Purpose: The McCoy levering laryngoscope is a modified Macintosh laryngoscope, which has a hinged tip controlled by a lever on the handle. The purpose of this study was to investigate whether the tip elevation of this laryngoscope results in better laryngeal visualization than using the Macintosh laryngoscope when the patient's neck is fixed in the neutral position.
Methods: Fifty female patients (ASA physical status I-II) undergoing elective surgery during general anaesthesia were investigated. The patient's neck was manually fixed in the neutral position by an assistant, and laryngeal visualization was attempted first with a size #3 Macintosh laryngoscope (Macintosh trial), and then with a size #3 McCoy levering laryngoscope with blade tip elevation (McCoy trial), and tracheal intubation was attempted. Trials of laryngeal visualization were evaluated with the Cormack score.
Results: In the Macintosh trial, 36 of 50 (72%) patients were evaluated grade 3, and two grade 4. In most of the patients graded 2 and 3 in the Macintosh trial (70% of the grade 2 and 83% of the grade 3 cases), the laryngeal view was improved by using the McCoy levering laryngoscope. The Cormack grade in the McCoy trial was less than that in the Macintosh trial (P < 0.01). No complications were observed during the study.
Conclusion: The McCoy levering laryngoscope improved laryngeal visualization in patients whose neck cannot be extended.