Failure to evaluate the airway and predict difficulty is the single most important factor leading to a failed airway.1,2
The Difficult Airway is something you anticipate; the Failed Airway is something you experience. (Walls, 2002)
“Airway management” may be defined as the application of therapeutic interventions that are intended to effect gas exchange, namely oxygenation and the removal of carbon dioxide, and to protect the airway from aspiration in patients who are unable to do it for themselves. Gas exchange is fundamental to this definition.3 A number of devices and techniques are commonly employed in health care settings to achieve this goal. These include the use of face-mask ventilation (FMV), extraglottic airway devices (EGDs), oral or nasal endotracheal intubation (ETI), and invasive or front-of-neck airway (FONA) techniques.
The failure to adequately manage the airway has been identified as a major factor leading to poor outcomes in anesthesia, critical care, emergency medicine, hospital medicine, and emergency medical services (EMS). Adverse respiratory events constituted the largest single cause of injury in the 1991 American Society of Anesthesiologists (ASA) Closed Claims Project.2 These medical legal actions have persisted over 30 years despite major advances in the identification and management of the difficult airway, the failed airway, inadvertent esophageal intubation, and improvement in airway management devices.4
The 4th National Audit Project (NAP4) conducted in the United Kingdom over a 1-year period of time identified major airway management complications in the operating rooms (ORs), intensive care units (ICUs), and emergency departments (EDs) leading to death, brain damage, emergency FONA, or unexpected ICU admission.5,6 NAP4 reinforced the findings of the National Reporting and Learning System in the United Kingdom that found 18% of 1085 airway management complications in ICU over a 2-year period (2005-2007) were directly related to the act of intubation.7
The following narrative will discuss what is new or has changed in the evaluation of the airway prior to airway intervention since the last edition of this textbook.
RECENT INSIGHTS IN ASSESSING THE DIFFICULT AIRWAY
What Are the Dimensions of Difficult Airway?
The Value of Anatomic Predictors Redefined
The first ASA Guidelines for the Management of the Difficult Airway was published almost 30 years ago.1 In the ASA Closed Claims Analysis conducted 12 years later, Peterson et al.8 reported that there is evidence to suggest that the incidence of airway management failure could be minimized, or perhaps eliminated, by a prior airway examination to identify anatomic predictors of difficulty.
However, a large Danish study (188,064 patients) evaluated the diagnostic accuracy of predicting difficult airway management in everyday anesthetic practice.9 The investigators found that when difficult FMV was predicted based on the preoperative evaluation it was actually difficult in only 22% of ...