Which test best predicts difficult endotracheal intubation? A prospective cohort study

BACKGROUND: It is critical to identify patients whose intubation will be difficult to ensure that necessary precautions are taken. In this study, we aimed to show the power of almost all tests used to predict difficult endotracheal intubation (DEI), and to determine which test are more accurate for this purpose. METHODS: This observational study conducted between May 2015 and January 2016 at department of anesthesiology of a tertiary hospital in Turkey (n=501). A total of 25 parameters and 22 tests used for DEI were compared according to groups formed according to the Cormack-Lehane classification (gold standard). RESULTS: The mean age was 49.83±14.00 years, and 259 (51.70%) patients were males. We found difficult intubation frequency to be 7.58%. Mallampati classification, atlanto-occipital joint movement test (AOJMT), upper lip bite test, mandibulohyoid distance (MHD), maxillopharyngeal angle, height-to-thyromental distance ratio, and mask ventilation test were independently associated with difficult intubation. CONCLUSION: Despite comparing 22 tests, the results obtained in this study cannot definitively identify any single test that predicts difficult intubation. Nonetheless, our results show that MHD (high sensitivity and negative predictive value) and AOJMT (high specificity and positive predictive value) are the most useful tests to predict difficult intubation.