Urinary leukotriene E-4 levels are not increased prior to high-altitude pulmonary edema

Study objective: To examine whether increased urinary cysteinyl-leukotriene E-4 (LTE4) excretion, which has been found to be elevated in patients pres enting with high-altitude pulmonary edema (HAPE), precedes edema formation, Design: Prospective studies in a total of 12 subjects with susceptibility t o HAPE, Setting: In a chamber study, seven subjects susceptible to HAPE and five no nsusceptible control subjects were exposed for 24 h to an altitude of 450 m (control day), and exposed for 20 h to 4,000 m after slow decompression ov er 4 h, In a field study, prospective measurements at low and high altitude were performed in five subjects developing HAPE at 4,559 m, Participants: Mountaineers with a radiographically documented history of HA PE and control subjects who did not develop HAPE with identical high-altitu de exposure, Interventions: 24-h urine collections. Measurements and results: In the hypobaric chamber, none of the subjects de veloped HAPE, The 24-h urinary LTE, did not differ between HAPE susceptible and control subjects, nor between hypoxia and normoxic control day, In the field study, urinary LTE4 was not increased in subjects with HAPE compared to values obtained prior to HAPE at high altitude and during 2 control day s at low altitude. Conclusions: These data do not provide evidence that cysteinyl-leukotriene- mediated inflammatory response is associated with. HAPE susceptibility or t he development of HAPE within the context of our studies.