Bubble-PAPR: Phase I clinical evaluation of an ‘in-house’ developed prototype powered air-purifying respirator for use by healthcare workers
Authors: McGrath Brendan A , Shelton Cliff , Gardner Angela , Coleman Ruth , Lynch James , Alexander Peter G , Cooper Glen 
Published: July 2022

Structured abstractObjectivesWe aimed to design and produce a low-cost, ergonomic, hood-integrated Powered Air-Purifying Respirator (Bubble-PAPR) for pandemic healthcare use, offering optimal and equitable protection to all staff. We hypothesised that participants would rate Bubble-PAPR more highly than current FFP3 face mask respiratory protective equipment (RPE).DesignRapid design and evaluation cycles occurred based on the identified user needs. We conducted diary card and focus group exercises to identify relevant tasks requiring RPE. Lab-based safety standards established against British Standard BS-EN-12941 and EU2016/425. Questionnaire-based usability data from participating frontline healthcare staff before (usual RPE) and after using Bubble-PAPR.SettingOverseen by a trial safety committee, evaluation progressed sequentially through laboratory, simulated, low-risk, then high-risk clinical environments of a single tertiary NHS hospital.Participants15 staff completed diary cards and focus groups. 91 staff from a range of clinical and non-clinical roles completed the study, wearing Bubble-PAPR for a median of 45 minutes (IQR 30-80 [15-120]). Participants self-reported a range of heights (mean 1.7m [SD 0.1, range 1.5-2.0]), weights (72.4kg [16.0, 47-127]) and body mass indices (25.3 [4.7,16.7-42.9]).Outcome measuresPrimary: “How comfortable do you feel in your PPE?” (Likert scale bounded by 1 [very uncomfortable] to 7 [very comfortable]). Secondary outcomes: perceived safety, communication, anxiety, discomfort, and performance.ResultsBubble-PAPR mean comfort score was 5.64(SD 1.55) versus usual FFP3 2.96(1.44) (mean difference 2.68 (95% CI 2.23-3.14, p<0.001). There was a significant difference in favour of Bubble-PAPR across all secondary outcomes.ConclusionsBubble-PAPR achieved its primary purpose of keeping staff safe from airborne particulate material whilst improving comfort and the user experience. The design and development of Bubble-PAPR were conducted using a careful evaluation strategy addressing key regulatory and safety steps, in contrast to many devices rapidly developed and deployed during the pandemic.Trial registrationIRAS ID:288493, REC Ref:21/WA/0018. ClinicalTrials.gov (NCT04681365).Strengths and limitations of this studyWe employed user-centred design, engineering optimisation and staged feasibility testing to develop a novel Powered Air-Purifying Respirator (Bubble-PAPR) for use specifically in frontline healthcare settings.Diverse, frontline healthcare staff compared Bubble-PAPR with usual FFP3 face masks.The design and development of Bubble-PAPR were conducted using a careful strategy addressing key regulatory and safety steps, in contrast to many devices rapidly developed and deployed during the pandemic.Bubble-PAPR is an excellent example of developing a cosmopolitan network that could become a key feature of future system resilience.