at the last gasp

from The Collaborative International Dictionary of English v.0.48

Gasp \Gasp\, n.
   The act of opening the mouth convulsively to catch the
   breath; a labored respiration; a painful catching of the
   breath.
   [1913 Webster]

   {At the last gasp}, at the point of death. --Addison.
      [1913 Webster]