Grant: Project Grant

Critically ill patients in the intensive care unit (ICU) are at high risk of developing blood clots in the legs or lungs. To prevent these clots, most ICU patients receive a standard "fixed dose" of a blood thinner called low-molecular-weight heparin. However, in critical illness the effect of this medication can vary widely from person to person. Some patients may receive too little medication effect and remain at risk for clots, while others may receive too much and have a higher risk of bleeding. PROVE-ICU is a multi-centre pilot randomized trial in five Canadian ICUs. The goal is to determine whether a larger definitive trial is feasible. Adults expected to remain in the ICU for at least 72 hours will be randomized 1:1 to (1) usual fixed-dose thromboprophylaxis or (2) a personalized, weight-based approach where doses are adjusted using a simple blood test that measures the medication's effect. Because many ICU patients cannot provide informed consent at enrolment, consent will be obtained from a substitute decision-maker, or using deferred consent when appropriate and permitted. This pilot trial will measure feasibility outcomes including recruitment rate, the proportion of participants with consent ultimately confirmed, and adherence to the assigned dosing strategy and blood test timing. We will also assess whether the personalized strategy can reliably achieve the target blood-test range within ICU workflows and within clinically meaningful timelines. Safety outcomes (bleeding) and clinical outcomes (blood clots) will be tracked to inform the design of the larger trial. If PROVE-ICU is feasible, the subsequent definitive trial could determine whether personalized dosing improves blood clot prevention without increasing bleeding, supporting safer and more effective care for ICU patients and informing future practice guidelines.