Effect of increased intraabdominal pressure on cardiac output and tissue blood flow assessed by color-labeled microspheres in the pig

Background: Studies of the hemodynamic effects associated with the pneumope ritoneum have had controversial results. We set out to investigate the effe ct of increased intraabdominal pressure (IAP) on cardiac output and tissue blood flow in Various intraabdominal and extraabdominal organs using the co lor-labeled microsphere (CLM) technique. Methods: IAP was induced by CO2 insufflation in anesthetized pigs; 0, 5, an d 10 mmHg was used in the low-pressure group and 0, 15, and 24 mmHg in the high-pressure group. Tissue blood flow (ml.min(-1).g(-1)) and cardiac outpu t (CO) (ml/min) were determined by the CLM technique. Results: CO decreased at IAP greater than or equal to 15 mmHg. Arterial PaC O2 and hydrogen ion concentration increased in response to all levels of IA P. Arterial PaO2, oxygen saturation, and bicarbonate ion concentration rema ined unchanged. Low IAP did not influence tissue blood flows in most of the organs. However, in the spleen, pancreas, esophagus, and gastric mucosal s pecimens, tissue blood flow was significantly decreased at 24 mmHg. Conclusion: The level of IAP used in current practice (10-12 mmHg) appears to be safe with regard to hemodynamic variables and tissues blood flow; how ever, higher levels may induce a decrease in cardiac output and tissue bloo d flow.