The effect of pneumoperitoneum in the steep Trendelenburg position on cerebral oxygenation

Abstract

daVinci robot-assisted laparoscopic radical prostatectomy (RALP) requires pneumoperitoneum in the steep Trendelenburg position, which results in increased intracranial pressure and cerebral blood flow. The aim of this study was to evaluate the effect of pneumoperitoneum in a 30 degrees Trendelenburg position on cerebral oxygenation using regional cerebral oxygen saturation (rSO2). Thirty-two male patients of ASA I and II physical status without previous episodes of cerebral ischemia or hemorrhage undergoing daVinci RALP were enrolled. The rSO2 was continuously monitored with near-infrared spectroscopy (INVOS) 5100) during the study period. Measurements were obtained immediately after anesthesia induction (T0; baseline), 5 min after a 30 degrees Trendelenburg position (T1), 5 min after 15 mmHg pneumoperitoneum in a supine position (T2), 30, 60 and 120 min after the pneumoperitoneum in a Trendelenburg position (T3, T4 and T5, respectively) and after desufflation in a supine position (T6). The change in the left and right rSO2 was statistically significant (Left P=0.004 and Right P=0.023). Both the right and the left rSO2 increased significantly during pneumoperitoneum in a Trendelenburg position (from T3 to T5) and at T6 compared with the baseline value at T0. The partial pressure of carbon dioxide (PaCO2) was increased significantly at T2, T3, T5 and T6 compared with the baseline value at T0. During daVinci RALP, cerebral oxygenation, as assessed by rSO2, increased slightly, which suggests that the procedure did not induce cerebral ischemia. The PaCO2 should be maintained within the normal limit during pneumoperitoneum in a Trendelenburg position in patients undergoing daVinci RALP because the rSO2 increased in conjunctions with the increase in PaCO2.