Dictionary.com
definitions

closed anesthesia

[klōzd]
n.
  1. Inhalation anesthesia in which there is complete rebreathing of all exhaled gases, except for carbon dioxide, which is removed by the anesthetic apparatus.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.