Decreasing the Risks Associated with Conscious

Sedation

Wael Galal; M.D.Anesthesia Consultant

KFH Al-Baha

Risk of Oversedation & Cardiopulmonary

complications

Risk of patient discomfort and distress

Safety

STATISTICS (large observational studies)

• > 14,000,000 EGDs are performed annually in the US alone

• Most of these done under conscious sedation

• Many states in the US as well as other countries forbid the use of propofol by non-anesthesiologists

• The overall complication rate was 13.5 events per 1,000 procedures

• The rate of serious cardiacor-respiratory complications was 5.4 per 1000

• Death was reported in 0.3 per 1,000 procedures

• There was no significant difference in the rate of complications between patients receiving midazolam and those receiving diazepam

Data evaluating the safety and efficacy of meperidine and diazepam or meperidine and midazolam, when used for moderate sedation during upper and lower GI endoscopic procedures performed over 2-year period:- •Revealed no deaths•There were no episodes of cardiopulmonary arrest or pulmonary aspiration reported in this series

A study using sedation-trained nurses administering propofol to 36,743 patients at three centers with a limited selection of busy endoscopists reported:-- No fatalities or intubations- Only 0.1% to 0.2% needing assisted ventilation-----------------------------------------------------------Other studies showed:-- Greater risk of apnoea & hypotension- Maladjustment of sedation easier (Narrow therapeutic window)- Airway manipulations more required

• Oxygen desaturation:

• Range around 45% with meperidine + midazolam/diazepam

• Propofol < narcotic+opioid

• The use of combinations regimes or opioid use increase the risks of:

- Oversedation- Cardio-respiratory complications

(particularly hypoxemia respiratory and airway complications)

___________________________________

Morbid obesity Older ageUnderlying cardiovascular diseasePulmonary diseaseRenal, hepatic, metabolic disease Neurologic disease

FACTS

• Any medical procedure imply a certain amount of risk. It is the human nature which has the tendency to look for “everything” in life as figures of chances and odds.

• This risk can be attenuated to a minimum by building experience, judicious steps, patient selection, safety measures, careful monitoring and good preparation

• Our target is to prevent the occurrence of these risks and their progression to life-threatening events

• Pulse oximetry is a monitor of oxygenation and not ventilation

• Supplemental oxygen can mask apnea or hypoventilation

• Reflex withdrawal from a painful stimulus is not considered a purposeful response

• Medico-legal claims about conscious sedation :– Complications were caused by respiratory

depression (45%)– Oversedation (> 1/3 of cases)– Polypharmacy with another(s) drug with

propofol (> 1/3 of cases)

General life-associated Risks Incidence Rate

To be hit by a Tsunami 1 per 50,000-500,000

To be killed by an asteroid 1 per 200,000 - 500,000

Having a heart disease 1 every 5

Having cancer 1 every 7

Stroke 1 in 23

Accidental injury 1 in 36

MVA 1 in 100Commit suicide 1 in 121Assault by a firearm 1 in 325

Electrocution 1 every 5000Drowning 1 in 8,942Airplane crash 1 in 20,000 individuals or 1 plane

every 8 Million flights

Sting by a snake, bee or others 1 in 100,000Being hit by lightening strike 1 in 83,930Death from a car accident 1.7 in 10000 drivers

Medical Risk Incidence Rate

Cardiac arrest from administration of anesthesia

4.6-19.7 per 10,000 anesthetics

Cardiac arrest during monitored anesthesia care

0.7 per 10,000 procedures

Cardiac arrest during neuraxial anesthesia 1.8 per 10,000 cases

Cardiac arrest during regional anesthesia 1.5 per 10,000 cases

In-hospital mortality related to anesthesia Was 1:10,000-20,000 anesthetics 20 years ago to 0.5-1.0 per 100,000 anesthetics now!

Death during low-risk anesthesia 1 per 500,000 anesthetics

Mortality from two operator dependent anesthesia

the risk went from 1:248,000 to 1:598,000

Death from conscious sedation* 1:500,000 - 1:1,000,000

Classification of Risk:-“How to interpret different odds”

• 1 in 10 – Extremely High• 1 in 100 – Very High• 1 in 1,000 – Quite High• 1 in 10,000 – Medium• 1 in 100,000 – Quite Low• 1 in 1 million – Very Low• 1 in 10 million – Extremely Low• 1 in 100 million – Minimal

Risks, Risks, Risks, …

Risks of Conscious Sedation

• Respiratory Depression First sign is lack of response to verbal stimulation

• Cardiovascular Depression

• Oversedation

• Paradoxical Reactions

• Wrong patient, site and procedure

75%

25%

Primum non nocere(primum nil nocere)

Latin phrase originated from the Hippocratic oath that means:

"first, do no harm"

The Essence of Prediction and Measuring Chances??

• Smith CM. Origin and uses of primum non nocere--above all, do no harm! J Clin Pharmacol. 2005 Apr;45(4):371-7.

• Oath (Primum non nocere): http://www.youtube.com/watch?v=94H0IlQnYa0

The rate of complications associated with conscious sedation are increased significantly with the combination of > 1 agent, with use of opioids and with the use of advanced sedation techniques/agents (e.g. involving propofol, dexmedetomidine, … etc.)

• MAC: Monitored Anesthesia Care

• MAC: Maximal “Anesthetist” Consumption

• MAC: Minimal Alveolar Concentration

• MAC: Maximal Anesthesia Caution!!

Procedural Sedation Risk Sources

1. Patients at risk (physician function)2. Who administer sedation3. Equipment failure (nurse function)4. Monitoring failure5. Unpredicted drug response6. Wrong patient, wrong site, wrong

procedure

“At Risk” Patients Categories• ASA status classification ≥ 3• Critical care patients• Extremes in age (<1 or >70 years of age)• Patients with chronic respiratory disease, chronic

obstructive pulmonary disease, emphysema• History of sleep apnea syndrome• Mentally and neurologically disabled patients• Patients at risk for aspiration (i.e. hiatal hernia with

regurgitation, diabetes with gastroparesis• Altered mental status• Obesity

Prevent Patient Risks

Prevent Risks

Prevent Complications

Timing: Pre-procedural By: (A) Careful Patient Selection

(B) Completing patient, drugs & Equipment checlists

Timing: Intra-procedural By: (A) Proper Patient Monitoring

(B) Proper Timley Intervention(C) Use of Reversal Agents

(D) Fulfilling Discharge Criteria

1

2

Predictors of Conscious Sedation-Related Complications*

• ASA Classification ≥ III• Inpatient procedures• Involvement of trainees• Use of supplemental oxygen

* This is studied in relation to cardiopulmonary events•Number of studied subjects 324,737 endoscopic procedures

How to Identify them?

Easy … Never hesitate!

Physician’s pre-sedation patient evaluation should utilize a checklist function to identify patients at risk.

Patient Selection for Conscious Sedation

• History:- Any poor anesthetic or Sedational history- Documented difficult airway- History of snoring/obstruction/cynosis

during sleep- Full stomach or upper GI bleeding

• Physical Examination– Respiratory distress (wheezing, stridor, etc.)– Hypotension– Morbid obesity– Craniofacial abnormalities– Short neck– Decreased hyoid-mental distance (<3cm in adult)– Distorted landmarks on anterior surface of neck

– Limited mouth opening– Receding chin– Large tongue– Unable to view base of uvula with mouth open

and tongue protruding

Now we can figure out the ASA class??

Modifying Fasting Guidelines

Intake Category Fasting Period for Low Risk Patients

Fasting Period for High Risk Patients

Clear Liquids 2 hours 8 hours

Breast Milk 4 hours 8 hours

Infant Formula 6 hours 8 hours

Non-human Milk 6 hours 8 hours

Regular Meal 8 hours 8 hours

Who Administers Sedation?

1) Minimum one physician and one nurse2) Certified in BLS. It should be periodically updated according to the SCFHS standards. 3) Should have certified basic training in sedation obtained from approved courses. including training in managing crises and complications. 4) The certification is valid for only two years and should be periodically renewed.

Proper Monitoring of Risks

Respiratory Cardiovascular

ParadoxesOversedation

Observation, RR, SpO2, EtCO2

ECG, BP, HR

Observe Level of Consciousness

Observe Behavioral Response

Prevent Equipment Failure

• Check ALL EQUIPMENT before beginning any procedure.

• USE CHECKLISTS (nursing checklist will target all equipment and drugs)

• General Description

• Responsiveness

• Airway• Ventilation• Cardiovascular

The Risk of Oversedation

Minimal• General Description “Anxiolysis”

• Responsiveness

• Airway• Ventilation• Cardiovascular

“appropriate”

unaffectedunaffectedunaffected

SEDATION LEVELS

Riskof

AdverseEvent

NoSedation

MildSedation

The Risk of Oversedation

Minimal Moderate• General Description “Anxiolysis” “Conscious”

• Responsiveness

• Airway• Ventilation• Cardiovascular

“appropriate”

unaffectedunaffectedunaffected

“Purposeful” to light stimulation

No interventionAdequate

Maintained

SEDATION LEVELS

Riskof

AdverseEvent

NoSedation

MildSedation

ModerateSedation

The Risk of Oversedation

Minimal Moderate Deep• General Description “Anxiolysis” “Conscious” “Deep sleep”

• Responsiveness

• Airway• Ventilation• Cardiovascular

“appropriate”

UnaffectedUnaffectedUnaffected

“Purposeful” to light stimulation

No interventionAdequate

Maintained

“Purposeful” to pain stimulation

(±) Intervention(±) Inadequate(±) Maintained

SEDATION LEVELS

Riskof

AdverseEvent

NoSedation

MildSedation

ModerateSedation

DeepSedation

The Risk of Oversedation

• Use agents with wide therapeutic window• Minimize combination regimes• Minimize use of unrequired narcotics• TALK to YOUR PATIENT

Oversedation

Management of Sedational Complications:

Active Interventions

• Stimulate the patient to wake up and take deep breaths. It is not sufficient to simply turn up the rate of oxygen delivery.

• If the patient does not respond, chin lift and jaw thrust is appropriate to provide a patent airway.

• Administer the appropriate antagonist (flumazenil for benzodiazepines; naloxone for opioids).

• If there is still no response to these measures, consider the use of bag mask ventilation as the next measure. Insertion of a nasopharyngeal of oropharyngeal airway may augment ventilation at this stage.

• The use of laryngeal mask airway or ET tube insertion as appropriate should then be considered.

Respiratory Depression

• Intravenous fluids• Atropine sulphate• Vasopressor agents

– Ephedrine

• Antidysrhythmic agents (Consult!!)

Cardiovascular Depression

• Increasing sedation• Adding an opioid agent to relief possible pain

Vasopressor Response

• Stop administering sedating agents• Maintain A …. B …. C• Use the specific reversal agents• Consult!!

Oversedation

• A state of excitement can occur in some patients as a reaction to sedation agent(s) which can prevent the performance of the targeted procedure.

• These reactions can include excessive talkativeness, movement, and emotional release.

• Relatively uncommon, occurring in less than 1% of cases.

Paradoxical Reactions

Predisposing Factors for Paradoxical Responses

Predisposing Patient Characteristics:

•Young and advanced age

•Genetic predisposition

•Alcoholism or drug abuse

•Psychiatric and/or personality disorders

Predisposing Pharmacologic Agents:

•Diazepam > Midazolam

•Sole ketamine sedation

Management of Paradoxical Reactions

• STOP the culprit agent. Additional doses of benzodiazepines and opioids usually worsen the problem.

• Flumazenil, a benzodiazepine antagonist, has been shown to be effective in managing these reactions with a minimum of side effects. 

• In some cases, the addition of droperidol may resolve the problem, but often propofol will need to be administered for better control

• Lidocaine is commonly used to suppress the gag reflex during upper GI endoscopic procedures via spray or gargling.

• This use was associated with severe adverse reactions including rare cases of fatal methemoglobinemia, causing cyto-toxic hypoxia.

• Methemoglobinemia should be suspected if clinical “cyanosis” is observed in the presence of normal arterial oxygen saturation.

Complications of LA agents

• Blood color ranges from dark red or brownish to blue. Pulse oximetry is not effective in measuring oxygen saturation in the presence of methemoglobinemia. High flow oxygen and possibly the use of IV methylene blue (2mg/kg) can be used to treat methemoglobinemia.

• The ASGE Guidelines for Conscious Sedation and Monitoring During Gastroenterology recommends against the routine use of topical pharyngeal anesthetics in most patients.  However, pharyngeal anesthesia before upper endoscopy improves ease of endoscopy and also improves patient tolerance, so may be acceptable under certain conditions, especially if light or no sedation is administered.

Development of Conscious Sedation Clinical Pathway

An evidence-based conscious sedation clinical pathway

The 10 Unaccepted Safety Breeching Situations

1. Unfamiliarity of the physician about any patient’s related comorbid condition or drug allergy

2. Breaking the NPO guidelines3. Unfamiliarity of all sedation parties with

drug dosing and concentrations4. Once started, all parties must remain at the

patient’s bed-side5. Unavailability of emergency drug or

reversal agent

6. Pushing advanced use agents like propofol or dexmedetomidine by syringe7. Last moment decision change particularlyomitting procedural sedation based on wrong suggestion8. Ignoring the ASA status implications9. Treating “reversed sedation” patients like regular cases10. Assuming conscious sedation necessarily implicates amnesia

Any Questions

?

Summary

• Choose your patient carefully, learn about his/her body weight and comorbidities.

• Check and understand your drugs, monitoring and resuscitation equipment

• Use medication judiciously, remember you can’t take it out but you can always give more!

• Have reversal agents available but always remember basic resuscitation techniques.

• Be vigilant and prepare for the unexpected.

Measures forRisk Reduction Associated with

Conscious Sedation

Causes of complicationsAssociated with Conscious Sedation Agents

• Inappropriate patient selection• Unanticipated response• Inappropriate monitoring of

pharmacological effects• Equipment failure• Over-medication (or over-sedation)

Improve Patient Selection

• Use the ASA classification

• Assess airway

• Assess neurologic, psychological, and cardiorespiratory fitness

• Follow NPO guidelines

Prepare for Unexpected Events

• Anticipate for known abnormal reactions

• Adequate preparation & checkup of all necessary equipment

• Call for help

• Basic/Advanced life support

Adequate Monitoring of Drug Effects

• Establish standard monitoring for ALL CASES

• Maintain continual patient contact and observation

• Never forget: First monitor is Continual Monitoring/Observation of the Level of Consciousness ? (maintain verbal contact with your patient)

• Use conscious sedation equipment checklist prior to every single procedure

• Record the checklist in each patient record

Prevention of Equipment Failure

Prevention of Oversedation

• Use standard drug dosage and precautions (use distributed leaflets)

• Titrate dosage to response

• Allow enough time to a drug to appear

• Get reversal agents as well as other emergency drugs in reach of your hand

• Basic/Advanced life support

Prevention of Risks

Respiratory Cardiovascular

ParadoxesOversedation

- Proper patient selection & monitoring- Proper checkup of all necessary equipment and drugs - Skill &Tools in opening the airway, assisting ventilation & supporting

hemodynamics (i.e. valid BLS/ACLS certification)- Periodic Mock codes- Secure Method for calling for help prior to each procedure

- Use dosing guidelines and strategies- Minimize the use of multiple agents- Minimize the use of opioids- Discontinue sedation agents & use

reversal- Prevent re-sedation following reversal

- Identify possible candidates- Select proper agents- Discontinue the culprit drug(s)- Use reversal agent(s)