pulmonary embolism

:  obstruction of a pulmonary artery or one of its branches that is usually produced by a blood clot which has originated in a vein of the leg or pelvis and traveled to the lungs and that is marked by labored breathing, chest pain, fainting, rapid heart rate, cyanosis, shock, and sometimes death … whether physical activity during flight is protective against pulmonary embolism remains to be demonstrated.—Frederic Lapostolle et al., The Journal of the American Medical Association, 13 Sept. 2001—abbreviation PE