Shock, Sepsis & Multisystem · Topic 9 of 14

Extremity & Abdominal Compartment Syndrome

Multisystem · trauma complications

Extremity & Abdominal Compartment Syndrome

Pressure in a closed space cuts off perfusion: suspect it from pain out of proportion, confirm by pressure, and decompress — fasciotomy or laparotomy.

Key numbers

Compartment > 30 or ΔP ≤ 30ΔP ≤ 30 mmHg

Abdominal: IAP > 20 plus organ failureIAP > 20 mmHg

01 · Defined byCompartment > 30 or ΔP ≤ 30

Confirm by measured pressure: compartment pressure > 30 mmHg, or within 30 mmHg of diastolic BP (ΔP = diastolic − compartment pressure ≤ 30 mmHg), supports the diagnosis and the need for fasciotomy.

02 · Defined byAbdominal: IAP > 20 plus organ failure

Abdominal compartment syndrome = sustained intra-abdominal pressure > 20 mmHg (with or without abdominal perfusion pressure < 60 mmHg) plus new organ dysfunction; intra-abdominal hypertension starts at a sustained IAP ≥ 12 mmHg.

03 · Look forPain out of proportion on stretch

The earliest sign of extremity compartment syndrome is worsening pain out of proportion to the injury, increased by passive stretch of the compartment's muscles, with a tense compartment; paresthesia, paralysis, pallor and pulselessness come late.

Causes & risk factors

Why it happens

Causes: fractures, crush, reperfusion, burns, castsExtremity compartment syndrome follows fractures, severe contusion or crush, reperfusion after vascular repair, burns, snakebite, tight casts or dressings, and prolonged limb compression during coma or drug overdose.

Massive fluid resuscitation raises abdominal pressureMeasure IAP whenever a risk factor is present: massive fluid resuscitation or positive balance, polytransfusion, major trauma or burns, damage-control laparotomy, pancreatitis, ileus, ascites, sepsis, mechanical ventilation, obesity.

Presentation

What you'll see

Most common sites: lower leg and forearmExtremity compartment syndrome is most common in the lower leg (typically the anterior or posterior compartments) and the forearm, but also occurs in the upper arm and buttock.

Diagnosis & monitoring

Work-up

IAH grades I–IV: 12–15, 16–20, 21–25, > 25Intra-abdominal hypertension grades: I = IAP 12–15 mmHg, II = 16–20, III = 21–25, IV = > 25 mmHg.

Do right now

In this order

First moves

Pain out of proportion on stretch

→

Compartment > 30 or ΔP ≤ 30ΔP ≤ 30 mmHg

→

Urgent fasciotomy of every involved compartment

Why each step

Pain out of proportion on stretchThe earliest sign of extremity compartment syndrome is worsening pain out of proportion to the injury, increased by passive stretch of the compartment's muscles, with a tense compartment; paresthesia, paralysis, pallor and pulselessness come late.

Compartment > 30 or ΔP ≤ 30Confirm by measured pressure: compartment pressure > 30 mmHg, or within 30 mmHg of diastolic BP (ΔP = diastolic − compartment pressure ≤ 30 mmHg), supports the diagnosis and the need for fasciotomy.

Urgent fasciotomy of every involved compartmentRemove casts or constricting dressings and correct hypotension at once; unless pressure and symptoms resolve rapidly, perform urgent fasciotomy through long incisions that open all compartments, debriding nonviable muscle.

Management

Orders

Overt abdominal compartment syndrome: decompressive laparotomy must knowTreat overt abdominal compartment syndrome with decompressive laparotomy and a temporary open abdomen, aiming for fascial closure in the same hospital stay.

Measure pressures early in obtunded patientsKeep a low threshold to measure compartment pressure (normal ≤ 8 mmHg) in sedated, intubated or head-injured patients who cannot report pain; measure every at-risk compartment near the injury.

Measure IAP via bladder at end-expirationMeasure intra-abdominal pressure through the bladder with no more than 25 mL sterile saline, supine, at end-expiration, abdominal muscles relaxed, transducer zeroed at the midaxillary line; normal in ICU adults is about 5–7 mmHg.

Medical therapy for intra-abdominal hypertensionLower IAP medically: sedation and analgesia, a brief trial of neuromuscular blockade, nasogastric or rectal decompression of dilated bowel, avoiding a positive fluid balance after resuscitation, and percutaneous drainage of intraperitoneal fluid.

Red flags & don'ts

Avoid harm

Watch potassium and CK for rhabdomyolysis complicationNecrosing muscle causes rhabdomyolysis, hyperkalemia, AKI and infection: monitor potassium and CK and treat hyperkalemia and rhabdomyolysis alongside decompression.

The rules

Know these

Pulses and normal pressure do not exclude itDistal pulses, capillary refill and even a normal measured pressure do not exclude compartment syndrome — tissue perfusion fails long before arterial pulses disappear; the diagnosis stays clinical.

Extremity or abdominal compartment syndrome?

Commonly confused

Normal pressure	≤ 8 mmHg
How measured	Needle manometer in each at-risk compartment
Diagnostic threshold	> 30 mmHg or within 30 mmHg of diastolic BP
Definitive treatment	Fasciotomy of all compartments

More detail

Reference

Show 5 reference facts

Abdominal perfusion pressure = MAP − IAP; WSACS could make no recommendation on monitoring it or using it as a resuscitation target.

Primary abdominal compartment syndrome arises from abdominopelvic injury or disease; secondary from conditions outside the abdomen (sepsis, capillary leak, massive resuscitation); recurrent after prior treatment.

Untreated extremity compartment syndrome leads to muscle necrosis and later contracture; extensive necrosis may require amputation.

Hypotension or arterial insufficiency can cause compartment syndrome at only mildly raised compartment pressures, because tissue perfusion stops once compartment pressure exceeds capillary pressure (about 8 mmHg).

Mortality after decompressive laparotomy remains high (reported up to 50%), so prevention — protocolized IAP monitoring and avoiding over-resuscitation — matters.

Pearl

Pain out of proportion that worsens with passive stretch is compartment syndrome until proven otherwise — pulses vanish only when it is too late.

Sources · Merck Manual Professional — Compartment Syndrome (Mar 2025) · Merck Manual Professional — How To Measure Compartment Pressure in the Lower Leg · Kirkpatrick AW et al. 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 Med 2013;39:1190–1206 · Merck Manual Professional — Burns (over-resuscitation and abdominal compartment syndrome) · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).