Journal: Can J Anesth 54(9):748-764, 2007. 119 References
Reprint: Dept of Anesthesiology, The Ottawa Hospital – Civic Campus, 1053 Carling Avenue, Ottawa, Ontario K1Y 4E9, Canada (DT Neilipovitz, MD, FRCPC)
Faculty Disclosure: Abstracted by S. Ouellette, who has nothing to disclose.
Aspiration of gastric contents is an uncommon complication of emergency airway management. The recommended approach to prevent aspiration and other complications during emergency airway management is the use of a rapid sequence induction (RSI) technique. The purpose of this structured, evidenced based, clinical update was to determine if RSI is a safe or effective technique to decrease the risk of aspiration or other complications of airway management.
A structured survey of MEDLINE from 1966 to present using OVID software was undertaken. A total of 184 clinical trials were identified, of which 163 were randomized controlled trials (RCTs). Of these, 126 evaluated different drug regimens with 114 being RCTs. Only 21 clinical trials evaluated non-pharmacologic aspects of the RSI with 18 RCTs identified. A parallel search found 52 trials evaluating cricoid pressure with 44 classified as RCTs. Conclusions were drawn from these studies.
The question of when to use or not use RSI could not be definitely answered from a review of the literature. Intuitively, patients at moderate to high risk for aspiration should be considered for RSI technique. It should be avoided if there are concerns about the ability to successfully ventilate the lungs or intubate the trachea. The use of induction drugs, and particularly neuromuscular blocking drugs, improves the success of tube placement during RSI. Since hypotension is the most common complication after RSI, the decision to employ rapid administration of induction drugs should be carefully considered. In some patients, incremental drug administration is preferred despite an increased incidence of aspiration. The use of RSI as a rescue airway management strategy in the setting of failed intubation from other airway management techniques cannot be supported by existing evidence.
Adequate preoxygenation is most rapidly achieved by tidal volume ventilation for at least 3 min or 8 deep breaths using fresh gas flow of 5 L min. The routine practice of rapid administration of drugs is not recommended except in situations when the risk of aspiration is exceptionally high. There is not a single induction agent for all situations. Etomidate is preferable for non-septic hypotensive patients and those with limited cardiac reserve requiring RSI. Propofol is the preferred induction drug when a nondepolarizing NMBD is used. The NMBD of choice is succinylcholine, at a dose of at least 0.6 mg/kg. Rocuronium, at a dose ≥ 0.6 mg/kg, is the best alternative to succinylcholine for RSI and the use of propofol should be considered if rocuronium is to be used.
Evidence supporting the use of esmolol and short-acting opioids in RSI is incomplete and prevents strong affirmative recommendations. The best available evidence does not support a role for lidocaine as an adjuvant drug for RSI. Due to the low risk but potential benefit, cricoid pressure (CP) would appear to be a benign practice and it continues to be recommended. Reduction of applied pressures during CP or its release if deemed to be interfering with airway management is acceptable. The routine practice of avoiding mask-bag ventilation after the induction of anesthesia to decrease the incidence of aspiration is not recommended. Bag-mask ventilation with airway pressures below 15-20 cm H2O during ventilation allows for oxygenation without increasing the risk of gastric air entry and is recommended.
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