title: Pulmonary carbon dioxide and panic-arousing sensations after 35% carbon dioxide inhalation: hypercapnia/hyperoxia versus hypercapnia/normoxia.
abstract: Experimental research has demonstrated that CO2 inhalation provides a valid laboratory model for acute panic. Earlier studies employed CO2/O2 mixtures that were not only hypercapnic but also hyperoxic, raising the question of the relative contribution of the hyperoxidity. A comparison between a hypercapnic/hyperoxic mixture (35% CO2/65% O2) and a hypercapnic/normoxic mixture (35% CO2/20% O2/45% N2) revealed no differences on self-reported panic symptoms or end tidal pCO2. It is concluded that findings from previous CO2/O2 inhalation studies should be attributed to the hypercapnic, rather than to the hyperoxic, nature of the mixtures.
mesh_terms: D000328:Adult; D002245:Carbon Dioxide / Q000494:pharmacology*; D004338:Drug Combinations; D005239:Fear / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D009584:Nitrogen / Q000494:pharmacology; D010100:Oxygen / Q000494:pharmacology*; D010200:Panic / Q000187:drug effects*
chemical_list: D004338:Drug Combinations; D002245:Carbon Dioxide; D009584:Nitrogen; D010100:Oxygen