orthopnea

noun

or·​thop·​nea

variants or chiefly British orthopnoea

ȯr-ˈthäp-nē-ə also ˌȯr-ˌthäp-ˈnē-ə

: difficulty in breathing that occurs when lying down and is relieved upon changing to an upright position (as in congestive heart failure)

orthopneic adjective

or chiefly British orthopnoeic

-ik