The Collaborative International Dictionary of English v.0.48:

Intubation \In`tu*ba"tion\, n. [Pref. in- in + tube.] (Med.)
   The introduction of a tube into an organ to keep it open, as
   into the larynx in croup.
   [1913 Webster]

WordNet (r) 3.0 (2006):

intubation
    n 1: the insertion of a cannula or tube into a hollow body organ
         [syn: cannulation, canulation, cannulization,
         cannulisation, canulization, canulisation,
         intubation]