The Collaborative International Dictionary of English v.0.48:

Hyperpnoea \Hy`perp*n[oe]"a\, n. [NL., fr. Gr. "ype`r over + ?,
   ?, breath.] (Physiol.)
   Abnormal breathing, due to slightly deficient arterialization
   of the blood; -- in distinction from eupn[oe]a. See
   Eupn[oe]a, and Dispn[oe]a.
   [1913 Webster]