Contents
Need Exploration and Identification
Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The disease was first identified in December 2019 in Wuhan, the capital of China’s Hubei province, and has since spread globally, resulting in the ongoing 2019–20 coronavirus pandemic. As of 14 April 2020, more than 1.94 million cases have been reported across 210 countries and territories,resulting in over 123,000 deaths. The pandemic has resulted in travel restrictions and nationwide lockdowns in several countries. With the sudden surges in patient volume during the COVID-19 outbreak, closing of borders and restrictions on international shipping, and temporary shutdown of manufacturers for medical supplies, personal protective equipment (PPE), ventilators and associated consumables, as well as many other medical supplies have become a scarce resource.
The recent increase in demand and subsequent shortages of personal protective equipment (PPE) has been placing medical staff in a difficult situation. Specifically, the respiratory protection requirements for staff working with COVID-19 patients makes the shortage of N95 masks a serious concern. One potential alternative to N95 masks are Powered Air-Purifying Respirators (PAPRs), which can provide equivalent or greater protection. Prior to the COVID-19 outbreak, PAPRs were commonly used by those who could not use an N95 mask due to inability to pass a fit test or inability to shave facial hair for religious reasons. Supply of PAPRs will need to be maintained for these workers, and should be considered for other workers as well in the face of N95 mask shortages. For this reason, the below information has been collected to assist identification of potential sources of PAPRs for use during the COVID-19 pandemic.
Existing Solutions
The simplest solution for providing PAPRs is to purchase them from suppliers. The table below is a list of particulate respirators which are HEPA filtered and have been evaluated by The National Personal Protective Technology Laboratory (NPPTL), which is the division of NIOSH that is responsible for PPE research and testing. Due to the pandemic, the range of acceptable equipment in the USA has been expanded to include the below devices, but be aware that some may not meet standards under normal circumstances. All of these PAPRs will provide appropriate respiratory protection, however some are designed for specific applications such as welding and may not be optimal for clinical use. This list was collected to help health care teams find alternative manufacturers and devices in the event that their typical PAPR supplier is experiencing a shortage.
HEPA Filtered Particulate Respirators Approved by NIOSH
Market Analysis
PAPRs are a viable alternative to N95 masks, which have been in short supply during the current pandemic. As healthcare systems across the nation continue to seek alternative solutions for N95 masks, it is reasonable to suspect that shortages of PAPR supplies will also be seen. PAPR supplies are also more specific than N95 masks, as each PAPR requires specific replacement components, so it is possible that certain PAPR systems will see shortages while others will not. Another factor to consider is that some providers are unable to use N95 masks due to religious restrictions on shaving facial hair. Regardless of N95 mask availability, PAPRs and their components will need to be made available for this provider population, and their clinical efficacy would be critically impacted by a shortage of PAPR supplies. For these reasons, we are developing this guide to help others identify different PAPR options already on the market, as well as alternative solutions in the event of a shortage of supplies for their specific PAPR.
Alternative Solutions
Operational Solutions
While most PAPRs have reusable components which can be cleaned by manufacturer instructions, many have disposable components such as hoods or face shields which are not designed for reuse. Though specific protocols have not been published, the FDA has made a report public on research which it contracted, of the title “Research to Mitigate a Shortage of Respiratory Protection Devices During Public Health Emergencies.” This report, while unofficial, details the results of decontamination attempts for various components of specific PAPR models (and N95 masks), which could be helpful as a starting point for those attempting to develop decontamination protocols for their own internal use. Details on the project can be found here, and the full report can be found here.
Re-engineering Solutions
With the appropriate resources, it is possible to meet PAPR demands by re-engineering current PAPR solutions either internally or locally. Most likely this would involve producing disposable components, such as hoods and face covers, but could also include replicating the entire PAPR design. Be aware that going down this route will have legal implications depending on the patent and intellectual property situation surrounding a specific PAPR. Additionally, any reproduction of a PAPR in part or whole will need to be re-evaluated to ensure its function is equivalent (see clinical regulations below.) Potential production strategies would include internal manufacturing or partnering with local industry.
Novel Design Solutions
One currently expanding resource for those with access to a 3D printer is the NIH 3D Print Exchange. This site provides designs which allow 3D printing of various items, including PPE components. There is a PAPR modelcurrently available for download, though the design has not been reviewed for clinical use by the NIH. Details on this PAPR model can be found here. Other minor components of PAPRs are also available for download, however this aspect of the 3D print exchange is limited for the time being.
Adapting available equipment or in-house production of replacement parts is another option for increasing availability of PAPR systems for healthcare workers. One project at Duke University has involved modifying surgical helmets to include a 3D printed adapter which allows the system to filter room air so that the apparatus could be repurposed as a PAPR system. More information on the project can be found here, and information on obtaining the designs can be found here under 3D SHIELD. This solution signals that medical equipment designed for alternative purposes can be modified and used as a PAPR system, and should be considered as a potential PPE source.
Concept Screening
When approaching a new concept for providing PAPR devices for clinical use, several factors must be taken into account. These include clinical, engineering, regulatory, and intellectual property considerations. Each is important to follow no matter what solution you are considering to ensure safety, efficacy, and compliance with the law. While this is not a comprehensive review, we hope that the below information and resources will help to direct your concept screening.
In response to COVID-19, the FDA provided alternative approved devices as of March 28th. This guidance includes approval of PAPRs compliant with 42 CFR Part 84 which are the public health regulations for approval of respiratory protective devices.This document provides details of the tests and regulations which are required for approval of a PAPR, among other respirators. When considering an alternative PAPR solution, these guidelines should be followed.
Factors to consider
Clinical Considerations
- Fit testing: Tight fitted PAPR devices, such as those with only nose and mouth coverage, will require fit testing. Loose fitting PAPR devices, such as those with hoods, will not.
- Battery life and low power indicators
- HEPA filter service life
- Operator field of view and visor fogging
- Donning/Doffing procedures
Engineering Considerations
- Minimum airflow rate: Tight fitting PAPRs must provide a constant airflow of 115 L/min, and loose fitting PAPRs must provide 170 L/min.
- Inhalation and exhalation resistance
- Open- versus closed-circuit design
- Power supply type
Regulatory Considerations
- PAPRs must be compliant with 42 CFR Part 84, which are the public health regulations for approval of respiratory protective devices. Optimally, the PAPR should be evaluated by The National Personal Protective Technology Laboratory (NPPTL), which is the division of NIOSH that is responsible for PPE research and testing.
- Manufacturing of the products should comply with Quality System Regulation (21 CFR 820) also known as “Good Manufacturing Practices” both for the manufacturing as well as the sterilization protocols.
- Individual states may have their own regulations on PAPRs. For example, California has additional regulations set in place by California’s Division of Occupational Safety and Health Administration (Cal/OSHA), so state regulations should be examined prior to evaluating a PAPR.
Intellectual Property Considerations
- Many PAPR designs and components are patented, so care must be taken both when re-engineering or designing custom PAPR devices to ensure that one does not infringe on intellectual property rights.
- Examples of patented components range from entire PAPR systems, to filter assembly designs, to specific aesthetic design components.
- Because of the variety and highly specific nature of patents surrounding PAPR devices, legal assistance should be sought throughout the design process.
Strategic Development
When looking for solutions for keeping PAPRs supplied to a hospital or clinic, the first approach should be to confirm that your supplier and any alternative suppliers of your PAPR cannot supply the consumable parts of your PAPR. If this is the case, then the next step is to consider purchasing a different PAPR model which suits your typical clinical needs. If this is not feasible, then alternative PAPR devices recently approved for use in the COVID-19 pandemic can be sourced and purchased (see the table above.) These options are preferred because they have already been evaluated and tested by the appropriate regulatory organizations and therefore are the safest options.
If existing supplies of PAPR equipment have already been exhausted, then the next step is to consider alternative solutions. Operational solutions are the simplest to develop. Reducing waste and reusing parts can help to extend the life of PPE and reduce dependence on exhausted supply chains. For example, developing sterilization procedures for disposable PAPR visors which allows reuse can extend the life of existing supplies. Re-engineering and novel design solutions can be pursued next, where disposable parts of a specific PAPR are produced in-house or locally, or completely new designs are developed. These solutions are likely the most difficult to develop, as the newly made components or entire PAPR devices must be evaluated for their safety and efficacy. Preferably, the newly made solutions would be tested by NIOSH as well, increasing the amount of time and money required to prepare the device for use. Additionally, re-engineering patented PAPR devices or components may lead to intellectual property violations. For these reasons, Re-engineering or novel design solutions should be approached with caution, and only after alternatives have been exhausted.
Once an alternative solution has been selected, clinical and regulatory considerations should be researched to determine if guidelines are available. For instance, if you are sterilizing PAPR visors then you would need to determine methods are approved and how to confirm the sterilization has met expectations. Next, research and development needs to be done to confirm the viability of the solution. This should start with an analysis of the cost and availability of materials to be used. Ensuring that the materials are affordable and can be reasonably expected to be purchased during the pandemic will prevent future redesigning and retesting. If the PAPR is being redesigned in whole or in part, then its function will need to be assessed. For example, this could include particle filtration, airflow, breathing resistance, visibility, and fit testing to ensure that the PAPR still serves its function. If possible, the altered PAPR should be tested by NIOSH to decide if it is compliant with 42 CFR Part 84, especially if the PAPR has been redesigned entirely or if components have been manufactured in-house.
After the efficacy of the device is confirmed, manufacturing and quality management protocols will need to be developed, as well as a means of distribution. This should preferably be done through partnership with FDA certified facilities where the process is regulated. Finally, one should consult with institutional legal counsel through the whole process to ensure that regulatory and intellectual property guidelines have been followed.