hksccm20logo
Position Statement of the Hong Kong Society of Critical Care Medicine
Prevention of Venous Thromboembolism in Intensive Care Units in Hong Kong 
Dr Thomas ST LI, Prince of Wales Hospital, on behalf of the Working Group for the Prevention of Venous Thromboembolism in ICU in Hong Kong and the HKSCCM
This Position Statement was endorsed by the HKSCCM Council in the 15th Council Meeting on 20th July 2010

Prevention of venous thromboembolism (VTE) in critically ill patients has been advocated by various international guidelines (1,2). The American College of Chest Physicians guideline in 2008 suggests that all patients should be assessed for risk of VTE on admission to ICU. Most patients should receive thromboprophylaxis. For patients who are at high risk for bleeding, mechanical prophylaxis with graduated compression stocking and/ or intermittent pneumatic compression should be used until bleeding risk decreases. For patients with moderate risk for VTE (eg. medically ill patients or postoperative patients), low dose unfractionated heparin or low molecular weight heparin is recommended. For patients with high risk for VTE (following major trauma or orthopaedic surgery), low molecular weight heparin is recommended.

The risk for VTE is lower in Chinese than Caucasian (3,4). It is also believed that the risk of bleeding complication from anticoagulation is higher in Chinese. Critically ill patients have multiple risk factors for VTE and bleeding. International guideline on prevention of VTE may not be directly applicable to Chinese critically ill patients.

During the first working group meeting, members of the working group reported that graduated compression stocking and/ or intermittent pneumatic compression are commonly used in Hong Kong ICU for prevention of VTE. However, except for Prince of Wales Hospital and Princess Margaret Hospital, pharmacological prophylaxis is seldom used. In PYNEH, pharmacological prophylaxis will be considered for high risk patients like trauma or neurosurgical patients.

Members of the working group think there is a need to identify and analyze literature concerning the benefits and risks of use of pharmacological prophylaxis in Chinese critically ill patients before advocating its use in Hong Kong ICU.

Using Pubmed search with keywords including Chinese, deep vein thrombosis, critically ill or intensive care, a number of articles are identified (5-11). Of relevance, two are epidemiology studies from intensive care units in Hong Kong; one is the guideline for prevention of deep vein thrombosis in ICU from the Chinese Society of Critical Care Medicine and Chinese Medical Association.

The local epidemiological studies document high prevalence of DVT among ICU patients in Hong Kong, 11% in patients requiring femoral vein cannulation and 19% in medical ICU patients.
The guideline from the Chinese Society of Critical Care Medicine and Chinese Medical Association recommend the followings:
1. Mechanical methods for VTE prevention in ICU patients with high risk of haemorrhage.
2. Low molecular weight heparin or unfractionated heparin for patients with moderate risk of DVT without high risk of haemorrhage
3. Low molecular weight heparin for patients with high risk of DVT.

However, the guideline did not clearly define low, moderate and risk of DVT. Also, risk stratification based on history and physical examination has also been found not be useful in predicting DVT in critically ill patients in Caucasian population. There is no similar study in Chinese population.

Using Pubmed search, no randomized control trials on prevention of VTE in Chinese critically ill patients can be found. There are 5 randomized control trials on prevention of VTE in non-critically ill Chinese patients (12-16). The results are conflicting. One recent study from Singapore on VTE prophylaxis in Asian patients after total knee arthroplasty found that patients on enoxaparin required more blood transfusion and some had major bleeding.

The best available evidence in literature does not specifically address the risks and benefits regarding the use of pharmacological prophylaxis on VTE in Chinese critically ill patients, it is difficult for the working group to give recommendation. Randomized controlled trials on pharmacological prophylaxis in Chinese critically ill patients are needed.

References
1. Geerts WH, Pineo GH, Bergqvist D et al. Prevention of venous thromboembolism: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition) Chest 2008; 133: 381S-453S.
2. Dellinger RP, Levy MM, Carlet JM et al. Surviving Sepsis Campaign: Interantional guidelines for management of severe sepsis and septic shock: 2008. Crit Care Med 2008; 36: 296 – 327.
3. Stein PD, Kayali Fadi, Olson RE et al. Pulmonary thromboembolism in Asians/Pacific Islanders in the United States: Analysis of data from the national hospital discharge survey and the United States Bureau of the Census. Am J Med 2004; 116:435-442.
4. White RH, Keenan CR. Effects of race and ethnicity on the incidence of venous thromboembolism. Thrombosis Research 2009; 123 Suppl. 4, S11-S17
5. Zhang W, Shi ZY, Fu WG, Wang YQ. Preliminary study on epidemiology of deepvenous thrombosis of lower extremity in patients with high risk. Zhonghua Yi Xue Za Zhi. 2009;89:3176-80.
6. Chinese Society of Critical Care Medicine; Chinese Medical Association. Guidelines for prevention of deep venous thrombosis in intensive care unit patients. Zhongguo Wei Zhong Bing Ji Jiu Yi Xue. 2009;21:514-7.
7. Ma XC. More attentions should be payed to deep venous thrombosis of intensive care unit patients. Zhongguo Wei Zhong Bing Ji Jiu Yi Xue. 2009; 21:513.
8. Joynt GM, Li TS, Griffith JF, Gomersall CD, Yap FH, Ho AM, Leung P. The incidence of deep venous thrombosis in Chinese medical Intensive Care Unit patients. Hong Kong Med J. 2009; 15: 24-30.
9. Xu XF, Yang YH, Zhai ZG, Liu S, Zhu GF, Li CS, Wang C. Prevalence and incidence of deep venous thrombosis among patients in medical intensive care unit. Zhonghua Liu Xing Bing Xue Za Zhi. 2008 ;29:1034-7.
10. Shen YX, Zhu B, Wang Q. Application of intermittent air compression in prevention of embolism from venous thrombosis in intensive care unit. Zhongguo Wei Zhong Bing Ji Jiu Yi Xue. 2007;19:574-6.
11. Joynt GM, Kew J, Gomersall CD, Leung VY, Liu EK. Deep venous thrombosis caused by femoral venous catheters in critically ill adult patients. Chest. 2000;117:178-83.
12. Chin PL, Amin MS, Yang KY, Yeo SJ, Lo NN. Thromboembolic prophylaxis for total knee arthroplasty in Asian patients: a randomised controlled trial. J Orthop Surg (Hong Kong). 2009;17:1-5.
13. Li T, Lv M, Li Q. Comprehensive prophylaxis for deep venous thrombosis after proximal femurfractures in geriatric patients. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2008; 22:453-5.
14. Li XL, Lu WJ, Yu NS. Prophylaxis for deep vein thrombosis with low molecular weight heparin following hip and knee surgery. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2001;15:39-41.
15. Ho YH, Seow-Choen F, Leong A, Eu KW, Nyam D, Teoh MK. Randomized, controlled trial of low molecular weight heparin vs. no deep vein thrombosis prophylaxis for major colon and rectal surgery in Asian patients. Dis Colon Rectum. 1999; 42:196-202; discussion 202-3.
16. Kew J, Lee YL, Davey IC, Ho SY, Fung KC, Metreweli C. Deep vein thrombosis in elderly Hong Kong Chinese with hip fractures detected with compression ultrasound and Doppler imaging: incidence and effect of low molecular weight heparin. Arch Orthop Trauma Surg. 1999;119:156-8