Joint Department of Medical Imaging, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.
The Lynn and Arnold Irwin Advanced Perioperative Imaging Lab, Department of Anesthesiology and Pain Management, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada.
PLoS One. 2021 Mar 17;16(3):e0247575. doi: 10.1371/journal.pone.0247575. eCollection 2021.
The COVID-19 pandemic has led to widespread shortages of N95 respirators and other personal protective equipment (PPE). An effective, reusable, locally-manufactured respirator can mitigate this problem. We describe the development, manufacture, and preliminary testing of an open-hardware-licensed device, the "simple silicone mask" (SSM).
A multidisciplinary team developed a reusable silicone half facepiece respirator over 9 prototype iterations. The manufacturing process consisted of 3D printing and silicone casting. Prototypes were assessed for comfort and breathability. Filtration was assessed by user seal checks and quantitative fit-testing according to CSA Z94.4-18.
The respirator originally included a cartridge for holding filter material; this was modified to connect to standard heat-moisture exchange (HME) filters (N95 or greater) after the cartridge showed poor filtration performance due to flow acceleration around the filter edges, which was exacerbated by high filter resistance. All 8 HME-based iterations provided an adequate seal by user seal checks and achieved a pass rate of 87.5% (N = 8) on quantitative testing, with all failures occurring in the first iteration. The overall median fit-factor was 1662 (100 = pass). Estimated unit cost for a production run of 1000 using distributed manufacturing techniques is CAD $15 in materials and 20 minutes of labor.
Small-scale manufacturing of an effective, reusable N95 respirator during a pandemic is feasible and cost-effective. Required quantities of reusables are more predictable and less vulnerable to supply chain disruption than disposables. With further evaluation, such devices may be an alternative to disposable respirators during public health emergencies. The respirator described above is an investigational device and requires further evaluation and regulatory requirements before clinical deployment. The authors and affiliates do not endorse the use of this device at present.
COVID-19 大流行导致 N95 呼吸器和其他个人防护设备（PPE）广泛短缺。一种有效的、可重复使用的、本地制造的呼吸器可以缓解这个问题。我们描述了一种开源许可设备“简易硅胶口罩”（SSM）的开发、制造和初步测试。
一个多学科团队在 9 个原型迭代的基础上开发了一种可重复使用的硅胶半面罩呼吸器。制造过程包括 3D 打印和硅胶铸造。对原型进行了舒适度和透气性评估。过滤性能通过用户密封检查和根据 CSA Z94.4-18 进行的定量 fit-testing 进行评估。
该呼吸器最初包括一个用于容纳过滤材料的盒式部件；由于过滤边缘周围的气流加速导致过滤性能不佳，而高过滤阻力又加剧了这种情况，因此在盒式部件过滤性能不佳后，将其修改为连接标准热湿交换（HME）过滤器（N95 或更高等级）。基于 HME 的所有 8 个迭代均通过用户密封检查提供了足够的密封，并在定量测试中达到了 87.5%（N = 8）的通过率，所有失败均发生在第一个迭代中。总体中位数拟合因子为 1662（100 = 合格）。使用分布式制造技术生产 1000 个呼吸器的单位成本估计为 15 加元的材料和 20 分钟的劳动力。
在大流行期间，小规模制造有效、可重复使用的 N95 呼吸器是可行且具有成本效益的。与一次性呼吸器相比，可重复使用呼吸器的需求量更可预测，并且不易受到供应链中断的影响。进一步评估后，此类设备在公共卫生紧急情况下可能成为一次性呼吸器的替代品。本文描述的呼吸器是一种研究设备，在临床部署之前需要进一步评估和监管要求。作者及其附属机构目前不支持使用该设备。
