Abdominal compartment syndrome

Abdominal compartment syndrome (ACS) is caused by increased pressure in the abdominal cavity (i.e., intraabdominal hypertension) and is most commonly seen in critically ill or injured patients. ACS can be caused by reduced abdominal wall compliance, visceral edema, increased luminal contents, or increased abdominal contents and manifests with organ dysfunction, including acute kidney failure, respiratory failure, and shock. Diagnosis is made with urinary bladder pressure measurement, which provides an indirect measure of intraabdominal pressure. Initial conservative measures are aimed at improving abdominal wall compliance, reducing abdominal cavity volume, and optimizing fluid balance and organ perfusion. If these measures fail to lower intraabdominal pressure, urgent decompressive laparotomy is required, typically followed by temporary abdominal closure.

For compartment syndromes of the extremities, see “Acute compartment syndrome” and “Chronic compartment syndrome.”

• Intraabdominal pressure (IAP): the pressure within the abdominal compartment; normally < 12 mm Hg
• Intraabdominal hypertension (IAH): a sustained or recurrent elevation of IAP to ≥ 12 mm Hg
• Abdominal compartment syndrome: a sustained IAP > 20 mm Hg that is associated with organ dysfunction

• Reduced abdominal wall compliance
  • Abdominal or pelvic trauma
  • Abdominal surgery
  • Major burns
  • Prone positioning
  • Mechanical ventilation
  • Morbid obesity
• Visceral edema
  • Massive volume resuscitation
  • Sepsis
• Increased luminal contents
  • Gastroparesis
  • Mechanical bowel obstruction
  • Paralytic ileus
• Increased abdominal contents
  • Acute pancreatitis
  • Intraabdominal tumor or abscess
  • Massive ascites
  • Hemoperitoneum
  • Pneumoperitoneum
  • Peritoneal dialysis
  • Status post organ transplant

• Primary: associated with abdominopelvic injury or disease (e.g., abdominal trauma or surgery, acute pancreatitis)
• Secondary: associated with conditions that are not due to a primary abdominopelvic pathology (e.g., third spacing caused by sepsis and/or aggressive fluid resuscitation)
• Recurrent: reoccurrence after treatment of primary or secondary abdominal compartment syndrome

Increased intraabdominal pressure → organ dysfunction ^[1][3]

• Cardiovascular: ↓ cardiac output
• Renal: ↓ glomerular perfusion and urine output
• Gastrointestinal: intestinal hypoperfusion and ischemia
• Pulmonary: ↓ pulmonary volume; ↑ peak airway pressures
• Cerebral: ↑ intracranial pressure

Symptoms typically manifest acutely or subacutely in critically ill patients. ^[3]

• Gastrointestinal: tight and distended abdomen, nausea, vomiting
• Renal: from oliguria to progressive renal failure
• Cardiovascular: signs of increased central venous pressure, hypotension, tachycardia
• Pulmonary: tachypnea, wheezing
• Cerebral: signs of increased intracranial pressure

Urinary bladder pressure measurement ^[1][2][4]

• Gold standard test that provides indirect measurement of intraabdominal pressure ^[3]
• Indications: risk factors for IAH or abdominal compartment syndrome in a critically ill patient
• Frequency: continuously or every 4–6 hours
• Interpretation
  • ≥ 12 mm Hg: Intraabdominal hypertension
  • > 20 mm Hg with organ dysfunction: Abdominal compartment syndrome

Additional diagnostics

Additional diagnostics are used to assess severity and identify underlying causes.

• Laboratory studies
  • CBC
  • CMP
  • ABG
  • Lactate
• Imaging
  • CT scan: Characteristic findings include elevated diaphragm, increased abdominal diameter, compression of the inferior vena cava, and intestinal wall thickening. ^[5]
  • Abdominal x-ray: may show signs of an underlying abdominal condition (e.g., free intraperitoneal air)

Maintain a low threshold for monitoring urinary bladder pressure in at-risk patients because the physical exam is not reliable in detecting raised intraabdominal pressure. ^[1][2]

Approach ^[1][4]

• All patients
  • ICU admission for IAP monitoring and medical management
  • Treatment of the underlying condition (e.g., sepsis management)
• Refractory ACS: urgent surgical decompression

Monitor IAP continuously or every 4–6 hours and titrate interventions to a target IAP of ≤ 15 mm Hg. ^[1]

Medical and supportive therapy ^[1][4]

• Removal of constrictive dressings
• Optimization of body position
• Goal directed IV fluid therapy
• Adequate sedation and analgesia
• Reduction of enteral nutrition/NPO
• Placement of nasogastric and/or rectal tube
• Paracentesis and/or percutaneous drainage of fluid collections
• Diuresis and/or ultrafiltration

Surgical treatment ^[1][2][4]

• Indication: ACS refractory to medical management
• Techniques ^[6][7]
  • Laparotomy for abdominal decompression
  • Temporary abdominal closure with negative pressure wound therapy
  • Delayed definitive closure

• ICU admission
• Urgent general surgery consult
• Measure IAP continuously or every 4–6 hours.
• Initiate medical and supportive therapy.
  • Removal of constrictive dressings
  • Optimization of body position
  • Goal directed IV fluid therapy
  • Adequate sedation and analgesia
  • Reduction of enteral nutrition/NPO
  • Nasogastric and/or rectal tube placement
  • Paracentesis and/or percutaneous drainage of fluid collections
  • Diuresis and/or ultrafiltration
• Consider urgent surgical decompression if refractory to medical management.