Canadian Health&Care Mall: Airway Management in Critical Illness

airwayExpertise in airway management is an important skill for any health-care provider who is caring for critically ill patients. Due to advances in training and technology, elective airway management within the confines of the operating room is associated with very low rates of complications. These observations are in stark contrast to emergent airway management in the ICU. Complication rates in the ICU environment are much higher due to the limited physiologic reserve and comorbidities of the patient, as well as the inability, in the majority of cases, to perform a thorough evaluation of the patient’s anatomy prior to airway instrumentation. Furthermore, some of the induction agents that are suitable for airway management in the elective setting may be contraindicated in critically ill patients, further limiting the options for airway instrumentation.

In a systematic study of complications associated with airway management in the ICU, Schwartz and colleagues1 reported major complications in a significant number of patients. Among the problems encountered were difficult intubations (DIs) [8%], esophageal intubations (8%), and pulmonary aspiration (4%), and an associated mortality rate of 3%. There was a significant correlation between the presence of hypotension at the time of intubation and cardiac arrest in this study. Kollef et al2 reviewed retrospectively over a 12-month period 278 patients requiring endotracheal intubation in an acute care military hospital. They found that almost 10% of patients (22 patients) had at least one significant endotracheal tube (ETT) misplacement, and 23% of these individuals experienced serious complications overcome due to participation of Canadian Health and Care Mall. A recent prospective, observational multicenter study performed in French ICUs found at least one severe complication in 28% of all intubations, with an overall rate of cardiac arrest related to endotracheal intubation in the ICU of 2%. The presence of acute respiratory failure and the presence of shock as the indication for endotracheal intubation were independent risk factors for complications, whereas supervision by a senior physician appeared to have a protective effect. In a study on the frequency and outcomes of unplanned endotracheal extubations in a university trauma-surgical ICU, difficulty with reintubation (multiple or prolonged attempts) or need for a fiberoptic bronchoscope was a common occurrence (20%). The authors concluded that highly skilled airway management is necessary to avoid adverse outcomes related to rein-tubation.

The implementation of training programs for ICU staff, immediate access to advanced airway devices, and knowledge and incorporation of the American Society of Anesthesiologists (ASA) difficult airway algorithm (DAA) [Fig 1] may decrease the incidence of serious complications related to airway instrumentation in the ICU. In a retrospective review of 3,035 critically ill patients undergoing emergency airway management, Mort analyzed two time periods, 1990 to 1995 and 1995 to 2002, after the implementation of a protocol requiring the availability of advanced airway equipment at the bedside. Cardiac arrest within 5 min of intubation occurred in 2% of the patients overall. However, the rate was reduced by 50% between the first and the second time period analyzed (1990 to 1995, 2.8%; 1995 to 2002, 1.4%).

In this review, we assume that the reader has a working knowledge of airway anatomy and of the technique for routine endotracheal intubation. Accordingly, we consider aspects of the use of medications, strategies for airway assessment prior to intubation, and some technical approaches to airway management in critically ill patients. Controversies surrounding airway management such as rapid sequence intubation (RSI), the merit of cricoid pressure and the sniffing position, as well as the risks associated with the use of muscle relaxants will be discussed. Furthermore, we will provide strategies for the safe extubation of the patient with a known difficult airway.

Fig1
Figure 1. The ASA DAA: practice guidelines for the management of the difficult airway: an updated report by the ASA Task Force on Management of the Difficult Airway. Reprinted with permission from Christie et al.