Assessing the Empirical Predictive Value of the ASA-Recommended Difficult Airway Predicting Factors

Srija Konduru, M2; Marilly Palettas, MPH; David Yablok, MD, Ling-Qun Hu, MD

Introduction: Predicting difficult airways has been a critical topic since the introduction of the Three Axis Alignment Theory in 1944 [1]. Still, an evidence-based method with high sensitivity and specificity for predicting difficult airways is needed. Additionally, the recommended risk factors for difficult airways by the American Society of Anesthesiologists (ASA) have either been defined subjectively, lack robust evidence, or both [2]. We undertook this study with the hypothesis that there is insufficient empirical support for predicting difficult airways based on the ASA-recommended factors. This prospective cohort observational study aimed to identify objective risk factors for difficult airways. Difficult airways in the study were categorized as:

1. Difficult laryngoscopy: Inability to visualize vocal cords, Modified Cormack-Lehane Grades ≥ 2b.

2. Difficult intubation: Intubation Difficulty Scales (IDS) ≥ 5.