Marik PE, Andrews L, Maini B.
The incidence of deep venous thrombosis in ICU patients.
Chest 1997 Mar;111(3):661-4

Department of Critical Care Medicine, St. Vincent Hospital, Worcester, MA 01604,
USA. pmarik@ultranet.com

STUDY OBJECTIVE: To determine the incidence, clinical presentation, and risk
factors of deep venous thrombosis (DVT) in a high-risk group of ICU patients
receiving DVT prophylaxis. DESIGN: A prospective cohort study. SETTING: Two ICUs
of a university-affiliated teaching hospital. PATIENTS: Patients admitted to the
ICUs within 48 h of hospitalization and who had an ICU stay of > or = 4 days
underwent venous duplex scans. INTERVENTIONS: None. RESULTS: One hundred two
patients were studied. Ninety-four (92%) patients received DVT prophylaxis.
Twelve patients (12%) were documented to have DVT by venous duplex scans. There
was proximal clot extension in eight of these patients, four of whom had
high-probability ventilation/perfusion scans. Of the 56 patients without signs or
symptoms of DVT, only two (3.6%) had abnormal scans. Leg swelling was present in
11 patients, six of whom had DVT (p = 0.004). One of 11 patients with unexplained
fever had an abnormal scan. Five of the 26 patients (19%) receiving pneumatic
compression developed DVT compared with five of 68 patients (7.4%) receiving
subcutaneous heparin (not significant). No specific factor was identified that
increased the risk of DVT. CONCLUSION: In this study, the incidence of DVT in a
group of high-risk ICU patients receiving DVT prophylaxis was 12%. Since scans in
patients without signs or symptoms suggestive of DVT were abnormal in only 3.6%
of patients, venous scans should be performed only in patients with features
suggestive of DVT or pulmonary embolism.