Abdominal compartment syndrome !

Pressure inside the belly rises so high that it squeezes the organs and blood vessels, causing kidney, lung and heart problems. It needs urgent care.

Updated 2026-11-01

Structures involved

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Why it happens

What it is

Organ dysfunction caused by a sustained rise in intra-abdominal pressure. By international consensus (WSACS), intra-abdominal hypertension is a sustained pressure of 12 mmHg or more, and abdominal compartment syndrome is a sustained pressure above 20 mmHg with new organ dysfunction or failure.

Who gets it

Mostly seen in intensive care, after major trauma, emergency abdominal surgery, severe acute pancreatitis, major burns and massive fluid resuscitation. Intra-abdominal hypertension is common in critically ill patients; full abdominal compartment syndrome is less frequent but has high mortality. In Colombia and Latin America, trauma from road crashes and violence, severe pancreatitis and burns are relevant settings.

Causes

Primary: abdominal or pelvic injury or disease (haemoperitoneum, damage-control surgery, ruptured abdominal aortic aneurysm, severe pancreatitis)
Secondary: conditions outside the abdomen that need massive fluid resuscitation (sepsis, major burns, shock)
Ileus, bowel obstruction or colonic distension
Tense ascites or large intra-abdominal haematoma
Abdominal closure under tension or tight dressings

Risk factors

Massive fluid or blood transfusion and positive fluid balance
Shock, acidosis, hypothermia and coagulopathy
Major burns, especially of the trunk
Severe acute pancreatitis
Obesity and prone positioning
Mechanical ventilation with high airway pressures

Pathophysiology

The abdomen behaves like a closed box with limited compliance. As pressure rises, venous return through the inferior vena cava falls and cardiac output drops. The diaphragm is pushed up, raising airway pressures and impairing ventilation. Renal vein and parenchymal compression reduce kidney perfusion, causing oliguria. Gut perfusion falls, promoting ischaemia, bacterial translocation and more oedema, a vicious cycle. Intracranial pressure can also rise. Abdominal perfusion pressure equals mean arterial pressure minus intra-abdominal pressure.

Classification

Intra-abdominal hypertension grade I: 12–15 mmHg
Grade II: 16–20 mmHg
Grade III: 21–25 mmHg
Grade IV: above 25 mmHg
Primary, secondary or recurrent abdominal compartment syndrome

Symptoms and signs

Tense, distended abdomen
Falling urine output despite fluids
Rising peak airway pressures and worsening oxygenation in ventilated patients
Hypotension and tachycardia
Abdominal pain and difficulty breathing in awake patients

Diagnosis

Clinical: Abdominal examination is unreliable for estimating pressure; measurement is required in at-risk patients. Suspect it when organ dysfunction appears together with a tense abdomen and risk factors.
Tests: Intravesical (bladder) pressure is the reference method: measured at end-expiration, supine, with the transducer zeroed at the mid-axillary line and a small saline instillation. Creatinine, urine output, blood gases and lactate assess organ dysfunction.
Imaging: Imaging is supportive: CT may show a round-belly sign, compressed inferior vena cava, bowel wall thickening or fluid collections; ultrasound guides drainage of ascites or collections.

Differential diagnosis

Hypovolaemic or septic shock without raised abdominal pressure
Acute kidney injury from other causes
Acute mesenteric ischaemia
Tension pneumothorax (rising airway pressures with hypotension)
Bowel obstruction without organ failure

Goal of treatment

Lower intra-abdominal pressure and restore organ perfusion, keeping abdominal perfusion pressure adequate, while treating the underlying cause.

Treatment

Follow-up: Serial bladder pressure measurements in patients at risk; nursing priorities include correct measurement technique, urine output, ventilator pressures, haemodynamics and fluid balance.
Conservative: Evacuate intraluminal contents with nasogastric and rectal tubes, avoid head-up positions that raise pressure, loosen tight dressings, and avoid a positive fluid balance after initial resuscitation.
Medical: Adequate analgesia and sedation, short trials of neuromuscular blockade, prokinetics for ileus, and blood-product ratios that limit crystalloids in massive haemorrhage.
Procedure: Percutaneous catheter drainage of ascites, blood or other free fluid when feasible.
Surgical: Decompressive laparotomy with temporary abdominal closure (open abdomen, negative-pressure dressings) for established abdominal compartment syndrome that does not respond to other measures.

Complications

Acute kidney injury
Respiratory failure
Low cardiac output and shock
Bowel ischaemia and sepsis
Multiple organ failure and death
Open-abdomen complications: fistula, ventral hernia

Prognosis

Untreated abdominal compartment syndrome has very high mortality. Early recognition and decompression improve organ function, but survivors of an open abdomen often need later abdominal wall reconstruction.

Prevention

Restrictive, goal-directed fluid resuscitation after the initial phase
Routine bladder pressure monitoring in high-risk ICU patients
Considering leaving the abdomen open after damage-control surgery

Test yourself

Think of the answer, then tap the question to see it.

How is abdominal compartment syndrome defined by the WSACS consensus?

A sustained intra-abdominal pressure above 20 mmHg, with or without abdominal perfusion pressure below 60 mmHg, associated with new organ dysfunction or failure.

What is the reference method to measure intra-abdominal pressure?

Intravesical (bladder) pressure, at end-expiration, supine, zeroed at the mid-axillary line.

How is abdominal perfusion pressure calculated?

Mean arterial pressure minus intra-abdominal pressure.

What is the definitive treatment of refractory abdominal compartment syndrome?

Decompressive laparotomy with temporary abdominal closure (open abdomen).

Why does urine output fall in abdominal compartment syndrome?

Raised pressure compresses the renal veins and parenchyma and reduces cardiac output, lowering kidney perfusion.

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Educational information, not medical advice. For any symptom, see a health professional.

Sources: Intra-abdominal hypertension and the abdominal compartment syndrome: updated consensus definitions and clinical practice guidelines from the World Society of the Abdominal Compartment Syndrome (Intensive Care Medicine, 2013).

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Representative model, for educational purposes only.

Rectus abdominis highlighted on the Durgical 3D model