Changes in visceral blood flow with elevated intraabdominal pressure.

Elevated intraabdominal pressure (IAP) occurs with intraabdominal bleeding, with tense ascites, or after application of military anti-shock trousers to trauma patients. While changes in renal perfusion with elevated IAP have been documented, there are no data available on blood flow to other viscera. Under pentobarbital anesthesia an inflatable bag was placed intraabdominally to create graded increases in IAP in 9 adult mongrel dogs (20 kg). Hemodynamic parameters and organ blood flow (OBF) using radioactive microspheres were measured at baseline and after increasing the IAP to 20 and 40 mm Hg. The organ blood flow index (OBFI = OBF/cardiac output) was determined for each organ (stomach, duodenum, jejunum, ileum, colon, pancreas, liver, spleen, kidney, and adrenal gland). Elevated IAP caused a decrease in OBF for all organs measured except the adrenal glands where the OBF was increased. The OBFI was decreased significantly for all intraabdominal viscera except the renal cortex and the adrenal gland. These changes in OBF are more marked than can be accounted for by changes in cardiac output alone, suggesting that local control mechanisms may be responsible for changes in OBF. Our data raise the possibility that elevation in IAP may result in visceral ischemia and organ dysfunction.