Exposure of patients to ethylene oxide during cardiopulmonary bypass using gas-sterilized pump components

We have shown that ethylene oxide (EO), absorbed by polyvinyl chloride (PVC) and rubber components of the cardiopulmonary bypass (CPB) circuit during sterilization, is subsequently eluted by the circulating blood-prime mixture and enters the patient. The amount of EO available for elution is diminished by increasing the airing period of the tubing after sterilization, but it is still appreciable after 72 hours' airing. When tubing is used after 24 hours' airing, the amount of EO which enters the patient during 90 minutes of CPB is probably at least 70 mg. During the first few hours after CPB, the amount of EO recoverable from the patient's blood rapidly diminishes, probably because of the binding of EO in irreversible chemical combination.