Compartment syndrome after revascularisation

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

After arterial flow is restored, damaged capillaries leak fluid into muscle that has little room to expand inside fixed fascia. Compartment pressure rises, the gradient between diastolic arterial pressure and tissue pressure falls, and capillary flow becomes inadequate. This can occur despite a patent repair and palpable pedal pulses. Prolonged severe ischaemia, large-volume reperfusion, crush injury, intraoperative hypotension, venous obstruction, bleeding and delayed presentation increase risk.

Diagnosis is primarily clinical and depends on repeated timed examination. Pain that is disproportionate or increasing, pain when the muscles are passively stretched, tense swelling, rising opioid requirement and evolving nerve dysfunction are the key pattern. Pain can disappear when nerves and muscle are infarcted; paralysis, anaesthesia and pulselessness are late findings. An obtunded, intubated or densely blocked patient cannot provide the usual warning and needs more objective surveillance.

BOASt distinguishes a clear diagnosis from uncertainty. A clear clinical diagnosis proceeds directly to immediate surgical decompression. Pressure measurement is for inconclusive signs or incomplete assessment: record the pressure in every suspected compartment together with the diastolic blood pressure. Complete fasciotomy opens the whole length of all involved compartments, permits muscle assessment and leaves wounds open for planned re-inspection, debridement and later coverage.

Key points

Suspect the trajectory: worsening pain, passive-stretch pain, tense swelling, analgesic escalation and neurological change after revascularisation matter more than one earlier normal examination.
Palpable distal pulses do not exclude compartment syndrome because capillary perfusion fails before flow in the larger arteries necessarily disappears.
When the clinical diagnosis is clear, immediate open decompression follows; do not delay fasciotomy to obtain compartment pressures, imaging or a creatine kinase result.
BOASt requires hourly assessment of patients at risk, documenting time, pain, analgesia and response, neurological and vascular status, interpretation and management rationale.
Release circumferential dressings to skin, expose and elevate the limb, and re-evaluate within 30 minutes while correcting systemic hypotension and escalating senior review.
Use pressure measurement when clinical signs are inconclusive or assessment is incomplete, measuring every suspected compartment with concurrent diastolic blood pressure.
A diastolic-minus-compartment pressure below 30 mmHg indicates increased risk; an absolute pressure above 40 mmHg supports urgent decompression consideration by a consultant surgeon.
Lower-leg surgery requires complete open decompression of all involved compartments, usually two-incision four-compartment fasciotomy, with wounds left open and planned re-exploration.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Reperfusion capillary leak

Ischaemia-damaged endothelium becomes permeable when flow returns, allowing rapid interstitial fluid accumulation inside a fixed fascial space.

Prolonged severe ischaemia

Longer and deeper preoperative oxygen deprivation produces greater endothelial and myocyte injury, increasing oedema after technically successful flow restoration.

Bleeding after intervention

Surgical haemostasis failure, thrombolysis, anticoagulation or access injury can add blood volume to a compartment already swollen by reperfusion.

Venous outflow obstruction

Venous thrombosis, tight dressings or positional compression impairs fluid removal and raises compartment volume after arterial inflow has returned.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Closed-space expansion
Oedema or blood accumulates within non-compliant fascia, raising tissue pressure because muscle cannot expand freely outward.
2
Perfusion gradient falls
As compartment pressure approaches diastolic pressure, capillary flow and oxygen delivery fall even while larger arterial pulses remain detectable.
3
Oedema amplifies ischaemia
Reduced capillary flow causes further endothelial injury and leak, creating a self-reinforcing rise in pressure and local oxygen debt.
4
Nerve and muscle infarct
Persistent low tissue perfusion causes nerve conduction failure and myonecrosis, progressing from pain and paraesthesia to anaesthesia, paralysis and contracture.
5
Necrosis becomes systemic
Dead muscle releases potassium, acid, phosphate and myoglobin, producing arrhythmia, shock and pigment-associated acute kidney injury.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Escalating pain patternRed flag

Increasing pain, passive-stretch pain and rising analgesic need in the reperfused limb are early warnings requiring immediate senior reassessment.

Progressive nerve dysfunctionRed flag

New tingling, reduced sensation or weakness in nerves crossing a swollen compartment shows declining tissue perfusion and accelerates surgery.

Tense postoperative swellingRed flag

A firm expanding calf after embolectomy, bypass or thrombolysis may represent reperfusion oedema or bleeding within a closed compartment.

Pulses remain presentRed flag

Restored pedal pulses confirm large-vessel flow but do not measure intramuscular capillary perfusion and cannot exclude compartment syndrome.

Unreliable pain reportRed flag

Sedation, delirium, neuropathy or regional block removes early symptoms and requires agreed serial assessment or pressure monitoring responsibility.

Late systemic toxicityRed flag

Anaesthesia, paralysis, dark urine, acidosis and hyperkalaemia imply advanced muscle necrosis requiring simultaneous renal and critical-care management.

Red flags requiring action

Increasing pain, passive-stretch pain and rising analgesic requirement after flow restoration require immediate repeat examination and senior surgical review.
New paraesthesia, sensory loss or weakness indicates nerve ischaemia and a shortening opportunity for functional limb salvage.
Paralysis, anaesthesia, muscle rigor, hyperkalaemia, acidosis or dark urine indicates advanced tissue injury and systemic reperfusion danger.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
First-line serial clinical examinationFirst stepFirst line
Why
Recognise change while decompression can still preserve muscle and nerve function.
Interpretation and limitations
Record at least hourly in an at-risk patient and more often if evolving; a convincing clinical diagnosis goes directly to surgery without confirmatory tests.
02
Intracompartmental pressure with diastolic pressure
Why
Support diagnosis when examination is incomplete or clinical findings remain inconclusive.
Interpretation and limitations
A delta pressure below 30 mmHg indicates increased risk; measure every suspected compartment and let a consultant integrate readings, trends and physiology.
03
Absolute compartment pressure
Why
Provide a second objective danger marker during an equivocal assessment.
Interpretation and limitations
A value above 40 mmHg supports considering urgent decompression, but systemic blood pressure, site and technique affect meaning and a single lower value does not clear deterioration.
04
Arterial Doppler and completion imaging
Why
Check revascularisation patency and distinguish concurrent re-occlusion from isolated compartment pressure.
Interpretation and limitations
Loss of the restored signal demands immediate vascular assessment; preserved signals do not exclude compartment syndrome and should never stop fascial evaluation.
05
Potassium, blood gas, CK and renal profile
Why
Detect systemic consequences of muscle ischaemia, necrosis and decompression-related reperfusion.
Interpretation and limitations
Treat hyperkalaemic ECG toxicity immediately rather than awaiting CK; rising potassium, acidosis, CK, creatinine or oliguria requires critical-care and renal escalation.
06
Operative muscle assessment
Why
Confirm complete release and determine tissue viability under direct vision.
Interpretation and limitations
Document colour, bleeding, consistency and contractility of every muscle group, excise clearly non-viable tissue and schedule review of uncertain areas.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Re-occlusion

Renewed coldness and lost Doppler signals suggest failure of the reconstruction, though macrovascular occlusion and compartment syndrome may coexist.

Expected postoperative pain

Routine wound pain should respond and stabilise, whereas compartment pain escalates, requires increasing analgesia and is provoked by passive muscle stretch.

Haematoma without syndrome

Local bleeding can cause swelling and pain before tissue perfusion becomes critical, but expansion requires the same urgent serial assessment.

Peripheral nerve injury

A fixed deficit from operative trauma may follow one nerve, while progressive dysfunction with swelling suggests ongoing compartment pressure and tissue ischaemia.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Worked caseRecognise the postoperative trajectoryFirst stepFour hours after femoral embolectomy, a patient has returned pedal pulses but worsening calf pain and new first-web-space tingling.

1Inputs: compare timed pain scores, opioid doses, passive-stretch pain, compartment tension, named nerve function, pulses, Doppler signals and systemic blood pressure.
2Reasoning: preserved pulses show macrovascular patency but worsening pain and deep fibular sensory change after reperfusion indicate evolving compartment syndrome.
3Action: release circumferential dressings, expose and elevate the limb, correct hypotension and summon a senior surgeon with authority to perform fasciotomy.
4Result: because the clinical diagnosis is clear, proceed to immediate open complete decompression without waiting for compartment pressure or CK confirmation.
5Verification: document release of all compartments, muscle viability, restored tissue expansion, postoperative nerve and vascular findings, systemic laboratories and the re-exploration plan.

02Uncertain diagnosisMeasure without losing the trendThe patient is obtunded, densely blocked or has inconclusive findings that do not yet establish compartment syndrome clinically.

1Continue hourly documented examination and ask anaesthesia and surgery to assign explicit responsibility for surveillance during regional blockade or impaired consciousness.
2Measure every suspected compartment using a validated technique and record simultaneous blood pressure so delta pressure can be interpreted.
3EscalationEscalate a delta pressure below 30 mmHg, absolute pressure above 40 mmHg or worsening clinical trend to a consultant decompression decision immediately.
4Repeat or continuously monitor when risk persists; do not let one reassuring site or reading overrule deterioration elsewhere in the limb.

03Confirmed diagnosisDecompress all involved compartmentsClinical findings establish compartment syndrome or consultant assessment of pressure and examination shows dangerous perfusion.

1Proceed to NCEPOD-1 surgery and open all involved fascial compartments for their full effective length without waiting for imaging or laboratory progression.
2For the lower leg, use a two-incision four-compartment approach, directly inspect each muscle group and debride clearly non-viable tissue.
3Leave fasciotomy wounds open, document uncertain tissue and every structure assessed, and coordinate vascular revision if the reconstruction is also compromised.
4Discuss with plastic surgery within 24 hours and re-explore within 72 hours or earlier when physiology, viability or contamination requires.

04AftercareControl systemic muscle injuryFasciotomy is complete or delayed presentation includes established necrosis and reperfusion toxicity.

1Monitor ECG, potassium, acid-base state, CK, creatinine, phosphate, calcium and urine output and treat hyperkalaemia immediately through the UKKA pathway.
2Reassess vascular patency, named nerves and all compartments after decompression, each transfer and every wound re-exploration.
3Plan delayed closure, graft or flap only when swelling, contamination and tissue viability allow tension-free durable coverage.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Permanent neurological loss

Delayed decompression causes persistent weakness, numbness, neuropathic pain and impaired walking even if the arterial reconstruction remains patent.

Muscle contracture

Necrotic muscle heals with fibrosis and shortening, producing fixed deformity, reduced joint range and chronic functional disability.

Rhabdomyolysis and renal failure

Myoglobin, potassium and acid released from injured muscle can cause malignant arrhythmia, acute tubular injury and dialysis requirement.

Infection and amputation

Dead muscle and open wounds invite deep infection; extensive necrosis or uncontrolled systemic toxicity may make limb salvage impossible.

Wound morbidity

Open fasciotomy needs repeated inspection and later closure, graft or flap, with scarring, graft morbidity and prolonged rehabilitation.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Use an hourly compartment chart for every at-risk patient, recording positive and negative findings, time, interpretation and the clinician responsible for action.
Record opioid dose, infusion rate, regional block and response so escalating analgesic requirement is visible as a clinical trend.
Repeat named motor, sensory, pulse, Doppler, temperature and capillary-refill findings after dressing release, fasciotomy, vascular revision and every handover.
After decompression, trend ECG, potassium, bicarbonate, CK, creatinine, phosphate, calcium and urine output for systemic muscle injury and reperfusion toxicity.
Inspect wounds and muscle at planned re-exploration, recording additional necrosis, infection, swelling and readiness for definitive coverage.
Follow joint range, muscle power, sensation, contracture, neuropathic pain, scar tolerance, gait and patient-defined functional goals.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

The artery can be open

Compartment syndrome is a microvascular perfusion failure, so a successful reconstruction and palpable pulses do not protect swollen muscle.

The diagnosis is dynamic

A normal examination immediately after revascularisation cannot clear a limb while capillary leak and oedema continue over subsequent hours.

Pressure is contextual

The same compartment pressure is more dangerous when diastolic blood pressure falls, which is why concurrent blood pressure and shock correction matter.

Clear signs outrank measurement

Pressure monitoring helps an incomplete or equivocal examination; requiring a number after the clinical diagnosis is established wastes salvage time.

Fasciotomy means complete release

A short skin opening or incomplete fascial incision leaves the causal pressure and ongoing muscle ischaemia uncorrected.

Late release is complex

Established necrosis may produce dangerous systemic release and infection; BOASt advises two-consultant decision-making and renal protection for delayed presentations.

11Common pitfallsFrequent interpretation and management errors.

01
Using returned pedal pulses as evidence that the reperfused calf compartments are safe.
02
Waiting for compartment pressure measurement, CK elevation, paralysis or pulselessness when the clinical diagnosis already requires immediate fasciotomy.
03
Recording neurovascularly intact without naming motor and sensory findings, timing, analgesia exposure and change from the prior examination.
04
Measuring only one convenient compartment or interpreting an isolated pressure without simultaneous diastolic blood pressure.
05
Opening only the visibly swollen compartment or using an incision too short for full fascial decompression.
06
Closing fasciotomy wounds under tension at the index operation or omitting re-exploration and plastic-surgical planning.

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