Thromboprophylaxis is the most important patient safety strategy in patients admitted to hospital. Pulmonary embolism (PE) remains the leading cause of preventable in-hospital death.
The risk of venous thrombosis in patients admitted to hospital depends on medical versus surgical admission and, among surgical patients, the type of surgery.
Evaluating venous thromboembolic risk factors within these patient groups helps further stratify the thrombotic risk.
Bleeding risk and possible contraindication to anti-thrombotic agents must be assessed before instituting thromboprophylaxis.
Although national and international thromboprophylaxis guidelines have repeatedly recommended thromboprophylaxis of patients admitted to hospital, only 40% to 50% of medical patients and 60% to 75% of surgical patients receive adequate thromboprophylaxis.
Computer-based decision systems and pre-printed orders are most effective in optimising physician adherence to thromboprophylaxis guidelines. Periodic audits by pharmacists or other health professionals reinforce the consistent use of venous thromboembolism prophylaxis.
Venous thromboembolism (VTE) prophylaxis consists of pharmacological and non-pharmacological measures to diminish the risk of deep vein thrombosis (DVT) and pulmonary embolism (PE).
DVT of the leg is the development of a blood clot in one of the major deep veins in the leg or thigh, which leads to impaired venous blood flow, usually causing leg swelling and pain.
PE is a consequence of thrombus formation in distal veins, most commonly those of the deep venous system of the lower extremities. Thrombus formation in the venous system occurs as a result of venous stasis, trauma, and hypercoagulability. About 51% of deep venous thrombi will embolise to the pulmonary vasculature, resulting in a PE. 
University of Montreal
NR declares that she has no competing interests.
General Internal Medicine Program Director
McGill University Division of Internal Medicine
Centre for Clinical Epidemiology of the Lady Davis Institute for Medical Research
Jewish General Hospital
VT declares that she has received an investigator-initiated grant from Sanofi-Aventis. She has also received consultancy fees from Bristol-Myers Squibb, Leo Pharma, Pfizer, and Sanofi-Aventis. VT is an author of a reference cited in this monograph.
Resident in Internal Medicine
Sacred Heart Hospital
University of Montreal
VBD declares that he has no competing interests.
Associate Medical Director
Consultant Emergency Medicine
Guy's and St Thomas' NHS Foundation Trust
Clinical Lead and Consultant
Accident Emergency Medicine
St Thomas' Hospital
AP declares that he has no competing interests.
University of Ottawa
Ottawa Health Research Institute
SS declares that he has no competing interests.
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