Box 1 Definitions Related to Intra-abdominal Pressure (IAP) According to the World Society for the Abdominal Compartment Syndrome (WSACS) 2013 Guidelines (Adapted from [8] Under the Terms of the Creative Commons Attribution Noncommercial License)
No. | Definition |
|---|---|
1. | IAP is the steady-state pressure concealed within the abdominal cavity |
2. | The reference standard for intermittent IAP measurements is via the bladder with a maximal instillation volume of 25 ml of sterile saline |
3. | IAP should be expressed in mmHg and measured at end expiration in the supine position after ensuring that abdominal muscle contractions are absent and with the transducer zeroed at the level of the midaxillary line |
4. | IAP is approximately 5–7 mmHg in critically ill adults |
5. | IAH is defined by a sustained or repeated pathological elevation in IAP ≥12 mmHg |
6. | ACS is defined as a sustained IAP >20 mmHg (with or without an APP <60 mmHg) that is associated with new organ dysfunction/failure |
7. | 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 | |
8. | Primary IAH or ACS is a condition associated with injury or disease in the abdominal pelvic region that frequently requires early surgical or interventional radiological intervention |
9. | Secondary IAH or ACS refers to conditions that do not originate in the abdominopelvic region |
10. | Recurrent IAH or ACS refers to the condition in which IAH or ACS redevelops following previous surgical or medical treatment of primary or secondary IAH or ACS |
11. | APP = MAP – IAP |
12. | A polycompartment syndrome is a condition where two or more anatomical compartments have elevated compartmental pressures |
13. | Abdominal compliance is a measure of the ease of abdominal expansion, which is determined by the elasticity of the abdominal wall and diaphragm. It should be expressed as the change in intra-abdominal volume per change in IAP |
14. | The open abdomen is one that requires a temporary abdominal closure due to the skin and fascia not being closed after laparotomy |
15. | Lateralization of the abdominal wall is the phenomenon where the musculature and fascia of the abdominal wall, most exemplified by the rectus abdominis muscles and their enveloping fascia, move laterally away from the midline with time |