Introduction

A compartment syndrome exists when the increased pressure in a closed space threatens the viability of surrounding tissue. When this occurs in the abdomen, the rise of intra-abdominal pressure (IAP) may have a marked impact on end-organ function within and outside the abdominal cavity. The development of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are of importance in the care of critically ill patients. Intra-abdominal hypertension is a graded phenomenon that can be acute or chronic, primary or secondary and localized or generalized. Abdominal compartment syndrome is considered to be an ‘all-or-nothing’ phenomenon.

Definitions

Intra-abdominal pressure is the steady-state pressure within the abdominal cavity. It is expressed in mmHg and measured at end-expiration in the complete supine position after confirming the absence of abdominal muscle contractions and with the transducer zeroed at the level of the midaxillary line. Normal IAP is approximately 5 to 7 mmHg in critically ill adults. Intra-abdominal hypertension is defined as a sustained or repeated elevation of IAP to 12 mmHg or higher.

Abdominal compartment syndrome is defined as a sustained IAP above 20 mmHg associated with new organ dysfunction. Abdominal perfusion pressure (APP), where APP = MAP – IAP

Recognition of intra-abdominal hypertension and abdominal compartment syndrome

Clinical awareness

There still appears to be underrecognition of the syndrome and one must be aware of its existence to recognize it. Some clinicians dispute its existence.