title: Postoperative nitrous oxide analgesia. Administration from air entrainment oxygen masks with a primary flow of Entonox.
abstract: Nitrous oxide is occasionally used as an analgesic agent in the postoperative period. The feasibility of administering a known concentration from an air entrainment oxygen mask, using a primary flow of Entonox, (50% oxygen/50% nitrous oxide) was investigated. Accurox (C.R. Bard Canada Inc.) blenders, disconnected from their facemasks, were studied using a primary flow of Entonox. An increase in air entrainment of approximately 13% was demonstrated. Concentrations of about 20% nitrous oxide in oxygen enriched air, appropriate for postoperative analgesia, can be produced, but the methods are extravagant in the use of Entonox and are likely to be slightly unreliable.
mesh_terms: D000388:Air; D004338:Drug Combinations / Q000008:administration & dosage / Q000627:therapeutic use; D006801:Humans; D008397:Masks; D009609:Nitrous Oxide / Q000008:administration & dosage* / Q000627:therapeutic use; D010100:Oxygen / Q000008:administration & dosage* / Q000627:therapeutic use; D010149:Postoperative Pain / Q000188:drug therapy*
chemical_list: D004338:Drug Combinations; C001147:Entonox; D009609:Nitrous Oxide; D010100:Oxygen