A comparison of the ease of tracheal intubation using a McGrath MAC(®) laryngoscope and a standard Macintosh laryngoscope

Abstract

We compared the McGrath MAC(®) videolaryngoscope when used as both a direct and an indirect laryngoscope with a standard Macintosh laryngoscope in patients without predictors of a difficult tracheal intubation. We found higher median Intubation Difficulty Scores with the McGrath MAC as a direct laryngoscope, 1 (0-3 [0-5]) than when using it as an indirect videolaryngoscope, 0 (0-1 [0-5]) or when using the Macintosh laryngoscope, 0 (0-1 [0-5]), p = 0.04. This was mirrored in the subjective user reporting, scored out of 10, of difficulty for each method 3.0 (2.0-3.4 [0.5-80]); 2.0 (1.0-3.9 [0-70]) and 2.0 (1.0-3.3 [0-70]), respectively (p = 0.01). This difficulty is in part explained by the poorer laryngeal views recorded using the Cormack and Lehane classification system (p < 0.001) and reflected in the higher than normal operator force required (25%, 4%, 8% for each method, respectively, p < 0.001) and the increased use of rigid intubation aids (21%, 6%, 2%, respectively, p < 0.001). There was no difference between the groups in time taken to intubate or incidence of complications. There was no statistical difference in the performances as measured between the McGrath MAC used as an indirect videolaryngoscope and the Macintosh laryngoscope. We cannot recommend that the McGrath videolaryngoscope be used as a direct laryngscopic device in place of the Macintosh.