Usefulness of intra-abdominal pressure in a predominantly medical intensive care unit

The deleterious effects of elevated intra-abdominal pressure (IAP) have been known for more than a century. The proposed objectives were to measure changes in IAP and analyze increase-related factors and complications and whether high IAP and its persistence are related to complications and mortality in a predominantly medical intensive care unit.

Over a 1-year period, we conducted a prospective cohort study in which IAP was measured using the bladder method. Hospitalization time, demographic variables, diagnosis on admission, APACHE II score, and clinical complications were recorded.

A total of 130 patients were studied. Overall mean IAP was 12.3 mm Hg (standard deviation [SD], 3.79; 95% confidence interval [CI], 11.7-13), and on the first day, 12.68 mm Hg (SD, 5.32; 95% CI, 11.8-13.6); maximum IAP was 16.4 mm Hg (SD, 4.6; 95% CI, 15.6-17.2). A positive correlation was found between IAP, APACHE (Acute Physiology And Chronic Health Evaluation) II, and age. Higher IAP values were independently associated with higher age, prolonged activated partial thromboplastin time, need for dialysis, and intolerance to enteral feeding. The value showing the best sensitivity and specificity in predicting mortality was persistence of IAP 20 mm Hg or greater for 4 days or more. The number of days with IAP 20 mm Hg or greater was a factor associated with a higher risk of death (odds ratio, 2.3). Patients who died showed a tendency to increased IAP.

In this study, a threshold IAP of 20 mm Hg and its permanence over time were the best predictive factors of complications and mortality. Among other relationships, we also observed that older patients had higher IAP. High IAP was a cause of intolerance to enteral nutrition.