CHAPTER 2: The Airway Management Algorithms

INTRODUCTION

What Is the Challenge of Difficult and Failed Airway Management?

Competency in airway management is fundamental to the practice of anesthesia, emergency medicine, emergency medical services (EMS), critical care medicine, hospital medicine, and other acute care specialties. The airway practitioner is faced with two particular challenges: to be able to accurately and expeditiously predict a difficult airway, and to be able to recognize when airway management has failed.¹ No matter the situation, reliably and reproducibly ensuring timely and effective oxygenation and ventilation is imperative. Appropriate planning, selection of the airway devices and techniques, clear communication of that plan, and calm execution based on learned methods and experience enhances success even in the most difficult cases. The need for clearly communicated Plan A (first line or initial plan), B (backup or salvage plan), and C (failed airway plan) cannot be overemphasized.

How Reliably Can We Predict a Difficult Airway?

There are several means through which effective ventilation occurs: spontaneous ventilation by the patient, or positive pressure ventilation provided through face-mask ventilation (FMV), extraglottic device (EGD), tracheal intubation, or surgical (front-of-neck) airway. The latter four of these are artificial or non-natural interventions, or methods of active airway management. If a patient is unable to sustain adequate spontaneous gas exchange, or if during therapy the patient’s ability to maintain adequate gas exchange is compromised or eliminated (e.g., due to the use of medications), one of these four methods must be employed successfully to assure survival. They constitute the four dimensions of airway management. Hence, before embarking on airway management, the patient should be assessed for predictors of the following:

• Difficult FMV

• Difficult laryngoscopy and tracheal intubation (e.g., using direct laryngoscopy [DL] or video laryngoscopy [VL])

• Difficult EGD use

• Difficult front-of-neck airway (FONA)

Ordinarily, FMV and orotracheal intubation are the usual methods employed in managing the airway of patients unable to adequately breathe for themselves. If a difficult airway is anticipated, and it is not to be managed “awake,” EGDs and FONA techniques are usually considered rescue options. Importantly, rescue techniques should not be considered de facto evidence of “failure” when they are part of the airway management plan, a fundamental concept advanced in this text. Techniques under consideration as first-line or rescue depend in large part on the context of the situation, including the indication for airway management, the condition of the patient, the skill of the practitioner, the availability of skilled assistance, the location and equipment available, and the time of day (see Chapter 7).

In elective situations, difficulty with FMV is uncommon. Langeron was the first to address codifying “difficult mask ventilation” (DMV) by prospectively reviewing the management of 1502 patients undergoing elective surgery under general anesthesia.² DMV was defined as:

1. An inability to maintain SpO₂ greater than 92% while using 100% O_...