Clinical Pearls & Morning Reports
Published April 3, 2019
Arabi et al. conducted the Pneumatic Compression for Preventing Venous Thromboembolism (PREVENT) trial, a randomized, controlled trial that evaluated whether adjunctive intermittent pneumatic compression in critically ill patients receiving pharmacologic thromboprophylaxis with unfractionated heparin or low-molecular-weight heparin would result in a lower incidence of proximal lower-limb deep-vein thrombosis than pharmacologic thromboprophylaxis alone. Read the Original Article here.
Q: How often does deep-vein thrombosis develop in critically ill patients, despite pharmacologic thromboprophylaxis?
A: Deep-vein thrombosis develops in 5 to 20% of critically ill patients despite pharmacologic thromboprophylaxis.
Q: Is intermittent pneumatic compression associated with skin injury?
A: Intermittent pneumatic compression has been reported to cause skin injury. The Clots in Legs or Stockings after Stroke (CLOTS) 3 trial involving hospitalized patients with stroke reported that skin injuries occurred in 3.1% of the patients who received intermittent pneumatic compression and in 1.4% of the patients who did not. In contrast, Arabi et al. observed no between-group difference in the percentage of patients who had skin injuries. This may be related, at least in part, to the younger age of the patients in the PREVENT trial, who were approximately 20 years younger and might have had less skin fragility and more mobility than the patients in the CLOTS 3 trial.
A: In the PREVENT trial, adjunctive intermittent pneumatic compression had no effect on the incidence of proximal deep-vein thrombosis among critically ill patients who were receiving pharmacologic thromboprophylaxis. The lack of effect was observed in the modified intention-to-treat and per-protocol analyses and across all subgroup and sensitivity analyses. The percentage of patients who had any lower-limb deep-vein thromboses also did not differ significantly between the pneumatic compression group and the control group. Pulmonary embolism occurred in 8 of 991 patients (0.8%) in the pneumatic compression group and in 10 of 1012 patients (1.0%) in the control group (relative risk, 0.82; 95% CI, 0.32 to 2.06). The rates of death from any cause (assessed at ICU discharge, 28 days, hospital discharge, and 90 days) did not differ significantly between the two trial groups.
A: The main limitation in the trial was the fact that the incidence of the primary outcome in the control group was lower than expected, which reduced the power of the trial; consequently, the results do not rule out the possibility of a clinically important treatment effect (a benefit of as much as 40% or a harm of as much as 44%). Because of the pragmatic nature of the trial, participating sites used different intermittent pneumatic compression devices, both knee-length and thigh-length sleeves, and foot pumps in some patients. The trial did not address the isolated effect of each component.