Background: We investigated changes in portal venous blood flow (PVBF) during carbon dioxide (CO2) pneumoperitoneum to evaluate the effects of different insufflation profiles and body positions.
Methods: An established rat model was extended by implanting a portal vein flow probe that would enable us to measure PVBF for 60 min [t0-t60] in animals subjected to a CO2 pneumoperitoneum with an intraabdominal pressure (IAP) of 9 mmHg. Forty-eight male Sprague-Dawley rats were randomized into the following four experimental and two control groups: decompression group D1 ( n = 8), desufflation for 1 min every 14 min; decompression group D2 ( n = 8), desufflation for 5 min, after 27 min; position group P1 ( n = 8), 35 degrees head-up position; position group P2 ( n = 8), 35 degrees head-down position; negative control group C1 ( n = 8), no insufflation; positive control group C2 ( n = 8), constant IAP of 9 mmHg for 60 min.
Results: Pneumoperitoneum and body positions, respectively, reduced PVBF [t1-t60] significantly ( p < 0.001) by 32.0% C2, 32.8% D1, 31.1% D2, 40.8% P1, and 48.5% P2, as compared to PVBF at t0 in each group. There was a significant difference in PVBF reduction between P1 and P2 and also between C2 and both P1 and P2 ( p < 0.04).
Conclusions: CO2 pneumoperitoneum reduces PVBF significantly (>30%). Extreme body positions (35 degrees tilt) significantly intensify PVBF reduction. PVBF reduction is significantly more dramatic in subjects placed in a 35 degrees head-down position. Short desufflation periods did not improve mean PVBF, but it may have beneficial immunological and oncological effects that warrant further investigation.