Aim: This study aimed to determine the sensitivity and specificity of various anatomic measurements, alone or in combination, in predicting difficult intubation. We hypothesized that goniomastoid distance (GMD), thyrogonial distance (TGD), and tongue movements are sensitive and specific tests for predicting difficult intubation.
Methods: We included the data of 170 patients (85 difficult intubations and 85 easy intubations) who underwent an abdominal surgery under general anesthesia. The groups of patients with difficult intubation (n=85) and easy intubation (n=85) were matched by age, BMI, and gender. Intubation difficulty scale (IDS) scores were recorded. Upward and downward maximal protrusions of tongue (UMPT and DMPT, respectively), as the tongue moves, were evaluated in all patients. Anthropometric measurements, including GMD, TGD, and IID were measured.
Results: Among the GMD, IID, TGD, interincisal distance, UMPT, DMPT, and their combinations, the GMD had the highest area under the curve (AUC) (AUC=1.0; p<0.001) and predictive values (sensitivity=100%, specificity=100%, PPV=100%, and NPV=100%), with a cut-off value of 53 mm in the classification of difficult intubation. IID achieved the second highest AUC (AUC=0.924; p<0.001) and predictive values (sensitivity=88.24%, specificity=96.47%, PPV=96.1%, and NPV=89.1%). Difficult intubation risk in patients whose UMPT level did not reach the target line was 5.6 times higher, and for those whose DMPT level did not reach the target line, it was 4.9 times higher.
Conclusion: GMD is the most powerful test when compared to the other predictive tests. Thus, it may be used in clinical practice for prediction of difficult intubation.
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