Intra-abdominal Hypertension and Postoperative Kidney Dysfunction in Cardiac Surgery Patients

Objective: To determine the incidence of intra-abdominal hypertension (IAH) in adult cardiac surgery patients and its association with postoperative kidney dysfunction.

Design: Prospective cohort study.

Setting: Single tertiary-care university hospital.

Participants: Forty-two adult patients having cardiac surgery with cardiopulmonary bypass.

Interventions: Intra-abdominal pressure (IAP) was measured preoperatively, immediately after surgery, and at the following time points after surgery: 3 hours, 6 hours, 12 hours, and 24 hours. Urine neutrophil gelatinase-associated lipocalin (NGAL) levels were measured as a marker of kidney dysfunction at the following time points: prior to surgery, immediately after surgery, 4 to 6 hours after surgery, and 16-to-18 hours after surgery.

Measurements and main results: Two hundred fifty-two IAPs were measured, and 90 (35.7%) showed IAH. Thirty-five of 42 patients (83.3%) had IAH at 1 time point or more. Peak urine NGAL levels were lower in patients with normal IAP (mean difference = -130.6 ng/mL [95% CI = -211.2 to -50.1], p = 0.002). There was no difference in postoperative kidney dysfunction by risk, injury, failure, loss of kidney function, and end-stage kidney disease (RIFLE) criteria in patients with normal IAP (mean difference = -31.4% [95% CI = -48.0 to 6.3], p = 0.09). IAH was 100% sensitive for predicting postoperative kidney dysfunction by RIFLE criteria, but had poor specificity (54.8%).

Conclusions: IAH occurs frequently during the perioperative period in cardiac surgery patients and may be associated with postoperative kidney dysfunction.