The relative merits of various methods of indirect measurement of intraabdominal pressure as a guide to closure of abdominal wall defects.

Visceral ischemia secondary to increased intraabdominal pressure (IAP) following closure of abdominal wall defects presents a serious postoperative problem. Currently, the method of closure and postoperative management are determined by clinical impressions rather than measurement of IAP. In this study various methods of indirectly measuring IAP were compared in 17 rabbits in which IAP was sequentially increased with an intraabdominal balloon. Vesical and inferior vena caval (IVC) pressures were found to have good statistical correlation with IAP. Other methods tested were gastric, rectal, superior vena caval, femoral and brachial artery, and rectus compartment pressures. All were found to be poor indicators of actual IAP. In nine of the rabbits, radiolabeled microspheres were used to assess cardiac output and visceral blood flow. Renal blood flow was very sensitive to increased IAP with dramatic impairment at IAP above 10 to 15 mmHg. Small intestinal flow was less sensitive and did not become significantly diminished until IAP exceeded 25 to 30 mmHg. Our studies suggest that vesical and IVC pressure monitoring should be used to evaluate IAP in the clinical setting. If IAP is in excess of 10 to 15 mmHg surgical intervention is indicated to prevent the development of renal ischemia.