Carbogen

Carbogen, also called Meduna's Mixture after its developer Ladislas Meduna, is a therapeutic gas mixture of carbon dioxide and oxygen, historically ranging from a 30 percent carbon dioxide and 70 percent oxygen blend to much leaner mixtures. Inhaling it makes the brain register a rise in blood carbon dioxide as suffocation, quickening breathing and heart rate. Meduna used it in psychedelic-era psychotherapy to induce a controlled crisis he believed helped patients confront neuroses, a use that declined alongside psychedelic psychotherapy generally. Modern medicine has explored carbogen for central retinal artery occlusion and sudden sensorineural hearing loss, and as an adjunct with nicotinamide in radiation therapy research.