复用医疗器械清洗后放置时间与污染度关系的研究

目的：研究不同污染程度的医疗器械清洗后放置时间与微生物繁殖的关系，以寻找最佳的灭菌时机。方法：将手术后器械按污染程度分为3组，根据WS310．2-2009规定的清洗流程进行清洗，采用ATP生物荧光法、肉眼裸视法、较正视力法、蛋白残留试验法分别对清洗后的清洁度及放置不同时间梯度的污染状况进行检测并比较。实验数据采用X2检验进行统计学分析。结果：四种方法对清洗后的轻度、中度、重度污染医疗器械检测结果均为阴性。对3组器械放置不同时间后的污染阳性率进行卡方检验，χ2=145．002，P〈0．05。说明清洗后放置时间不同，污染度也不完全相同，放置时间越长阳性率越高。对不同污染程度样本的污染阳性率进行卡方检验，χ2=28．473，P〈0．05，说明不同污染程度样本的污染度也不完全相同，中度污染和重度污染的阳性率高于轻度污染。结论：轻度污染的医疗器械清洗后放置时间不应超过4小时，中度、重度污染的医疗器械清洗后放置时间不应超过2小时。

The relationship between standing time and pollution degree of reusable medical instruments after cleaning

Objective： To observe the relationship between standing time and reproduction of microorganism of medical instruments after cleaning with different contamination degree and to find out the optimal sterilization time. Methods： We devided polluted medical instruments after operations into 3 groups according to their determination degree and cleaned them with the standard cleaning process regulated by WS 310. 2-2009. We compared in parallel the cleanliness after cleaning and the pollution status of the instruments with different standing time gradients before sterilization respectively by ATP bioluminescence method, naked eye observation, corrected eyesight method and residual protein test method. The experimental data were analyzed by chi square test. Results： The results of the four test methods of mild, moderate and severe polluted medical instruments were all negative after cleaning. The positive rate of 3 groups instruments with different standing time had significant difference by chi-square test（χ2=145.002, P〈0.05）. It showed that the positive rate was not identical with different standing time. The longer the instruments were stored, the higher positive rate it got. We compared the positive rate of samples with different contamination degree by chi-square test .The results showed that the positive rate was not identical with different contamination degree and the positive rate of moderate and severe contamination degree was higher than that of the mild pollution degree（χ2=28.473, P〈0.05）. Conclusions： Mild polluted medical instruments should not be stored more than 4 hours after cleaning. Moderate and severe polluted medical instruments should not be stored more than 2 hours after cleaning.