A recent editorial and a letter to the editors of Anaesthesia challenge the usefulness, safety and validity of the teaching that one should “prove the ability to ventilate by mask before giving a muscle relaxant”. Both authors claim that the opposite may occur; that the act of trying to ventilate a lightly anesthetized patient by mask may actually create the airway obstruction and that NMBs are probably a better rescue approach for not being able to ventilate than hoping the patient will resume spontaneous ventilation. Refs: Calder I: Could “safe practice” be compromising safe practice? Should anaesthetists have to demonstrate that face mask ventilation is possible before giving a neuromuscular blocker? Anaesthesia 2008;63:113-115; Priebe HJ: Could “safe practice” be compromising safe practice? Should anaesthetists have to demonstrate that face mask ventilation is possible before giving a neuromuscular blocker (letter)? Anaesthesia 2008;63:671-672.
Dr. Levy a senior faculty member at the University of Pennsylvania rebuts as follows: “the assumption by both the editorial and the letter to the editor is that the inability to ventilate the patient will not result in a change in clinical approach and that, in most cases, the administration of a neuromuscular blocking drug will occur anyway. What the authors failed to consider is that, based on the ability (or inability) to ventilate, the selected neuromuscular blocking drug may change. For example, instead of giving vecuronium, one might opt to use succinylcholine for more rapid onset. Even if face mask ventilation were successful, one might elect a more rapidly acting agent if there were considerable difficulty in obtaining air exchange. Although this does not invalidate the arguments presented, it does suggest that more complete consideration of the process might lead to different conclusions than those presented.”
Warren Levy, M.D., is Associate Professor of Anesthesiology and Critical Care at the University of Pennsylvania
David S. Smith, M.D., Ph.D.