[Studies on the method of sterilization with ethylene oxide gas. 1. Sterilization procedure and sterilizing effect]

Undertaken to ensure perfection of sterilization with ethylene oxide gas (EO gas) in routine clinical laboratory practice, an investigation was made of the relationship between sterilization procedure and sterilizing effect using the film bag delivery system and chamber system. Using a biological indicator as a monitor of sterilizing effect, the efficiency of sterilization was studied under various likely conditions and compared. The results led to the following conclusions: 1. Sterilization with EO gas by the film bag delivery system, because of this procedure being unable to be performed at a constant temperature, was shown to prove inadequate due to insufficient exposure to gas especially in winter season (when room temperature fell below 10 degrees C). 2. With the EO gas sterilization method using the film bag delivery system, which is believed to be effective within the ordinary range of humidity of the atmosphere, sterilizing effect was recognized to be affected by excess wetting of an object of sterilization that was caused by inadvertent manipulation or due to a predisposing attribute of the object, such as shape or outline. 3. All materials are sterilized upon being packaged. It is necessary therefore to make best choice of package material with respect of texture and size. Reuse influence to sterilizing effect. 4. The method of sterilization with EO gas using the chamber system has the advantage in that operating conditions are all automatically controlled. For this reason, there was not a single instance of failure to sterilize due to inappropriateness of temperature and humidity. From these results it is concluded that sterilising effect was affected by sterilization procedure and condition.(ABSTRACT TRUNCATED AT 250 WORDS)