Background: Difficult intubation is a common problem. The Perioperative and Anesthetic Adverse Events in Thailand (PAAd Thai) Study was performed in 22 hospitals across Thailand in 2015 to investigate incidence of anesthesia related adverse events including the difficult intubation events.

Objective: To evaluate the difficult intubation events in terms of prediction, management, complications, contributing factors, and corrective strategies, and compare the management of the unanticipated (UDI) and anticipated difficult intubation (ADI).

Materials and Methods: The multicenter-observational study was prospectively performed. The research on difficult intubation was obtained using data from the first 2,000 events of the study. There were 115 difficult intubation events. The described details of each report on management of difficult intubation and outcomes were reviewed by two anesthesiologists. The opinions on causative factors, contributing preventive factors, and strategies for correction were agreed by three reviewers.

Results: Sixty-nine and forty-six cases were indicated as UDI and ADI, respectively. Almost all of the patients in UDI group were successfully intubated under general anesthesia (95.7%) by switching of intubators (67.7%), using stylet (20%), and/or using different laryngoscopic blades (50.7%). The most successful blade in UDI was the direct laryngoscopic blade. The main rescue blade after failed direct laryngoscopy was the videolaryngoscopic blade. Most of the ADI were successfully intubated by using the videolaryngoscopic blade. Immediate complications were not significantly different. Cardiac arrest was found only in the immediate postoperative period. The contributing factors included inadequate experience, inappropriate decision, and inadequate airway evaluation.

Conclusion: Most of the UDI and ADI were successfully intubated by using conventional technique and videolaryngoscope, respectively. The immediate adverse effects were not significantly different. Proper preparation, additional training, and presence of experienced anesthesia personnel would decrease the incidences and improve anesthetic outcomes.

Keywords: Anticipated difficult intubation, Unanticipated difficult intubation, Complication, Adverse events, Anesthesia