Knudson MM, Morabito D, Paiement GD, Shackleford S.
Use of low molecular weight heparin in preventing thromboembolism in trauma
patients.
J Trauma 1996 Sep;41(3):446-59

Department of Surgery, University of California, San Francisco, San Francisco
General Hospital 94110, USA.

OBJECTIVE: To investigate the safety and effectiveness of low molecular weight
heparin (LMWH) in preventing deep venous thrombosis (DVT) in high-risk trauma
patients, compared with mechanical methods of prophylaxis. DESIGN: A prospective
randomized trial conducted over a 19-month period in an urban, academic trauma
center. METHODS: All trauma patients with the following risk factors for the
development of DVT were considered for enrollment in this study: any injury with
an Abbreviated Injury Scale score > or = 3; major head injury (Glasgow Coma Scale
score < or = 8); spine, pelvic, or lower extremity fractures; acute venous
injury; or age > 50 years. After a screening venous duplex examination, the
patients were assigned to a Heparin versus No-Heparin group, depending upon the
presence of injuries precluding the use of heparin. In the Heparin group, the
patients were then randomized to receive either LMWH or optimal mechanical
compression (defined as bilateral sequential gradient pneumatic compression (SCD)
or, in the presence of lower extremity injuries precluding the use of the SCD,
the arteriovenous impulse (AVI) compression system). All the patients in the
No-Heparin group received optimal compression. Enrolled patients underwent
sequential duplex examinations every 5 to 7 days until discharge. RESULTS: Of the
487 consecutive patients initially enrolled in this study, 372 were available for
at least the first two duplex examinations and comprise the study population.
Only nine (2.4%) patients developed DVT, compared with the predicted 9.1% rate in
high-risk trauma patients receiving no prophylaxis (p = 0.037). Of the 120
patients who were randomized to receive LMWH, only one (0.8%) developed DVT. In
the SCD group, there were 5 of 199 patients (2.5%) with DVT, and 3 of 53 (5.7%)
in the AVI group. One patient with DVT also had clinical symptoms of pulmonary
embolism, but there were no deaths secondary to pulmonary embolism. There was one
major bleeding complication potentially associated with the use of LMWH.
CONCLUSIONS: The administration of LMWH is a safe and extremely effective method
of preventing DVT in high-risk trauma patients. When heparin is contraindicated,
aggressive attempts at mechanical compression are warranted.