Workplace Health, Fraser Health, Burnaby, BC, Canada.
J Occup Environ Hyg. 2011 May;8(5):267-70. doi: 10.1080/15459624.2011.566016.
Many agencies recommend that health care workers wear N95 filtering facepiece respirators (N95-FFR) to minimize occupational exposure to bioaerosols, such as tuberculosis and pandemic influenza. Published standards outline procedures for the proper selection of an N95-FFR model, including user seal checks and respirator fit-testing. Some health officials have argued that the respirator fit-test step should be eliminated altogether, given its additional time and cost factors, and that only a user seal check be utilized to ensure that an adequate face seal has been achieved. One of the aims of the current study is to examine whether a user seal check is an appropriate surrogate for respirator fit-testing. Subjects were assigned an N95-FFR and asked to perform a user seal check (as per manufacturer's instructions) after which they immediately underwent a respirator fit-test. Successfully passing a respirator fit-test was based on not detecting a leakage through the face seal (either qualitatively with a test agent or quantitatively with a particulate counter). The sample population consisted of 647 subjects who had never been previously fit-tested (naive), while the remaining 137 participants were experienced respirator users. Only four of the 647 naive subjects (0.62%) identified an inadequate seal during their user seal check. Of the 643 remaining naive subjects who indicated that they had an adequate face seal prior to fit-testing, 158 (25%) failed the subsequent quantitative fit-test and 92 (14%) failed the qualitative fit-test. All 137 experienced users indicated that they had an adequate seal after performing the user seal check; however, 41 (30%) failed the subsequent quantitative fit-test, and 30 (22%) failed the qualitative fit-test. These findings contradict the argument to eliminate fit-testing and rely strictly on a user seal check to evaluate face seal.
许多机构建议医护人员佩戴 N95 过滤式面罩（N95-FFR），以最大程度地减少职业性暴露于生物气溶胶，如结核分枝杆菌和大流行性流感。已发布的标准概述了正确选择 N95-FFR 型号的程序，包括使用者密封检查和呼吸器适配性测试。一些卫生官员认为，由于其额外的时间和成本因素，应完全取消呼吸器适配性测试步骤，而仅利用使用者密封检查来确保达到足够的面部密封。本研究的目的之一是检验使用者密封检查是否可以替代呼吸器适配性测试。研究对象被分配了一个 N95-FFR，并按照制造商的说明进行使用者密封检查，然后立即进行呼吸器适配性测试。成功通过呼吸器适配性测试的标准是未检测到通过面部密封的泄漏（定性地使用测试剂或定量地使用粒子计数器）。样本人群由 647 名从未进行过适配性测试的受试者（新手）组成，其余 137 名参与者为有经验的呼吸器使用者。在他们的使用者密封检查中，只有 647 名新手受试者中的 4 名（0.62%）确定密封不充分。在 643 名之前表示具有足够面部密封的新手受试者中，有 158 名（25%）在随后的定量适配性测试中失败，92 名（14%）在定性适配性测试中失败。所有 137 名有经验的使用者在进行使用者密封检查后均表示他们的密封良好；然而，41 名（30%）在随后的定量适配性测试中失败，30 名（22%）在定性适配性测试中失败。这些发现与取消适配性测试并仅依靠使用者密封检查来评估面部密封的论点相矛盾。
