Nonthrombotic embolism

Last updated: May 12, 2022

Summarytoggle arrow icon

Embolisms of fat, air, and amniotic fluid are uncommon but potentially life-threatening events caused when these substances enter the circulatory system. Fat emboli mostly originate from the bone marrow in patients with long bone fractures. Air can enter the circulatory system during surgical procedures (mostly neurosurgery), while amniotic fluid emboli occur during delivery. The emboli usually lodge within the pulmonary arteries and cause right ventricular outflow obstruction and circulatory collapse. Clinical features of nonthrombotic embolisms typically include acute onset of hypoxia, hypotension, and neurological symptoms (altered consciousness, seizures, coma). The diagnostic sign of fat embolism is a petechial rash on the upper body (if present), while that of venous air embolism is a mill wheel cardiac murmur. Diagnosis of any nonthrombotic embolism is primarily clinical, with arterial blood gas evaluation, ECG, and chest x-ray providing additional evidence. Treatment is mainly supportive and includes oxygenation, mechanical ventilation, and administration of vasopressors, if necessary. Mortality rates of all nonthrombotic embolisms are high.

Gurd's criteria
Major criteria Minor criteria

1 major + 4 minor criteria

confirms fat embolism

Petechial rash Fever


Neurological symptoms (see above) Anemia
Increased ESR
Renal dysfunction (anuria, oliguria, lipiduria)
Retinal changes (petechiae, fatty inclusions);
Fat globules in sputum
Schonfeld's criteria
Feature Score

Total score > 5 points

is diagnostic of fat embolism

Petechial rash 5
Bilateral infiltrates on chest x-ray 4
Hypoxia 3
Fever 1
Tachycardia 1
Tachypnea 1
Confusion 1


Venous air embolism Arterial air embolism


  • Air enters the venous system → embolization to the right ventricle of the heart → right ventricular outflow block (air block) → circulatory collapse
Clinical features



  • Definition: respiratory insufficiency because of embolization of bone cement material or indirect systemic effects after bone cement implantation
  • Occurrence: after orthopedic procedures using bone cement material
  • Pathophysiology: direct mechanical embolization and thermal effects or an immunological-mediated release of vasoactive substances; often associated with fat embolism
  • Clinical features
  • Diagnostics: CT pulmonary angiogram for the detection of mechanical embolization
  • Treatment
    • Supportive (intensive care) measures, including mechanical ventilation and catecholamine therapy
    • If necessary, interventional or surgical removal of the embolic cement material
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