of unstable patients– Rapid response teams

• CPR remains the mainstay of resuscitation• Poor performance of floor staff prior to arrival of

emergency team (next slide)• Poor resident confidence in code situations identified

on UNMH exit interviews and surveys

Department Staff PerformanceEinav et al. “Performance of department staff in the window between discovery of collapse to cardiac arrest team arriaval” Resuscitation

(2006) 69, 213-220

Recommendation DenominatorThe percent of events in which the specified recommendation was not followed (n = 244)

Basic diagnostic measures

Assess pulsea All 19.3% (47/244)

Attach monitor/defibrillator when availableb

Patients not previously connected to an electrocardiogram 34% (35/103)c

Assess rhythmb All 33.6% (82/244)

Patients connected to an electrocardiogram by department teams 50% (28/56)

Patients who were already monitored by electrocardiography prior to the event 7.9% (11/140)

Therapeutic Measures

Basic

Provide positive pressure ventilations (bag-mask)b Patients with agonal breathing 43.5% (50/115)

Patients in full respiratory arrest 17.3% (13/75)

If no pulse-start chest compressionsb Patients diagnosed as pulseless 12.5% (13/104)

Attempt defibrillationb Patients diagnosed with VF/pulseless VT 44% (15/34)

Get With The Guidelines (GWTG)-Resuscitation

• formerly National Registry of Cardiopulmonary Resuscitation (NRCPR)

• AHA-sponsored, prospective, multisite, observational study of in-hospital resuscitation

• all adult (≥18 years of age) and pediatric (<18 years of age) patients, visitors, employees, and staff within a facility (including ambulatory care areas) who experience a resuscitation event

Peberdy MA, et al. Cardiopulmonary resuscitation of adults in the hospital: a report of 14720 cardiac arrests from the National Registry of Cardiopulmonary Resuscitation. Resuscitation. 2003 Sep;58(3):297-308. PMID: 12969608.

Epidemiology

• 3rd leading cause of US deaths (1-cancer, 2-CAD)• Table below from Get with the Guidelines data

IOM (Institute of Medicine). 2015. Strategies to improve cardiac arrest survival: A time to act. Washington, DC: The National Academies Press. p. 249.

Statistical Update

Out-of-Hospital Cardiac Arrest In-Hospital Cardiac Arrest

IncidenceBystander

CPR (overall)

Survivor rate*

(overall)Incidence

Survival rate*

Adults Children

2013 359,400 40.1% 9.5% 209,000 23.9% 40.2%

2012 382,800 41.0% 11.4% 209,000 23.1% 35.0%

Outcomes

• Return of Spontaneous Circulation (ROSC)– “restoration of a spontaneous perfusing rhythm

that results in more than an occasional gasp, fleeting palpated pulse, or arterial waveform”

• Survival to discharge• Neurologic outcome/Return to prior level of

functioning

Cardiac Arrest and Cardiopulmonary Resuscitation Outcome Reports: Update and Simplification of the Utstein Templates for Resuscitation Registries: A Statement for Healthcare Professionals From a Task Force of the International Liaison Committee on Resuscitation. Jacobs I, et al. Circulation. 2004; 110: 3385-3397

Cerebral Performance Category (CPC) Scale

CPC 1. Good cerebral performance: Conscious, alert, able to work and lead a normal life. May have minor psychologic or neurologic deficits (mild dysphasia, non-incapacitating hemiparesis, or minor cranial nerve abnormalities)CPC 2. Moderate cerebral disability: Conscious. Sufficient cerebral function for part-time work in sheltered environment or independent activities of daily life (dress, travel by public transportation, food preparation). May have hemiplegia, seizures, ataxia, dysarthria, or permanent memory or mental changes.CPC 3. Severe cerebral disability: Conscious. Dependent on others for daily support (in an institution or at home with exceptional family effort). Has at least limited cognition. This category includes a wide range of cerebral abnormalities, from patients who are ambulatory but have severe memory disturbances or dementia precluding independent existence, to those who are paralyzed and can communicate only with their eyes, as in the “locked in” syndrome.CPC 4. Coma or vegetative state: any degree of coma without the presence of all brain death criteria. Unawareness, even if appears awake (vegetative state) without interaction with environment; may have spontaneous eye opening and sleep/awake cycles. Cerebralunresponsiveness.CPC 5. Brain death: apnea, areflexia, EEG silence, etc. circulation preserved.

Safar P. Resuscitation after Brain Ischemia, in Grenvik A and Safar P Eds: Brain Failure and Resuscitation, Churchill Livingstone, New York, 1981; 155-184.

All Codes are not created equal

• Survival and Outcomes are directly affected by a number of variables– Presenting rhythm– Patient demographics (age, race)– Location of cardiac arrest– Pre-existing co-morbidities– Knowledge of emergency respondents

Survival for IHCA improving

Chan PS. Public health burden of in-hospital cardiac arrest. Paper commissioned by the Committee on the Treatment of Cardiac Arrest: Current Status and Future Directions. 2015. http://www.iom.edu/~/media/Files/Report%20Files/2015/GWTG.pdf (accessed June 30, 2015).

It’s good to be male and 50

Racial disparities

Don’t code at night

Peberdy MA, et al, ; for the National Registry of Cardiopulmonary Resuscitation Investigators. Survival From In-Hospital Cardiac Arrest During Nights and Weekends. JAMA. 2008;299(7):785-792. doi:10.1001/jama.299.7.785.

Chan PS. Public health burden of in-hospital cardiac arrest. Paper commissioned by the Committee on the Treatment of Cardiac Arrest: Current Status and Future Directions. 2015. http://www.iom.edu/~/media/Files/Report%20Files/2015/GWTG.pdf (accessed June 30, 2015).

IOM (Institute of Medicine). 2015. Strategies to improve cardiac arrest survival: A time to act. Washington, DC: The National Academies Press. p. 251.

Nadkarni VN, et al; for the National Registry of Cardiopulmonary Resuscitation Investigators. First Documented Rhythm and Clinical Outcome From In-Hospital Cardiac Arrest Among Children and Adults. JAMA. 2006;295(1):50-57. doi:10.1001/jama.295.1.50.

With all these variables, what do you say to a patient?

• Rough Estimates:– ROSC: 40-60%– Survival to discharge: 15-30%– Good neurologic outcome: 2-5%

• Go-Far scoring system for “likelihood of good outcome in resuscitation”

Ebell MH, Jang W, Shen Y, Geocadin RG. Development and Validation of the Good Outcome Following Attempted Resuscitation (GO-FAR) Score to Predict Neurologically Intact Survival After In-Hospital Cardiopulmonary Resuscitation. JAMA Intern Med. 2013 Sep 9.

Cardiac arrest

DefinitionSudden cessation of heartbeat and cardiac function resulting in the loss of effective circulation.

But is it that simple?

3-Phase, Time-Sensitive Model of Cardiac Arrest

• Electrical Phase (0-4mins)– Primary problem is disorganized electricity– Shock should be first intervention if possible– Supported by efficacy of ICD (shock 15-20secs into rhythm,

rarely fails to restore perfusing rhythm)• Circulatory Phase (4-10mins)

– Primary problem is lack of blood/O2 flow to heart– Chest compressions/ventilation should be initiated first,

initial defib should occur after 1st cycle of CPR (2min after initiation of code)

Weisfeldt ML, Becker LB. Resuscitation After Cardiac Arrest A 3-Phase Time-Sensitive Model. JAMA. 2002;288(23):3035-3038. doi:10.1001/jama.288.23.3035.

Evidence?

• Yakaitis et al. (1980) Dog models with VF arrest, initial defib 1, 3, 5, 9min– Initial Defib is optimal in 1/3min groups

• Niemann et al. (2000) showed after 7.5min untreated VF, 5min of CPR + epi vs. immediate defib was 64% (9/14) vs. 21% (3/14) chance of ROSC

• Niemann also showed no change in outcome for CPR + defib vs. immediate defib in <5min of untreated VF

5min group Immediate defib CPR 1min, 1mg Epi then Defib

Successful Shock 30% (3/10) 70% (7/10)

ROSC 0% (0/10) 40% (4/10)

Yakaitis et al. Influence of time and therapy on ventricular defibrillation in dogs. Crit Care Med 1980;8 157-163

Niemann et. Al. Immediate countershock vs. CPR before countershock in a 5-min swine model of VF arrest. Ann Emerg Med. 2000;36:543-546

Metabolic Phase (10+ mins)

• Theorized because many studies show dramatic decrease in efficacy for CPR and Defib when cardiac arrest has occurred for >10min prior to initiation

• Irreversible injury from ischemia vs. toxic metabolites• Gut mucosal translocation resulting in cytokine release?• Peripheral vasoconstrictors cause organ ischemia?• Increased risk of reperfusion injury?• Forms basis of “therapeutic hypothermia” theory• No change in basic CPR recommendations, though there is

some consideration for changes in post-arrest care under presumption of worsened tissue injury etc. (i.e. hypothermia)

Evidence for Three-Phase Model in humans

Gilmore CM, et al. Three-Phase Model of Cardiac Arrest: Time-Dependent Benefit of Bystander Cardiopulmonary Resuscitation. Am J Cardiol 2006;98:497– 499

Guideline development process

American Heart Association. Highlights of the 2010 American Heart Association Guidelines for CPR and ECC.

Major Challenges to Delivering High-Quality ACLS

AHA evaluation of ACLS found:

•Poor quality: inconsistent rate or inadequate depth and lack of fidelity to ACLS cycle•Harmful interruptions•Inadequate cerebral and cardiac perfusion•Inadequate support for defibrillation

Performance in CPR?

• Abella examined University of Chicago Hospitals and found:– Chest compression rate was too slow– Chest compression depth was too shallow– Ventilation rate was too high– Time without compressions was too frequent and

too prolonged

(Abella, B.S. et al. Quality of cardiopulmonary resuscitation during in-hospital cardiac arrest. JAMA 2005;293:305-310)

Coronary Blood Supply

Fed by backfill pressure called Coronary PerfusionPressure

Diastolic Aortic Pressure – Right Atrial Diastolic Pressure

Calculated to require 15mmHg CPP for ROSC

CPP vs. ROSC

Paradis NA et al. JAMA 1990 Feb 23;263(8): 1106-13

Establishing Coronary Perfusion Pressure with Chest Compressions

Impact of CC interruption on CPP

How important are pauses in chest compressions prior to defibrillation? (Cheskes et al. 2011)

• 815 patients with out of hospital cardiac arrest (OHCA)• Pre-shock chest compression pause ≥ 20 seconds had OR

0.47 for survival vs pauses < 10 seconds• Pre-shock chest compression pause ≥ 40 seconds had OR

0.54 for survival vs pauses < 20 seconds

• Second study by Tang et al. noted that after CPP was established, ~60 seconds were required to recover CPP for 10 second interruption

Circulation. 2011 Jul 5;124(1):58-66. doi: 10.1161/CIRCULATIONAHA.110.010736. Epub 2011 Jun 20

Tang et al. “Adverse effects of interrupting precordial compression during cardiopulmonary resuscitation” Crit Care Med 1997; 25:733-736

High-Quality Chest Compressions

• Uninterrupted

High-Quality Chest Compressions

• Uninterrupted• Rate of 100

Rate compared to Likelihood of ROSC

Abella et al. “Chest compression rates during cardiopulmonary resuscitation are suboptimal” Circulation. 2005 Feb 1;111(4):428-34

Rate of CC divided into 30 second intervals

1626 30-sec intervalsRate between 90-110 ~37% of the intervals

(Abella BS et al., Circulation 2005;111;428-434)

High-Quality Chest Compressions

• Uninterrupted• Rate of 100• Depth of 5cm (2in)

Likelihood of Successful Defibrillation as compared to CC depth

(Edelson DP et al., Resuscitation 2006;71;137-145) 

High Variation of Depth During CPR<50% of 30 second intervals were 38-51mm

(Abella BS, Proceedings of ERC Symposia: Squeezing High Performance Out of CPR Medcom 2006)

High-Quality Chest Compressions

• Uninterrupted• Rate of 100• Depth of 5cm (2in)• Recoil• Location (center of chest, lower 1/3)

Hand position

Appropriate Ventilation

• Synchronous ventilation (OHCA) – 30:2 in CPR cycle

• Asynchronous ventilation (IHCA) – 6-10 breaths per minute (wait 6-10 seconds

between each breath)

• Increased air and pressure within the lungs increases impedance to blood flow

Why limit ventilations? Isn’t more better?

Ordelman et al. Circulation 2013; 128:A290

Impact of Ventilatory Rate on Survival

Aufderheide TP et al. “Hyperventilation-induced hypotension during cardiopulmonary resuscitation” Circulation 2004

Average Ventilatory Rates

• Aufderheide et al. demonstrated that in out-of-hospital rescues the frequency of ventilation averaged 30 times per minute

Aufderheide et al. “Hyperventilation-induced hypotension during cardiopulmonary resuscitation”. Circulation. 2004 Apr 27;109(16):1960-5. Epub 2004 Apr 5

• Abella showed a similar effect for in-hospital rescues, noting ventilation rates greater than 20 times per minute in 60.9% of the CPR segments measured.

Dr. Claude Beck’s 1st defibrillator

Cooper JA, Cooper JD, Cooper JM. Cardiopulmonary Resuscitation: History, Current Practice, and Future Direction.Circulation. 2006;114:2839-2849.

Relation of collapse to CPR and defibrillation to survival

Valenzuela TD et al. Estimating effectiveness of cardiac arrest interventions: a logistic regression survival model. Circulation. 1997 Nov 18;96(10):3308-13.

Graphical representation of simplified (includes collapse to CPR and collapse to defibrillation only) predictive model of survival after witnessed, out-of-hospital cardiac arrest due to VF. Each curve represents change in probability of survival as delay (minutes) to defibrillation increases for a given collapse-to-CPR interval (minutes).

For every minute of delay from collapse to CPR or defibrillation, death is 1.1 times more likely.

Shorter pauses before defibrillation better

Edelson DP et al. Effects of compression depth and pre-shock pauses predict defibrillation failure during cardiac arrest. Resuscitation. 2006 Nov;71(2):137-45. Epub 2006 Sep 18.

Delayed defibrillation is associated with lower rates of survival after in-hospital cardiac arrest

Chan PS et al. Delayed time to defibrillation after in-hospital cardiac arrest. NEJM. 2008 Jan 3;358(1):9-17. doi: 10.1056/NEJMoa0706467.

What about the drugs?

Olasveengen TM et al, Intravenous drug administration during out-of-hospital cardiac arrest: a randomized trial.JAMA. 2009 Nov 25;302(20):2222-9. doi: 10.1001/jama.2009.1729.

Is that really true? Really?

Donnino et al. BMJ 2014;348:g3028

There must be other studies

• Meta-Analysis on OHCA performed for Resuscitation in 2014 by Lin et al.– Epinephrine gives increased rate of survival to

admission and ROSC– No change in survival to discharge or neurologic

outcome– Addition of vasopressin did not change outcome

Lin et al. “Adrenaline for out of hospital cardiac arrest resuscitation” Resuscitation 84 (2014) 732-740

What about a more recent study?

Association Between Outcome and Early Dose of EPI and According to the Initial RhythmThe odds ratios were adjusted according to baseline characteristics (age, sex, hypertension, diabetes mellitus, smoking, witnessed status, bystander cardiopulmonary resuscitation, length of resuscitation), and hospital covariates (PCI, hypothermia, post–cardiac arrest shock, blood lactate level).

Dumas et al. “Is epinephrine during cardiac arrest associated with worse outcomes in resuscitated patients? JACC 64;22 (2014)

So? What to do?

• Epinephrine remains a part of the algorithm and plays a role in immediate peri-code survival

• It remains to be seen if timing of epinephrine is the key element (remember the 3-phase model?)

• Continue to use, but emphasis should be placed on chest compressions and defibrillation

Summary

• Cardiac arrest remains a catastrophic event with poor outcomes– We are beginning to be able to anticipate who is

likely to have a worse outcome, but this remains challenging

• Resuscitation is likely a time-dependent activity with different interventions (shock vs. meds/CC) being indicated based on time from arrest

Summary (Cont’d)• Chest Compressions and defibrillation are the

mainstay of resuscitation– Success of CPR is dependent on high-quality

compressions and ventilation– Avoidance of interruption when providing defib is vital

to outcomes

• We have room to improve on our performance in resuscitation as a profession

• Medications in ACLS remain useful, but their role is secondary to the above interventions

Questions?