Airway Pressure Variations During Robot Assisted Laparoscopic Radical Prostatectomy: Comparative Evaluation of Modified Z Trendelenburg Position and Conventional Steep Trendelenburg Position

Background and Aims: The steep Trendelenburg position (STP) (40 degree head down, low lithotomy) with pneumoperitoneum optimizes surgical exposure during robotic prostatectomy at the expense of increased respiratory, cardiovascular, intracranial, and intraocular pressures. We aimed to compare airway pressures in STP and modified Z Trendelenburg position (MZTP, horizontal upper torso positioning, low lithotomy position with OT table break at lower thoracic vertebral level by 15 to 20 degree head up) along with any difference in surgical exposure in both the groups. Methods: In this prospective, double blind, observational study, Ventilator airway parameters (Peak, plateau, mean airway pressures) were recorded in 100 patients STP (n=50), MZTP (n=50) undergoing robotic radical prostatectomy. Time points included, T0 -Post intubation after 10 minutes, T1 - 5 minutes after STP / MZTP without pneumoperitoneum, T2 - STP / MZTP with pneumoperitoneum 20 mmHg at the end of port placement, T3 - 10 minutes after robot dock with Pneumoperitoneum of 15 mmHg, T4 - 30 minutes after robot dock, T5 - 60 minutes after robot dock, T6 - 120 minutes after robot dock, T7 - Reposition to supine, T8-skin closure. Student t test was used for comparison of quantitative outcome parameters. Results: Peak, plateau, mean airway pressures were lower in MZTP at all time points (p<0001) with lesser incidence of conjunctival oedema (MZTP=4, STP=10) and no difference in surgical exposure. Conclusion: MZTP can be a better position to perform Robotic radical prostatectomy. A lesser increase in airway pressures causes less barotrauma and better lung protection.