Assessment of Compartment Syndrome After IV Infiltration
Compartment syndrome after IV infiltration is primarily a clinical diagnosis based on severe pain out of proportion to injury and pain with passive muscle stretching, with compartment pressure measurement reserved for equivocal cases or patients unable to cooperate with serial examination. 1
Clinical Assessment: The Foundation
The diagnosis is fundamentally clinical, and imaging plays no role in the acute diagnostic workup. 1 Your assessment should focus on:
Primary Clinical Signs (Early and Actionable)
Severe pain: This is the most sensitive clinical symptom, with strength of evidence level I. 1 Pain alone gives only approximately 25% chance of correctly diagnosing compartment syndrome, so it must be combined with other findings. 2
Pain with passive stretching: Passively stretch the muscles in the affected compartment—this is the most reliable early indicator. 1, 3
Paresthesia: Assess for numbness or tingling in the distribution of nerves traversing the compartment. 1
Paresis: Test for weakness of muscles within the affected compartment. 1
Late Signs (Indicating Irreversible Damage)
- Pulselessness and pallor: These should never be awaited before intervention, as they indicate irreversible tissue damage has already begun. 1 The upper extremity is involved in 89.6% of IV infiltration events. 4
Physical Examination Technique
- Palpate the suspected compartment: While palpation alone is unreliable in isolation, assess for tense swelling and firmness of the compartment. 2 In sedated patients, regularly assess limbs for swelling, muscle softness, and peripheral pulses or peripheral oxygen saturation. 5
When to Measure Compartment Pressure
Pressure measurement should be performed in specific scenarios: 1
- Uncertain or equivocal clinical diagnosis
- Patients unable to cooperate with serial examination (sedated, obtunded, or young children) 1, 3
- Peripheral neuropathy or diabetic neuropathy where pain sensation may be unreliable 1
Pressure Measurement Technique and Interpretation
Use appropriate equipment: An 18-gauge needle can overestimate compartment pressure by up to 18 mmHg compared to a slit catheter or side-ported needle, potentially leading to unnecessary fasciotomies. 2
Absolute pressure threshold: ≥30 mmHg suggests compartment syndrome (sensitivity 85%, specificity 90%), but should not be used in isolation without clinical correlation. 1
Differential pressure (preferred): Diastolic blood pressure minus compartment pressure <30 mmHg is the most recognized threshold for intervention when combined with clinical signs (strength of evidence level II). 1
Critical Pitfall to Avoid
Never rely solely on pressure measurements without clinical correlation—the absence of clinical signs is more accurate in excluding compartment syndrome than their presence is in making the diagnosis. 2 No single sign or investigation is guaranteed to diagnose or exclude compartment syndrome. 2
Laboratory Monitoring
While the diagnosis is clinical, laboratory tests help assess the extent of muscle damage:
Serum creatine kinase (CK): The most important laboratory marker, but may not peak until up to 24 hours after the initial event. 5, 6 Trending CK levels over 24-48 hours is more valuable than a single measurement. 6
Serum and urine myoglobin: Indicates muscle breakdown and risk of acute kidney injury. 6 Maintain urine output >2 ml/kg/h if myoglobinuria develops. 5
Renal function tests: Monitor creatinine and BUN for acute kidney injury secondary to myoglobinuria. 6
Reassuring Context for IV Infiltration
In a large retrospective review of 495 IV infiltration events, there were zero cases of compartment syndrome, and only 5.1% resulted in any long-term defects with no functional deficits of the extremity. 4 However, isolated cases of compartment syndrome after IV infiltration have been reported, particularly with certain medications like doxycycline. 7
Serial Examination Protocol
For alert, cooperative patients after IV infiltration:
Examine every 2-4 hours initially: Assess pain level, passive stretch pain, sensation, motor function, and compartment tension. 1
Continuous monitoring: May be the safest approach when serial examination is unreliable (sensitivity 90%, specificity 85%), though it shows little evidence of reducing missed compartment syndrome compared to serial clinical examination in alert patients. 2, 1
Immediate Management if Compartment Syndrome Suspected
- Remove all constricting dressings, bandages, or splints immediately 8
- Keep the limb at heart level: Avoid elevation (reduces arterial perfusion) or dependency (increases venous pressure) 8
- Optimize tissue perfusion: Avoid hypotension and maintain adequate blood pressure 8
- Emergent fasciotomy: If compartment syndrome is diagnosed, immediate fasciotomy of all involved compartments is required, as delays result in irreversible muscle necrosis and nerve damage within 6 hours. 1, 8