II. Epidemiology

  1. Uncommon

III. Pathophysiology

  1. Abdominal Compartment Syndrome occurs when intraabdominal pressure (IAP) >20-25 mmHg
    1. Normal intraabdominal pressure is typically 5-7 mmHg
    2. Intraabdominal Hypertension is 12 mmHg or greater
    3. Pregnant patients and the morbidly obese may have intraabdominal pressures 10-15 mmHg
  2. Abdominal perfusion pressure (APP) = pMeanArterial - pIntraAbdominal
    1. where pMeanArterial is Mean arterial pressure (MAP)
    2. where pIntraAbdominal is Intraabdominal Pressure
    3. Abdominal perfusion pressure (APP) decreases when intraabdominal pressures rapidly rise
    4. Best outcomes occur when APP is maintained >60 mmHg
  3. Reduced abdominal perfusion pressure is associated with multiple extraabdominal adverse effects
    1. Decreased cardiac venous return
    2. Decreased renal perfusion
    3. Decreased diaphragm excursion
  4. Abdominal Compartment Syndrome is a diagnosis at the far end of the spectrum of decreased perfusion pressure
    1. Occurs when APP drops below adequate level (e.g. <60 mmHg)

IV. Causes

  1. Abdominal Trauma or hemoperitoneum
  2. Acute Pancreatitis
  3. Massive fluid third spacing (e.g. severe Burn Injury, multi-system Trauma, fluid Resuscitation)
  4. Massive Ascites
  5. Rapidly increasing free air
  6. Rapid bowel distention
  7. Retroperitoneal source (ruptured AAA, Pelvic Fracture with Hemorrhage)

VI. Signs

  1. General
    1. Critically ill appearing patient
  2. Abdomen
    1. Marked, firm, tense Abdominal Distention
    2. Mesenteric Ischemia
  3. Cardiopulmonary findings
    1. Hypotension, shock state (reduced Preload from IVC compression)
    2. Dyspnea and Hypoxia (reduced diaphragm excursion)
    3. Tachycardia
    4. Peripheral Edema
  4. Renal findings
    1. Oliguria and Renal Failure (decreased renal perfusion)

VII. Diagnosis: Abdominal Compartment Pressure Measurement

  1. Insert Foley Catheter
    1. Drain the catheter and clamp the tubing
    2. Instill 25-60 cc sterile water into side port and clamp
  2. Pressure measurement
    1. Technique
      1. Patient lies supine
      2. Keep head and body in same position each time a measurement is obtained
      3. Perform measurement at end expiration
      4. Ensure Abdomen as relaxed as possible (adequate sedation and analgesia)
    2. Option 1
      1. Connect Foley Catheter to pressure transducer (via 18 gauge needle or needleless system)
      2. Connect pressure transducer to Arterial Line, zeroing to the level of the Bladder
      3. Unclamp foley after obtaining measurement
    3. Option 2
      1. Raise the Foley Catheter end vertically and unclamp
      2. Measure the distance (in cm) from Bladder level to the level of rising water in the catheter
      3. Each 1.36 cm H2O is equivalent to 1 mmHg (positive if >27.2 to 34 cm H2O)
    4. Interpretation
      1. Significant pressure consistent with Abdominal Compartment Syndrome: >=20 mmHg
      2. Compartment Pressure >=12 mmHg should be rechecked every 4 to 6 hours
      3. Compartment Pressure <10mmHg is unlikely to be Abdominal Compartment Syndrome
      4. Compartment Pressure may be inaccurate in neurogenic Bladder

VIII. Management

  1. Emergent surgical decompression with exploratory laparotomy
  2. General
    1. Avoid excessive fluid infusions which may worsen fluid third spacing
    2. Use adequate Analgesics and sedation (may help relax the abdominal wall)
  3. Ventilated patients will have falsely elevated plateau pressures
    1. Increase allowed Ventilator pressures to ensure adequate Tidal Volume
    2. Position in reverse Trendelenburg
  4. Temporizing measures while awaiting surgical management
    1. Nasogastric Tube
    2. Foley Catheter
    3. Large volume Paracentesis of Ascites may be attempted if significant surgery delay
    4. Escharotomy in a burn patient when indicated
    5. Veno-venous hemofiltration Dialysis

IX. Prognosis

  1. Mortality: >60%

X. References

  1. Jhun and Roepke in Herbert (2016) EM:Rap 16(1): 16-7
  2. Gestring in Sanfrey and Bulger (2015) UpToDate, Wolters-Kluwer, accessed 1/6/2016
  3. Swaminathan and Hope in Herbert (2019) EM:Rap 19(2): 3
  4. Weingart and Swaminathan (2023) Critical Care Mailbag: Abdominal Compartment Syndrome, EM:Rap, accessed 8/1/2023

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