Fat embolism syndrome
Stem
A 24-year-old man, 80 kg, crashed his motorcycle 36 hours ago and has a closed midshaft femur fracture in skeletal traction, now booked for intramedullary nailing. Since this morning he has needed 4 L/min of oxygen by nasal cannula to keep his SpO2 at 92%, his heart rate is 118, and the nurse says he is "not himself." You see petechiae across his axillae and conjunctivae. Platelets have fallen from 240 to 110.
Question
What is going on, and how does it change your anesthetic plan for the nailing?
Ideal answer
HeadlineFat embolism syndrome until proven otherwise: hypoxemia, new confusion and petechiae 24 to 72 hours after a long-bone fracture.1 I still fix the femur early.
- Confirm; exclude mimics. Gurd's criteria: three major features plus tachycardia and falling platelets;1 head CT for confusion, arterial gas.
- Agree the fixation with the surgeon. Early stabilization best prevents progression;1 reamed nailing if stable, else damage-control external fixation first.
- Arterial line before a gentle, hemodynamically stable induction, because lungs and right ventricle are already compromised.
- Ventilate protectively, for a lung-injury picture: low tidal volumes by predicted body weight, PEEP, plateau below 30 cmH2O, SpO2 88–95%.2
- Well hydrated, norepinephrine and an inotrope ready. Hydration helps;1 TEE watches fat release during reaming,1 and I warn reaming can trigger a second, larger shower.
Watch for: ICU afterwards, still intubated if his gas exchange is no better.
Breaking down the answer
- Timeline and incidence — fat in the blood is far more common than the syndrome itself, which occurs in about 1 to 11% of cases.1 Linking the timing to the fracture shows judgment.
- A named criteria set — Gurd's criteria need one major and four minor, or two major features;1 the majors are petechiae, respiratory insufficiency and cerebral involvement.1 Petechiae favor the conjunctivae, anterior chest and axillae.
- How to fix the bone — early fixation is strongly recommended;1 reamed nail versus external fixation in a patient already failing is a joint decision. Changes if: a worsening gas pushes me to damage control.
- The right ventricle is the threat — emboli raise pulmonary vascular resistance; the syndrome can cause pulmonary hypertension with right ventricular failure and cardiovascular collapse.1 Euvolemia, early vasopressors and TEE keep me ahead of it.
- Supportive, not specific — prophylactic corticosteroids reduced the risk of the syndrome in a meta-analysis of seven trials but did not change mortality;1 heparin has no proven clinical benefit, and steroids remain controversial.1
Follow-up question
During reaming of the femoral canal, end-tidal CO2 falls from 36 to 21 mmHg, SpO2 drops to 84% on FiO2 0.6, and blood pressure falls to 68/40. TEE shows a dilated, hypokinetic right ventricle with echogenic particles streaming through the right heart.
What do you do?
Follow-up answer
HeadlineAn intraoperative fat embolic shower with acute right ventricular failure; reaming stops, the wound is packed, and I call for help.
FiO2 1.0. Norepinephrine holds coronary perfusion pressure for the right ventricle, then an inotrope such as dobutamine or milrinone once the pressure is held, if contractility stays poor.1 No large fluid boluses into a dilated right ventricle; moderate PEEP so its afterload does not climb. Arrest means ACLS; refractory shock, an early ECMO call. I reassess with TEE, gases and lactate, decide with the surgeon whether to finish the nail or abandon to external fixation, and take him to the ICU for supportive care; neurologic recovery may lag for days.
Pitfalls that cost points
- Calling it pulmonary thromboembolism and reaching for heparin or thrombolysis.
- Treating the confusion as alcohol withdrawal or pain medication without imaging.
- Delaying fixation indefinitely "until he is better."
Rapid-fire
Q: Why are the petechiae on the upper body? A: Fat droplets float in the aortic arch and enter the subclavian and carotid branches, so the rash favors the chest, axillae and conjunctivae.
Q: What does the brain MRI show? A: It is the most sensitive test, showing scattered lesions in the subcortical white matter, centrum semiovale, basal ganglia and thalamus.1
Q: What are the minor Gurd criteria? A: Fever above 38.5 °C, heart rate above 110, retinal changes, jaundice, renal signs, anemia, thrombocytopenia, a raised ESR and fat macroglobulinemia.1
Q: Who is at highest risk? A: Young patients with closed or multiple long-bone fractures and prolonged conservative management.1
Q: What is the mortality? A: About 7 to 10% in recent studies.1
Numbers to know
| Item | Value |
|---|---|
| Onset after injury | 24–72 h1 |
| Incidence of the syndrome | ~1–11%1 |
| Gurd diagnosis | 1 major + 4 minor, or 2 major1 |
| Plateau pressure goal | ≤30 cmH2O2 |
| Oxygenation goal | SpO2 88–95% or PaO2 55–80 mmHg2 |
| Mortality | ~7–10%1 |
Links
- Trauma: initial management and damage control, ARDS and lung-protective ventilation, Pulmonary embolism, Bone cement, tourniquets and hip fracture, Delayed emergence
- Atlas: Pulmonary embolism and air embolism
- ARDS Network ventilation protocol; Gurd and Wilson criteria
Sources
- 1.Fat Embolism · StatPearls, 2022 · dev3.statpearls.comIncidence 1–11%, onset 24–72 h, mortality 7–10%; steroid meta-analysis of 7 RCTs; TEE fat release during reaming; Gurd/Wilson major and minor criteria; RV failure; no proven benefit of heparin; MRI most sensitive.
- 2.NIH NHLBI ARDS Clinical Network Mechanical Ventilation Protocol Summary · ARDS Network, 2008 · adventhealth.com
Facts on this page were checked against these sources on Oct 16, 2026. Guidelines change; confirm doses against current institutional protocols.