Stony Brook University Medical Center, Pulmonary, Critical Care and Sleep Division, Stony Brook, NY 11794-8172, USA.
J Aerosol Med Pulm Drug Deliv. 2013 Jun;26(3):131-7. doi: 10.1089/jamp.2012.0998. Epub 2013 Apr 1.
Placing a surgical mask on an infected patient (respiratory source control) may offer a health-care worker (HCW) more protection than donning an N95 respirator (receiver protection). This observation was made in an in vitro study that used hard, nondeformable faces, and the lack of proper N95 fit may have accounted for the observed results. In the present study, we test the effects of fit on respiratory source control protection, using a soft, deformable mannequin head.
Resusci Anne CPR mannequin heads were placed in a chamber allowing 6 air exchanges/hr (14 cubic feet per minute), to simulate an infected patient (source) and an HCW (receiver). The heads were ventilated with a tidal breathing pattern. The source exhaled radioactive aerosols, and a filter was attached to the receiver to quantify inhaled exposure. N95 respirators and surgical masks were tested on both heads. The degree of protection was expressed by calculating the reduction in exposure expressed as a simulated workplace protection factor (sWPF; the ratio of exposure with mask to exposure without mask) compared statistically using confidence intervals.
Use of the Resusci Anne heads resulted in improved fit, with higher sWPF than previously reported, for example, for source N95 mask combinations (7,174 vs. 317) as well as receiver (7.53 vs. 1.37). Masks placed on the receiver provided minimal exposure protection (sWPF range 0.99-7.53), except when sealed with Vaseline (sWPF 63.1). Any mask applied to the source mannequin resulted in significant reductions in exposure (sWPF range 214-17,038).
Improved fit significantly enhanced the effects of source control protection. A Vaseline-sealed N95 respirator on the receiver offered less protection when compared with any mask on the source. Respiratory source control can offer more protection to HCW and potentially decrease the spread of aerosolized infections.
在感染患者（呼吸源控制）上放置外科口罩可能比佩戴 N95 呼吸器（受体保护）为医护人员提供更多保护。这一观察结果是在一项使用坚硬、不可变形面部的体外研究中得出的，而缺乏适当的 N95 适配可能是造成观察结果的原因。在本研究中，我们使用柔软、可变形的模拟人头测试适配对呼吸源控制保护的影响。
将 Resusci Anne 心肺复苏模拟人头放置在允许每小时进行 6 次空气交换（每分钟 14 立方英尺）的室中，模拟感染患者（源）和医护人员（受体）。头部通过潮式呼吸模式通气。源呼出放射性气溶胶，受体上连接一个过滤器以量化吸入暴露量。对两个头测试 N95 呼吸器和外科口罩。通过计算暴露量减少量来表示防护程度，以模拟工作场所保护系数（sWPF；戴口罩时的暴露量与不戴口罩时的暴露量之比）表示，并使用置信区间进行统计学比较。
使用 Resusci Anne 头可改善适配度，与之前报道的相比，sWPF 更高，例如源 N95 口罩组合（7174 比 317）以及受体（7.53 比 1.37）。放在受体上的口罩只能提供最小的暴露防护（sWPF 范围 0.99-7.53），除非用凡士林密封（sWPF 为 63.1）。应用于源模拟人的任何口罩都会显著降低暴露量（sWPF 范围为 214-17038）。
改善适配度显著增强了呼吸源控制保护效果。与源上任何口罩相比，受体上密封的凡士林 N95 呼吸器提供的保护作用较小。呼吸源控制可为医护人员提供更多保护，并可能减少气溶胶感染的传播。
