Risk factors:
(1) pre-existing history of lymphedema or risk factors for lymphedema (surgery to axilla or groin, radiation therapy, etc)
(2) low atmospheric pressure in the cabin
(3) inactivity during the flight (little or no muscular pumping activity)
(4) lack of hosiery or other compression wrappings to counter increased relative pressures (including compression glove or stockings to cover the affected hand or foot)
(5) constriction in clothing near trunk
(6) long duration flight (>= 10 hours, although lymphedema can occur in flights lasting 1-2 hours)
Lymphedema needs to be distinguished from edema occurring during the flight. Findings suggesting lymphedema:
(1) involvement of an arm
(2) involvement of a single limb
(3) presence of pain in the limb
