Studies of pneumatic compression in cardiac surgery and neurosurgical patients have shown a distinct improvement in the incidence of deep venous thrombosis (DVT) without the added risk of bleeding.
However, the effect is less impressive in higher-risk patients, and compliance can be difficult. Timing and duration of prophylactic agents has also been determined to have a significant effect the development of DVT. Early prophylaxis in surgical patients with low molecular weight heparin (LMWH) has been associated with significant reductions in postoperative venous thrombosis. A study by Hull et al found that initiation of therapy within 8 hours of surgery had the greatest effect.
The ninth edition of the clinical practice guidelines for prevention of venous thromboembolism (VTE) from the American College of Chest Physicians (ACCP) recommended that LMWH be given to patients undergoing major orthopedic procedures at least 12 hours preoperatively or postoperatively.
Venous thromboembolism is the most common preventable cause of death in surgical patients. Thromboprophylaxis, using mechanical methods to promote venous outflow from the legs and antithrombotic drugs, provides the most effective means of reducing morbidity and mortality in these patients. Despite the evidence supporting thromboprophylaxis, it remains underused because surgeons perceive that the risk of venous thromboembolism is not high enough to justify the potential hemorrhagic complications of anticoagulant use. The risk of venous thromboembolism is determined by patient characteristics and by the type of surgery that is performed. In this paper we identify the risk factors for venous thromboembolism and provide a scheme for stratifying surgical patients according to their risk. We describe the mechanism of action of the various forms of thromboprophylaxis and outline the evidence supporting thromboprophylaxis in different surgical settings. Finally, we recommend optimal forms of thromboprophylaxis in patients who undergo various types of surgery. Intermittent pneumatic compression, with or without elastic stockings, can be used for thromboprophylaxis in patients who undergo neurosurgical procedures; for patients who undergo vascular or cardiovascular procedures, long-term acetylsalicylic acid should be used for thromboprophylaxis. Low-molecular-weight heparin (LMWH) or warfarin is the choice for patients with spinal cord operations and all patients with major trauma who do not have contraindications to anticoagulation should receive thromboprophylaxis with LMWH 1).
Unfractionated heparin (UFH), low molecular weight heparin or fondaparinux are recommended for venous thromboembolism (VTE) prophylaxis in acutely ill medical patients.