Video Laryngoscopy versus Direct Laryngoscopy for Orotracheal Intubation in the Out-of-Hospital Environment: A Systematic Review and Meta-Analysis

Abstract

Objective

To determine the effect of video and direct laryngoscopy on first-pass success rates for out-of-hospital orotracheal intubation.

Methods

MEDLINE, Embase, and Cochrane databases were searched from inception to January 2023. Out-of-hospital studies comparing video and direct laryngoscopy on either first-pass or overall intubation success were included. A random effects meta-analysis was performed with a primary outcome of first-pass success stratified by clinician type and laryngoscope blade geometry. The secondary outcomes were overall intubation success stratified by clinician type, and intubation time. All hypotheses and subgroup analyses were determined a priori.

Results

Twenty-five studies involving 35,489 intubations met inclusion criteria. Substantial heterogeneity (>75%) precluded reporting point estimates for nearly all analyses. For our primary outcome, video laryngoscopy was associated with improved first-pass success in 3/5 physician studies, 4/6 critical care paramedic/registered nurse studies, and 7/10 paramedic studies. Video laryngoscope devices with Macintosh blade geometry were associated with improved first-pass success in 7/10 studies, while devices with hyperangulated geometry were associated with improved first-pass success in 3/7 studies. Overall intubation success was greater with video laryngoscopy in 2/6 studies in the physician subgroup and 9/10 studies in the paramedic subgroup. Video laryngoscopy was not associated with overall intubation success among critical care paramedics/nurses (OR = 1.89, 0.96 to 3.72, I² = 34%). Lastly, 4/5 studies found video laryngoscopy to be associated with longer intubation times.

Conclusions

We found substantial heterogeneity among out-of-hospital studies comparing video laryngoscopy to direct laryngoscopy on first-pass success, overall success, or intubation time. This heterogeneity was not explained with stratification by study design, clinician type, video laryngoscope blade geometry, or leave-one-out meta-analysis. A majority of studies showed that video laryngoscopy was associated with improved first pass success in all subgroups, but only for paramedics and not physicians when looking at overall success. This improvement was more common in studies that used Macintosh blades than those that used hyperangulated blades. Future research should explore the heterogeneity identified in our analysis with an emphasis on differences in training, clinical milieu, and specific video laryngoscope devices.

Acknowledgments

We would like to thank Edward Gracely (University of Drexel College of Medicine) for his assistance in reviewing our statistical plan.

Disclosure Statement

No potential conflict of interest was reported by the authors.

Author Contributions

MK, BS, and ZB developed the research question and overall study design. MK and BS designed the systematic review search protocol, independently performed the systematic review of the literature and assessed study quality. Statistics were performed by MK. MK drafted the manuscript and all authors contributed to its revision. Overall guidance and supervision was provided by SP throughout the study. MK takes responsibility for the paper as a whole.