The incidence of deep venous thrombosis in Chinese medical Intensive Care Unit patients

Abstract

OBJECTIVE. To evaluate the incidence of deep venous thrombosis in critically ill, Intensive Care Unit patients of Chinese ethnicity.

DESIGN. Prospective, observational study.

SETTING. Intensive Care Unit in a Hong Kong teaching hospital.

PATIENTS. Consecutive adult Chinese medical patients not receiving pharmacological or mechanical prophylaxis for deep venous thrombosis.

MAIN OUTCOME MEASURES. Compression and duplex Doppler ultrasound examinations of the lower limbs within 24 hours of admission and twice weekly thereafter during their Intensive Care Unit stay. After discharge, a 1-week follow-up investigation was also performed. Demographic data and risk factors for deep venous thrombosis were prospectively recorded.

RESULTS. Over a 9-month study period, 80 patients were investigated. Deep venous thrombosis was detected by ultrasound examination in 15 (19%) of the patients (95% confidence interval, 14-23%). Nine of 15 had isolated below-knee deep venous thrombosis, and of these, five had bilateral involvement. Characteristics of patients with or without deep venous thrombosis were similar. Of the 15 patients who had a positive ultrasound examination, only four (27%) had clinical signs of deep venous thrombosis. Of the 65 patients without a positive ultrasound examination, only two (3%) had positive clinical signs (P=0.01). This yielded a moderate positive likelihood ratio of 9 (95% confidence interval, 2-43) and a small negative likelihood ratio of 0.76 (95% confidence interval, 0.56-1.03). There were no cases of pulmonary embolism. Hospital mortality in those with and without deep venous thrombosis was 33% and 28%, respectively.

CONCLUSIONS. In the absence of prophylaxis, the incidence of deep venous thrombosis in Chinese medical Intensive Care Unit patients is lower than that reported in similar Caucasian patients, but higher than expected. As clinical features are not able to reliably exclude the presence of deep venous thrombosis, early routine prophylaxis for deep venous thrombosis in Chinese medical Intensive Care Unit patients should be considered.