A predictive test for difficult intubation in laryngeal microsurgery. Validation study

Abstract Background In 2003 a simple test to detect difficult intubation (DI) in patients underwent laryngeal microsurgery was described. The present study was conducted to validate the test. Methods Patients with laryngeal disease scheduled for laryngeal microsurgery were included. The variables evaluated were eleven parameters: Mallampati Score ≥ III, thyromental distance  iii – iv and/or if auxiliary equipment was required to achieve orotracheal intubation. A comparison of ROC curves was conducted to estimate the best predicting cut-off, as well as differences between the index described in 2003 and the rapid assessment by an expert anaesthesiologist. Results One hundred and five patients were included in the study. The incidence of DI according to the predefined criteria was 45% (47 patients). The score at the cut-off of 5 provides a sensitivity of 89% and a specificity of 55%. The fast-evaluation by an expert anaesthesiologist obtained similar sensitivity (89%) and better specificity (81%). Area under curve (AUC) was 0.87, similar to a fast evaluation (AUC: 0.85; P  = .71). Conclusion The index was validated at a cut-off of ≥5, being a useful and reliable test to predict DI in patients with laryngeal diseases and it is a useful tool for anaesthesiologists with conventional training.