JNA Journal Club
Video laryngoscopy has revolutionized airway management but data on comparative efficacy to direct laryngoscopy in nonoperating room scenarios remains limited. The Clinical Research in Intensive Care and Sepsis (CRICS) Group conducted a prospective randomized trial to compare the first-pass success rate of orotracheal intubation with video laryngoscopy compared with direct laryngoscopy. The study was called MACMAN (McGrath Mac Videolaryngoscope Versus Macintosh Laryngoscope for Orotracheal Intubation in the Critical Care Unit).
MACMAN was a multicenter, open-label prospective randomized trial; funded through institutional sponsorship. The trial was conducted at 7 intensive care units (ICU) in France between May and December 2015. Follow-up was through 28 days postintubation. Adult patients requiring orotracheal intubation for mechanical ventilation were enrolled. Exclusion criteria included unstable spine conditions contraindicating orotracheal intubation and insufficient time for enrollment and randomization. Randomization was stratified by treatment center and experience of the person performing the intubation. Experts were defined as physicians who had at least 5 years of ICU experience or 1 year of ICU experience after at least 2 years of anesthesiology training. All physicians received manikin training with the video and direct laryngoscopes. Experts always supervised nonexperts. Patients were preoxygenated and induced with etomidate or ketamine. Succinylcholine or rocuronium was used to achieve neuromuscular blockade. Interestingly, no stylet was used for the first-pass intubation attempt. Use of the Sellick maneuver was at the physician’s discretion. Sample size was set at 370 (185 per group) based on an expected 65% first-pass success rate in the direct laryngoscopy group and 80% success rate in the video laryngoscopy group (ie, 15% absolute increase in successful intubation; α=0.05; 1-β=0.80). A mixed-effects logistic model was used to analyze proportions of patients with successful first-pass intubation accounting for stratification factors; with center as a random effect and operator experience as a fixed effect.
In total, 489 patients were assessed and 371 randomized, with 186 to the McGrath video laryngoscopy group (size 3 or 4 blade) and 185 to the direct laryngoscopy group (size 3 or 4 MacIntosh blade). Mean age was 62.8 years and 36.7% of patients were female. In total, 83.8% of first intubation attempts were by nonexperts and 16.2% by experts. A total of 5 patients had no data on first-pass success and were considered intubation failures for data analysis purposes in the intent-to-treat analysis (366 were intubated successfully). First-pass success was 67.7% in the video laryngoscopy group and 70.3% in the direct laryngoscopy group (P=0.60). Adjustment for operator expertise and for difficult airway (defined by the MACOCHA score—Mallampati 3 or 4, apnea syndrome, cervical spine limitation, mouth opening <3 cm, coma, hypoxemia, nonanesthesiologist intubator) still did not result in any significant between group differences. First-pass intubation failure was related to inability to visualize the glottis in the direct laryngoscopy group, and due to inability to catheterize the trachea in the video laryngoscopy group.
Median intubation duration was 3 minutes in both groups. Gum elastic bougie use was more common in the video laryngoscopy group during first-attempt intubation (12% vs. 5.5%; P=0.03). Glottic visualization was better in the video laryngoscopy group as assessed by Cormack-Lehane grade and glottis opening score (P<0.001).