Knudson et al identified risk factors associated with venous thromboembolism in trauma patients enrolled in the American College of Surgeons National Trauma Data Bank. These can help identify patients most likely to benefit from prophylactic interventions. The authors are from the University of California in San Francisco.


High risk factors:

(1) age >= 40 years

(2) pelvic fracture

(3) lower extremity fracture

(4) shock

(5) injury to the spinal cord

(6) head injury with AIS >= 3


Very high risk factors:

(1) >= 2 high risk factors (from previous list)

(2) major operative procedure (operation lasting > 2 hours)

(3) venous injury

(4) > 3 days on the mechanical ventilator


These risk factors would identify 90% of patients in the trauma data bank who developed thromboembolism. The odds ratio for venous thromboembolism is 2 to 3 if a high risk factor is present, and 4 to 10 if the very high risk criteria is met.


Risk Criteria

Contraindications to Heparin


very high risk


low molecular weight heparin and mechanical compression

very high risk


(1) mechanical compression and serial color flow Doppler imaging OR (2) temporary inferior vena cava filter

high risk


low molecular weight heparin

high risk


mechanical compression

low risk


monitor the patient


Low molecular weight heparin is administered in a prophylactic dose (enoxaparin 30 mg bid).


Contraindications to heparin included:

(1) head injury with documented intracranial hemorrhage pending neurosurgical consultation and evidence of stability of bleeding

(2) history or development of heparin-induced thrombocytopenia

(3) uncontrolled coagulopathy or uncontrolled surgical bleeding


Sequential compression devices include stockings, sleeves and pump.


Inferior vena cava filters were used only when there was a very high risk of venous thromboembolism and contraindications to low molecular weight heparin.


Management that can further reduce risk of thromboembolism:

(1) early fracture fixation

(2) aggressive fluid resuscitation

(3) early ambulation

(4) early hospital discharge



• The algorithm needs to be validated in a multi-institution study.


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