Date Published: June 24, 2012
Publisher: Hindawi Publishing Corporation
Author(s): Darwin Viernes, Allan J. Goldman, Richard E. Galgon, Aaron M. Joffe.
Background. Teaching direct laryngoscopy is limited by the inability of the instructor to simultaneously view the airway with the laryngoscopist. Our primary aim is to report our initial use of the GlideScope Direct, a video-enabled, Macintosh laryngoscope intended primarily as a training tool in direct laryngoscopy. Methods. The GlideScope Direct was made available to anyone who planned on performing direct laryngoscopy as the primary technique for intubation. Novices were those who had performed <30 intubations. Results. The GlideScope Direct was used 123 times as primarily a direct laryngoscope while the instructor viewed the intubation on the monitor. It was highly successful as a direct laryngoscope (93% success). Salvage by indirect laryngoscopy occurred in 7/9 remaining patients without changing equipment. Novices performed 28 intubations (overall success rate of 79%). In 6 patients, the instructor took over and successfully intubated the patient. Instructors used the video images to guide the operator in 16 (57%) of those patients. Seven different instructors supervised the 28 novices, all of who subjectively felt advantaged by having the laryngoscopic view available. Conclusions. The GlideScope Direct functions similarly to a Macintosh laryngoscope and provides the instructor subjective reassurance, while providing the ability to guide the trainee laryngoscopist.
Many experts predict that video laryngoscopy (VL) will eventually replace direct laryngoscopy (DL) as the primary laryngoscopic technique when attempting tracheal intubation. However, recent studies comparing the GlideScope video laryngoscope (Verathon, Bothell, WA, USA) and the Pentax AWS (Ambu, Inc., Glen Burnie, MD, USA) to Macintosh DL for intubating morbidly obese subjects failed to support the superiority of VL in this patient population [1, 2]. Additionally, financial constraints, particularly in developing nations, make substitution of the far more costly VL devices for the traditional DL blades impractical. Thus, for the foreseeable future, DL will remain an essential skill for health care providers responsible for tracheal intubation .
This study was approved by the University of Washington Minimal Risk Institutional Review Board (Seattle, WA) without the need for informed consent, and conducted from March 1, 2011 through April 1, 2011 at the Harborview Medical Center (HMC, Seattle, WA), a 413-bed municipal medical center affiliated with the University of Washington, having 28 dedicated operating rooms, staffed by attending anesthesiologists, either working solo or supervising anesthesiology trainees and/or nurse anesthetists. Additionally, the operating rooms are a primary airway management training location for a number of nonanesthesia trained providers, including local emergency medical services personnel, flight nurses, and emergency and internal medicine trainees.
During the study period, 123 patients were intubated using the GSD. Patient and primary laryngoscopist characteristics are given in Tables 1 and 2. Overall intubation success using the GSD was 98% (121/123). First, second, and third intubation attempt success rates using the GSD for direct laryngoscopy were 87% (99/114), 12% (14/114), and 1% (1/114), respectively. In 9 cases, direct laryngoscopy was difficult and the laryngoscopist converted to using the video screen to perform indirect laryngoscopy, which proved successful in 7 of the 9 cases (77%) within 2 attempts. Two patients (1.6%) could not be intubated using the GSD, regardless of the approach (direct or indirect). These patients were successfully intubated using the GlideScope GVL. A summary of all 123 intubations is provided in Figure 3. Twenty-eight patients were intubated by novices with first and second attempt intubation success rates of 61% (17/28) and 18% (5/28), respectively. Six (21%) intubations were completed by the attending anesthesiologist. In comparison, experienced operators had first and second attempt direct laryngoscopy intubation success rates of 86% (82/95) and 8% (8/95), respectively. The instructor used the video images to aid the novice laryngoscopist 57% (16/28) of the time.
The main finding of our study is that the GSD can be used for direct laryngoscopy and tracheal intubation with a high success rate in patients without predictors of difficult intubation by both novice and experienced laryngoscopists, while its integrated video view provides an instructor with information to help guide tracheal intubation, which was utilized in a majority of cases. Subjectively, our users considered the GSD to have a similar feel to our standard direct laryngoscope handle and blade. It’s light source allowed adequate visualization of airway structures without undue glare or reflection and attending anesthesiologists commented that they felt “comforted” by having the ability to share the airway view using the monitor. The instructors who were able to provide direct video feedback to trainees also noted single touch video recording to be helpful. Due to construction of the GSD blade being similar to that of a Macintosh blade (Figure 2), there are no limitations to the type of tube used (endotracheal tube, nasotracheal tube, double lumen tube, etc.) or intubation adjuncts (Magill forceps, bougie, airway exchange catheters, etc.) (Figure 4).