Mosier J et al. West J Emerg Med. 2015;16(7):1109-1117
"Airway management in critically ill patients involves the identification and management of the potentially difficult airway in order to avoid untoward complications. This focus on difficult airway management has traditionally referred to identifying anatomic characteristics of the patient that make either visualizing the glottic opening or placement of the tracheal tube through the vocal cords difficult. This paper will describe the physiologically difficult airway, in which physiologic derangements of the patient increase the risk of cardiovascular collapse from airway management. The four physiologically difficult airways described include hypoxemia, hypotension, severe metabolic acidosis, and right ventricular failure. The emergency physician should account for these physiologic derangements with airway management in critically ill patients regardless of the predicted anatomic difficulty of the intubation.
The difficult airway is well recognized as a clinical entity and is classically based on anatomic considerations. In this paper we describe another aspect of the difficult airway that involves physiologic abnormalities that must be considered in developing an intubation plan. These physiologic abnormalities must be considered and addressed prior to intubation. If they are not, significant untoward outcomes can result. We present four physiologic disturbances that must be considered carefully when planning for and performing tracheal intubation in the ED to avoid complications from the very procedure intended to be life saving. Many of the recommendations presented are based on clinical experience and physiologic principles and thus represent opportunities for formal investigation."