title: Venous thromboembolism in association with prolonged air travel.
abstract: 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.
  
  
  RESULTS
  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.
authors.affiliation: Straub Clinic and Hospital, Honolulu, HI 96813, USA.
authors.forename: B
authors.initials: B
authors.lastname: Eklof
authors.forename: R L
authors.initials: RL
authors.lastname: Kistner
authors.forename: E M
authors.initials: EM
authors.lastname: Masuda
authors.forename: B V
authors.initials: BV
authors.lastname: Sonntag
authors.forename: H P
authors.initials: HP
authors.lastname: Wong
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D000368:Aged; D000369:Aged, 80 and over; D002406:Catheterization, Peripheral; D002908:Chronic Disease; D004231:Diuresis; D015914:Estrogen Replacement Therapy; D005260:Female; D005268:Femoral Vein; D006801:Humans; D006813:Humidity; D000860:Hypoxia / Q000150:complications; D007084:Iliac Vein; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications; D011152:Popliteal Vein; D011187:Posture; D011655:Pulmonary Embolism / Q000209:etiology*; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D013924:Thrombophlebitis / Q000209:etiology*; D013927:Thrombosis / Q000209:etiology; D014195:Travel