Ohio No. 8

Brigham and Women's Hospital Department of Anesthesiology, Perioperative and Pain Medicine collection.

Ohio No. 8 Vaporizer, circa 1940s

A standard vaporizer on the popular Kinet-O-Meter anesthesia machines created by the Ohio Chemical and Manufacturing company from the 1930s through the 1960s, the Ohio No. 8 vaporizer improved the Boyle Bottle by adding a control dial for pushing the carrier gas through the liquid anesthetic, a wick to create more surface area to vaporize the liquid anesthetic, and a bypass valve to control the flow of gas to the patient. It did not address the problem of cooling. Mounted within “in-circuit” systems (designed so patient rebreathes exhaled gases) the Ohio No. 8 could be dangerous due to an unmeasurable buildup of anesthetic in the patient, possibly leading to death. The anesthetist relied completely on the patient’s clinical signs for monitoring.