Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 51 3 2013 03 15 168 171 EN Parisa Adimi Naghan Chronic Respiratory Disease Research Center, National Research Institute of Tuberculosis and Lung Disease, Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Majid Malekmohammad Tracheal Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran. Hamidreza Jamaati Tobacco Prevention and Control Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences,Tehran, Iran. Babak Sharifkashani Lung Transplantation Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran. Arvin Najafi Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran. Seyed Mohammadreza Hashemian Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran. 2015 10 11 The objective of this study was to determine the prevalence and incidence of venous thromboembolism among critically ill medical surgical patients. In this cross sectional and retrospective study, we observed 243 patients who were first admitted at the intensive care unit. Patients who were diagnosed with deep venous thrombosis or embolism either by clinical or paraclinical methods were enrolled. Among 243 patients of ICU ward 12 cases of them were confirmed to have thromboembolism (prevalence of 9.4%).But the incidence of venous thromboembolism after 48 hour of ICU admission was 5.2%(6 cases). Among 6 VTE cases 3 of them didn't receive any anticoagulant prophylaxis, 2 patients received LDUH 5000 unit twice a day and one patient received LMWH 60 mg daily but all developed VTE although receiving prophylaxis. We found that the prevalence of proximal lower limb DVT among medical-surgical critically ill patients remaining in the ICU for ≥3 days is about 9.4% and the incidence of that is about 5.2%. Further studies should be performed in order to assess the benefits and risks of venous thromboprophylaxis in Iranian patients. https://acta.tums.ac.ir/index.php/acta/article/view/4469 https://acta.tums.ac.ir/index.php/acta/article/download/4469/4442