Cerebral oxygen metabolism measured by near-infrared laser spectroscopy during laparoscopic cholecystectomy with CO2 insufflation.

To clarify the influence of carbon dioxide (CO2) on cerebral oxygen metabolism and blood volume during laparoscopy with CO2 insufflation in 12 patients who underwent laparoscopic cholecystectomy, changes in the concentrations of cerebral oxyhemoglobin (HbO2), reduced hemoglobin (HbR), total hemoglobin (total Hb), and oxidized cytochrome aa3 (Cyt aa3) were measured using near-infrared laser spectroscopy. Anesthesia was maintained with nitrous oxide (66%)-oxygen-sevoflurane. Pneumoperitoneum was maintained at an endoabdominal pressure of 10 to 12 mm Hg using CO2. Minute ventilation was constant before and after CO2 insufflation. End-tidal CO2 tension (PETCO2) increased significantly, from 33.9 +/- 1.3 to 52.8 +/- 3.3 mm Hg, after CO2 insufflation. The concentration of HbO2 increased significantly, from 0 to 7.3 +/- 2.8 mumol/L, after CO2 insufflation. The concentration of HbR increased significantly, from 0 to 2.2 +/- 1.2 mumol/L, after CO2 insufflation. Therefore, the concentration of total Hb increased significantly, from 0 to 8.8 +/- 3.3 mumol/L after CO2 insufflation. The concentration of Cyt aa3, however, did not change significantly during pneumoperitoneum. These results suggest that cellular respiration remained intact despite a concomitant increase in PETCO2 and cerebral blood volume during laparoscopy with CO2 insufflation.