orthopnea

noun

or·thop·nea

variants: or chiefly British orthopnoea \ ȯr-ˈthäp-nē-ə also ˌȯr-ˌthäp-ˈnē-ə \

Medical Definition of orthopnea

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