Emergency Medicine Hub / Trauma & Orthopedics • 3 min read • 3 sections

Extremity Compartment Syndrome, Crush Injury & Rhabdomyolysis

Comprehensive emergency protocol for acute extremity compartment syndrome, crush syndrome, and traumatic rhabdomyolysis. Covers the clinical evaluation of muscle compartment ischemia, pain with passive stretch, objective intracompartmental pressure measurement (Stryker device), the Delta-P diagnostic threshold for emergent operative fasciotomy, and pre-extrication fluid resuscitation to prevent lethal reperfusion hyperkalemia.

Resuscitation Quick Actions • First 2 Minutes

High-Acuity

Earliest Clinical Sign

Severe pain out of proportion to exam and exquisite PAIN WITH PASSIVE STRETCH of compartment muscles

Delta-P Fasciotomy Trigger

Delta Pressure (Diastolic BP - Compartment Pressure) <= 30 mmHg -> Immediate Emergent Fasciotomy

Late Findings Warning

Pulselessness, pallor, and paralysis are late, ominous findings indicating established irreversible muscle death

Pre-Extrication Crystalloids

Infuse Normal Saline 1.0-1.5 L/hr BEFORE releasing crush compression to dilute washed-out potassium and myoglobin

Four Leg Compartments

Complete lower leg fasciotomy must decompress ALL 4 compartments: Anterior, Lateral, Superficial Posterior, Deep Posterior

Bottom-Line Clinical Pearl

Acute compartment syndrome is a surgical emergency; pain with passive stretch of muscles within the compartment is the earliest, most sensitive physical finding. A Delta Pressure (Diastolic BP minus Compartment Pressure) <= 30 mmHg mandates immediate emergency operative fasciotomy; irreversible nerve damage begins within 4 hours, and permanent muscle necrosis occurs by 6 to 8 hours. In crush injury, initiate aggressive IV isotonic crystalloids (1.0–1.5 L/hr) BEFORE releasing compressive entrapment to prevent fatal post-extrication hyperkalemic cardiac arrest.

1. Acute Compartment Syndrome: Pathophysiology & The 6 Ps

Acute compartment syndrome (ACS) occurs when tissue pressure within an unyielding, non-compliant osteofascial compartment rises above capillary perfusion pressure (typically > 30 mmHg). This compromises microvascular venular flow, creating tissue ischemia, worsening cellular edema, further elevating pressure in a lethal positive-feedback loop. Muscle undergoes irreversible ischemic necrosis within 6 to 8 hours, while peripheral nerves suffer permanent axonotmesis after 4 hours:

Symptom/Sign	Clinical Presentation & Sensitivity	Diagnostic & Pathophysiologic Significance
1. Pain Out of Proportion	Severe, unremitting, deep, burning, or aching pain completely disproportionate to the underlying injury, requiring escalating opioid doses.	Early sign. Often the earliest warning in alert patients. May be completely absent in comatose, sedated, or polytrauma patients (who require objective compartment pressure monitoring).
2. Pain with Passive Stretch	THE EARLIEST & MOST SENSITIVE PHYSICAL FINDING: Exquisite pain elicited by gently stretching the muscles that originate in or traverse the suspect compartment (e.g., passive plantarflexion of toes stretches the anterior compartment).	High sensitivity. When muscle fibers become ischemic, passive elongation maximally stimulates sensitive intramuscular stretch receptors.
3. Paresthesias & Sensory Loss	Numbness, tingling, or decreased two-point discrimination in the cutaneous distribution of the peripheral nerve traversing the compartment.	Early finding. Nerves are exquisitely sensitive to hypoxemia. (e.g., webspace between 1st and 2nd toes = Deep Peroneal nerve in anterior leg compartment).
4. Firmness/Tense Compartment	Tense, 'woody', non-compressible compartment on direct palpation.	Physical palpation alone has an accuracy of only 50%; objective pressure manometry is required if clinical suspicion exists.
5. Pallor & Poikilothermia	Pale, cool extremity with prolonged capillary refill (> 3-4 seconds).	Late finding. Indicates severe cutaneous and microvascular hypoperfusion.
6. Pulselessness & Paralysis	Absence of distal arterial pulses and inability to actively contract compartment muscles.	LATE, OMINOUS FINDINGS: Indicates established, irreversible transmural muscle infarction and Volkmann ischemic contracture. Never wait for pulselessness to diagnose compartment syndrome!

2. Objective Pressure Manometry: The Delta-Pressure Rule

Direct compartment pressure measurement (using a handheld Stryker device, transducer needle, or arterial line setup) is indicated in unresponsive, intubated, or equivocal patients. The diagnostic decision is governed by Perfusion Pressure (Delta Pressure):

Diagnostic Parameter	Formula & Numerical Threshold	Emergency Action & Interpretation
Delta Pressure (Delta-P) (GOLD STANDARD)	$$\Delta P = \text{Diastolic Blood Pressure} - \text{Compartment Pressure}$$ CRITICAL CUTOFF: Delta-P <= 30 mmHg	MANDATORY EMERGENCY OPERATIVE FASCIOTOMY: Perfusion depends on the gradient between systemic diastolic pressure and local tissue pressure. In a hypotensive trauma patient (Diastolic BP 45 mmHg), a compartment pressure of 20 mmHg produces a Delta-P of 25 mmHg, causing total ischemia despite an 'absolute' pressure < 30 mmHg!
Absolute Compartment Pressure	Intracompartmental Pressure > 30 mmHg	Historically used as an isolated cutoff. Valid in normotensive patients, but can miss compartment syndrome in hypotensive shock.
Technical Measurement Rules	Insert Stryker needle within 5 cm of the fracture site (highest pressure zone). Keep needle angle perpendicular to skin; zero device; inject 0.3 mL saline.	Measure ALL compartments of the involved anatomical limb: Lower leg has 4 distinct compartments (Anterior, Lateral, Superficial Posterior, Deep Posterior); Forearm has 3 compartments (Volar, Dorsal, Mobile Wad).

3. Crush Syndrome & Traumatic Rhabdomyolysis Protocol

Crush syndrome is the systemic manifestation of traumatic rhabdomyolysis resulting from prolonged, continuous pressure on large muscle masses (> 2 to 4 hours in building collapses, vehicular entrapment, or prolonged downtime):

Phase/Pathology	Lethal Reperfusion Cascade	Pre- & Post-Extrication Resuscitation Protocols
The 'Smiling Death' (Reperfusion Catastrophe)	While trapped, compressive force halts local circulation. The patient may look alert and stable. The moment the crushing object is removed, blood suddenly reperfuses the ischemic muscle, washing massive quantities of potassium, myoglobin, lactic acid, and thromboplastin into the systemic circulation, triggering instantaneous asystole.	PRE-EXTRICATION RESUSCITATION (CRITICAL): 1. Establish large-bore IV access in an uncompressed extremity BEFORE RELEASING THE CRUSH FORCE. 2. Infuse 0.9% Normal Saline at 1.0 to 1.5 L/hr for 2 hours prior to extrication. 3. Prepare IV Calcium Gluconate (30 mL) and Sodium Bicarbonate (100 mEq) at the scene to treat instantaneous hyperkalemic arrest upon release.
Myoglobinuric Renal Failure	Massive circulating myoglobin (heme pigment) filters across glomeruli into renal tubules, precipitating with Tamm-Horsfall proteins in acidic urine to form obstructive casts; generates toxic free iron and renal vasoconstriction.	Post-Extrication Fluid & Alkalinization Protocol: 1. Maintain high-volume urine output: target 200 to 300 mL/hour (3-4 mL/kg/h in children) using balanced crystalloids. 2. Urinary Alkalinization: Add Sodium Bicarbonate (50 mEq in 1 L D5W) targeting urine pH > 6.5 (prevents myoglobin cast dissociation into nephrotoxic ferrihemate). 3. Avoid loop diuretics (Furosemide acidifies tubular urine!).

Delta Pressure <= 30 mmHg: Emergency Operative Fasciotomy Mandate

Acute compartment syndrome is a surgical emergency with a narrow window for salvage. Never delay surgical mobilization for serial laboratory tests, CT scans, or prolonged observation. A Delta Pressure (Diastolic Blood Pressure minus Compartment Pressure) <= 30 mmHg is the definitive indication for immediate emergency operative fasciotomy. If a surgical specialist is delayed and transfer will exceed 2 to 4 hours, prepare for bedside emergency decompressive fasciotomy in the emergency department. Remember that a complete lower leg fasciotomy requires full two-incision longitudinal decompression of ALL FOUR COMPARTMENTS (Anterior, Lateral, Superficial Posterior, and Deep Posterior). Incompletely releasing only the superficial compartments guarantees deep muscle necrosis, foot drop, and limb amputation.

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