Venous Thromboembolism in Association with Prolonged Air Travel

objective To study risk factors for the development of air travel‐related acute venous thromboembolism. methods A retrospective study of 254 patients admitted from 1988 to 1993 under the diagnosis of deep vein thrombosis (DVT) and/or pulmonary embolism (PE) identified 44 patients who developed symptoms during or after air flight. result There were 24 males and 20 females with a mean age of 63 years. Flight times were 5–17 hours. Twenty‐eight patients (63.6%) had DVT only, five patients (11.4%) PE only, and 11 patients (25%) DVT and PE. Ninety‐five percent had extension of the thrombus above the calf: popliteal vein, 10 patients; superficial femoral vein, 13 patients; common femoral vein, six patients; and iliac vein, eight patients. Five patient‐related risk factors were identified: history of previous DVT (34%), presence of chronic disease or malignancy (25%), hormone therapy (16%), recent lower limb injury (11%), and recent surgery or femoral catheterization (9%). conclusions We can speculate about the role of seven cabin‐related risk factors: low humidity, hypoxia, diuretic effect of alcohol, insufficient fluid intake, smoking, “coach” position, and immobilization. In travelers with patient‐related risk factors, the cabin‐related risk factors are superimposed and may increase the risks for air travel‐related acute venous thromboembolism. Active prophylaxis is recommended.