Medical College of Georgia at Augusta University, Department of Emergency Medicine, Augusta, Georgia.
West J Emerg Med. 2021 Aug 17;22(5):1045-1050. doi: 10.5811/westjem.2021.3.50516.
The coronavirus 2019 (COVID-19) pandemic has reinforced the importance of facial protection against droplet transmission of diseases. Healthcare workers wear personal protection equipment (PPE), including face shields and masks. Plastic face shields may have advantages over regular medical masks. Although many designs of face shields exist, there is a paucity of evidence regarding the efficacy of shield designs against droplet transmissions. There is even less published evidence comparing various face shields. Due to the urgency of the pandemic and the health and safety of healthcare workers, we aimed to study the efficacy of various face shields against droplet transmission.
We simulated droplet transmission via coughing using a heavy-duty chemical spray bottle filled with fluorescein. A standard-adult sized mannequin head was used. The mannequin head wore various face shields and was positioned to face the spray bottle at either a 0°, 45°, or 90° angle. The spray bottle was positioned at and sprayed from 30 centimeters (cm), 60 cm, or 90 cm away from the head. These steps were repeated for all face shields used. Control was a mannequin that wore no PPE. A basic mask was also tested. We collected data for particle count, total area of particle distribution, average particle size, and percentage area covered by particles. We analyzed percent covered by particles using a repeated measures mixed-model regression with Tukey-Kramer pairwise comparison.
We used least square means to estimate the percentage area covered by particles. Wearing PPE regardless of the design reduced particle transmission to the mannequin compared to the control. The LCG mask had the lowest square means of 0.06 of all face-shield designs analyzed. Tukey-Kramer pairwise comparison showed that all PPEs had a decrease in particle contamination compared to the control. LCG shield was found to have the least contamination compared to all other masks (P < 0.05).
Results suggest the importance of wearing a protective covering against droplet transmission. The LCG shield was found to decrease facial contamination by droplets the most of any tested protective equipment.
2019 年冠状病毒（COVID-19）大流行强调了针对疾病飞沫传播进行面部保护的重要性。医护人员佩戴个人防护设备（PPE），包括面罩和口罩。塑料面罩可能比普通医用口罩具有优势。尽管存在许多面罩设计，但针对面罩设计对飞沫传播的效果的证据很少。有关各种面罩的比较的文献就更少了。由于大流行的紧迫性和医护人员的健康与安全，我们旨在研究各种面罩在防止飞沫传播方面的效果。
我们使用装满荧光素的重型化学喷雾瓶模拟咳嗽时的飞沫传播。使用标准成人大小的人头模型。人头模型戴上各种面罩，以 0°、45°或 90°角面对喷雾瓶。喷雾瓶置于距头部 30 厘米（cm）、60 cm 或 90 cm 处并从该处喷雾。对所有使用的面罩重复此步骤。对照为不戴任何个人防护装备的人头模型。还测试了基本口罩。我们收集了粒子计数、粒子分布总面积、平均粒子大小和粒子覆盖面积百分比的数据。我们使用重复测量混合模型回归和 Tukey-Kramer 两两比较来分析粒子覆盖面积的百分比。
我们使用最小二乘法估计粒子覆盖面积的百分比。无论设计如何，佩戴 PPE 均可减少飞沫传播到人模型，与对照相比。在分析的所有面罩设计中，LCG 口罩的平方均值最低，为 0.06。Tukey-Kramer 两两比较显示，与对照相比，所有 PPE 的粒子污染均有所减少。与所有其他口罩相比，LCG 盾牌被发现污染最少（P <0.05）。
结果表明佩戴防护装置防止飞沫传播的重要性。与任何经过测试的防护设备相比，LCG 盾牌被发现能最大程度地减少面部飞沫污染。
