Table 1.

Definitions.

Open abdomen	Non-closure of fascia and skin
Normal intra abdominal pressure (IAP)	5–7 mmHg in critically ill adults
Intra Abdominal Hypertension (IAH)	Sustained or repeated pathological elevation in IAP ≥12 mmHg
IAH grade 1	12–15 mmHg
IAH grade 2	16–20 mmHg
IAH grade 3	21–25 mmHg
IAH grade 4	>25 mmHg
Abdominal Compartment Syndrome	Sustained IAP >20 mmHg (with or without an abdominal perfusion pressure <60 mmHg) that is associated with new organ dysfunction/failure
Primary ACS	Associated with injury or disease in the abdomino-pelvic region
Secondary ACS	Without the presence of intra-abdominal injury
Recurrent ACS	Condition in which ACS develops after previous surgical or medical treatment of primary or secondary ACS