Use of 3D printing to support COVID-19 medical supply shortages: a review

Design of customizable personal protective equipment for 3-D printing: Performance evaluation of N95 respirators using computational fluid dynamics

3-D printing the structural components of facemasks and personal protective equipment (PPE) based on 3-D facial scans creates a high degree of customizability. As a result, the facemask fits more comfortably with its user's specific facial characteristics, filters contaminants more effectively with its increased sealing effect, and minimizes waste with its cleanable and reusable plastic structure compared to other baseline models. In this work, 3-D renditions of the user's face taken with smartphone laser scanning techniques were used to generate customized computer-aided design (CAD) models for the several components of an N95 respirator, which are each designed with considerations for assembly and 3-D printing constraints. Thorough analyses with computational fluid dynamics (CFD) simulations were carried out to verify the respirator's efficiency in filtering airborne contaminants to comply with industry safety guidelines and generate data to showcase the relationships between various input and output design parameters. This involved a comparative study to identify the ideal cross-sectional geometry of exposed filter fabric, a sensitivity study to evaluate the respirator's ability to protect the user in various scenarios, and the 3-D printing of several prototypes to estimate printing time, cost of materials, and comfort level at the user's face. Results showed that the combination of different digital tools can increase efficiency in the design, performance assessment, and production of customized N95-rated respirators.

Benchtop assessment of sealing efficacy and breathability of additively manufactured (AM) face masks

The onset of the 2019 novel coronavirus disease (COVID-19) led to a shortage of personal protective equipment (PPE), medical devices, and other medical supplies causing many stakeholders and the general public alike to turn to additive manufacturing (AM) as a stopgap when normally accessible devices were not available. However, without a method to test these AM constructs, there continued to be a disconnect between AM suppliers and the community's needs. The objective of this study was to characterize the pressure drop and leakage of four different publicly available AM face mask models with two filter material combinations, as well as to investigate the impact of frame modification techniques including the use of foam strips and hot-water face forming to improve fit when the masks are donned on manikin head forms. AM face mask frame designs were downloaded from public repositories during the early stages of the COVID-19 pandemic. AM face masks were fabricated and tested on manikin head forms within a custom chamber containing dry aerosolized NaCl. Pressure drops, particle penetration, and leakage were evaluated for various flow rates and NaCl concentrations. Results indicated that filter material combination and frame modification played a major role in the overall performance of the AM face masks studied. Filter material combinations showed improved performance when high filtration fabric was used, and the cross-sectional area of the fabric was increased. AM frame modifications appeared to improve AM face mask leakage performance by as much as 69.6%.

A Narrative Review of Innovative Responses During the COVID-19 Pandemic in 2020

Objectives: The coronavirus disease 2019 (COVID-19) pandemic presented unprecedented challenges to healthcare systems worldwide. While existing studies on innovation have typically focused on technology, health providers still only have a vague understanding of the features of emergency responses during resource exhaustion in the early stage of a pandemic. Thus, a better understanding of innovative responses by healthcare systems during a crisis is urgently needed. Methods: Using content analysis, this narrative review examined articles on innovative responses during the COVID-19 pandemic that were published in 2020. Results: A total of 613 statements about innovative responses were identified from 296 articles and were grouped under the following thematic categories: medical care (n = 273), workforce education (n = 144), COVID-19 surveillance (n = 84), medical equipment (n = 59), prediction and management (n = 34), and governance (n = 19). From the four types of innovative responses extracted, technological innovation was identified as the major type of innovation during the COVID-19 pandemic, followed by process innovations, frugal innovation, and repurposing. Conclusion: Our review provides insights into the features, types, and evolution of innovative responses during the COVID-19 pandemic. This review can help health providers and society show better and quicker responses in resource-constrained conditions in future pandemics.