Incidence, risk factors and outcome associations of intra-abdominal hypertension in critically ill patients

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are significantly associated with morbidity and mortality. We performed a prospective observational study and applied recently published consensus criteria to measure and describe the incidence of IAH and ACS, identify risk factors for their development and define their association with outcomes. We studied 100 consecutive patients admitted to our general intensive care unit. We recorded relevant demographic, clinical data and maximal (max) and mean intra-abdominal pressure (IAP). We measured and defined IAH and ACS using consensus guidelines. Of our study patients, 42% (by IAPmax) and 38% (by IAPmean) had IAH. Patients with IAH had greater mean body mass index (30.4 +/- 9.6 vs 25.4 +/- 5.6 kg/m(2), P=0.005), Acute Physiology and Chronic Health Evaluation III score (78.2 +/- 28.5 vs 65.5 +/- 29.2, P=0.03) and central venous pressure (12.8 +/- 4.8 vs 9.2 +/- 3.5 mmHg, P <0.001), lower abdominal perfusion pressure (67.6 +/- 13.5 vs 79.3 +/- 17.3 mmHg, P <0.001) and lower filtration gradient (51.2 +/- 14.8 vs 71.6 +/- 17.7 mmHg; P <0.001). Risk factors associated with IAH were body mass index >= 30 (P <0.001), higher central venous pressure (P <0.001), presence of abdominal infection (P=0.005) and presence of sepsis on admission (P=0.035). Abdominal compartment syndrome developed in 4% of patients. IAP was not associated with an increased risk of mortality after adjusting for other confounders. We conclude that, in a general population of critically ill patients, using consensus guidelines, IAH was common and significantly associated with obesity and sepsis on admission. In a minority of patients, IAH was associated with abdominal compartment syndrome. In this cohort IAH was not associated with an increased risk of mortality.