Evaluation of intubation success by critical care physicians using different videolaryngoscopes

Background: Airway management and early successful intubation in emergency situations plays a crucial role in patient outcome. Direct laryngoscopy using the Macintosh laryngoscope is the most widely used technique. However, this is acknowledged to be a difficult skill for occasional users to master. Thus, an easy teaching method would be beneficial. Videolaryngoscopes have demonstrated benefits for the novice or infrequent laryngoscopist [1]. The channeled and non-channeled video-laryngoscopes seem to provide an easier learning curve [2]. We sought to evaluate four devices: The Airtraq®, the Pentax® AWS, the GlideScope®, and the McGrath® videolaryngoscopes to discover which one provides the most success in the hands of non-frequently intubating physicians in the simulator setting and in the operating room. Methods: The Investigational Review Board approved the study and the subjects were 17 Critical Care physicians in fellowship training. The subjects underwent a structured educational process which included: 1) a didactic lecture on direct and videolaryngoscopy, and 2) hands-on training with each device on easy and difficult airway simulators. Three to six days later the subjects came to the operating room where they were allowed to intubate four individual patients using each respective device. Patients were screened to include only Mallampati Class 1-2 with an inter-incisor gap of greater than 4 cm and no symptoms of gastric reflux. Under the supervision of an attending anesthesiologist the following parameters were measured in the anesthetized patients: duration of tracheal intubation, attempts and the rate of successful ETT placement, number of intubation attempts, the number of optimization maneuvers required to aid tracheal intubation and the objective and subjective views of the larynx. Results: No patients suffered airway injury during the operating room portion of the study and all patients were successfully intubated. The collected data were analyzed by independent specialists: age, gender, and BMI did not appear to be confounders in the results. There were no statistically significant differences in the overall time to intubation among the 4 devices (using chi-square and Fisher's Exact test). Overall, the channeled devices were associated with a greater number of intubation attempts and longer intubation times compared to the non-channeled devices (Table 1). The intubation times and number of attempts differed in the simulator portion of the study compared to the OR portion, with little difference between the devices. Discussion: Video-laryngoscopy is the latest in an expanding array of airway devices for difficult and failed intubation. While this study did not compare videolaryngoscopes with direct laryngoscopy, it demonstrated the ease and usefulness of the devices in the hands of infrequent laryngoscopists to achieve intubation. The difference in intubation times and success in simulator training compared to anesthetized patients was an incidental finding that is important for determining the overall clinical benefit of the device.