Background The COVID-19 pandemic has led to profound shortages in personal protective equipment worldwide. The availability of filtering facepiece class 3 (FFP3) respirators could be greatly increased if they could be reused after sterilisation. Aims To determine the effects of repeated autoclave cycles on the fit and filter function of the 3M 1863 FFP3 disposable respirator. Methods Participants underwent fit tests with 3M 1863 FFP3 respirators. Respirators were subjected to autoclave cycles and a repeat fit test was conducted after each cycle until failure. The filter function of both unused and autoclaved respirators was determined by quantitatively assessing the differential pressures and filter penetration of aerosolised sodium chloride particles. Mask structural inspection was also carried out by light microscopy. Results A total of 38 participants were recruited. Repeat fit testing with a new respirator was passed by 30 of 38 (79%) participants in comparison with 31 of 38 (82%) of participants after the respirator had undergone one autoclave cycle. There was fit test failure with further rounds of autoclave. There was no evidence of structural changes after one autoclave cycle, but the nose foam began to separate from the mask following further cycles. Filter efficiency of all 15 autoclaved respirators that underwent filter testing was 97.40% or more. Differential pressure (breathability) of respirators was unaffected by autoclaving. Conclusions 3M 1863 FFP3 respirator retains good fit and filter function after a single autoclave cycle. Addressing nose foam separation and further testing to EN149 standards would be required before respirators could be considered for reuse. Data are available upon reasonable request. The datasets generated during the current study are available from the corresponding author on reasonable request.

中文翻译：

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经过多次高压灭菌循环后，呼吸面罩的安装和过滤完整性

背景 COVID-19 大流行导致全球个人防护设备严重短缺。如果过滤面罩 3 类 (FFP3) 呼吸器可以在灭菌后重复使用，它们的可用性将大大增加。目的 确定重复高压灭菌循环对 3M 1863 FFP3 一次性呼吸器的贴合和过滤功能的影响。方法 参与者使用 3M 1863 FFP3 呼吸器进行适合性测试。呼吸器经受高压灭菌循环，并在每个循环后进行重复拟合测试直至失效。通过定量评估雾化氯化钠颗粒的压差和过滤器渗透率来确定未使用和高压灭菌的呼吸器的过滤功能。掩模结构检查也通过光学显微镜进行。结果共招募了38名参与者。38 名参与者中的 30 名 (79%) 通过了使用新呼吸器的重复适合性测试，而呼吸器经过一个高压灭菌循环后，38 名参与者中的 31 名 (82%) 通过了测试。再多轮高压灭菌器出现拟合测试失败。在一个高压釜循环后没有任何结构变化的证据，但在进一步循环后鼻泡开始与面罩分离。进行过滤器测试的所有 15 个高压灭菌呼吸器的过滤效率为 97.40% 或更高。呼吸器的压差（透气性）不受高压灭菌的影响。结论 3M 1863 FFP3 呼吸器在单次高压灭菌循环后仍能保持良好的贴合性和过滤功能。在考虑重复使用呼吸器之前，需要解决鼻部泡沫分离问题并根据 EN149 标准进行进一步测试。可应合理要求提供数据。当前研究期间生成的数据集可根据合理要求从相应的作者处获得。