[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Nursing](https://durgical.com/en/nursing/) › [Medical–surgical nursing](https://durgical.com/en/nursing/areas/med-surg/) › Compartment syndrome and fat embolism: catching them early # Compartment syndrome and fat embolism: catching them early - Assessment Two fracture complications the nurse must catch early: rising pressure inside a muscle compartment, and fat emboli to the lungs and brain. Updated Nov 13, 2026 ## Key points - Compartment syndrome: the earliest sign is pain out of proportion to the injury, worse when the muscles are passively stretched. - Numbness, weakness and loss of pulse are late signs; do not wait for them. - First response: loosen dressings, split or remove the cast as ordered, keep the limb at heart level (not raised), and call at once. - A nerve block or epidural can mask the pain, so check these patients more closely. - Fat embolism: breathlessness, falling saturation, confusion and petechiae on the chest, armpits, neck or conjunctivae one to three days after the fracture. ## What it is In acute compartment syndrome, swelling inside a closed muscle compartment raises the pressure until blood flow to muscle and nerves fails. It follows fractures (above all of the tibia), crush injuries, tight casts or dressings and surgery; it is treated by urgent surgical decompression (fasciotomy), and delay can leave permanent damage. Fat embolism syndrome appears usually one to three days after a long-bone or pelvic fracture, with breathing problems, confusion and a petechial rash. For both, the nurse's job is to recognise the early signs, act at once and call. ## Reference values - Normal compartment pressure at rest is a few mmHg; a pressure of about 30 mmHg or more is treated as critical. - Permanent nerve damage can follow less than 12 to 24 hours of high pressure, and muscle damage sooner. - Fat embolism usually appears 24 to 72 hours after the injury. - Patients at higher risk: tibial and forearm fractures, crush injuries, anticoagulants or bleeding disorders, tight casts, and young men for compartment syndrome; long-bone, pelvic and multiple fractures for fat embolism. ## What you need - Neurovascular observation chart and the service's pain scale. - The other limb for comparison. - Pulse oximeter, preferably continuous in patients at high risk of fat embolism. - A torch to look for petechiae in the conjunctivae and armpits. ## How to measure it (and why) - Ask about pain at every check and compare it with the injury — pain out of proportion is the earliest sign of compartment syndrome. - Gently stretch the fingers or toes of the limb and watch the response — pain on passive stretch points to raised compartment pressure. - Feel the compartment: tense, hard swelling is a warning — the closed fascia does not stretch. - Check sensation, movement, colour, temperature and pulses against the other side — numbness and weakness come before loss of pulse. - If suspected, loosen bandages, report the cast for splitting per protocol and keep the limb at heart level — raising it higher lowers perfusion. - Avoid flexing the knee or pulling the foot up in a suspected leg compartment syndrome — these postures raise the pressure. - In long-bone or pelvic fractures, monitor breathing rate and saturation, continuously if ordered — low oxygen can appear before breathlessness. - Check the level of consciousness and look for petechiae on the chest, armpits, neck and conjunctivae — confusion and rash complete the picture of fat embolism. - Record the time of each finding and of each call — in both conditions delay changes the outcome. ## How to read it - Compartment syndrome is a clinical diagnosis: no single sign is reliable, so the trend of pain and nerve signs matters. - Not all the classic signs appear; a pink limb with a pulse can still be in compartment syndrome. - Fat embolism is also a clinical diagnosis: breathing problems and low oxygen often come first, and the rash may be missing. - Tachycardia and fever are non-specific but add to the picture. - After compartment syndrome, muscle breakdown can damage the kidneys: watch urine output. ## Next step: when to call for help - Call the doctor at once for pain out of proportion or pain on passive stretch; do not just give more pain relief. - Call at once for numbness, weakness, a tense compartment, or a pale, cold or pulseless limb. - Call urgently for a fall in oxygen saturation, rising respiratory rate, new confusion or petechiae after a fracture; give oxygen as ordered. - Escalate with SBAR and the times of the findings: both conditions are surgical or medical emergencies. - After a fasciotomy, report falling urine output. ## Test yourself Think of the answer, then tap the question to see it. ## What is the earliest sign of acute compartment syndrome? Pain out of proportion to the injury, especially when the muscles of the compartment are passively stretched. ## Why is a limb with suspected compartment syndrome not raised above the heart? Raising it further lowers the arterial pressure reaching the compartment; keep it at heart level to protect perfusion. ## When does fat embolism usually appear and what does it look like? About 24 to 72 hours after a long-bone or pelvic fracture, with breathing problems and low oxygen, confusion and petechiae. ## Why should patients with a nerve block be checked more closely for compartment syndrome? Because the block can hide the pain, which is usually the first warning sign. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/nursing/compartment-syndrome-and-fat-embolism-catching-them-early/) ## Elsewhere in DurgiPedia - [Compartment syndrome: the early signs](https://durgical.com/en/clinical-exam/compartment-syndrome-the-early-signs/) ## Connections ## Related 3 - [The patient with a fracture: neurovascular checks, elevation, pain and complications](https://durgical.com/en/nursing/the-patient-with-a-fracture-neurovascular-checks-elevation-pain-and-complication/) - [Recognising deterioration and calling the rapid response team](https://durgical.com/en/nursing/recognising-deterioration-and-calling-the-rapid-response-team/) - [Cast and splint care: drying, checks, skin, itching and teaching](https://durgical.com/en/nursing/cast-and-splint-care-drying-checks-skin-itching-and-teaching/) ## Related conditions 2 - [Acute compartment syndrome](https://durgical.com/en/conditions/acute-compartment-syndrome/) - [Fat embolism syndrome](https://durgical.com/en/conditions/fat-embolism-syndrome/) [← All of nursing](https://durgical.com/en/nursing/) Educational content for students; it does not replace your institution's protocols, supervised clinical training or a prescriber's order. Dose-calculation examples use made-up numbers: they are educational, not a clinical order. Sources: [Pechar J, Lyons MM. Acute compartment syndrome of the lower leg: a review. J Nurse Pract 12(4):265-270](https://pmc.ncbi.nlm.nih.gov/articles/PMC4970751/) (The Journal for Nurse Practitioners (PubMed Central, open access), 2016); [Compartment syndrome, MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/001224.htm) (MedlinePlus, US National Library of Medicine, 2026); [Shaikh N. Emergency management of fat embolism syndrome. J Emerg Trauma Shock 2(1):29-33](https://pmc.ncbi.nlm.nih.gov/articles/PMC2700578/) (Journal of Emergencies, Trauma, and Shock (PubMed Central, open access), 2009); [Shaikh N et al. Fat embolism syndrome: evolving perspectives on diagnosis and care. Cureus 17(11):e96136](https://pmc.ncbi.nlm.nih.gov/articles/PMC12679895/) (Cureus (PubMed Central, open access), 2025). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/nursing/compartment-syndrome-and-fat-embolism-catching-them-early/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/nursing/compartment-syndrome-and-fat-embolism-catching-them-early/