How to Check for Compartment Syndrome
Diagnose compartment syndrome primarily through clinical assessment, with pain out of proportion to injury being the earliest and most reliable warning sign, and use direct compartment pressure measurement only when the diagnosis remains uncertain, particularly in obtunded or uncooperative patients. 1
Clinical Assessment Algorithm
Primary Clinical Signs (In Order of Appearance)
Pain out of proportion to injury is your most important early indicator and should trigger immediate heightened surveillance 1, 2. This symptom alone has only 25% positive predictive value, but its absence makes compartment syndrome unlikely 3.
Pain on passive stretch of the affected muscle compartment is considered the most sensitive early sign 1, 2. When combined with severe pain, the positive predictive value increases to 68% 3.
Progressive firmness/tension of the compartment develops as intracompartmental pressure rises 1. However, palpation alone is unreliable with only 54% sensitivity and 76% specificity in children 3, 1.
Late Signs (Indicate Irreversible Damage)
Paresthesia (sensory changes) results from nerve ischemia 1.
Paralysis (motor deficits) is a late sign indicating significant tissue damage has already occurred 3, 1. When pain, pain on passive stretch, and paralysis are all present, positive predictive value reaches 93%, but by this stage irreversible muscle ischemia has likely occurred 3.
Pulselessness, pallor, and decreased temperature are extremely late signs indicating severe tissue damage 1, 2. Never wait for these signs to make the diagnosis 4, 1.
Structured Documentation Approach
Use standardized scoring charts (such as those from the UK Royal College of Nursing) to maintain heightened awareness and ensure systematic assessment 3. While clinical signs are not completely reliable, their serial recording helps track progression 3.
Compartment Pressure Measurement
When to Measure
Measure compartment pressures when:
- The diagnosis remains in doubt despite clinical assessment 3, 1
- The patient is obtunded, confused, sedated, or uncooperative and cannot reliably report pain 3, 1
- The patient is a young child who cannot communicate symptoms effectively 1
Measurement Techniques
Available methods include: traditional needle manometry, multiparameter monitors (typically used for arterial blood pressure), or dedicated transducer-tipped intracompartmental pressure monitors 3, 1.
Technical considerations: An 18-gauge needle may overestimate compartment pressure by up to 18 mmHg compared to a slit catheter or side-ported needle 3. Measure pressure in all relevant compartments of the affected limb 3.
Pressure Thresholds for Diagnosis
Absolute pressure threshold: Compartment pressure ≥30 mmHg traditionally indicates compartment syndrome 3, 1.
Differential pressure threshold (preferred): Fasciotomy is indicated when the differential pressure (diastolic blood pressure minus compartment pressure) is ≤30 mmHg 3, 1. This accounts for the patient's perfusion pressure—hypotensive patients develop ischemia at lower absolute compartment pressures, while hypertensive patients can tolerate higher pressures 3.
Combined approach: When differential pressure threshold is combined with continuous pressure monitoring in tibial shaft fractures, sensitivity reaches 94% with 98% specificity 3.
Continuous vs. Single Measurement
Continuous monitoring may be considered in high-risk, obtunded patients who cannot undergo serial clinical examination 3, 1. However, there is little evidence that continuous monitoring reduces missed cases compared to serial examination in alert, cooperative patients 3.
Critical Pitfalls to Avoid
Never wait for late signs (pallor, pulselessness, paralysis) as these indicate significant irreversible tissue damage has already occurred 4, 1, 2.
Never rely solely on palpation for diagnosis—it has only 54% sensitivity and 76% specificity 3, 1, 2.
Never elevate the limb excessively when compartment syndrome is suspected, as this further decreases perfusion pressure and worsens ischemia 4, 1, 2. Position the limb at heart level 4, 1.
Never delay diagnosis in obtunded patients—measure compartment pressures earlier in these populations rather than waiting for clinical signs that cannot be elicited 3, 1, 2.
Never miss compartment syndrome in patients without fractures—it can occur with soft tissue injuries alone, including crush injuries, vascular injuries, burns, and in patients on anticoagulation 1, 2.
High-Risk Populations Requiring Heightened Surveillance
- Young men under 35 years with tibial fractures 1
- Patients with high-energy trauma or crush injuries 1
- Patients with vascular injuries or burns 1
- Patients on anticoagulation therapy 1
- Any patient after revascularization for acute limb ischemia 2
Immediate Management When Suspected
Remove all constricting dressings, casts, or splints immediately 4, 1.
Position the limb at heart level (not elevated) 4, 1, 2.
Arrange urgent surgical consultation for fasciotomy without delay 4, 1.
Measure compartment pressures only if diagnosis remains in doubt and the patient cannot reliably report symptoms 1, 2.