This was vaguely mentioned in the discussion of Question 4 from the first paper of 2003, "Critically evaluate the strategies for prevention of deep venous thrombosis in the critically ill.".
LIFL have an excellent page on VTE prophylaxis in the ICU.
Cook, Deborah, et al. "Dalteparin versus unfractionated heparin in critically ill patients." The New England journal of medicine 364.14 (2011): 1305-1314.
Attia, John, et al. "Deep vein thrombosis and its prevention in critically ill adults." Archives of Internal Medicine 161.10 (2001): 1268-1279.
Arabi, Yaseen M., et al. "Use of Intermittent Pneumatic Compression and Not Graduated Compression Stockings Is Associated With Lower Incident VTE in Critically Ill Patients Mechanical Prophylaxis in Critically Ill Patients A Multiple Propensity Scores Adjusted Analysis." CHEST Journal 144.1 (2013): 152-159.
Sachdeva, Ashwin, et al. "Elastic compression stockings for prevention of deep vein thrombosis." Cochrane Database Syst Rev 7.7 (2010).
Alikhan, Raza, Rachel Bedenis, and Alexander T. Cohen. "Heparin for the prevention of venous thromboembolism in acutely ill medical patients (excluding stroke and myocardial infarction)." status and date: New search for studies and content updated (no change to conclusions), published in 5 (2014). Cochrane Database of Systematic Reviews 2014, Issue 5.