4Sch~lnemann I-I J, Jaeschke R, Cook DJ, et al. An official ATS statement: grading the quality of evidence and strength of recommendations in ATS guidelines and recommendations. Am J Respir Crit Care Med,2006,174:605-614.
5A Geerts WH, Pineo GF, Heit JA, et al. Prevention of venous thromboembolism: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest, 2004, 126 (3 Suppl) :338S-400S.
6Cook D, Crowther M, Meade M,et al. Deep venous thrombosis in medical-surgical critically ill patients : prevalence, incidence, and risk factors. Crit Care Med,2005,33 : 1565-1571.
7Ibrahim EH, Iregui M, Prentice D, et al. Deep vein thrombosis during prolonged mechanical ventilation despite prophylaxis. Crit Care Med ,2002,30:771-774.
8Short AF, Williams MD. Venous thromboembolism in critically ill patients. Observations from a randomized trial in sepsis. Thromb Haemost,2009,101 : 139-144.
9Muscedere JG, Heyland DK, Cook D. Venous thromboembolism in critical illness in a community intensive care unit. J Crit Care, 2007,22:285-289.
10Hirsch DR, Ingenito EP, Goldhaber SZ. Prevalence of deep venous thrombosis among patients in medical intensive care. JAMA, 1995,274:335-337.
