Division of Infectious Diseases, Department of Internal Medicine, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
J Korean Med Sci. 2021 May 31;36(21):e140. doi: 10.3346/jkms.2021.36.e140.
For protection against coronavirus disease 2019 (COVID-19), the Korean government recommended the KF94 mask or that a mask at the same level as the KF94 should be worn when contacting a patient with COVID-19. Furthermore, adequately fitted N95 respirators and KF94 masks are essential. We investigated the fit tests to determine whether healthcare workers had adequate protection with N95 respirators and KF94 masks.
In this prospective single-center simulation study, five N95 respirators (two made in the USA by 3M and three made in Korea) and six KF94 masks, the Korean standard medical masks, were tested. The fit factor (FF) and leakage rate were evaluated using a two-fit test device. Adequate protection (defined as FF ≥ 100 or leakage rate ≤ 5) rates were compared between N95 respirators and KF94 masks, and between made in Korea and the 3M N95 respirators. For KF94 masks, adequate protection rates were compared before and after ear strap fixation.
Overall, 30 participants were enrolled, and 330 fit tests were performed for FF and leakage rate. Adequate protection rates of all tested N95 respirators and KF94 masks were 22.7% (n = 75) by FF and 20.6% (n = 68) by leakage rate. N95 respirators showed a significantly higher adequate protection rate than KF94 masks for FF (48.7% vs. 1.1%, < 0.001) and leakage rate (42.0% vs. 2.8%, < 0.001). Adequate protection rate of 3M-made N95 respirators was significantly higher than that of those made in Korea (83.3% vs. 25.6% in FF, < 0.001; 73.3% vs. 21.1% in leakage rate, < 0.001). In KF94 masks, after fixation of ear strap with a hook, adequate protection rate improved significantly (1.1% vs. 12.8% in FF, < 0.001; 2.8% vs. 11.1%, < 0.001).
Although adequate protection rate of N95 respirators was higher than that of KF94 masks, N95 respirator protection rate was not optimum. Thus, it is necessary to minimize exposure to risk by selecting an appropriate mask or respirator that adequately fits each person, and by wearing respirators or masks appropriately, before contacting the patients. With their superior protection rate, wearing N95 respirators is recommended instead of KF94 masks, especially when performing aerosol-generating procedures.
为了预防 2019 年冠状病毒病（COVID-19），韩国政府建议在接触 COVID-19 患者时佩戴 KF94 口罩或同等防护级别的口罩。此外，应正确佩戴 N95 呼吸器和 KF94 口罩。我们进行了适合性检验，以确定 N95 呼吸器和 KF94 口罩是否能为医护人员提供充分的防护。
本前瞻性单中心模拟研究纳入了 5 个 N95 呼吸器（美国 3M 公司生产的 2 个，韩国生产的 3 个）和 6 个 KF94 口罩（韩国标准医用口罩）。使用双适合性检验装置评估适合因子（FF）和泄漏率。比较了 N95 呼吸器和 KF94 口罩、韩国产和 3M 产 N95 呼吸器之间的足够防护（定义为 FF≥100 或泄漏率≤5）率。对于 KF94 口罩，比较了耳带固定前后的足够防护率。
共有 30 名参与者入组，进行了 330 次 FF 和泄漏率的适合性检验。所有测试的 N95 呼吸器和 KF94 口罩的足够防护率分别为 FF 为 22.7%（n=75）和泄漏率为 20.6%（n=68）。N95 呼吸器的 FF（48.7%对 1.1%，<0.001）和泄漏率（42.0%对 2.8%，<0.001）的足够防护率显著高于 KF94 口罩。3M 产 N95 呼吸器的足够防护率明显高于韩国产 N95 呼吸器（FF 为 83.3%对 25.6%，<0.001；泄漏率为 73.3%对 21.1%，<0.001）。KF94 口罩耳带用挂钩固定后，足够防护率显著提高（FF 为 1.1%对 12.8%，<0.001；泄漏率为 2.8%对 11.1%，<0.001）。
尽管 N95 呼吸器的足够防护率高于 KF94 口罩，但 N95 呼吸器的防护率并不理想。因此，在接触患者之前，通过选择适合每个人的合适口罩或呼吸器并正确佩戴呼吸器或口罩，尽量减少接触风险是必要的。由于具有更高的防护率，建议佩戴 N95 呼吸器而不是 KF94 口罩，特别是在进行产生气溶胶的操作时。
