University of Minnesota Medical School, Department of Pediatrics, Minneapolis, MN; University of Minnesota Medical School, Division of General Internal Medicine, Minneapolis, MN.
University of Minnesota, Department of Mechanical Engineering, Minneapolis, MN.
Am J Infect Control. 2020 Oct;48(10):1237-1243. doi: 10.1016/j.ajic.2020.06.203. Epub 2020 Jun 27.
To mitigate potential exposure of healthcare workers (HCWs) to SARS-CoV-2 via aerosol routes, we have developed a portable hood which not only creates a barrier between HCW and patient, but also utilizes negative pressure with filtration of aerosols by a high-efficiency particulate air filter.
The hood has iris-port openings for access to the patient, and an opening large enough for a patient's head and upper torso. The top of the hood is a high-efficiency particulate air filter connected to a blower to apply negative pressure. We determined the aerosol penetration from outside to inside in laboratory experiments.
The penetration of particles from within the hood to the breathing zones of HCWs outside the hood was near 10 (0.01%) in the 200-400 nm size range, and near 10 (0.1%) for smaller particles. Penetration values for particles in the 500 nm-5 μm range were below 10 (1%). Fluorometric analysis of deposited fluorescein particles on the personal protective equipment of an HCW revealed that negative pressure reduces particle deposition both outside and inside the hood.
We find that negative pressure hoods can be effective controls to mitigate aerosol exposure to HCWs, while simultaneously allowing access to patients.
为了减轻医护人员（HCWs）通过气溶胶途径接触 SARS-CoV-2 的潜在风险，我们开发了一种便携式头罩，它不仅在 HCW 和患者之间形成了一道屏障，还利用了负压，并通过高效空气颗粒过滤器对气溶胶进行过滤。
头罩上设有虹膜端口，便于医护人员接触患者，还有一个足够大的开口，以便患者的头部和上半身进入。头罩的顶部是一个高效空气颗粒过滤器，连接着一个风机，以施加负压。我们在实验室实验中确定了气溶胶从外部渗透到内部的情况。
在 200-400nm 粒径范围内，从头罩内部到罩外 HCW 呼吸区域的粒子穿透率接近 10（0.01%），而较小粒径的粒子穿透率接近 10（0.1%）。粒径在 500nm-5μm 范围内的粒子穿透率低于 10（1%）。对 HCW 个人防护设备上沉积的荧光粒子进行荧光分析表明，负压可减少头罩内外的粒子沉积。
我们发现，负压头罩可以有效控制气溶胶对 HCWs 的暴露，同时允许医护人员接触患者。
