Comparison of the Macintosh, McCoy, Airtraq laryngoscopes and the intubating laryngeal mask airway in a difficult airway with manual in-line stabilisation: a cross-over simulation-based study.

CONTEXT: Patients with multisystem trauma undergoing intubation with manual in-line stabilisation (MILS) have a higher incidence of difficult or failed intubations.

OBJECTIVE: To compare the effectiveness of the Macintosh laryngoscope with three other intubating devices in a high fidelity simulation model.

DESIGN: Cross-over, simulation-based study.

SETTING: Tertiary referral and level 1 trauma centre between June and November 2011.

PARTICIPANTS: Thirty-five experienced airway physicians.

INTERVENTION: Each participant performed tracheal intubations on a Laerdal SimMan manikin in both a normal airway and a difficult airway scenario with MILS. The devices utilised in a randomised order were the Macintosh, McCoy, Airtraq laryngoscopes and the intubating laryngeal mask airway (iLMA).

MAIN OUTCOME MEASURES: The primary outcome was time to intubation. Success rates, grade of laryngoscopy and force of intubation were also measured.

RESULTS: One hundred and forty intubations were attempted by 35 participants in both the normal and MILS scenarios. In the normal airway, there was no difference in success rates and time to intubation. In the difficult airway with MILS, there was no difference in success rates. However, the Airtraq was associated with a longer time to intubation than the Macintosh, McCoy and iLMA, 39.3, 26.7, 23.3, 39.3, 22.8 s, respectively (P < 0.0001). The Airtraq delivered the best glottic view and lowest force of intubation in both scenarios (P < 0.0001), but was associated with the only failed intubation in the study. The McCoy was associated with a significant improvement in the glottic visualisation (P < 0.05) and reduction in the force of intubation (P <0.0001) compared with the Macintosh.

CONCLUSION: In this manikin study, the McCoy demonstrated multiple advantages over the Macintosh. The iLMA was associated with the fastest time to intubation and minimum force of insertion.