Placing an endotracheal tube is a life-saving measure. Direct laryngoscopy (DL) is traditionally the default method. Video laryngoscopy (VL) has been shown to improve efficiency, but there is insufficient evidence comparing VL versus DL in the prehospital settings. This study, comprising a systematic review and random-effects meta-analysis, assesses current literature for the efficacy of VL in prehospital settings.

PubMed and Scopus databases were searched from their beginnings through March 1, 2022 for eligible studies. Outcomes were the first successful intubation, overall success rate, and number of total DL versus VL attempts in real-life clinical situations. Cochrane’s Risk of Bias (RoB) tool and the Newcastle-Ottawa Scale (NOS) were applied to assess risk of bias and study quality; Q-statistics and I2 values were used to assess heterogeneity.

The search yielded seven studies involving 23,953 patients, 6,674 (28%) of whom underwent intubation via VL. Compared to DL, VL was associated with a statistically higher risk ratio for first-pass success (Risk Ratio [RR] = 1.116; 95% CI, 1.005-1.239; P = .041; I2 = 87%). The I2 value for the subgroup of prospective studies was 0% compared to 89% for retrospective studies. In addition, VL was associated with higher likelihood of overall success rate (RR = 1.097; 95% CI, 1.01-1.18; P = .021; I2 = 85%) and lower mean number of attempts (Mean Difference = -0.529; 95% CI, -0.922 to -0.137; P = .008).

The meta-analysis suggested that VL was associated with higher likelihood of achieving first-pass success, greater overall success rate, and lower number of intubation attempts for adults in the prehospital settings. This study had high heterogeneity, likely presenced by the inclusion of retrospective observational studies. Further studies with more rigorous methodology are needed to confirm these results.

Tracheal intubation is a high-risk intervention for exposure to airborne infective pathogens, including the novel coronavirus disease 2019 (COVID-19). During the recent pandemic, personal protective equipment (PPE) was essential to protect staff during intubation but is recognized to make the practical conduct of anesthesia and intubation more difficult. In the early phase of the coronavirus pandemic, some simple alterations were made to the emergency anesthesia standard operating procedure (SOP) of a prehospital critical care service to attempt to maintain high intubation success rates despite the challenges posed by wearing PPE. This retrospective observational cohort study aims to compare first-pass intubation success rates before and after the introduction of PPE and an altered SOP.

A retrospective observational cohort study was conducted from January 1, 2019 through August 30, 2021. The retrospective analysis used prospectively collected data using prehospital electronic patient records. Anonymized data were held in Excel (v16.54) and analyzed using IBM SPSS Statistics (v28). Patient inclusion criteria were those of all ages who received a primary tracheal intubation attempt outside the hospital by critical care teams. March 27, 2020 was the date from which the SOP changed to mandatory COVID-19 SOP including Level 3 PPE – this date is used to separate the cohort groups.

Data were analyzed from 1,266 patients who received primary intubations by the service. The overall first-pass intubation success rate was 89.7% and the overall intubation success rate was 99.9%. There was no statistically significant difference in first-pass success rate between the two groups: 90.3% in the pre-COVID-19 group (n = 546) and 89.3% in the COVID-19 group (n = 720); Pearson chi-square 0.329; P = .566. In addition, there was no statistical difference in overall intubation success rate between groups: 99.8% in the pre-COVID-19 group and 100.0% in the COVID-19 group; Pearson chi-square 1.32; P = .251.

Non-drug-assisted intubations were more than twice as likely to require multiple attempts in both the pre-COVID-19 group (n = 546; OR = 2.15; 95% CI, 1.19-3.90; P = .01) and in the COVID-19 group (n = 720; OR = 2.5; 95% CI, 1.5-4.1; P = <.001).

This study presents simple changes to a prehospital intubation SOP in response to COVID-19 which included mandatory use of PPE, the first intubator always being the most experienced clinician, and routine first use of video laryngoscopy (VL). These changes allowed protection of the clinical team while successfully maintaining the first-pass and overall success rates for prehospital tracheal intubation.

Structured review of video laryngoscopy recordings from physician team prehospital rapid sequence intubations (RSIs) may provide new insights into why prehospital intubations are difficult. The aim was to use laryngoscope video recordings to give information on timings, observed features of the airway, laryngoscopy technique, and laryngoscope performance. This was to both describe prehospital airways and to investigate which factors were associated with increased time taken to intubate.

Sydney Helicopter Emergency Medical Service (HEMS; the aeromedical wing of New South Wales Ambulance, Australia) has a database recording all intubations. The database comprises free-text case detail, airway dataset, scanned case sheet, and uploaded laryngoscope video. The teams of critical care paramedic and doctor use protocol-led intubations with a C-MAC Macintosh size four laryngoscope and intubation adjunct. First-pass intubation rate is approximately 97%. Available video recordings and their database entries were retrospectively analyzed for pre-specified qualitative and quantitative factors.

Prehospital RSI video recordings were available for 385 cases from January 2018 through July 2020. Timings revealed a median of 58 seconds of apnea from laryngoscope entering mouth to ventilations. Median time to intubate (laryngoscope passing lips until tracheal tube inserted) was 35 seconds, interquartile range 28-46 seconds. Suction was required prior to intubation in 29% of prehospital RSIs. Fogging of the camera lens at time of laryngoscopy occurred in 28%. Logistic regression revealed longer time to intubate was associated with airway soiling, Cormack-Lehane Grade 2 or 3, multiple bougie passes, or change of bougie.

Video recordings averaging 35 seconds for first-pass success prehospital RSI with an adjunct give bed-side “definitions of difficulty” of 30 seconds for no glottic view, 45 seconds for no bougie placement, and 60 seconds for no endotracheal tube placement. Awareness of apnea duration can help guide decision making for oxygenation. All emergency intubators need to be cognizant of the need for suctioning. Improving the management of bloodied airways and bougie usage may reduce laryngoscopy duration and be a focus for training. Video screen fogging and missed recordings from some patients may be something manufacturers can address in the future.

In the prehospital setting, many providers advocate for video laryngoscopy as the initial method of intubation to improve the likelihood of a successful first attempt. However, bright ambient light can worsen visualization of the video laryngoscope liquid crystal display (LCD).

A patient involved in a motor vehicle accident was evaluated by an Emergency Medical Services (EMS) crew. Initial endotracheal intubation attempt using video laryngoscopy was aborted after the patient desaturated. The primary reason for the failure was poor visualization of the video laryngoscope LCD, despite attempts to block direct sunlight. Debriefing revealed that the intubating provider was wearing polarized sunglasses.

Because LCDs emit polarized light, use of polarized sunglasses may cause the display to appear dark. Thus, the purpose of this Case Report is to raise awareness of a potential safety issue that is likely under-recognized by prehospital providers but can be easily avoided.

SmithAJ, JackimczykK, HorwoodB, ChristensonD. Use of Polarized Sunglasses During Video Laryngoscopy: A Cause of Difficult Prehospital IntubationPrehosp Disaster Med. 2019;34(1):104–107.

The primary goal of this study was to compare paramedic first pass success rate between two different video laryngoscopes and direct laryngoscopy (DL) under simulated prehospital conditions in a cadaveric model.

This was a non-randomized, group-controlled trial in which five non-embalmed, non-frozen cadavers were intubated under prehospital spinal immobilization conditions using DL and with both the GlideScope Ranger (GL; Verathon Inc, Bothell, Washington USA) and the VividTrac VT-A100 (VT; Vivid Medical, Palo Alto, California USA). Participants had to intubate each cadaver with each of the three devices (DL, GL, or VT) in a randomly assigned order. Paramedics were given 31 seconds for an intubation attempt and a maximum of three attempts per device to successfully intubate each cadaver. Confirmation of successful endotracheal intubation (ETI) was confirmed by one of the six on-site physicians.

Successful ETI within three attempts across all devices occurred 99.5% of the time overall and individually 98.5% of the time for VT, 100.0% of the time for GL, and 100.0% of the time for DL. First pass success overall was 64.4%. Individually, first pass success was 60.0% for VT, 68.8% for GL, and 64.5% for DL. A chi-square test revealed no statistically significant difference amongst the three devices for first pass success rates (P=.583). Average time to successful intubation was 42.2 seconds for VT, 38.0 seconds for GL, and 33.7 for seconds for DL. The average number of intubation attempts for each device were as follows: 1.48 for VT, 1.40 for GL, and 1.42 for DL.

The was no statistically significant difference in first pass or overall successful ETI rates between DL and video laryngoscopy (VL) with either the GL or VT (adult).

HodnickR, ZitekT, GalsterK, JohnsonS, BledsoeB, EbbsD. A Comparison of Paramedic First Pass Endotracheal Intubation Success Rate of the VividTrac VT-A 100, GlideScope Ranger, and Direct Laryngoscopy Under Simulated Prehospital Cervical Spinal Immobilization Conditions in a Cadaveric Model. Prehosp Disaster Med. 2017;32(6):621–624.

Management of contaminated patients in the decontamination corridor requires the use of hazardous material (HazMat) personal protective equipment (PPE). Previous studies have demonstrated that HazMat PPE may increase the difficulty of airway management. This study compared the efficiency of video laryngoscopy (VL) with traditional direct laryngoscopy (DL) during endotracheal intubation (ETI) while wearing HazMat PPE.

Post-graduate year (PGY) 1-3 Emergency Medicine residents were randomized to VL or DL while wearing encapsulating PPE. Video laryngoscopy was performed using the GlideScope Cobalt AVL video laryngoscope. The primary outcome measure was time to successful ETI in a high-fidelity simulation mannequin. Three time points were utilized in the analysis: Time 0 (blade at lips), Time 1 (blade removed from lips after endotracheal tube placement), and Time 2 (bag valve mask [BVM] attached to endotracheal tube). Secondary outcome measures were perceived ease of use and feasibility of VL and DL ETI modalities.

Twenty-one of 23 (91.3%) eligible residents participated. Mean time to ETI was 10.0 seconds (SD=5.3 seconds) in the DL group and 7.8 seconds (SD=3.0 seconds) in the VL group (P=.081). Mean times from blade insertion until BVM attachment were 17.4 seconds (SD=6.0 seconds) and 15.6 seconds (SD=4.6 seconds), respectively (P=.30). There were no unsuccessful intubation attempts. Seventeen out of 20 participants (85.0%) perceived VL to be easier to use when performing ETI in PPE. Twelve out of 20 participants (60%) perceived DL to be more feasible in an actual HazMat scenario.

The time to successful ETI was not significantly different between VL and DL. Video laryngoscopy had a greater perceived ease of use, but DL was perceived to be more feasible for use in actual HazMat situations. These findings suggest that both DL and VL are reasonable modalities for use in HazMat situations, and the choice of modality could be based on the clinical situation and provider experience.

AberleSJ , SandefurBJ , SungaKL , CampbellRL , LohseCM , Alecastro PulsH , LaudonS , SztajnkrycerMD . Intubation Efficiency and Perceived Ease of Use of Video Laryngoscopy vs Direct Laryngoscopy While Wearing HazMat PPE: A Preliminary High-fidelity Mannequin Study. Prehosp Disaster Med. 2015;30(3):1–5.