Comparison of McGrath Series 3 and Macintosh Laryngoscopes for Tracheal Intubation in Patients With Normal Airway by Inexperienced Anesthetists: A Randomized Study

Abstract

Difficult and failed intubations account for the major causes of morbidity and mortality in current anesthetic practice. Several devices including McGrath Series 3 videolaryngoscope are available which may facilitate tracheal intubation by improving view of the larynx compared with Macintosh blade laryngoscopy. But no studies demonstrate whether McGrath Series 3 performs better than Macintosh laryngoscope in normal airway intubations by inexperienced anesthetists so far. We therefore designed this randomized controlled study to compare McGrath with Macintosh in routine tracheal intubation performed by inexperienced anesthetists.In total, 180 adult patients with normal-appearing airways requiring orotracheal intubation for elective surgery were randomly allocated to be intubated by 9 inexperienced anesthetists with McGrath or Macintosh. The primary outcome was time to intubation. Ease of intubation was assessed by a 5-point ordinal scale. Intubation attempts/failures, best laryngoscopy view using the Cormack-Lehane grade, associated complications and hemodynamic changes during intubation were recorded.We found that there was no significant difference between McGrath and Macintosh in the median time to intubation (P = 0.46); the Cormack-Lehane views attained using McGrath were superior (P < 0.001); the difference of ease of intubation was statistically significant (P = 0.01). No serious trauma occurred in both groups. And there was statistically significant difference in the systolic blood pressure changes between 2 groups (P < 0.05).We demonstrated that in orotracheal intubation in patients with normal airway by inexperienced anesthetists, McGrath compared with the Macintosh allows superior glottis views, greater ease of intubation, less complications, and hemodynamic changes with noninferior intubation time. And it remained a potential selection for inexperienced anesthetists in uncomplicated intubation.

FIGURE 1

Flow diagram showing recruitment into study.

FIGURE 2

Kaplan–Meier plot demonstrating the proportion of patients successfully intubated vs time. The 3 patients (2 in McGrath group and 1 in Macintosh group) who were assigned times of 120 s (see “Methods” section) are not included in the figure; therefore, the proportion of patients successfully intubated was 88/90 (98%) in the McGrath group, and 89/90 (99%) in the Macintosh group. Groups were compared using the Mann–Whitney test.

FIGURE 3

Ease of intubation by operators was measured on a 5-point scale, separated by group. The scale of the data collection form was marked “the easiest” (1) and “the most difficult” (5). Groups were compared using the Mann–Whitney test.