Randomized controlled comparison of combined general and epidural anesthesia versus general anesthesia on diaphragmatic function after laparoscopic prostatectomy.

Background: Little is known about the effect of anesthetic technique on postoperative diaphragmatic function, which is associated with postoperative morbidity and recovery in patients undergoing laparoscopic pelvic surgery. The aim of this trial was to study the effect of combined general and epidural anesthesia versus general anesthesia on postoperative diaphragmatic function measured by ultrasonography in patients undergoing robot-assisted laparoscopic radical prostatectomy (RALRP).
Methods: Fifty-four patients undergoing RALRP were enrolled prospectively. Study population was randomized to receive general (group G, N.=27) or combined general and epidural (group GE, N.=27) anesthesia. Diaphragmatic inspiratory amplitude (DIA), and inspiration and expiration time (Ti and Te, respectively) were measured by M-mode ultrasonography during quiet/deep breathing and sniffing before the surgery and on postoperative days (POD) 1 and 2. Diaphragmatic inspiratory and expiratory velocities (DIV and DEV) were also calculated (DIA/Ti and DIA/Te, respectively). Spirometry was performed in addition to ultrasonography.
Results: DIA during deep breathing and sniffing was significantly decreased on POD 1 in group G, while it was preserved in group GE. These reductions in diaphragmatic function were restored to preoperative values on POD 2 in both groups. Vital capacity and peak expiratory flow were diminished in group G on POD 1 and 2. However, spirometry revealed no impairment in group GE except for vital capacity on POD 1. The correlation coefficients (R2) between diaphragmatic function and spirometry variables ranged from 0.231 to 0.286. Postoperaitve pain was comparable.
Conclusion: Combined general and epidural anesthesia may attenuate the severity of postoperative diaphragmatic dysfunction after RALRP compared to conventional general anesthesia.