What’s New in the Patient Safety World


July 2009


Unintended Consequences of a DVT Prevention Strategy



Often we implement quality improvement or patient safety strategies without considering all the possible unintended consequences (or we simply do not know what unintended consequences to look for!). For years, graduated compression stockings have been used as a strategy to prevent DVT in patients with stroke. Though in the US we have felt that the evidence for use of these (as opposed to pneumatic compression stockings) in stroke patients was scant, they have been used extensively in other countries. And, while we were skeptical about their effectiveness, most of us took an attitude that “it can’t hurt”. Well, now a new study published in Lancet (CLOTS trial 1) shows that not only do thigh-high graduated stockings not prevent DVT in stroke patients, they actually cause harm. Skin breaks, ulcers, blisters, and skin necrosis were significantly more common in patients allocated to GCS than in those allocated to avoid their use.


The same group is now looking at both the efficacy and safety of pneumatic compression stockings in stroke patients (in the CLOTS-3 trial).


Whereas there is evidence to support use of graduated compression stockings in surgical patients, there will now undoubtedly also be studies now looking at the overall efficacy and unintended consequences of graduated compression stockings in other conditions.





The CLOTS Trials Collaboration. Effectiveness of thigh-length graduated compression stockings to reduce the risk of deep vein thrombosis after stroke (CLOTS trial 1): a multicentre, randomised controlled trial. The Lancet 2009; 373:1958 - 1965, 6 June 2009















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