Changes in airway dimensions after robot assisted surgeries in steep Trendelenburg position

Abstract

Robotic surgeries in the extreme Trendelenburg position can lead to changes in the airway dimensions. We conducted a prospective, observational trial to explore the use of ultrasound to quantify these changes in the airway dimensions and identify the factors associated with it. Fifty-two American society of Anaesthesiologists physical status I-II patients between 18 and 70 years of age of either sex scheduled to undergo robot assisted urological procedures in steep Trendelenburg position were enrolled. Anterior soft tissue thickness at the level of hyoid bone and vocal cords, tongue thickness, Malampatti grading and neck circumference were measured at predefined postoperative intervals in the immediate postoperative period, at 2-, 6- and 12-h period postoperatively. Linear stepwise regression analysis was done to explore the factors associated with change in anterior tissue thickness immediately after surgery. The mean difference (95%; CI) in the anterior soft tissue thickness in the immediate postoperative period at the level of hyoid was 0.023 (0.029-0.016) cm, p < 0.001 and at level of vocal cords was - 0.012 (- 0.017 to - 0.008) cm, p < 0.001 from the baseline. There was a significant increase in tongue thickness (0.002), Mallampati score (p = 0.002) and neck circumference (p < 0.001) in immediate postoperative period. The change in anterior tissue thickness at the level of hyoid was affected by total intraoperative fluids used (r = 0.602, p < 0.001), airway trauma (r = 0.275, p = 0.002) and duration of surgery (r = 0.243, p = 0.025). Significant changes in airway dimensions after robotic surgeries in Trendelenburg position persist till 2 h in the postoperative period which warrant vigilant monitoring for any airway compromise during this period.

Keywords: Airway assessment; Head down position.; Ultrasonography; Upper airway anatomy.