Procedural Sedation & Analgesia in the Emergency Department

Objectives Review the current guidelines Review commonly used agents Briefly discuss alternatives to PSA

What’s not covered Pediatric procedural sedation & analgesia

Procedural Sedation & Analgesia Positives Avoids discomfort associated with local or regional anaesthetic techniques. Doesn’t affect anatomy Relatively simple technique Negatives Consumes resources Relative higher risk than local/regional General anaesthesia in the ED is frowned upon…

Goals of PSA To consider patient safety & welfare the first priority. To provide adequate analgesia, anxiolysis, sedation and amnesia during the performance of painful diagnostic or therapeutic procedures in the ED. To minimize the adverse psychological responses associated with painful or frightening medical interventions. To control motor behavior that inhibits the provision of necessary medical care. To return the patient to a state in which safe discharge is possible. From Procedural sedation and analgesia in emergency department. Canadian Consensus Guidelines The Journal of Emergency Medicine January 1999

Considerations for PSA in the ED Personnel requirements Patient assessment Fasting status Equipment & supplies Choice of agent Assessment & monitoring Adapted from: Clinical policy: procedural sedation and analgesia in the emergency department ACEP Clinical Policies Committee on Procedural Sedation and Analgesia February 2005

Personnel Requirements “… a qualified support person should be present for continuous monitoring of the patient.” Class C Evidence Clinical policy: procedural sedation and analgesia in the emergency department ACEP Clinical Policies Committee on Procedural Sedation and Analgesia “An additional qualified patient observer… must be present during sedation.” Class B, Level III Procedural sedation and analgesia in the emergency department Canadian Consensus Guidelines

Patient Assessment The AMPLE history Physical Exam Allergies Medications Past medical history Last meal Events before & after the incident Physical Exam Airway assessment Respiratory exam Cardiovascular exam

ASA Physical Status Classification Healthy Patient Mild systemic disease – no functional limitation Severe systemic disease – definite functional limitation Severe systemic disease that is a constant threat to life Moribund patient that is not expected to survive with the operation Low inter-observer reliability.

“It’s only a little chest pain” ASA Scores & PSA The ASA classification is not validated outside of the OR. Malviya et al showed an increased risk of adverse sedation-related events in paediatric patients with an ASA > 2. The ASA was developed to help identify patients at risk of developing complications as a result of undergoing general anesthesia. ASA: No formal support by emergency medicine associations; Supported by the American society of anestheologists

And the guidelines say… “The patient’s ASA status should be determined. For non-emergent procedures, ED sedation and analgesia should be limited to ASA class 1 or 2 patients.” Class B, Level III Procedural sedation and analgesia in the emergency department Canadian Consensus Guidelines The guidelines go on to say that for ASA III-IV patients, anesthesia should be consulted and OR management should be considered. ASA status was not addressed in the American guidelines.

Airway Assessment Can you bag? Can you intubate?

Predictors of Difficult BVM Ventilation Beard Obesity Old (age > 55 yrs) Toothless Snores Langeron O, Masso E, Huraux C, et al. Prediction of difficult mask ventilation. Anesthesiology. 2000; 92:1229-36.

The LEMON Method of Airway Assessment Look for external characteristics known to causes problems with BVM or intubation. Evaluate the 3-3-1 Rule: Mouth opening > 3 fingers Hyoid – chin distance > 3 fingers Anterior low jaw subluxation > 1 finger Mallampati Score Obstruction – any pathology within or surrounding the upper airway Neck Mobility - full flexion & extension

The Last Supper Fasting & PSA The Canadian recommendations are based of American Society of Anaesthesiologists recommendations for healthy elective GA patients: 2 h NPO for liquids 6 h NPO for solids The risk of aspiration during PSA is extremely low. There is no evidence that fasting improves outcome during procedural sedation and analgesia. One large paediatric study of ED procedural sedation showed no increase in the number of adverse events in patients that were not fasting. In addition, the ASA indicates that there is no role for the use of antacids and gastric motility agents to prevent aspiration during elective GA in healthy patients. The ACEP guidelines apply this recommendation to ED PSA patients, while the Cdn guidelines recommend their use in patients who do not meet NPO criteria. Green proposes a number of reasons why the the ASA guidelines should not be generalized to ED PSA Aspiration is most likely to occur during airway manipulation – this should not be happening during PSA. PSA is typically performed in younger patients. The risk of aspiration is higher in older patients. Most agents used during PSA are not pro-emetic, unlike the gases which are commonly used in the OR. Ideally, PSA should be in the range of moderate sedation with intact airway reflexes The use of dissociative amnestics (ketamine) theoretically reduces the risk of aspiration because airway reflexes are “intact”

Guidelines for Pre-sedation Fasting “Recent food intake is not a contraindication for administering procedural sedation and analgesia, but should be considered in choosing the timing and targeted level of sedation.” Class C Evidence Clinical policy: procedural sedation and analgesia in the emergency department ACEP Clinical Policies Committee on Procedural Sedation and Analgesia “Pre-procedure fasting decreases aspiration risk, though optimal fasting duration remains controversial… the practitioner should consider keeping the patient NPO for 2 h (liquids) or 6 h (solids) before sedation.” Class C, Level III Procedural sedation and analgesia in the emergency department Canadian Consensus Guidelines

The Perfect Drug Provides adequate sedation and analgesia for: Patient comfort Easy completion of the procedure Maintains airway reflexes Does not affect hemodynamics Does not affect respiratory function

Commonly Used Agents Propofol Fentanyl Ketamine Midazolam Etomidate

What are we using? Propofol is the most commonly used agent. Fentanyl + midazolam is the next most common. Source: Articles in the March 2006 edition of CJEM by Campbell et al and Mensour et al regarding at PSA in the ED.

Commonly Used Agents Propofol Category Sedative-Hypnotic What is it? 2,6-diisopropofol, an alkylphenol oil in an emulsion How does it work? Potentiates GABA activity How much do you need? Starting dose of 0.5 - 1 mg/kg Actual half-life of propofol is 4-7 hrs Clearance is independent of renal or liver function and is not affected by renal or hepatic disease. Onset is one arm-brain circulation with peak affect at 90-100 s. Anti-emetic properties

Commonly Used Agents Propofol What else does it do? CNS: Mild analgesic properties; euphoria CVS: Myocardial depressant; vasodilation Resp: Respiratory depressant GI: Antiemetic MSK: Myoclonus What does the body do with it? Rapid redistribution Hepatic and extrahepatic metabolism

Commonly Used Agents Propofol Pros Shown to be safe for ED PSA use Rapid onset and recovery Cons Must be combined with an analgesic agent May cause apnea & loss of airway reflexes Myocardial depressant and vasodilator Must be administered via special IV pump Symington and Thakore conducted a review of the safety of using propofol for procedural sedation in the ED and concluded that while the rate of “minor” adverse events (including transient hypoxia) was similar to other agents, the drug was overall very safe and offered advantages over other agents.

Commonly Used Agents Fentanyl Category Analgesic agent What is it? Synthetic opioid How does it work? Decreases conduction along nociceptive pathways and increases activity in pain control pathways in the brain. How much do you need? Starting dose of 1-2 mcg/kg Doses > 5 mcg/kg bolused rapidly are required to cause chest wall rigidity. Rigidity is managed with paralysis or reversal agents. May cause coughing in 50% of patients. Peak effect in 2-3 min

Commonly Used Agents Fentanyl What else does it do? CNS: Euphoria (or dysphoria) Resp: Respiratory depressant; chest wall rigidity CVS: May decrease HR GI: Decreased motility What does the body do with it? Hepatic metabolism (inactive metabolite) Renal excretion

Commonly Used Agents Fentanyl Pros Good hemodynamic stability Rapid onset and recovery Cons Must be combined with an amnestic agent May cause bradycardia May cause chest wall rigidity in high doses May cause apnea & loss of airway reflexes Cardiology study using high dose fentanyl for cardiac surgery – patients were hemodynamically stable and pain free.

Commonly Used Agents Midazolam Category Amnestic What is it? Benzodiazepine How does it work? Bind to benzodiazepine receptors which up-regulate GABA activity How much do you need? 0.02 – 0.1 mg/kg IV Use with caution in patients with renal failure b/c of potential buildup of metabolite.

Commonly Used Agents Midazolam What else does it do? CNS: Anxiolysis CVS: Slight decrease in PVR & decreased contractility. Resp: Respiratory depression What does the body do with it? Hepatic metabolism (active metabolite) Renal excretion

Commonly Used Agents Ketamine Category Dissociative Amnestic What is it? Derivative of phencyclidine with some opioid properties. How does it work? Stimulates the limbic system while inhibiting the thalamus & cortex (dissociation) Binds to NMDA and opioid receptors Metabolite (norketamine) has 20-30% less activity than ketamine Onset within 30 s of administration (IV) Distribution half life is 11-16 minutes (two compartment metabolism)

Commonly Used Agents Ketamine What else does it do? CNS: Emergence reactions - nightmare/hallucination, Increase intracranial pressure CVS: Increased contractility, HR and PVR through sympathetic stimulation. Direct myocardial depressant. Resp: Laryngospasm, bronchodilation, increased secretions (bronchorrhea), virtually universal maintenance of airway reflexes GI: Emesis is common What does the body do with it? Hepatic metabolism Renal excretion

But won’t it give him nightmares? Ketamine & Emergence Reactions Frequency is reported to be anywhere from 10% to 20% in adults. Pre-procedural agitation is the best predictor of emergence reaction. Co-administered benzodiazepine has NOT been found to reduce incidence in children but may do so in adults. Ann Emerg Med. 2009 Aug;54(2):171-80 Am J Emerg Med. 2008 Nov;26(9):985-1028. Emergence reaction: Anxiety, nightmares, hallucinations & delirium while waking up Ketamine is extensively used in developing countries with great success. Evidence for benzos is debateable – several peds trials show no benefit. Anecdotally, some people will wait for signs of emergence before giving midazolam while others give it with ketamine. Two trials from the 70’s show a reduction in the incidence of emergence reactions when adult patients were pretreated with midazolam

The Bottom Line Ketamine can be useful for adult PSA in the ED. Contraindications for use in PSA: Ischemic heart disease Prolonged stress response Poorly controlled hypertension Recent respiratory tract infection History of psychotic illness Possible intracranial or ocular injury Consider co-administration of midazolam to decrease the risk of emergence reaction. Consider anti-emetic to reduce vomiting. Green, SM and Li J. “Ketamine in Adults: What Emergency Physicians Need to Know about Patient Selection and Emergence Reactions” Academic Emergency Medicine. 2000. 7:278-281.

Commonly Used Agents Ketamine How much do you need? 2 mg/kg IV, 3-4 mg/kg IM How much midazolam? 3-5 mg given at the time of ketamine injection. Several authors pointed out that this dose of midazolam may be higher than required to prevent emergency reactions.

Mix & Match Commonly used combinations: Propofol + Fentanyl Fentanyl + Midazolam Propofol + Midazolam + Fentanyl Ketamine + Midazolam Combinations of propofol + fentanyl, fentanyl + midazolam etc lead to synergistic effects on the cardiovascular system. This results in greater than expected amounts of hypotension, which is tolerated in the young health individual, but may be problematic in someone with less reserve. Midazolam may decrease the rate of ketamine metabolism, resulting in greater duration of sedation.

How low should you go? Depth of Procedural Sedation Minimal Sedation (Anxiolysis) Moderate Sedation/Analgesia Deep Sedation/Analgesia General Anaesthesia Normal LOC ASA/Joint Commission of Accreditation of Healthcare Organizations – Definitions of Levels of Sedation Minimal sedation: normal response to verbal commands. Ventillatory & CV function unaffected. Moderate sedation: pt responds to verbal commons +/- light tactile stimulus. No interventions required to maintain airway. Spont resp. CV function maintained. Deep sedation: pt cannot be aroused, but responds purposefully to repeated or painful stimulation. May require assistance maintaining a patent airway. Spont vent may be inadequate. General anaesthesia: Pt is unarousable. Patient typically requires assistance maintaining an airway +/- PPV.

Guidelines for Monitoring “Frequent” monitoring of BP, HR & RR Continuous O2 sat monitoring “Frequent” assessment of level of responsiveness Continue monitoring until the patient is fully awake.

Local & Regional Anaesthesia Trend towards less analgesia and compromise of reduction in patients receiving a hematoma block versus intravenous regional anesthesia. Insufficient evidence to draw conclusions re other combinations (IV vs regional, etc.) HHG Handoll, R Madhok & C Dodds. “Anaesthesia for treating distal radial fractures in adults.” Cochrane Database of Systemic Reviews. Issue 3. July 2002.

Questions?

Key Points Be prepared Know your drugs and your drug interactions Consider all your options

Other References Guidelines Godwin SA, Caro DA, Wolf SJ, Jagoda AS, Charles R, Marett, BE and Moore J. Clinical policy: procedural sedation and analgesia in the emergency department. Annals of Emergency Medicine. 45:2. February 2005; pp 177-196. Innes G, Murphy M, Nijessen-Jordan C, Ducharme J and Drummond A. Procedural sedation and analgesia in the emergency department. Canadian consensus guidelines. The Journal of Emergency Medicine. 17:1. January 1999; pp 145 – 156. Textbooks Miller RD. Miller’s Anesthesia, 6th Ed. 2005 Marx JA. Rosen’s Emergency Medicine, 5th Ed. 2002. Roberts JR. Clinical Procedures in Emergency Medicine, 4th Ed. 2004 Tintinalli JE. Emergency Medicine: A Comprehensive Study Guide, 6th Ed. 2004

Other References Journal Articles Syminton L and Thakore S. A review of the use of propofol for procedural sedation in the emergency department. Emergency Medicine Journal. 2006:23. 89-93. Green SM and Krauss B. Propofol in emergency medicine: pushing the sedation frontier. Annals of Emergency Medicine. 2003:42. 792-797. Bahn EL and Holt KR. Procedural sedation and analgesia: a review and new concepts. Emergency Medicine Clinics of North America. 2005:23. 503-517. Green SM. Fasting is a consideration – not a necessity – for emergency department procedural sedation and analgesia. Annals of Emergency Medicine. 2003:42. 647-650. Green SM and Sherwin TS. Incidence and severity of recovery agitation after ketamine sedation in young adults. American Journal of Emergency Medicine. 2005:23. 142-144. Green SM and Li J. Ketamine in adults: what emergency physicians need to know about patient selection and emergency reactions. Academic Emergency Medicine. 2000:7(3). 278-280