The Aerospace Medical Association published a booklet for physicians in 1997 called Medical Guidelines for Air Travel, covering things a physician would need to know. The booklet can be ordered for $14.50 (plus $3.50 S&H;) from their website at www.asma.org Following is an excerpt used by permission from ASMA editor Pam Day:
If intrinsic risk factors are evident, consider other preventive measures. This can be facilitated by classifying patients as follows.
1. A single relatively minor risk factor or a general tendency to develop leg swelling indicates only a very low risk. Elastic stockings and other compressive devices should be worn.
2. Patients with a significant elevated risk (e.g., postthrombosis status, known malignancy, general or leg immobility or postoperative status) should be given subcutaneous heparin before boarding and again upon arrival.
3. High risk patients (e.g. with multiple thrombosis or pulmonary embolism in their medical history) should be considered for full oral anticoagulation (pregnancy excepted). If this treatment is not possible, the patient should be advised to abandon the trip.
(Note re. pregnancy: Women who are pregnant or might become pregnant, are cautioned “If the patient becomes pregnant while taking warfarin, she should be apprised of the potential risks to the fetus, and the possibility of terminating the pregnancy should be discussed in light of those risks.” Nor is heparin without risk. Dupont says 10% of pregnant women have severe vaginal bleeding after a heparin shot, and that the benzyl alcohol preservative in Innohep can cross the placenta and cause fetal damage such as “gasping syndrome” observed in premature infants. Since pregnancy is definitely a risk factor for DVT and anticoagulants are not recommended, it would appear that for pregnant women air travel should be avoided or, if unavoidable, using frequent leg flexing, compression stockings, and electrolytic beverages, one cup per hour.)
Treatment guidelines for DVT and PE are well established and not discussed here except:
1. Dr. Bo Eklof at the Straub Clinic in Hawaii recommends more aggressive treatment with the aim of reducing the number (27%) of DVT victims who later develop chronic DVT with leg ulcers. Contact the Straub Clinic for further details.
2. At least one recent study found that long-term warfarin use is usually not advisable, with incidents of bleeding outnumbering the numbers of recurrent DVT in those who stopped taking warfarin. However, a newer study finds that after initial warfarin treatment of three to six months, the dosage can be reduced for effective ongoing protection against recurrent DVT/PE. An experimental treatment is being studied at National Institutes of Health by Dr. Richard Chang, using recombinant tissue plasminogen activator (rt-PA) to dissolve clots. By dissolving clots immediately instead of waiting weeks for lysing to dissolve them, the chance of permanent vein damage is greatly reduced. But the treatment must begin within two weeks of clot formation, after which the clot resists this treatment. For free treatment, contact Richard Chang at RChang@mail.cc.nih.gov.