Study on Performance of Infectious Waste Sterilizing Set in Kashan Shahid Beheshti Hospital and Determination of its Optimum Operating Condition

Background and Objectives; Autoclaving is one of the methods which sterilizes infectious solid wastes. Since variety of parameters such as temperature, time, and pressure influence autoclave performance, this study was carried out to evaluate the parameters and set optimum condition for the autoclave apparatus applied in Shahid Beheshti Hospital in Kashan. In this descriptive-analytical study, the performance of subjected autoclave was surveyed based on biological index and through setting 144 tests. Variables were packaging type in two groups (open and wrapped), loading type in three groups (light, medium and heavy), and four temperature-time features in fixed pressure equal to 101 kpa. Biological index was ATCC 7953 which contained Stearotermophilus Geobacillus spores. Finally obtained results were analyzed by Chi-Square test. The results of statistical test showed that there isnt any meaningful relation between packaging type of waste, system loading, and efficiency of sterilization(P>0.05),while meaningful relation was found between system performance and variety states of temperature-time feature(P<0.05), illustrating temperature and time effects in fixed pressure on sterilization of solid waste. Based on the results, the best autoclave operational condition for sterilizing infectious solid wastes are: temperature-time equal to 10 min-140°C and 15 min-134°C in fixed pressure of 101 kpa, respectively. It was also revealed that temperature-time condition suggested by manufactory, i.e. 20min-121°C, is not sufficient for complete sterilization of solid waste.