Synopsis
Recognise evolving compartment ischaemia from serial clinical change, release external pressure, use concurrent blood-pressure and compartment-pressure data when examination is uncertain, and achieve immediate complete decompression before irreversible injury.
- Suspect acute compartment syndrome from the trajectory: worsening pain, passive-stretch pain, swelling, sensory change and analgesic escalation matter more than any single normal earlier examination.
- Do not use palpable pulses to exclude it. Pulselessness is late or indicates a separate arterial emergency and should prompt simultaneous vascular and orthopaedic action.
- BOASt requires hourly assessment of an at-risk patient, documenting time, mechanism, consciousness, neurology, circulation, pain, analgesic dose and response, interpretation and management rationale.
- For symptoms or signs, split or remove circumferential dressings, expose and safely elevate the limb, correct systemic hypotension and re-evaluate within 30 minutes with senior review.
- If clinical assessment is incomplete or inconclusive, measure every suspected compartment with concurrent blood pressure; a diastolic-minus-compartment pressure below 30 mmHg indicates increased risk.
- An absolute compartment pressure above 40 mmHg supports considering urgent decompression, but a reassuring single reading does not overrule progressive clinical findings or exclude another compartment.
- Once diagnosed, perform immediate open decompression of every involved compartment and excise non-viable muscle; lower-leg treatment generally uses a two-incision four-compartment fasciotomy.
- Discuss the patient with plastic surgery within 24 hours and re-explore within 72 hours or earlier when indicated, leaving a documented plan for definitive soft-tissue management.
Key red flags
Increasing pain out of proportion to the injury, pain on passive stretch of muscles crossing the compartment, a tense swollen segment or rapidly rising opioid requirement requires immediate reassessment and escalation.
New paraesthesia, sensory loss or weakness indicates progressive nerve ischaemia; paralysis, pallor and absent pulses are late findings or suggest concurrent arterial injury and must never be awaited.
An obtunded, intubated, very young or cognitively impaired patient and a limb under dense regional blockade cannot report pain reliably, so objective surveillance and pressure measurement thresholds become particularly important.
Revascularisation, crush, high-energy tibial or forearm fracture, tight casts, bleeding disorders and prolonged limb compression create high-risk settings even when the initial examination was reassuring.
Investigation priorities
Detect change early enough for limb-saving decompression.
Management branches
An at-risk limb develops disproportionate pain, passive-stretch pain, tension, analgesic escalation or neurological change.
- Contact senior orthopaedics immediately and record examination, time, analgesia, blood pressure and the change that triggered concern.
- Remove circumferential dressings to skin, correct hypotension, expose and position the limb safely and re-evaluate within 30 minutes.
- Continue hourly structured examination and obtain concurrent pressure monitoring when pain reporting or the clinical picture is incomplete.
- Maintain arterial surveillance and activate vascular care if perfusion remains abnormal after realignment or external pressure release.