Development of a new user-centered design for respiratory protection in hospitals for tackling a supply crisis
TimeThursday, April 152:00pm - 3:00pm EDT
DescriptionIn a medical scenario, the use of respiratory protection varies from common checkups and interactions between doctors and patients, to surgeries and handling of live pathogens and bio-contaminants (Chen & Wang, 2015). The recent pandemic caused strain on supply of masks and could not meet the high demand. To counter this, health organizations (CDC) allowed for protocols to sterilize and reuse surgical masks and accepted homemade cloth mask alternatives for general use. The design of such surgical masks is based upon facial anthropometric data and are generally designed to fit 95% of the human population (Zhuang, et al., 2010). However, due to this wide range in anthropometry, a reduced fit can be observed for specific ethnic and gender populations. For example, a mask designed for the entire population may not fit the racial and gender groups which lie at the extremes of anthropometric sizes. Implications of the lack of fit could lead to leakage in masks, which is of highest priority, especially, in the sensitive hospital environments (Suen, et al.,2020). Although multiple surgical masks can be worn, it only adds to the strain on breathing and increases the pressure on the ears (Suen et al., 2020). Such cases of discomfort can compromise safety. For example, a person not liking the feeling of the nose-clip of a mask leads to incorrect mounting and risk of exposure. To better understand the differences between masks, we studied the face-mask interface using four masks (N95, Elastomeric Respirator, surgical mask, Readimask). Further tests were conducted over a period of one week (6 hrs./day) while the wearer engaged in non-strenuous activities (light woodwork). Moreover, we interviewed users of these masks to get insight on comfort and general awareness towards respiratory protection. The findings show that simple fabric and surgical masks provided high comfort but low protection, suggesting a trade-off between comfort and filtering capabilities (Uniyal, 2020). Our observations show the need for a new mask with a better user-mask fit, higher comfort and quick fabrication (can be made readily available when needed).
With the highest comfort offered by fabrics along with the ability to block bioaerosols, we considered fabric as the main material-medium for a new design. As medical personnel are not required to wear a fully specialized elastomeric respirator in their common use-cases, we have developed a new mask by combining the simplicity of a fabric wrapped around the face in a well-fitting form. The mounting method for the new design consists of wrapping the facepiece around the neck and does not need securing to the ears and can lead to higher comfort. Moreover, our development method considers obtaining facial anthropometric measurements from specific populations of interest, which can lead to a better fit with the wearers. Moreover, the design permits adjustability using a velcro strap which allows us to accommodate sizes obtained from the maximum to minimum of our anthropometric data. For situations with higher chances of contamination, the design allows for an additional filter to be added. Fabricating our designed mask requires using the cut-pattern template to achieve the facepiece form and attaching the fixture components to it. Moreover, all the components can be fully replaced with locally obtained materials.
We have provided a protocol for designing our proposed mask design, which can be customized and developed for specific populations. Our methodology includes three stages of development: data collection, design, and testing. First, we conducted an experiment wherein the sample group (graduate-level university students) was selected, for which the mask is to be designed. Next, a data collection session was conducted which included recruiting of 8 participants from among the population of interest (Uniyal, 2020). The session included a simple experiment and was divided into two parts: Seal-deformation test, and Anthropometric assessment. The seal deformation test was performed to obtain areas of seal-failure across the facial profiles and jaw positions. Participants were instructed to wear two strips of foam (one over nose and other under the jaw) and instructed to perform a series of facial postures. In the second part, we conducted an assessment wherein facial anthropometric measures were obtained using a cloth on which key landmarks were marked after wearing the facepiece. The novelty of this method lies in the quick nature of obtaining the data from a simple cloth and a marker. The landmarks included 6 points representing chin, lips, nose (tip and sides), cheekbone and zygomatic process; and were selected from literature survey and the findings of the seal-deformation test. The participant was instructed to wear the facepiece, followed by locating and marking them using a marker. The facepiece was then removed, unfolded, and scanned to obtain the coordinates. This was repeated for each participant. Using the obtained data, mean for each landmark was obtained along with the maximum deviations based upon which the contour and adjustability range of the new design was decided. Finally, preliminary testing of the new mask was conducted wherein a participant wore the mask for extended periods of time after which, feedback relating to comfort and usability was obtained.
Results from the seal-deformation assessment indicated a high level of deformation occurred in the jaw-region, especially in positions which emulate speech patterns. Even within the specific population of interest considered for the anthropometric test, we observed variations in anthropometric measurements for all landmarks. However, our results depict that despite such variations, a common fitting contour can be obtained. In fact, the differences between the measures can be used to provide adjustability. Using the results obtained through testing, the new mask was designed. Results from the preliminary testing of the new mask indicate that the new design is lightweight and causes no discomfort around or the back of the ear along with unrestricted movement of head. The participant also reported that the new design’s visual signifiers would benefit from tactile cues for the ease of donning and doffing the mask.
Although our study focused on developing a new method and a design for a mask, we have not yet compared the performance of the mask with existing designs. The future work will try to compare and quantify the performance of the new mask design to a surgical mask through a laboratory assessment. Further, quantitative methods have not yet been applied to optimize the contours and adjustability in our design, and would be a part of the next stage of our work. Our proposed design could be a better alternative (both comfort and performance) for the specific subset of population since it contains an adjustable form, resizable between the extremes of the subset. Moreover, such a design could prove highly beneficial in scenarios wherein a shortage of existing masks is observed. The comfortable features, higher fit and quick development-deployment of such a mask could mitigate the spread of pathogens, especially in a pandemic situation, and ultimately improve safety in the healthcare sector.
Chen, Y., & Wang, J. (2015). The human factors / ergonomics studies for respirators : a review and future work. International Journal of Clothing Science and Technology, (51305077). https://doi.org/10.1108/IJCST-06-2014-0077
Suen, L. K. P., Guo, Y. P., Ho, S. S. K., & Lam, S. C. (2020). Comparing mask fit and usability of traditional and nanofibre N95 filtering facepiece respirators before and after nursing procedures. 104, 336–343. https://doi.org/10.1016/j.jhin.2019.09.014
Uniyal, A. (2020). VA-U: Addressing the gaps in respiratory protection through a holistic open-sourced design alternative. Rochester Institute of Technology.
Zhuang, Z., Landsittel, D., Benson, S., Roberge, R., & Shaffer, R. (2010). Facial anthropometric differences among gender, ethnicity, and age groups. Annals of Occupational Hygiene, 54(4), 391–402. https://doi.org/10.1093/annhyg/meq007