Definitions

• IAH - intra-abdominal hypertension: is the pathologic elevation of IAP. IAH is defined by a sustained or repeated IAP > 12 mmHg or an APP < 60 mmHg.

• ACS - abdominal compartment syndrome

• IAP - intra-abdominal pressure: is the pressure concealed within the abdominal cavity. IAP varies with respiration. The normal adult IAP is around 5mmHg, but can be non-pathologically increased in the obese. Elevated IAP is a common finding among critically ill medical and surgical patients.

• APP - abdominal perfusion pressure (MAP-IAP) > 60 mmHg  assesses not only the severity of IAP, but also the adequacy of the patient’s systemic perfusion. APP = mean arterial pressure (MAP) – IAP.

• Primary ACS -  conditions associated with injury or disease in the abdomino-pelvic region requiring emergent surgical or angioradiological intervention (damage control laparotomy, bleeding pelvic fractures, massive retroperitoneal hematomas, failed nonoperative management) or following elective abdominal surgery (secondary peritonitis, liver transplantation)

• Secondary ACS - ACS due to conditions that do not originate from the abdomino-pelvic region (sepsis, capillary leak, major burns, other conditions requiring massive fluid resuscitation).

• Recurrent ACS - The condition in which ACS redevelops following previous surgical or medical treatment of primary or secondary ACS or following closure of a previous decompressive laparotomy