Intra-abdominal hypertension and abdominal compartment syndrome in patients admitted to the ICU

Intra-abdominal hypertension is frequently present in critically ill patients and is an independent predictor for mortality. Risk factors for intra-abdominal hypertension and abdominal compartment syndrome have been widely investigated. However, data are lacking on prevalence and outcome in high-risk patients. Our objectives in this study were to investigate prevalence and outcome of intra-abdominal hypertension and abdominal compartment syndrome in high-risk patients in a prospective, observational, single-center cohort study.

Between March 2014 and March 2016, we included 503 patients, 307 males (61%) and 196 females (39%). Patients admitted to the intensive care unit with a diagnosis of pancreatitis, elective or emergency open abdominal aorta surgery, orthotopic liver transplantation, other elective or emergency major abdominal surgery and trauma were enrolled. One hundred and sixty four (33%) patients developed intra-abdominal hypertension and 18 (3.6%) patients developed abdominal compartment syndrome. Highest prevalence of abdominal compartment syndrome occurred in pancreatitis (57%) followed by orthotopic liver transplantation (7%) and abdominal aorta surgery (5%). Length of intensive care stay increased by a factor 4 in patients with intra-abdominal hypertension and a factor 9 in abdominal compartment syndrome, compared to patients with normal intra-abdominal pressure. Rate of renal replacement therapy was higher in abdominal compartment syndrome (38.9%) and intra-abdominal hypertension (8.2%) compared to patients with normal intra-abdominal pressure (1.2%). Both intensive care mortality and 90-day mortality were significantly higher in intra-abdominal hypertension (4.8% and 15.2%) and abdominal compartment syndrome (16.7% and 38.9%) compared to normal intra-abdominal pressure (1.2% and 7.1%). Body mass index (odds ratio 1.08, 95% confidence interval 1.03-1.13), mechanical ventilation at admission (OR 3.52, 95% CI 2.08-5.96) and Apache IV score (OR 1.03, 95% CI 1.02-1.04) were independent risk factors for the development of intra-abdominal hypertension or abdominal compartment syndrome.

The prevalence of abdominal compartment syndrome was 3.6% and the prevalence of intra-abdominal hypertension was 33% in this cohort of high-risk patients. Morbidity and mortality increased when intra-abdominal hypertension or abdominal compartment syndrome was present. The patient most at risk of IAH or ACS in this high-risk cohort has a BMI > 30 kg/m² and was admitted to the ICU after emergency abdominal surgery or with a diagnosis of pancreatitis.