Venous thromboembolism (VTE) is one of the major public health problems in Western country. More than 100,000 Americans die each year from VTE. VTE is also a common complication of critical illness,1-2 and probably related to poor outcome in this patient group. Although there are guidelines about VTE prophylaxis in acutely ill medical patients and patients in medical ICU3, they are overlooked in our daily practice frequently in our country. There are many reasons for our common practice, including inadequate knowledge for the ICU physicians, more patients with bleeding tendency in ICU and low prevalence of VTE in our (eastern) country. However, the true prevalence of VTE in ICU and if thromboprophylaxis still needed in certain high risk patients are not unknown. Besides, if there is a difference in the VTE rate between western and eastern patients, what is the underlying mechanism? The major objective of this application is to answer the first part of the problem, i.e. to delineate the scope of this problem.

The specific aims of this application are as follows:

• prevalence of venous thromboembolism in ICU in Taiwan
• specific risk in subgroups of ICU patients
• prevalence and risk factors for silent pulmonary embolism

Inclusion Criteria:

• All patients admitted to medical ICU with age over 18 y/o are eligible

Exclusion Criteria:

• Patients who do not sign the informed consent will be excluded from this study

All patients admitted to ICU with age over 18 y/o are eligible