Difficult Airway Management

Definition and Classification

A difficult airway is defined as a clinical situation in which a physician trained in anesthesia care experiences anticipated or unanticipated difficulty or failure with face-mask ventilation, laryngoscopy, ventilation using a supraglottic airway, tracheal intubation, extubation, or invasive airway, according to the American Society of Anesthesiologists (ASA) 1
Difficult laryngoscopy is defined as inability to visualize any portion of the vocal cords after multiple attempts at laryngoscopy, as stated by the ASA 1, 3
The Cormack & Lehane classification is used to grade difficult laryngoscopy, with grade 3 being subdivided into 3a (epiglottis can be lifted) and 3b (epiglottis cannot be lifted from the posterior pharyngeal wall), as described by the Anaesthesia society 4

Absent or inadequate exhaled carbon dioxide is a sign of inadequate ventilation, as indicated by the ASA 2
Absent or inadequate chest movement is a sign of inadequate ventilation, as indicated by the ASA 2
Decreasing or inadequate oxygen saturation is a sign of inadequate ventilation, as indicated by the ASA 2
Changed mental status or somnolence can be a sign of inadequate ventilation, as stated by the ASA 1, 3

The definitions of difficult airway apply to all airway management and anesthetic care delivered in ambulatory settings, such as surgery centers and office-based procedures, as stated by the ASA 5, 7
The guidelines are intended for use by anesthesiologists and all others who perform anesthesia care or airway management, as stated by the ASA 7

Management of difficult airways should follow a structured algorithm with Plans A through D, as outlined by airway management societies, including the Anaesthesia society 4, 8, 9
Each plan should be implemented sequentially based on the outcome of the previous plan, as described by the Anaesthesia society 4