Chapter 85: Approaches to Difficult Airway Management

INTRODUCTION

Analysis of the American Society of Anesthesiologists (ASA) Closed Claims database (1985–1992) focusing on management of difficult airway, in part, led to development of the ASA Difficult Airway Algorithm in 1993. Subsequently, death and brain damage claims resulting from difficult airway management on induction of anesthesia decreased. In contrast, claims associated with the other phases of anesthesia (maintenance, emergence, and recovery) did not change. Over the years, many techniques have been developed to manage a difficult airway. Each technique has been proven valuable. However, anatomy and disease state of an individual patient and the clinical judgment and experience of the operator influence the technique applied to each patient.

Managing a patient with a known or suspected difficult airway has, as its central goal, to avoid major complications, including, but not limited to injury to airway structures, hypoxic brain injury, cardiopulmonary arrest, unnecessary tracheostomy, or death. To this end, securing the airway while the patient is awake and breathing spontaneously may be indicated or necessary.

INDUCTION

Airway Avoidance

This technique involves the exclusive use of regional or neuraxial anesthesia, avoiding the use of apnea-inducing sedatives or protective airway reflex compromise. While this technique poses the risks of incomplete block, local anesthetic systemic toxicity, and patient anxiety, it effectively achieves the goal of anesthesia while maintaining a patent airway. Before attempting, practitioners should consider regional anesthetic contraindications, patient anxiety level, duration, and anatomic extent of the surgery relative to the duration and anatomic distribution of the block and intraoperative airway access.

Laryngeal Mask Airway

Laryngeal mask airway (LMA) is an inflatable, supraglottic device that overlies the laryngeal inlet and seals the hypopharynx, allowing for delivery of positive pressure (up to 20 cm H₂O). Since it overlies the larynx, an LMA serves as a conduit through which an endotracheal tube (ETT) can be passed (either blindly or fiberoptically) into the trachea. As there is no subglottic cuff, LMAs do not provide definitive airway protection from aspiration.

Flexible Fiberoptic Intubation

This technique uses a fiberoptic bronchoscope (FOB) as a visually guided stylet over which an ETT is directed into the trachea. This technique can be administered nasally or orally when the patient is asleep or awake. Supplemental oxygen, either via a nasal cannula or through the bronchoscope itself, maintains oxygenation during intubation. If performed with anesthetized patient, jaw-thrust or gentle anterior traction on the tongue opens the pharynx, raises the epiglottis, and aids in glottic opening visualization.

If attempted in an awake patient, psychological and anesthetic (topically and/or airway nerve blocks) preparation is necessary. Psychological preparation of the patient begins with an explanation of what is to occur and why. While physical preparation includes the judicious use of anxiolytics (while maintaining airway protective reflexes and spontaneous ventilation). Anti-sialagogue ...