Reply: Did Video Kill the Direct Laryngoscopy Star? Not Yet!

We read with interest “Difficult Airway Characteristics Associated with First Attempt Failure at Intubation Using Video Laryngoscopy in the Intensive Care Unit” (1). In that article, Joshi and colleagues assessed determinants of unsuccessful efforts by physicians in training to perform orotracheal intubation, using predominantly combined video and direct laryngoscopy devices (C-MAC; Karl Storz, Tuttlingen, Germany). After each intubation, the operators completed a data collection form, allowing the authors to analyze factors associated with failure of first-pass placement of an endotracheal tube. They identified several factors that contributed to first-pass failure; notably, blood in the airway, cervical immobility, airway edema, and obesity. The study by Joshi and coauthors adds to the existing literature in several ways, including the use of a nonanesthesia house staff intubating cohort, data on video-assisted intubations, trainee performance using combined video and direct laryngoscopy equipment, and the pinpointing of possible impediments to successful intubation. However, there are several items that require further clarification. First, the standard approach employed in this study when trainees used a device with both direct and indirect capabilities, such as the Storz C-MAC or GlideScope Direct Intubation Trainer (Verathon, Bothell, WA), is of clinical consequence. If glottis visualization was obscured, did the residents and fellows perform primarily direct laryngoscopy with a video “rescue,” or did they use primarily an indirect approach with a direct laryngoscopy rescue? The reason why blood in the airway caused failure is also of interest. Were these failures primarily a result of inability to visualize the larynx with the video device, or primarily a failure of an effort that combined direct and indirect laryngoscopy? In addition, it would be helpful to disclose details regarding bougie/introducer devices or laryngeal manipulation techniques in patients for whom a view was not possible using a video approach (assuming a nonhyperangulated blade was used). Second, the influence of the supervising physician is relevant, regarding the success of the procedures. Two recent investigations comparing success rates of direct-to-video laryngoscopy attempted by pulmonary and critical care fellows included immediate attending feedback and coaching (verbal communication) (2, 3). Information on the supervisory role of attending physicians is not included in the current report. Third, in their investigation of factors associated with failure to achieve first-pass successful intubation, Joshi and associates found that limited mouth opening was highly prevalent in both groups (24/166 of first-attempt failures, 64/740 in first-attempt success). However, an operational definition of limited mouth opening is not clearly stated in the report. In a multivariate risk index study of preoperative endotracheal intubation attempts by experienced anesthesiologists, mouth opening, defined as an interincisor tooth gap of ,4 cm, was found to have a positive predictive value for difficult intubation of 25% (4). In another study of difficult routine preoperative intubations, measured mouth opening (interincisor distance) was also strongly associated with easy vs. difficult intubation (5). Therefore, it would be of interest to know how limited mouth opening was defined and measured in the Joshi study. Finally, knowing the urgency of the endotracheal attempts is necessary to place the results of this investigation in an appropriate clinical context (1).