Difficult Airway Management in the Emergency Department: GlideScope Videolaryngoscopy Compared to Direct Laryngoscopy

Abstract

Background

Videolaryngoscopy has become a popular method of intubation in the Emergency Department (ED), however, little research has compared this technique with direct laryngoscopy (DL).

Objective

To compare the success rates of GlideScope (Verathon Inc., Bothell, WA) videolaryngoscopy (GVL) and DL in emergent airways with known difficult airway predictors (DAPs).

Methods

We evaluated 772 consecutive ED intubations over a 23-month period. After each intubation, the physician completed a data collection form that included: demographics, DAPs, Cormack-Lehane view, optical clarity, lens contamination, and complications. DAPs included: cervical immobility, obesity, small mandible, large tongue, short neck, blood or vomit in the airway, tracheal edema, secretions, and facial or neck trauma. Primary outcome was first-attempt success rates. Multivariate logistic regression was performed to evaluate the odds of failure for DL compared to GVL.

Results

First-attempt success rate with DL was 68%, GVL 78% (Fisher’s exact test, p = 0.001). Adjusted odds of success of GVL compared to DL on first attempt equals 2.20 (odds ratio [OR] 2.2, 95% confidence interval [CI] 1.51–3.19). After statistically controlling for DAPs, GVL was more likely to succeed on first attempt than DL (OR 3.07, 95% CI 2.19–4.30). Logistic regression of DAPs showed that the presence of blood, small mandible, obesity, and a large tongue were statistically significant risk factors for decreasing the odds of success with DL and increasing the odds of success of GVL.

Conclusion

For difficult airways with the presence of blood or small mandible, or a large tongue or obesity, GVL had a higher success rate at first attempt than DL.

Introduction

The difficult airway is one in which the intubator predicts difficulty in securing an airway. Several anatomic and pathologic conditions have been identified that, if present, can reliably predict a difficult airway (Table 1). In contrast, a failed airway is one that is not predicted but is experienced after three failed attempts, or that has inability to maintain adequate oxygen saturations (1). The significance of a predicted difficult airway is that it may require alternative management strategies based on how well the patient can be oxygenated and ventilated through alternative means, and the physician’s confidence in securing the airway with paralysis. If oxygenation cannot be maintained, the airway becomes a crash, or failed, airway.

Modern direct laryngoscopy with the Macintosh laryngoscope was developed in the 1940s as a method of aligning the oral, pharyngeal, and laryngeal axes to provide the operator a direct view of the glottic inlet so an endotracheal tube could be inserted under visualization (2). Any factor that prohibits the aligning of these axes, or obscures the view of the vocal cords, creates a difficult or failed airway situation. Several devices exist for managing difficult airways, including flexible fiberoptic scopes, intubating laryngeal mask airways, optical and lighted stylets, and videolaryngoscopy. Ultimately, if these modalities fail or when adequate oxygenation cannot be maintained, surgical airway management is the next step (1). Videolaryngoscopy may provide superior intubating conditions compared to direct laryngoscopy that allows the operator to manage more difficult airways with rapid sequence intubation (RSI) 3, 4, 5, 6, 7, 8, 9, 10, 11. Platts-Mills et al. (2009) report the only published comparison between direct laryngoscopy and video laryngoscopy in the emergency department (ED) setting (12). They found an equivalent success rate between the devices with minimal to no previous experience with video laryngoscopy, suggesting it is at least as good as, if not superior to, direct laryngoscopy.

In this study we examined the comparison between direct laryngoscopy and GlideScope (Verathon Inc., Bothell, WA) videolaryngoscopy in the presence of known difficult airway predictors in the ED. Primary outcome was first-attempt success rates between the devices in the presence of each difficult airway predictor listed in Table 1.