Comparative Evaluation of Macintosh, McCoy and Truview Laryngoscope in Simulated Difficult Laryngoscopy Using Rigid Neck Collar in Overweight Patients : A Randomized, Controlled Clinical Trial

ABSTRACT

Background: To compare the safety and efficacy of Macintosh, McCoy and Truview laryngoscope in simulated difficult laryngoscopy using rigid neck collar in overweight patients. Methods: It was a Prospective, randomized, controlled clinical trial conducted in a tertiary care teaching hospital. Overweight patients (BMI= 25-29.9) with American Society of Anesthesiologists physical status I and II, age 18 to 60 years and scheduled recruited for elective surgery requiring general anesthesia with oral endotracheal intubation were included. The patients were divided into three groups comprising of 40 patients each in which Macintosh, McCoy and Truview laryngoscopes were used respectively. Difficult laryngoscopy was simulated using rigid neck collar. The primary outcome measure was modified Intubation Difficulty Score (IDS ). The secondary outcome measures were number of attempts, ease of intubation, overall success rate, time of intubation, Percentage of Glottic Opening score, hemodynamic parameters and complications. Results: The mean Intubation Difficulty Score was significantly lower with Truview Laryngoscope (1.68) as compared to Macintosh (4.21)and MacCoy (3.03) laryngoscopes. The median Percentage of Glottic Opening score was also significantly improved in the Truview group(78.21) compared to the other groups. Number of successful first intubation attempt was significantly higher in the Truview group(63.16%) compared to the other groups. The overall success rate was similar among groups. However, the time of intubation was significantly higher for Truview (41.21±2 sec) compared to Macintosh and McCoy laryngoscopes. Conclusion: The Truview laryngoscope allowed better glottic visualization, greater ease of intubation, fewer intubation attempts, but a longer intubation time compared to Macintosh and MacCoy laryngoscopes.