Cook D, McMullin J, Hodder R, Heule M, Pinilla J, Dodek P,
Stewart T; Canadian ICU Directors Group.
Prevention and diagnosis of venous thromboembolism in critically ill patients: a
Canadian survey.
Crit Care 2001 Dec;5(6):336-42

Department of Medicine, McMaster University, Hamilton, Canada. debcook@mcmaster.ca

BACKGROUND: Venous thromboembolism (VTE) confers considerable morbidity and
mortality in hospitalized patients, although few studies have focused on the
critically ill population. The objective of this study was to understand current
approaches to the prevention and diagnosis of deep venous thrombosis (DVT) and
pulmonary embolism (PE) among patients in the intensive care unit (ICU). DESIGN:
Mailed self-administered survey of ICU Directors in Canadian university
affiliated hospitals. RESULTS: Of 29 ICU Directors approached, 29 (100%)
participated, representing 44 ICUs and 681 ICU beds across Canada. VTE
prophylaxis is primarily determined by individual ICU clinicians (20/29, 69.0%)
or with a hematology consultation for challenging patients (9/29, 31.0%).
Decisions are usually made on a case-by-case basis (18/29, 62.1%) rather than by
preprinted orders (5/29, 17.2%), institutional policies (6/29, 20.7%) or formal
practice guidelines (2/29, 6.9%). Unfractionated heparin is the predominant VTE
prophylactic strategy (29/29, 100.0%) whereas low molecular weight heparin is
used less often, primarily for trauma and orthopedic patients. Use of pneumatic
compression devices and thromboembolic stockings is variable. Systematic
screening for DVT with lower limb ultrasound once or twice weekly was reported by
some ICU Directors (7/29, 24.1%) for specific populations. Ultrasound is the most
common diagnostic test for DVT; the reference standard of venography is rarely
used. Spiral computed tomography chest scans and ventilation-perfusion scans are
used more often than pulmonary angiograms for the diagnosis of PE. ICU Directors
recommend further studies in the critically ill population to determine the test
properties and risk:benefit ratio of VTE investigations, and the most
cost-effective methods of prophylaxis in medical-surgical ICU patients.
INTERPRETATION: Unfractionated subcutaneous heparin is the predominant VTE
prophylaxis strategy for critically ill patients, although low molecular weight
heparin is prescribed for trauma and orthopedic patients. DVT is most often
diagnosed by lower limb ultrasound; however, several different tests are used to
diagnose PE. Fundamental research in critically ill patients is needed to help
make practice evidence-based.