What are the key components of clinical assessment for suspected compartment syndrome?

Clinical Assessment of Compartment Syndrome

The key components of clinical assessment for suspected compartment syndrome include repetitive evaluation (every 30-60 minutes) for pain (especially on passive stretch), tension, paresthesia, and paresis, along with compartmental pressure monitoring when indicated.

Risk Factors for Compartment Syndrome

Identifying patients at high risk for compartment syndrome is the first step in clinical assessment:

• Fractures (especially tibial shaft fractures)
• Crush injuries
• Hemorrhagic injuries
• Reperfusion after ischemia
• Hypotension
• High-energy injuries
• Open fractures
• Intramedullary nailing
• Anticoagulation
• Vascular injuries
• Burns
• Tourniquet use
• Haemophilia

Clinical Signs and Symptoms

The clinical assessment should focus on the "6 Ps," with emphasis on the early signs:

Early Signs (Most Important)

• Pain: Out of proportion to injury
• Pain on passive stretch: Considered the most sensitive early sign
• Paresthesia: Decreased sensation in the affected area
• Pressure/Tension: Swelling and firmness of the compartment

Late Signs (Indicate Irreversible Damage)

• Pulselessness: Absent pulses
• Pallor: Pale appearance
• Paralysis: Motor weakness or loss of function

It's crucial to understand that pulselessness, pallor, and paralysis are late signs that often reflect irreversible damage 1. The absence of clinical signs is more accurate in excluding compartment syndrome than their presence is in confirming it 1.

Diagnostic Approach

1. Serial Clinical Examinations:

   • Perform assessments every 30-60 minutes during the first 24 hours in high-risk patients 1
   • Use standardized scoring charts to maintain awareness 1
   • Assess all compartments in the affected limb

2. Compartment Pressure Measurement:

   • Indicated when clinical diagnosis is uncertain
   • Essential in obtunded, confused, or uncooperative patients 1
   • Measurement techniques:
     • Needle manometry
     • Multiparameter monitors
     • Dedicated transducer-tipped monitors
   • Avoid using 18-G needles (may overestimate pressure by up to 18 mmHg) 1

3. Pressure Thresholds for Intervention:

   • Absolute pressure ≥30 mmHg is concerning 1
   • Differential pressure (diastolic BP - compartment pressure) is more reliable:
     • Fasciotomy indicated when differential pressure is <30 mmHg with clinical signs 1
     • In hypotensive patients, consider fasciotomy at lower absolute thresholds (≥20 mmHg) 1

4. Laboratory Assessment:

   • Elevated creatine phosphokinase (CPK) levels
   • Elevated myoglobin levels
   • Assess for hyperkalemia and hypocalcemia (may cause arrhythmias) 2

Special Considerations

1. Sedated or Unconscious Patients:

   • Lower threshold for compartment pressure measurement
   • Consider continuous pressure monitoring in high-risk cases
   • More liberal use of fasciotomy may be warranted 1

2. Children:

   • May have higher baseline compartment pressures
   • Pain assessment can be challenging
   • Monitor analgesic requirements - increasing needs may signal developing compartment syndrome 3

3. Reperfusion Scenarios:

   • Particularly vigilant monitoring after revascularization
   • Consider prophylactic fasciotomy in high-risk cases 1

Common Pitfalls to Avoid

1. Relying solely on clinical signs: Individual clinical signs have low sensitivity and positive predictive value 1

2. Delayed diagnosis: Benefits of fasciotomy decrease significantly when performed late (>8 hours after onset) 1

3. Overlooking compartment syndrome in non-fracture cases: Can occur with soft tissue damage alone 1

4. Waiting for late signs: By the time pulselessness and pallor develop, irreversible damage has likely occurred 1

5. Inadequate monitoring frequency: High-risk patients require vigilant, frequent assessments 1

6. Excessive limb elevation: This may reduce blood flow and worsen compartment syndrome 1

7. Missing subtle increases in pain medication requirements: May be an early warning sign before classic symptoms develop 3

By implementing a systematic approach to clinical assessment with frequent monitoring of early signs and appropriate use of compartment pressure measurements, clinicians can identify compartment syndrome early and intervene before irreversible tissue damage occurs.