Though the use of flexible fiberoptic bronchoscopes has been recommended when confronted with a patient whose trachea is difficult to intubate, video-laryngoscopes (VLS) have become the new standard of care for managing difficult airways. Stylets are often needed when video-laryngoscopes are used. However, the user cannot adjust the angulation of the stylet while attempting intubation. A flexible tracheoscope has been designed that is similar to a fiberoptic bronchoscope and can be maneuvered during intubation.
Dr. Rainer Lenhardt, Department of Anesthesiology and Perioperative Medicine, University of Louisville School of Medicine, Louisville, Kentucky, and the Outcomes Research Consortium, Cleveland, Ohio, and colleagues compared intubation times and attempts in 140 patients with anticipated difficult airway who were randomly assigned to have their endotracheal tube placed either with use of a preformed stylet or a flexible tracheoscope after insertion of a video-laryngoscope. The results of the authors’ study are presented in this month’s issue of Anesthesia & Analgesia in the article titled “Is Video Laryngoscope-Assisted Flexible Tracheoscope Intubation Feasible for Patients with Predicted Difficult Airway? A Prospective, Randomized Clinical Trial.”
Following induction of anesthesia patients were paralyzed with succinylcholine or rocuronium. Laryngoscopy was not performed until full paralysis was confirmed with a nerve stimulator. In both groups, a GlideScope®was used to visualize the epiglottis. In the control group, an endotracheal tube with a rigid preformed stylet was used. In the intervention group, a flexible tracheoscope (aScope®) was “loaded” with an endotracheal tube. The tracheoscope was advanced underneath the epiglottis guided by the GlideScope® video screen, and then to the carina as guided by the video screen on the tracheoscope. The endotracheal tube was then advanced over the flexible tracheoscope. If intubation failed after three attempts, it was attempted using the opposite technique. If both methods failed, the plan was to awaken the patient.
All patients’ tracheas were successfully intubated. The number of patients in both groups who required one or two intubation attempts was almost the same. Time for successful intubation was not different between groups. The tracheas of four patients with cervical spine pathology in the control group could not be intubated using the preformed stylet but could be successfully intubated using the tracheoscope.
As the authors note, when the tracheoscope is used, two people are needed, one to hold the VLS in place and another to intubate the trachea with the tracheoscope. This is an issue if there’s no skilled person to assist with intubation. In the study, only experienced attending anesthesiologists performed the intubations. These results may not be the same with less experienced individuals. Should a flexible tracheoscope be used instead of a rigid stylet? The study does not support that, as the tracheoscopes add an additional expense. However, in patients where the risk of failure with a GlideScope® are fairly high, the availability of a flexible tracheoscope as an immediate supplement to videolaryngoscopy is a reasonable consideration.