Comparison of Three Stylet Angulations for Intubation of Obese Patients via McGRATH® MAC Video Laryngoscope. A Randomised Controlled Trial

Author(s): Binbin Zhu, Xiang Wu, Hongmei Wan, Bin Gao

Purpose: To compare three stylet angulations used with reinforced plastic endotracheal tube guided by McGRATH® MAC video laryngoscope (MMVL) for tracheal intubation in obese patients. 

Materials and Methods: 180 obese patients of ASA grade II-III received intubation guided by MMVL, were randomly divided into three groups depending on three angulations: 60°, 75° and 90° Angled stylet group (n=60). Airway evaluation indexes were recorded preoperatively, the primary values were first time success rate for intubation, the secondary values included the time to intubation (TTI), the number of cases requiring more than one intubation attempt, and the time required for additional maneuvers. The incidence of airway trauma, sore throat or hoarseness postoperatively were also recorded.

Results: The first attempt success rate for intubation in the 75° Angled stylet group was significantly higher (98% versus 90% and 91.6%, P<0.05). The TTI for 60°, 75° and 90° Angled stylet group was 33s (16-45 [21-38]), 29s (17-33 [22-31]) and 39s (33-57 [35-48]) respectively. The number of intubation attempt and time of optimization maneuvers of 75° Angled stylet were significantly lower than other groups (3.3% versus 20%, 10%, P<0.05). 60° Angled stylet group saw more sore throats and hoarseness (10%, P=0.026).

Conclusion: 75° Angulation of the stylet during intubation for the obese with MMVL had the highest success rate and shortest time to intubatation.