2. Department of Anesthesiology, University of Rochester Medical Center 601 Elmwood Ave, Rochester, New York, USA.
3. Division of Clinical and Translational Sciences, Department of Internal Medicine University of Texas Health Science Center at Houston 6410 Fannin Street, Houston, Texas, USA.
4. Department of Anesthesiology, Maastricht University Medical Centre, 6202 AZ Maastricht Maastricht, The Netherlands.
Background: Airway management, including proper airway devices sizing, is dependent on airway features, which ultimately should correlate with body features: unfortunately such correlation has been inconsistent. The aim of this study was to determine the correlation of normal values of several external neck landmark (airway features) measurements with with age, gender, height and weight (body features) for normal weight adult subjects to establish a consistent correlation.
Methods: After IRB approval, 200 subjects (100 male and 100 female) were enrolled. External neck landmarks were measured using a measuring tape. Measurements were also assessed by digital caliper to compare marginal errors. Only non-obese (BMI≤30 kg/m2) adults presenting for preoperative anesthesia assessment were screened.
Results: A total of 200 subjects completed the study. The difference between female and male hyocricoid distance (6.0±1.3 cm and 6.5±1.4 cm; P<0.01) and thyroid width (4.9±0.8 cm and 5.3±0.7 cm; P<0.001) was statistically significant. Univariate regression analysis demonstrated ENLs measurements were correlated with different physical characteristics except the occipital distance which did not provide any correlation with the airway anatomical variables.
Conclusion: There was a significant correlation between: thyromental, hyoidcricoid and thyroid width distances with height and weight (P≤0.0001); thyroid height and thyrocricoid distances with height (P=0.027 and P=0.008, respectively); hyoidmental with age (P=0.037), and sternomental distance with height and age (P<0.0001). Results from multivariate regression provided interesting insight into the association between each ENL, airway features and physical characteristics. These findings may be useful to determine prediction models of important neck landmarks measurements when actual measurements are not feasible.
Keywords: Airway management, external neck landmark, anatomy, supraglottic airway device