Intra-abdominal hypertension is an independent cause of postoperative renal impairment

Hypothesis: Intra-abdominal hypertension exerts an effect on renal function independent of other confounding variables. Design: A prospective study of all patients admitted to an intensive care u nit following abdominal surgery was undertaken between September 1, 1994, a nd July 31, 1997, in a single university hospital. Main Outcome Measures: Intra-abdominal pressure (IAP) was measured even 8 h ours (normal IAP, 0-17 mm Hg); 18 mm Hg or higher was considered increased. Forward stepwise logistic regression determined whether intra-abdominal hy pertension is an independent cause of renal impairment. Results: A total of 263 patients (174 after emergency surgery), whose mean +/- SD age was 61.0 +/- 18.7 years and Acute Physiology and Chronic Health Evaluation II score was 14.6 +/- 7.7, were studied. Intra-abdominal pressur e was increased in 107 (40.7%) of the 263 patients. Renal impairment occurr ed in 35 (32.7%) of the 107 patients with intra-abdominal hypertension and in 22 (14.1%) of the 156 with a normal IAP (odds ratio, 1.62-5.42). Using t he Wald maximizing model, renal impairment was independently associated wit h 4 antecedent factors. hypotension (P =.09), sepsis (P =.006), age older t han 60 years (P=.03), and increased IAP (P=.004). Conclusions: To our knowledge, for the first time in a large clinical study , IAP has been shown to be an independent cause of renal impairment, and it ranks in importance after hypotension, sepsis, and age older than 60 years . Surgeons need to be aware of the importance of intra-abdominal hypertensi on in patients post-operatively.