Table 1 Definitions
From: Abdominal Compartment Syndrome: pathophysiology and definitions
Definition 1 | IAP is the steady-state pressure concealed within the abdominal cavity. |
Definition 2 | APP = MAP - IAP |
Definition 3 | FG = GFP - PTP = MAP - 2 * IAP |
Definition 4 | IAP should be expressed in mmHg and measured at end-expiration in the complete supine position after ensuring that abdominal muscle contractions are absent and with the transducer zeroed at the level of the mid-axillary line. |
Definition 5 | The reference standard for intermittent IAP measurement is via the bladder with a maximal instillation volume of 25 mL of sterile saline. |
Definition 6 | Normal IAP is approximately 5–7 mmHg in critically ill adults. |
Definition 7 | IAH is defined by a sustained or repeated pathologic elevation of IAP ≥ 12 mmHg. |
Definition 8 | IAH is graded as follows: |
|  |    • Grade I: IAP 12–15 mmHg |
|  |    • Grade II: IAP 16–20 mmHg |
|  |    • Grade III: IAP 21–25 mmHg |
|  |    • Grade IV: IAP > 25 mmHg |
Definition 9 | ACS is defined as a sustained IAP > 20 mmHg (with or without an APP < 60 mmHg) that is associated with new organ dysfunction/failure. |
Definition 10 | Primary ACS is a condition associated with injury or disease in the abdomino-pelvic region that frequently requires early surgical or interventional radiological intervention. |
Definition 11 | Secondary ACS refers to conditions that do not originate from the abdomino-pelvic region. |
Definition 12 | Recurrent ACS refers to the condition in which ACS redevelops following previous surgical or medical treatment of primary or secondary ACS. |