Middle cerebral artery blood flow velocity during laparoscopic surgery in head-down position.

Laparoscopic surgery using intraperitoneal CO2 insufflation has become popular in many fields of surgical procedures. In this study, the authors examined the effects of intraperitoneal CO2 insufflation on the middle cerebral artery blood flow velocity (MCABFV) of patients in the head-down position. Fourteen patients undergoing laparoscopic surgery in the head-down position were studied. The MCABFV was measured at the following times: before CO2 insufflation and 15, 30, and 45 min after insufflation. The MCABFV increased significantly (61.4 +/- 14.5, 71.1 +/- 25.5, and 67.2 +/- 18.9 cm/s at 15, 30, and 45 min after insufflation, respectively) as compared with control (49.8 +/- 13.5 cm/s) following the CO2 insufflation. A positive correlation was observed between blood flow velocity and PaCO2 (y = 1.718 + 2.102x; r = 0.669). Our results suggest that the cerebral BFV is increased by intraperitoneal CO2 insufflation during laparoscopic surgery.