Introduction: This study arose because a number of patients volunteered that flying had triggered, or worsened, their lymphedema. The nature of lymphedema is discussed, including the pre-lymphedematous latent-phase. In this phase the limb is clinically normal, but lymphostatic. There are many of the alterations found in clinical lymphedema involving blood vessels, tissues, lymphatics, and proteolytic cells. Since edema itself impairs many of the safety factors against edema (increased tissue hydrostatic pressure, dilution of proteins in tissue fluid, increased lymphatic transport, and increased proteolysis), any edema occurring in such a limb is likely to persist as chronic lymphedema.
Method & results: Questionnaires were sent to 1,020 patients with lymphedema; 749 replied, with 531 answering a question about what triggered the condition. It was present from near birth in 41, but developed later in 490 (163 post-mastectomy lymphedemas, and 136 primary and 191 secondary leg lymphedemas). In 27 of the 490, it started during an aircraft flight (15 legs and 12 arms). In addition, flying caused existing lymphedema to permanently worsen in 23 arms and 44 legs in the 749 respondents. Some typical case histories are given.
Conclusions: Because of its frequency in arms and legs, it is highly likely that this triggering, or worsening, of lymphedema is produced by lowered cabin pressure. Obstruction of veins and lymphatics, and reduced muscle pumping, may contribute to this in the legs. Using additional compression for existing lymphedema, or limbs at risk, would prevent this. If it occurs, it should be treated by additional compression, using inflated splints or pressure bandages.