Compartment Syndrome in the Field
Objective: Recognize limb compartment syndrome before the pulse disappears. Tell it apart from crush-release high potassium. Move the patient toward a surgeon. Do not reassure them because a pulse is still there.
Why this matters
The foot pulse is present, so the chart says circulation, motor, and sensory are intact. That does not clear compartment syndrome. This is a pressure problem inside a closed muscle space. Loss of the pulse is late.
Crush syndrome is a different clock. That lesson is about release of a trapped limb, high potassium, and fluids. This lesson is the closed limb that is dying from the inside: a tibia fracture, a forearm fracture, crush that has not been released, a burn, or a splint or cast that is too tight.
- Pain is the early finding, especially pain when you stretch the muscle. Pallor, pins and needles, paralysis, a limb that cools to room temperature, and a missing pulse come later.
- Remove rings, tight boots, and anything constricting a burned limb. Loosen a splint you made too tight. You may have caused the pressure.
- Do not ice a suspected closed compartment the way you ice a sprain. Go to a hospital that can measure the pressure and operate.
- Pain out of proportion. Think compartment syndrome.
- A pulse does not clear it.
- Loosen the splint, the boot, and the rings.
- This patient needs a surgeon.
Clinical sequence
- Run MARCH: massive hemorrhage, airway, respirations, circulation, then hypothermia and head injury. Then look at the limb. Feel for tightness. Stretch the muscles in that compartment by moving the joint so those muscles lengthen. Pain with that stretch is the finding that matters.
- Splint in a position of function. Check the limb again after you splint. A splint that is too tight can create the compartment.
- Treat pain per protocol. The pain is real. Do not withhold pain medicine only to keep the exam unchanged. This site does not list a milligram dose.
- If this followed a long entrapment, also run the crush and high-potassium pathway. The two problems can exist together.
Teaching points
- A pulse does not mean the limb is fine. Waiting for a missing pulse means waiting for muscle death.
- Pain on passive stretch of the muscles in that compartment is the early field finding.
- This is not crush syndrome by itself. Crush syndrome is the sudden release of potassium and acid after a trapped limb is freed. Compartment syndrome can happen while the limb is still trapped, or hours later in a closed fracture.
- Opening the fascia is not a field procedure. Recognize it, remove constriction, and get a surgeon.
Common errors
- Writing that pulses, movement, and sensation are intact, then staying on scene because a pulse is present.
- Icing and elevating a rock-hard calf as if it were an ankle sprain.
- Leaving a tight splint that you never recheck after you leave the scene.
Practice
One-minute check
A tibia fracture has a tight calf. The patient screams when you move the foot so the calf muscles stretch. The foot pulse is present. Say three actions. Say what you will not write in the chart. How is this different from crush release?
Related: Crush Syndrome, Pediatric Trauma in the Field.
Sources & Further Study
Named guidelines for further study. They are not clinical orders and do not replace your protocol or medical direction.
- NASEMSO National Model EMS Clinical Guidelines (2022) — U.S. EMS model language; your protocol decides
- ACS COT / ATLS tradition — compartment syndrome is clinical — do not wait for pulselessness
- EMRA compartment syndrome review — pain on passive stretch is early; pulse is a late finding
Education only. Apply learning within your protocols and medical direction. This is not clinical care guidance.
Check Your Understanding
Questions drawn only from this lesson. After you check, the key is highlighted. Education practice — not a certification exam.