Critically evaluate the strategies for prevention of deep venous thrombosis in the critically ill.
Many different strategies are employed and should be considered. Reviews and recommendations are widely published (eg. Geerts, WH, Heit, JA, Clagett, GP, et al. Prevention of venous thromboembolism. Chest 2001; 119:132S). Good placebo controlled RCTs are rare.
Simple techniques such as passive mobilisation, and early active mobilisation are encouraged but not well studied. The use of elastic compression stockings (knee-length or whole leg) is simple, widespread and effective for low risk patients. The addition of intermittent pneumatic compression devices has been recommended (limited evidence) where higher risk exists but other pharmacology is deemed contraindicated. Most studies have assessed the use of low dose unfractionated heparin or low molecular weight heparins (though few studies have used placebo control). LMW heparins (when compared with unfractionated heparin) seem to provide similar or better prophylaxis, with less thrombocytopaenia, though with a small increase in the incidence of bleeding. Other agents including pentasaccharides or hirudin are showing promise. Older agents such as dextran and warfarin are used less frequently.
Other controversies include cost-benefit, and side-effect profiles etc.
A systematic approach to this answer would resemble the following:
Rationale:
Therapeutic options
Advantages:
Disadvantages:
Evidence:
The PROTECT trial (2011) is the most recent large entry into the DVT prophylaxis arena. It was negative- there was no difference between LMWH and UFH. However, a significant reduction in the incidence of PE was found with LMWH, which has led some authors to recommend it as the first choice in renally normal patients.
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.