II. Epidemiology
- Uncommon
III. Pathophysiology
- Abdominal Compartment Syndrome occurs when intraabdominal pressure (IAP) >20-25 mmHg- Normal intraabdominal pressure is typically 5-7 mmHg
- Intraabdominal Hypertension is 12 mmHg or greater
- Pregnant patients and the morbidly obese may have intraabdominal pressures 10-15 mmHg
 
- Abdominal perfusion pressure (APP) = pMeanArterial - pIntraAbdominal- where pMeanArterial is Mean arterial pressure (MAP)
- where pIntraAbdominal is Intraabdominal Pressure
- Abdominal perfusion pressure (APP) decreases when intraabdominal pressures rapidly rise
- Best outcomes occur when APP is maintained >60 mmHg
 
- Reduced abdominal perfusion pressure is associated with multiple extraabdominal adverse effects- Decreased cardiac venous return
- Decreased renal perfusion
- Decreased diaphragm excursion
 
- Abdominal Compartment Syndrome is a diagnosis at the far end of the spectrum of decreased perfusion pressure- Occurs when APP drops below adequate level (e.g. <60 mmHg)
 
IV. Causes
- Abdominal Trauma or hemoperitoneum
- Acute Pancreatitis
- Massive fluid third spacing (e.g. severe Burn Injury, multi-system Trauma, fluid Resuscitation)
- Massive Ascites
- Rapidly increasing free air
- Rapid bowel distention
- Retroperitoneal source (ruptured AAA, Pelvic Fracture with Hemorrhage)
V. Symptoms
- Malaise
- Dyspnea
- Abdominal Pain
- Abdominal Bloating
VI. Signs
- 
                          General- Critically ill appearing patient
 
- 
                          Abdomen
                          - Marked, firm, tense Abdominal Distention
- Mesenteric Ischemia
 
- Cardiopulmonary findings- Hypotension, shock state (reduced Preload from IVC compression)
- Dyspnea and Hypoxia (reduced diaphragm excursion)
- Tachycardia
- Peripheral Edema
 
- Renal findings- Oliguria and Renal Failure (decreased renal perfusion)
 
VII. Diagnosis: Abdominal Compartment Pressure Measurement
- Insert Foley Catheter- Drain the catheter and clamp the tubing
- Instill 25-60 cc sterile water into side port and clamp
 
- Pressure measurement- Technique- Patient lies supine
- Keep head and body in same position each time a measurement is obtained
- Perform measurement at end expiration
- Ensure Abdomen as relaxed as possible (adequate sedation and analgesia)
 
- Option 1- Connect Foley Catheter to pressure transducer (via 18 gauge needle or needleless system)
- Connect pressure transducer to Arterial Line, zeroing to the level of the Bladder
- Unclamp foley after obtaining measurement
 
- Option 2- Raise the Foley Catheter end vertically and unclamp
- Measure the distance (in cm) from Bladder level to the level of rising water in the catheter
- Each 1.36 cm H2O is equivalent to 1 mmHg (positive if >27.2 to 34 cm H2O)
 
- Interpretation- Significant pressure consistent with Abdominal Compartment Syndrome: >=20 mmHg
- Compartment Pressure >=12 mmHg should be rechecked every 4 to 6 hours
- Compartment Pressure <10mmHg is unlikely to be Abdominal Compartment Syndrome
- Compartment Pressure may be inaccurate in neurogenic Bladder
 
 
- Technique
VIII. Management
- Emergent surgical decompression with exploratory laparotomy
- 
                          General- Avoid excessive fluid infusions which may worsen fluid third spacing
- Use adequate Analgesics and sedation (may help relax the abdominal wall)
 
- Ventilated patients will have falsely elevated plateau pressures- Increase allowed Ventilator pressures to ensure adequate Tidal Volume
- Position in reverse Trendelenburg
 
- Temporizing measures while awaiting surgical management- Nasogastric Tube
- Foley Catheter
- Large volume Paracentesis of Ascites may be attempted if significant surgery delay
- Escharotomy in a burn patient when indicated
- Veno-venous hemofiltration Dialysis
 
IX. Prognosis
- Mortality: >60%
X. References
- Jhun and Roepke in Herbert (2016) EM:Rap 16(1): 16-7
- Gestring in Sanfrey and Bulger (2015) UpToDate, Wolters-Kluwer, accessed 1/6/2016
- Swaminathan and Hope in Herbert (2019) EM:Rap 19(2): 3
- Weingart and Swaminathan (2023) Critical Care Mailbag: Abdominal Compartment Syndrome, EM:Rap, accessed 8/1/2023
