Comparative Analysis of the Usefulness of the GlideScope, Macintosh, and McCoy Laryngoscopes for Endotracheal Intubation in Patients with Obesity: A Randomized, Clinical Trial.

Background: Difficult intubation is dangerous and sometimes fatal, especially in patients with obesity. In difficult intubation cases the best device should be applied to decrease the risk of complications. The current study aimed at comparing laryngoscopes, Macintosh, McCoy, GlideScope and devices for intubation purposes.

Methods: A total of 102 patients with obesity and ASA (American society of anesthesiologists) class I or II, and body mass index (BMI) of > 30 kg/m were selected. After obtaining the informed consent, the patients were divided into 3 groups based on the 3 laryngoscope types. Preoperative airway assessment including the Mallampati score, thyromental distance (TMD), and neck circumference was performed and all the patients were anesthetized based on the same protocol. Subsequently, all of the patients were intubated using a Macintosh, McCoy, or GlideScope laryngoscope. Laryngoscopy time, Cormack-Lehane score (1 - 4), and the percentage of glottic opening (POGO; 1 - 100) were evaluated. Data were analyzed using SPSS version 16, and results were considered statistically significant at P ≤ 0.05.

Results: There was no significant difference between demographic characteristics and preoperative airway evaluations. The shortest and longest laryngoscopy time were obtained in the GlideScope and McCoy laryngoscope groups, respectively (P = 0.001). The highest Cormack-Lehane score was obtained using the GlideScope method (P = 0.04). The POGO was higher and, therefore, more appropriate in the McCoy laryngoscope group (P = 0.009). A direct relationship was observed between neck circumference (P = 0.008), BMI (P = 0.023), Mallampati score (P = 0.000), and laryngoscopy.

Conclusions: In the current study, the shortest and longest intubation time in patients with obesity was observed in the GlideScope and the McCoy laryngoscope groups, respectively. Moreover, the direct relationships of BMI and neck circumference with laryngoscopy time were observed in all 3 groups. These results suggested using GlideScope in patients with high BMI to reduce laryngoscopy time.