Direct vs. Video Laryngoscopy in a Helicopter Emergency Medical Service (HEMS) Setting: A Retrospective Comparison

Abstract

Introduction In the prehospital setting, when caring for critically ill patients, the ability to quickly and effectively secure a definitive airway can be a matter of life of death. As such, all helicopter emergency medical service (HEMS) providers must be able to safely perform this procedure with speed and efficacy. Video laryngoscopy (VL) was invented and introduced as an improved technique for performing orotracheal intubation, and its use has become widespread amongst pre-hospital and HEMS organizations. Despite this, little information is available regarding the efficacy of VL when compared to standard direct laryngoscopy (DL) in this pre-hospital setting. As such, there is sparse evidence to guide the HEMS provider's decision on which to use when attempting to secure the airway of a critically ill patient. Provider preference often comes into play in this situation. In a preliminary survey, Nolen and Pokorney found that while the majority of Wisconsin Flight For Life (FFL) HEMS providers choose VL, variation does exist between providers in regards to VL vs DL preference. Self-reported success rates by providers suggested 100% first pass success with DL and 87.5 success with VL. This survey relied on provider recall, and further review of records is required to evaluate the accuracy of these reports. Currently, there is no protocol regarding which laryngoscopy modality to employ in the HEMS setting. This research aims to improving the quality of care received by patients who require orotracheal intubation by HEMS providers. To do this, we investigate whether the use of VL or DL increases successful orotracheal intubations by HEMS providers. We hypothesized that the first pass and overall success would be greater with VL and the overall complications would be less with VL when compared to DL. Methods A retrospective chart review was performed of all intubated patients transported by HEMS providers from January 2015 to July 2017. Inclusion Criteria Adult patients transported by HEMS providers that required orotracheal intubation and underwent at least one attempt at orotracheal intubation. Results When comparing the survey results, we found similar rates of DL vs VL attempts (15/21 vs 104/120). First pass success rates were overestimated for both modalities (100%/90.5% vs 87.5%/84.8%). First Pass Success Rate No statistically significant difference was found in 1st pass success rate. The top reported reason for failed DL attempts was inability to pass tube, while the top reported reason for failed VL attempts include blood/secretions on camera, followed by inability to pass tube. Overall Success Rate No statistically significant difference was found between the two modalities. However, there was notably no difference between 1st pass and overall success rate in the DL group, while the overall success improved over fist pass in the VL group. While not statistically significant, this trend results from more attempts and alterations by those performing VL prior to resorting to a rescue airway. The most common alteration made was change in VL blade, followed by changing from VL to DL. Complications DL and VL groups had nearly identical complication rates. In both groups, the primary complication was hypoxia, so BVM ventilation was utilized. There was one cardiac arrest in the DL group. Influencing Factors Overwhelmingly, the method of intubation favored by HEMS providers is video laryngoscopy (VL). In the survey by Pokorney and Nolan, provider preference was the most common reason for choosing a modality. Of the patient characteristics observed, no significant differences were found. Initial GCS showed near statistical significance, with lower initial GCS trending to VL. Perhaps VL is more utilized when indication for intubation is apparent immediately upon arrival on scene. Unresponsiveness as reason for intubation, however, did not vary significantly. Respiratory failure alone demonstrated a statistically significant difference with proportionally more VL intubations in these patients. No definition for what constitutes respiratory failure was present in the charts and the reason for this variance between modality used is unknown. Conclusion In the data reviewed, no significant differences were found in first pass or overall success rates for direct and video laryngoscopy. Additionally no significant difference was observed in the complication rates and no factors were found that influenced the decision to perform DL vs VL.