Direct Versus Video Laryngoscopy for Prehospital Intubation: A Systematic Review and Meta‐analysis

Abstract

Objectives: The use of video laryngoscopy (VL) for intubation has gained recent popularity. In the prehospital setting, it is unclear if VL increases intubation success rates compared to direct laryngoscopy (DL). We sought to conduct a systematic review and meta-analysis of studies comparing VL to DL in the prehospital setting to determine whether the use of VL increases overall and first-pass endotracheal intubation success rates compared to DL.Methods: A systematic search was performed of the PubMed, Embase, and SCOPUS databases through May 2016 to include studies comparing overall and first-pass success for VL versus DL in patients requiring intubation in the prehospital setting. Data were abstracted by two reviewers. A meta-analysis was performed using a random-effects model. Results:Of a potential 472 articles, eight eligible studies were included. Considerable heterogeneity (I 2 > 90%) precluded reporting an overall pooled estimate across all studies. When stratified by provider type, the pooled estimates for overall intubation success using VL versus DL were a risk ratio (RR) of 0.05 (95% confidence interval [CI] = 0.01-0.18) in studies of physicians and RR = 2.28 (95% CI = 1.00-5.20) in nonphysicians. For firstpass intubation success the pooled RR estimates for using VL versus DL were 0.32 (95% CI = 0.23-0.44) and 1.83 (95% CI = 1.18-2.84) among studies using physicians and nonphysicians, respectively. There was moderate to significant heterogeneity between studies when stratified by provider.Conclusions: Among physician intubators with significant DL experience, VL does not increase overall or firstpass success rates and may lead to worsening performance. However, among nonphysician intubators with less experience with DL, VL may provide benefit in the prehospital setting.

In Reply: Comparing Direct and Video Laryngoscopy for Prehospital Intubation: Can Meta‐analysis Provide an Exact Solution?

“…We noted this difference, and in our discussion, we remarked that “our study suggests that physician intubators do not experience the same benefit from indirect laryngoscopy as nonphysician intubators. We suspect this difference lies largely with the amount of previous experience physician providers reportedly had with direct laryngoscopy.” We ultimately agree that the difference in success rates was likely not due to the intrinsic quality or functionality of the individual devices, but instead the experience of the operator combined with the learning curve of each device.…”

“…We reported a summary assessment of study quality to be strong or moderate in the randomized trials and gave overall lower ratings to the observational studies. We tried to name this concern in our summary of limitations by writing that “a likely reason for the heterogeneity we observed is the varied study designs.” While we agree that randomized trials are of overall higher quality in addressing questions of clinical interventions, we also feel that given the dearth of randomized trials on this subject, we may be excluding valuable data by rejecting observational studies outright. Prior work has suggested that including both observational studies and randomized studies in a meta‐analysis could outweigh the disadvantages in many situations and that observational studies should not be excluded a priori .…”

“…The first comment refers to the difference in video laryngoscopy devices and how “… pooling of results from studies evaluating performance of different VLs for prehospital intubation may lead to intrinsic inconsistencies in the primary endpoints.” This is an important limitation, and we tried to specifically draw attention to it by noting that “an additional potential source of heterogeneity may be the varying types of indirect devices employed between studies. While all of the devices compared against direct laryngoscopy were indirect devices, there is evidence, based on airway simulation studies, that all indirect devices do not necessarily perform equally.” We pointed out that the differences in the devices may have led to heterogeneity in the estimates, what the authors term “intrinsic inconsistencies in the primary endpoints.”…”

Comparison of the McGrath MAC EMS Videolaryngoscope with a Conventional Laryngoscope for Standard and Difficult Airway Intubation: A Randomized, Cross-over, Simulation Trial

“…Endotracheal intubation in pre-hospital settings can be challenging even for experienced intubators (22,23). It should be remembered that each intubation performed within an emergency medical service is emergency intubation (24).…”

Comparing Direct and Video Laryngoscopy for Prehospital Intubation: Can Meta‐analysis Provide an Exact Solution?

“…The recent systemic review and meta‐analysis by Savino et al . comparing performance of video versus direct laryngoscopy for prehospital intubation was of great interested to us.…”