Comparison of predictive capability of different methods for difficult laryngoscopy / 临床麻醉学杂志

ABSTRACT

Objective To explore the predictive capability of different methods for difficult la-ryngoscopy and analyze its optimal cutoff value.Methods Three hundred consecutive patients (aged 18-65 years,weighing 42-88 kg,ASA physical status Ⅰ or Ⅱ)scheduled to undergo general anesthe-sia and surgery were invited to participate.Difficult airway assessments were performed by thyromen-tal height (TMH),thyromental distance (TMD),sternomental distance (SMD),modified Mallam-pati test (MMT)and ratio of height and TMD (RHTMD)before anesthetic induction.Cormack-Le-hane (C-L)grade of laryngoscopy view was assessed after induction.Sensitivity,specificity,positive predictive value (PPV),negative predictive value (NPV)and accuracy of these tests were calculated. Receiver operator characteristic (ROC)curve of TMH was performed to determine the optimal cutoff value of TMH.Results There were 22 patients diagnosed as difficult airway.Sensitivity,specificity, PPV,NPV and accuracy of TMH were higher than those of TMD,SMD and MMT tests.Sensitivity of RHTMD was lower than that of TMH test,and specificity,PPV,NPV and accuracy of RHTMD were similar to that of TMH.The optimal cutoff value of TMH was 4.9 cm through ROC curve. Conclusion The optimal cutoff value of TMH detecting difficult laryngoscopy was 4.9 cm.Similar to RHTMD,TMH appears to be more effective for prediction of difficult laryngoscopy than TMD, SMD and MMT.