[1] Carbon dioxide (CO2) is an abundant gas produced as the final product of glucose metabolism in animals.
[2] But it has also been considered as a fast acting anesthetic in small laboratory animals.
The patients would receive 70% CO2 in combination with 30% oxygen causing rapid and reversible loss of continuousness.
[5] The most abundant endogenous anesthetics are small hydrophobic gaseous metabolites of catabolism and likely work through a membrane-mediated mechanism of general anesthesia.
The first private demonstration of an anesthetic was carbon dioxide by Henry Hill Hickman in a dog cerca 1823.