Highlights
- •Powered air-purifying respirators (PAPRs) are not designed for the use in hospital settings, certainly not the operating room.
- •The disinfection of PAPRs is challenging.
- •Surgical helmets are readily available, but do not provide respiratory protection.
- •A 3D-printed filter adaptor renders surgical helmets into PAPRs for the use in the operating room.
- •The surgical helmet PAPR provides 430 times better protection than FFP3.
Abstract
Background
Methods
Results
Discussion
Conclusions
Key words
Introduction
Filtering facepieces
Powered air-purifying respirators
Surgical helmets
- 1)be fitted with an efficient particulate filter medium
- 2)supply a sufficient airflow through the filter medium to vent out the user's carbon dioxide (CO2) and bring in oxygen
- 3)produce a constant positive differential pressure inside the helmet.
Methods
Design concept

Prototyping and manufacturing
CO2 concentrations
Disinfection
Particle loading tests
HEPA test rig
Total Inward Leakage test in an aerosol chamber
Total inward leakage test in an operation theatre
Differential pressure measurements
Results
Prototyping and manufacturing
CO2 concentrations

Disinfection
Particle loading test
HEPA test rig
Exercise | TIL average | TIL max | TIL min |
---|---|---|---|
Head side to side (2 min) | 0.00641 % | 0.01183 % | 0.00331 % |
Head up and down (2 min) | 0.00480 % | 0.00685 % | 0.00284 % |
Speech (2 min) | 0.00383 % | 0.00611 % | 0.00253 % |
Walking (2 min) | 0.00356 % | 0.00556 % | 0.00267 % |
Average | 0.00465 % | 0.00759 % | 0.00284 % |

Total inward leakage test in an operation theatre

Differential pressure measurements
Discussion
Disinfection
Carbon dioxide
Previous literature
Limitations
Conclusion
Disclaimer
Acknowledgments
Appendix. SUPPLEMENTARY MATERIALS
References
- COVID-19 in health care workers - a systematic review and meta-analysis.Am J Emerg Med. 2020; 38: 1727-1731
- Surgery in a time of uncertainty.JAMA. 2020; 323: 2254
- Surgery and COVID-19.JAMA. 2020; 324: 1151
WHO. Rational use of personal protective equipment (PPE) for coronavirus disease (COVID-19). 2020.
- Covid-19: the crisis of personal protective equipment in the US.BMJ. 2020; 369: m1367
- Respiratory protective devices - Filtering half masks to protect against particles - Requirements, testing, marking.European Comittee for Standardization, Brussels2009
- Assessing the effect of beard hair lengths on face masks used as personal protective equipment during the COVID-19 pandemic.J Exposure Sci Environ Epidemiol. 2021; 31: 953-960
- The effect of subject characteristics and respirator features on respirator fit.J Occup Environ Hyg. 2005; 2: 641-649
- The effect of gender and respirator brand on the association of respirator fit with facial dimensions.J Occup Environ Hyg. 2007; 4: 923-930
Foereland S, Robertsen O, Hegseth MN. Do various respirator models fit the workers in the norwegian smelting industry? Safety and Health at Work. 2019;10:370-6.
- The prevalence, characteristics, and prevention status of skin injury caused by personal protective equipment among medical staff in fighting COVID-19: a multicenter, cross-sectional study.Adv Wound Care (New Rochelle). 2020; 9: 357-364
- SARS-CoV-2: eye protection might be the missing key.Lancet Microbe. 2021; 2: e173-e1e4
- The eye as the discrete but defensible portal of coronavirus infection.Ocul Surf. 2021; 19: 176-182
- Microbial contamination of powered air purifying respirators (PAPR) used by healthcare staff during the COVID-19 pandemic: an in situ microbiological study.Am J Infect Control. 2021; 49: 707-712
- Does a surgical helmet provide protection against aerosol transmitted disease?.Acta orthopaedica. 2020; : 1-5
- Surgical helmets and SARS infection.Emerg Infect Dis. 2004; 10: 277-279
- High efficiency air filters (EPA, HEPA and ULPA)- Part 1: Classification, performance testing, marking.European Comittee for Standardization, Brussels2019
- Respiratory protective devices - Power filtering devices incorporating a helmet or a hood - Requirements, testing, marking.European Comittee for Standardization, Brussels1998
- Microbiological cleanliness in the operating room - Preventing airborne contamination - Guidance and fundamental requirements.Stockholm Swedich Standard Institute, Stockholm, Sweden2015
- Helmet modification to PPE with 3D printing during the COVID-19 pandemic at duke university medical center: a novel technique.J Arthroplasty. 2020; 35: S23-SS7
- Improvising the surgical helmet system for aerosol-generating procedures in the OR: Surgeon designed 3D printed mould for augmented filtration system.J Clin Orthop Trauma. 2021; 12: 27-32
- Custom solution for personal protective equipment (PPE) in the orthopaedic setting: retrofitting Stryker Flyte T5 PPE system.J Hosp Infect. 2021; 108: 55-63
- Modification of stryker T5TM and stryker flyte® personal protection surgical helmets to function as powered air-purifying respirators.Surg Innovat. 2020; 1553350620967246
- Particulate air filters for general ventilation - Determination of the filtration performance.European Comittee for Standardization, Brussels2012
- Pall International.2021
Article Info
Publication History
Footnotes
Funding/support: This project won the "Corona Idea Award" with a limited grant from the South-Eastern Norway Regional Health Authorities technology transfer office, Inven2 AS, in 2020. The Norwegian Hospital Procurement Trust and the South-Eastern Norway Regional Health Authority funded the Norwegian Defence Research Establishment (FFI) for the CO2 and TIL testing in the aerosol chamber.
Conflicts of interest: The first author owns the intellectual property (IP) rights of the device described in this paper with a patent-pending.
Ethics approval and consent to participate: This investigation has been approved by the research board of the department of orthopedics at our institution [02.04.2020]. This investigation does not fall under the Norwegian law of “medical and health-related research” (“Lov om medisinsk og helsefaglig Forskning”). Therefore, ethical committee approval does not apply in the Norwegian jurisdiction.
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