Description

Low-Dose Prophylaxis of Postoperative Thromboembolism 
A number of well-controlled clinical trials have demonstrated that low-dose heparin prophylaxis, given 
just prior to and after surgery, will reduce the incidence of postoperative deep vein thrombosis in the 
legs (as measured by the I-125 fibrinogen technique and venography) and of clinical pulmonary 
embolism. The most widely used dosage has been 5000 units 2 hours before surgery and 5000 units 
every 8 to 12 hours thereafter for 7 days or until the patient is fully ambulatory, whichever is longer. 
The heparin is given by deep subcutaneous injection in the arm or abdomen with a fine needle (25- to 
26-gauge) to minimize tissue trauma. A concentrated solution of heparin sodium is recommended. 
Such prophylaxis should be reserved for patients over the age of 40 who are undergoing major surgery. 
Patients with bleeding disorders and those having neurosurgery, spinal anesthesia, eye surgery or 
potentially sanguineous operations should be excluded, as should patients receiving oral anticoagulants 
or platelet-active drugs (see WARNINGS). The value of such prophylaxis in hip surgery has not been 
established. The possibility of increased bleeding during surgery or postoperatively should be borne in 
mind. If such bleeding occurs, discontinuance of heparin and neutralization with protamine sulfate are 
advisable. If clinical evidence of thromboembolism develops despite low-dose prophylaxis, full 
therapeutic doses of anticoagulants should be given unless contraindicated. All patients should be 
screened prior to heparinization to rule out bleeding disorders, and monitoring should be performed 
with appropriate coagulation tests just prior to surgery. Coagulation test values should be normal or 
only slightly elevated. There is usually no need for daily monitoring of the effect of low-dose heparin 
in patients with normal coagulation parameters.