Economy class syndrome: what is it and who are the individuals at risk?

Abstract The term 'economy class syndrome' refers to the occurrence of thrombotic events during long-haul flights that mainly occur in passengers in the economy class of the aircraft. This syndrome results from several factors related to the aircraft cabin (immobilization, hypobaric hypoxia and low humidity) and the passenger (body mass index, thrombophilia, oral contraceptives or hormone replacement therapy, cancer), acting together to predispose to excessive blood coagulation, which can result in venous thromboembolism. Several risk factors, both genetic and acquired, are associated with venous thromboembolism. The most important genetic risk factors are natural anticoagulant deficiencies (antithrombin, protein C and protein S), factor V Leiden, prothrombin and fibrinogen gene mutations and non-O blood group individuals. Acquired risk factors include age, pregnancy, surgery, obesity, cancer, hormonal contraceptives and hormone replacement therapy, antiphospholipid syndrome, infections, immobilization and smoking. People who have these risk factors are predisposed to hypercoagulability and are more susceptible to suffer venous thromboembolism during air travel. For these individuals, a suitable outfit for the trip, frequent walks, calf muscle exercises, elastic compression stockings and hydration are important preventive measures. Hence, it is essential to inform about economic class syndrome in an attempt to encourage Brazilian health and transport authorities to adopt measures, in partnership with the pharmaceutical industry, to prevent venous thromboembolism.

The changes of venous blood before and after travel by high speed train / 中华普通外科杂志

Objective To prospectively study the changes of venous blood before and after travel by high speed train.Method From December 2013 to August 2015,following the appropriate inclusion and exclusion criteria,50 volunteers and 20 high speed rail crew member were recruited.Blood samples were collected,and lower extremity venous ultrasound was performed in general information,and recorded activities (including walking distance,number of steps,etc.) and drinking water volume,before and after travel.Results After 5 hours in the train,in all the participants venous blood coagulation indicators were on the rise.Doppler ultrasound examination showed:the lower extremity venous diameter increased,the venous return slowed down,the leg circumference diameter increased (all P ＜ 0.05).High speed rail crew had increased leg circumference (P ＜ 0.05).Conclusion 5 hours high-speed train travelling increases the likelihood of economy class syndrome.High speed rail crew working 10 hrs are with increased circumference of the lower extremity veins.

The changes of venous blood before and after travel by high speed train / 中华普通外科杂志

Objective To prospectively study the changes of venous blood before and after travel by high speed train.Method From December 2013 to August 2015,following the appropriate inclusion and exclusion criteria,50 volunteers and 20 high speed rail crew member were recruited.Blood samples were collected,and lower extremity venous ultrasound was performed in general information,and recorded activities (including walking distance,number of steps,etc.) and drinking water volume,before and after travel.Results After 5 hours in the train,in all the participants venous blood coagulation indicators were on the rise.Doppler ultrasound examination showed:the lower extremity venous diameter increased,the venous return slowed down,the leg circumference diameter increased (all P ＜ 0.05).High speed rail crew had increased leg circumference (P ＜ 0.05).Conclusion 5 hours high-speed train travelling increases the likelihood of economy class syndrome.High speed rail crew working 10 hrs are with increased circumference of the lower extremity veins.

The Effect of Long Distance Air-travel on Serum Viscosity and Prothrombin Time

BACKGROUND: Economy class syndrome is medically described as deep vein thrombosis, it is worldwide issued that Long-Distance Air-Travel is a risk factor for venous thromboemborism. Some study provides evidence and theoretical explanations for the hypothesis that long-distance is a risk factor for venous thromboembolism. The purpose of this study is to provide the useful prevention of venous thromboembolism for long-distance travelers in comparison to the effect of long distance air-travel on serum viscosity and prothrombin time between flight level and ground level. METHODS: Subjects selected healthy volunteers that had no abnormal findings in evaluation (alpha2-plasmin inhibitor, plasminogen, anti-thrombin III, protein C, protein S) for hypercoagulability. 5subjects (1 male, 4 females) had a seat on economy class of ground training facility designed for flight attendant and their activities limited as possible during about 8 hours at Sep. 16, 2001. Also, 5 subjects had a seat on the economy class of Asiana Airlines (B-777) from Sydney in Australia to Seoul in Korea at Mar. 3, 2002. In the flight, Actual flight altitude was 31,000 feet, cabin altitude was 4,800 feet and cabin temperature was 25degrees C. We have investigated the serum viscosity used by viscometer and prothrombin time. These data were analyzed statistically by General linear model (spsswin ver. 10.0). RESULTS: The results showed that there were no differcence between Flight Group and Ground Group statistically. However, the serum viscosity of flight group by position was some higher than ground group but these defference was not statistically significance (P=0.419). Also, the serum viscosity of flight group by time had a decreased trend but these trend was not statistically significance (P=0.061). The prothrombin time of flight group by position was some lower than ground group but these defference was not statistically significance (P=0.472). Also, the prothrombin time of ground group by time had a decreased trend but these trend was not statistically significance (P=0.217). CONCLUSION: This study shows the prediction to venous thrombosis more closely relates to prothrombin time than serum viscosity under immobilization to healthy people on the ground environment. Exercise is more useful method than hydration to prevent venous thrombosis on the ground environment. In the flight environment, we think that hydration is also useful method to prevent venous thrombosis because of more dry environment inside flying aircraft. But, this study was decreased serum viscosity between samples according to time. I think serum viscosity can be reduced by vibration effect inside flying aircraft. Serum viscosity and prothrombin time between samples according to position were not statistically significant. I think that risk for the healthy people is poorly quantified and possibly overestimated that long-distance air-travel is a risk factor for venous thromboembolism.