This article is intended to help nurses understand the physiologic rationale for the measurement of IAP. We were able to see a time relationship between increasing IAP and decreasing urine output in our patients. When measures were taken to reduce IAP, urine output improved. No causal relationship is implied because no formal study was done and many other factors may have influenced the IAP measurement and the renal function of these patients. Critical care nurses may be called upon to measure this clinical parameter more frequently in the future. Our experience with IAP may help other critical care nurses when they begin to measure the IAP of their patients.