Effects of abdominal CO2 insufflation and changes of position on hepatic blood flow in anesthetized pigs.

During surgical laparoscopy, total hepatic blood flow (THBF) may be modified by CO2 insufflation, changes of tilt, ventilation with high tidal volume, hypercapnia, and anesthesia, but little information is available on the THBF during the procedure. To investigate the changes of hepatic blood flow following the combination of abdominal CO2 insufflation and changes of tilt, we measured mean arterial pressure (MAP), cardiac output, portal vein blood flow (PVBF), and hepatic artery blood flow (HABF) in anesthetized and ventilated pigs. CO2 was insufflated in the abdomen [intra-abdominal pressure (IAP) approximately 15 mmHg], and the hepatic blood flow was measured in various positions (horizontal, 10 degrees and 20 degrees head down, and 10 degrees and 20 degrees head up) before and during CO2 insufflation. CO2 insufflation in the horizontal position did not modify MAP, cardiac output, or PVBF but increased HABF. The head-up tilt decreased MAP, cardiac output, and both hepatic flows in the absence of pneumoperitoneum, but in the presence of abdominal CO2 only cardiac output and PVBF were decreased. The head-down tilt increased MAP and THBF in the absence of pneumoperitoneum, whereas no change was observed in the presence of abdominal CO2. The combination of CO2 insufflation and changes of tilt was not deleterious to hepatic perfusion. These results suggest that hepatic blood flow may be preserved during surgical laparoscopy if the tilt does not exceed 20 degrees and if IAP after CO2 insufflation remains <15 mmHg.