Abstract
Ethylene oxide (EO) gas is widely used for sterilization of medical instruments and supplies. The gas being used in our hospital consists of 20% EO and 80% carbon dioxide and is packed in a cylinder as liquefied gas. We investigated the relationship between the composition of the gas and the amount of EO gas used by measuring the EO concentration in a sterilizer. The concentration of EO was increased as the amount of gas increased, and it decreased sharply when the remaining gas in the cylinder decreased up to about 12% of its initial value. This value agreed with the calculated one by gas-liquid equilibrium when all of the liquefied gas was consumed and only saturated gas remained in the cylinder.
