De novo Powered Air-Purifying Respirator Design and Fabrication for Pandemic Response (preprint)

ABSTRACT

Importance The rapid spread of COVID-19 and disruption of normal supply chains resulted in severe shortages of personal protective equipment (PPE), particularly devices with few suppliers such as powered air-purifying respirators (PAPRs). A scarcity of information describing design and performance criteria represents a substantial barrier to new approaches. Objective: We sought to apply open-source product development to PAPRs to enable alternative sources of supply and further innovation. Design: We describe the design, prototyping, validation, and user testing of locally manufactured, modular, PAPR components, including filter cartridges and blower units, developed by the Greater Boston Pandemic Fabrication Team (PanFab). Two designs, one with a fully custom-made filter and housing, and the other with commercially available variants (the "Custom" and "Commercial designs) were developed. Prototype testing was conducted at academic laboratories using equipment available during COVID-19. The designs and software are in the common domain for use or further modification. Setting: User feedback on the functionality and comfort of the design was obtained at a major US academic medical center. Participants: Feedback on designs was obtained from four individuals, including two clinicians working in an ambulatory clinical setting and two research technical staff for whom PAPR use is a standard part of occupational PPE. Main Outcomes and Measures: Engineering performance was measured using NIOSH-equivalent tests on an apparatus available in university laboratories. Clinical feedback was assessed by (1) comparison to existing PPE; (2) sense of security in a clinical setting; and (3) comfort. Results: Custom and Commercial Designs were developed for filter cartridges and blower units. The two PAPR variants passed testing for PAPR certification using an apparatus available under pandemic shortages. Respondents rated the PanFab Custom PAPR a 4 to 5 on a 5 Likert-scale across every survey question. The three other versions of the designs (with a commercial blower unit, filter, or both) also performed favorably, with survey scores of 3-5. Conclusions and Relevance Engineering testing and clinical feedback demonstrate that the PanFab design represents a favorable alternative PAPR in terms of user comfort, mobility, and sense of security. A nonrestrictive license promotes innovation in respiratory protection for current and future medical emergencies.