| Flight < 12 h - all travellers |
|---|
| Avoid stasis, move around cabin, isometric calf exercises. Avoid dehydration, alcohol and caffeinated drinks. |
| Flight ≥ 12 h - low risk |
| Avoid stasis, move around cabin, isometric calf exercises. Avoid dehydration, alcohol and caffeinated drinks. |
| Flight ≥ 12 h - moderate risk** |
| Avoid stasis, move around cabin, isometric calf exercises. Avoid dehydration, alcohol and caffeinated drinks. Below knee graduated pressure stockings; if elastic stockings not used, ASA 160 mg to 325 mg 4 h before flight (data for efficacy of ASA is inconclusive). |
| Flight ≥ 12 h - high risk*** |
| Avoid stasis, move around cabin, isometric calf exercises. Avoid dehydration, alcohol and caffeinated drinks. Below knee graduated pressure stockings; if elastic stockings not used, low molecular weight heparin (4000 to 5000 anti-Xa units subcutaneously) 2 h before flight. |
* Literature supports 12 hours as threshold for risk of developing thromboembolism but many would consider 9 hours long haul.
** Moderate risk: healthy people age > 75, women > 45 taking estrogen containing hormone replacement therapy, pregnant and postpartum women, people up to age 45 who are heterozygous carriers of mutations for Factor V Leiden and Prothrombin gene mutation, varicose veins, heart failure, myocardial infarction within previous 6 weeks, recent lower limb trauma within 6 weeks.
*** High risk: history of previous VTE, recent major surgery (within 6 weeks), active malignancy, gross obesity or marked immobility due to neuromuscular or cardiorespiratory disease, people age >45 with deficiencies of antithrombin, protein C or protein S, people age >75 with cardiac or pulmonary disease (8,9).