碩士 / 弘光科技大學 / 職業安全與防災研究所 / 96 / Objectives - This study aimed to study the emission characteristics of ethylene oxide (EO) sterilized medical products under various environmental conditions, compare the differences in kinetics among test variables and estimate the EO emission factors. Furthermore, control strategies were developed based on the current findings to reduce the EO air concentration in the aeration area to minimize workers exposures. Methods - The experiments were performed in a controlled-environment facility, in which temperature, relative humidity and air change rate were controlled. The kinetic parameters, maximum concentration (Cmax), time to maximum concentration (Tmax), area under concentration-time curve (AUCT), area under curve-first day (AUC1), area under curve-second day (AUC2) and decay rate constant (k) were examined between two different product types (1 ml and 30 ml polypropylene syringes) across various environmental factors.Results - The increase (25 to 40℃) of temperature impacted all the kinetic parameters (p<.05), while increasing (50 to 80%) relative humidity affected all the kinetic parameters, except for AUC1 and AUC2 (p<.05). Similarly, increasing (0.5 to 2 hr-1) air change rate affected all the kinetic parameters but Cmax (p<.05), and change of products influenced all the kinetic parameters except k (p<.05). The average EO emission factors for the first day, the second day and at 48th hours for 1ml and 30ml syringes were 3592, 1924, 108 and 3441, 2005, 38 mg/m3/h, respectively. The decay half-lives, estimated from one-phase exponential model, for 1ml and 30ml products were 27.6 and 32.3 hours, respectively. The times required for the air EO concentration from the tested products to return to near zero and permissible limit (1ppm) were 417 and 218 hours, respectively. Additionally,a multiple linear regression model was established for prediction of various kiaetics parameters.Conclusions – Previous studies have found that residual EO remaining in sterilized medical can diffuse into the surrounding environment, resulting in occupational exposure. This study demonstrated that products, temperature, relative humidity and air change rate affected the EO emission characteristics, and a long time was required to return to a low value. Such findings can be considered when designing an aeration area/room for EO-sterilized products. Furthermore, after-sterilization purge cycles are known to reduce EO residue, thus it should be implemented if possible.
| Identifer | oai:union.ndltd.org:TW/096HKU05590005 |
| Date | January 2008 |
| Creators | Po Chi Sue, 蘇栢祺 |
| Contributors | Yeh-Chung Chien, 錢葉忠 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 126 |
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