Ultrasonography relative to Cormack-Lehane in predicting difficult laryngoscopy: a systematic review of diagnostic test accuracy.

OBJECTIVE The objective of this review is to determine the diagnostic test accuracy of point-of-care ultrasound anterior soft tissue quantification techniques for predicting difficult laryngoscopy in relation to Cormack-Lehane scores. INTRODUCTION Difficult airway management is a critical challenge for anesthesia providers, and a non-invasive test to confidently predict difficult airway is lacking. When difficult airway is not anticipated, the provider's management of the event deteriorates, resulting in significant morbidity or mortality. This systematic review of the diagnostic efficacy of newer ultrasound techniques has potential to advance difficult airway prediction and patient safety. INCLUSION CRITERIA This review will consider human subjects 18 years and older presenting for elective surgery, who undergo a preoperative point-of-care ultrasound anterior soft tissue airway exam that is referenced to an intraoperative Cormack-Lehane airway exam, obtained using direct laryngoscopy under general anesthesia. METHODS Data sources will include Ovid MEDLINE, Trip Database, EMBASE, CINAHL Complete, Clinicaltrials.gov, Google Scholar, MedNar, Grey Literature Report, and ProQuest Dissertations. Only studies published in English after the advent of the Cormack-Lehane reference test (1984) will be included. Studies will be critically appraised using a checklist for studies of diagnostic test accuracy. Details about the index tests, populations, study methods, and outcomes of significance to the review will be extracted. Where possible, sensitivity and specificity will be pooled in statistical bivariate meta-analysis. Diagnostic thresholds will be displayed on a paired forest plot or summary receiver operator characteristic curve, depending on the degree of variability. SYSTEMATIC REVIEW REGISTRATION NUMBER Registration completed August 28, 2020; registration number pending.