Incidence and diagnostic validity of difficult airway in emergency departments in China: a cross-sectional survey.

Background: The difficult airway is a topic of concern for any physician performing intubation. Severe adverse events which can happen because of an unexpected difficult airway emphasize the importance of prediction. This study aimed to investigate the incidence of difficult airways in emergency departments in mainland China and ascertain the predictive value of common assessment formulas. Methods: This study was a multicentral, cross-sectional investigation of patients intubated in emergency departments in mainland China between March 1-30, 2021. Frequencies and percentages were calculated for patient characteristics. Diagnostic values were analyzed by sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, the area under the curve, and corresponding P values. Results: Nine hundred and eighty-five patients in 41 hospitals were enrolled in the study. Elderly male patients occupied most of the intubated patients. The difficult face mask ventilation rate (8.2%) was higher, but the difficult glottic exposure (6.8%) and intubation (2.1%) rates were low, while there was widespread use of enhanced visualization equipment (80.6%). Four combined emergency applicable evaluation methods showed a certain predictive value for the difficult airway with a sensitivity [0.71; 95% confidence interval (CI): 0.47-0.89], specificity (0.79; 95% CI: 0.76-0.81), and the area under the curve (0.75; 95% CI: 0.64-0.87, P<0.01). Conclusions: Despite an insufficient predictive ability for current difficult airway evaluation methods, there were relatively low rates of difficult airways during ED intubations in mainland China. Continuing focus on the difficult airway problems and optimizing airway assessment are required.