By Alexander Niven, MD
Senior Associate Consultant, Division of Pulmonary/Critical Care Medicine, Mayo Clinic, Rochester, MN
Dr. Niven reports no financial relationships relevant to this field of study.
SYNOPSIS: In the largest prospective, randomized trial to date, use of video laryngoscopy improved glottic visualization but did not increase procedural success or decrease complications compared to direct laryngoscopy in medical ICU patients.
SOURCE: Janz DR, Semler MW, Lentz RJ, et al. Randomized trial of video laryngoscopy for endotracheal intubation of critically ill adults. Crit Care Med 2016;44:1980-1987.
Intubation in the critically ill is a high-risk procedure, with complication rates that remain unacceptably high despite significant advances over the past decade. The incidence of a difficult airway in ICU patients is approximately 10%, and prospective identification of these patients remains challenging. Increasing availability and experience with video laryngoscopy (VL) has led many to suggest that these tools should be preferentially used for endotracheal intubation in the ICU. Uncontrolled series and small prospective, randomized trials have suggested that VL provides a higher rate of first pass success than direct laryngoscopy (DL) in the critically ill, but this topic remains the subject of considerable debate.
The FELLOW investigators conducted a single center, prospective, randomized trial to compare the rate of first attempt success using VL and DL in critically ill patients intubated by pulmonary/critical care fellows in the medical ICU. Of the first 196 patients who met inclusion criteria, 23 (12%) were excluded because clinical urgency precluded randomization and 18 (9%) because the treating clinicians felt video or fiberoptic intubation was warranted. The remaining 150 patients were randomized to VL or DL for their first laryngoscopy attempt in an intention-to-treat analysis. Operators could select their preferred airway tools and medications within these arms, and all procedures were supervised by a staff intensivist or anesthesiologist.
There were no significant differences between study groups. Most patients were intubated for hypoxic or hypercarbic respiratory failure in the setting of sepsis or septic shock, and approximately one-third were obese (body mass index [BMI] > 30 kg/m2). Fellows performing the procedure were experienced (≥ 47 prior intubations), although operators performing VL had performed less of these procedures (median of 10 cases, IQR 5-22). Almost all VL procedures were performed using the McGrath MAC (98.6%), and most patients received etomidate and either rocuronium or succinylcholine.
There was no difference in the first attempt success rate between VL and DL groups (68.9% vs. 65.8%, odds ratio, 1.15; 95% confidence interval, 0.58-2.28; P = 0.68), even when adjusted for operator experience, APACHE II score, and BMI. Most patients with an unsuccessful first intubation attempt were intubated using either an endotracheal tube introducer (SunMed Introducer Adult Bougie with Coude Tip) or VL. Use of VL significantly improved glottic visualization (P = 0.001) compared to DL, but time to intubation, lowest oxygen saturation and percent change, procedure-related complications, duration of mechanical ventilation, length of stay, and mortality were no different.
COMMENTARY
VL has provided consistently better glottic visualization in prior studies, with variable reports of better first pass success and some concern about possible longer times to intubation. In the most comparable prospective, randomized study by Silverberg et al, first attempt success by fellows was achieved in 74% of patients using VL (GlideScope) and only 40% using DL (P < 0.001). High-risk patients were excluded in this trial, and procedures were performed both in the ICU and the less-controlled environment of ward cardiac arrests and rapid response team evaluations. Most patients received propofol 1 mg/kg or etomidate without neuromuscular blockade, and the level of fellow experience, although not directly reported, was likely less, based on the substantially lower rate of DL intubation than comparative trials.
The FELLOW trial is the largest prospective, randomized trial to compare VL with DL to date, and provides clinicians with important conclusions. VL offers better glottic visualization than DL but little more in an optimized ICU setting with experienced operators using both induction agents and neuromuscular blockade, even in obese patients without urgent need for intubation or other high-risk features. The investigators’ post-hoc, qualitative observation that better glottic visualization may matter more in less experienced operators is concordant with the findings of Silverberg et al and a meta-analysis by Griesdale et al and perhaps also may be true in less controlled intubation settings. The small but significant population of patients excluded from randomization in the FELLOW trial due to urgency or clinician judgment unfortunately limits the generalization of these findings to other high-risk populations. Less rigorous studies in this setting also support the clear trend toward use of the bougie or VL when first intubation attempts fail.
The more traditional pharmacologic approach used in the FELLOW trial contrasts sharply with recent publications reporting a high rate of first attempt success using VL with propofol alone, frequently with vasopressor premedication. The best pharmacologic approach in ICU airway management, and the best use of VL (and which tool to use) in high-risk or failed airways in the critically ill, are all issues that warrant further study in well-designed, prospective, randomized trials such as this one.
REFERENCES
- Silverberg MJ, Li N, Acquah SO, Kory PD. Comparison of video laryngoscopy versus direct laryngoscopy during urgent endotracheal intubation: A randomized controlled trial. Crit Care Med 2015;43:636-641.
- Yeatts DJ, Dutton RP, Hu PF, et al. Effect of video laryngoscopy on trauma patient survival: A randomized controlled trial. J Trauma Acute Care Surg 2013;75:212-219.
- Griesdale DE, Liu D, McKinney J, Choi PT. Glidescope video-laryngoscopy versus direct laryngoscopy for endotracheal intubation: A systematic review and meta-analysis. Can J Anaesth 2012;59:41-52.
- Lakticova V, Koenig SJ, Narasimhan M, Mayo PH. Video laryngoscopy is associated with increased first pass success and decreased rate of esophageal intubations during urgent endotracheal intubation in a medical intensive care unit when compared to direct laryngoscopy. J Intensive Care Med 2015;30:44-48.
- Koenig SJ, Lakticova V, Narasimhan M, et al. Safety of propofol as an induction agent for urgent endotracheal intubation in the medical intensive care unit. J Intensive Care Med 2015;30:499-504.
In the largest prospective, randomized trial to date, use of video laryngoscopy improved glottic visualization but did not increase procedural success or decrease complications compared to direct laryngoscopy in medical ICU patients.
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