Health care workers must move to reusable respirators now: Here’s how

Reusable respirator (Source: Glia, CC-BY-SA)

Acknowledgements: Dr. Alex Pavlosky and Jake Bender researched an important proposal; and Dr. Sydney Todorovich wrote an excellent summary. This article is based on their work.

Note: Fill out this survey if you have or want reusable respirators.

We are running out of disposable N95 respirators just as researchers seem to be finding evidence that the corona virus that causes COVID-19 has some airborne component to its spread. While N95 respirators are not the only personal protective equipment (PPE) to be running low, the raw materials needed to create the filters for these respirators are very difficult to source and largely unavailable in Canada.

The problem is disposability

Over the past decade, the move to disposable PPE and medical devices has accelerated. London Health Sciences Centre in Ontario, Canada, moved to disposable gowns and suture trays despite significant concerns about sustainability and quality. During an average shift, a physician might have 30 separate encounters with patients. If respirators are disposed of each time, that is a significant problem.

The root of the current shortage of PPE is not a lack of resources, but that we have taught health care workers to throw away functional PPE after every. single. encounter. And so here we are, with our colleagues in the richest countries in the world using bandanas as PPE.

Reuse of respirators and their filters can be done safely and with no effect to filtration quality over repeated uses so long as there is no gross contamination to the filter.

Move your institution to reusable respirators NOW

Nurses at Henry Ford Hospital wearing reusable respirators (Source: Facebook)

Running out of disposable N95 respirators is imminent. It might take days or weeks, but it will happen. You and your institution should switch to a reusable respirator now. Several providers and institutions have already begun this transition. There are several compelling reasons for this:

• Your institution will take some time to digest and implement policies for the safe decontamination and reuse of respirators. You don’t want to do this once you’re stocked out
• You making the switch will preserve disposable respirators for institutions that either can’t or won’t switch
• It will free up your purchasers to pursue other PPE that are not easily reusable
• It will make a durable and meaningful long-term contribution to the environment
• Better comfort and reduced works of breathing during long shifts
• Reusable respirators are often rated higher than N95

Glia Project guidelines for reusable respirator use

Every front line health care worker I speak to is convinced of the need to change to reusable respirators immediately. However, institutions have had a hard time catching up. The Glia Project presents our guidelines for acquiring, fitting, cleaning and maintaining reusable respirators for health care workers. We have not yet run controlled trials on this advice. However, we rely on the best available evidence where possible. We will occasionally update this post as new information becomes available, but you should look at Glia’s repository on respirator reuse for the latest.

Acquiring reusable respirators

The respirators we currently recommend are the following:

• 3M 7500 series (7501 (S), 7502 (M), 7503 (L))
• 3M 6500 series (6501 (S), 6502 (M), 6503 (L))

If these are unavailable, the 3M 6200 series is less comfortable but usable. Any other respirator with a silicone interface and a bayonet connector is acceptable. However, there should be enough 7500 and 6500 series respirators to go around.

Acquiring filters

Filters connect to respirators to filter particulate. For health care workers, N95 to N100 and P95 to P100 are all acceptable. We recommend:

• 3M 2091
• 3M 2097
• 3M 2291
• 3M 2297

Glia will help you get respirators and filters

If you do not have logistics capabilities and are based in Canada, Glia will help you find respirators and filters for yourself or your centre. Simply fill out the following questionnaire and we will assess and prioritize your request and work with you to ensure your PPE needs are met. We will start with Southern Ontario and expand from there. If you are a supplier of these respirators, please also fill out the survey, as it has a track for suppliers.

Fitting

3M’s video for how to fit reusable respirators (Source: 3M)

Your respirator must be fitted appropriately as above. Please view the entirety of this painfully boring corporate video. Then watch it again periodically as a refresher.

According to 3M, these reusable respirators should be fitted every year. Glia endorses this recommendation and recommends using pre-existing hospital fit-testing procedures.

Cleaning your respirator

Clean your respirator with a solution containing 5 000 ppm of available chlorine. You can calculate the amounts at this chlorine calculator. Sodium hypochlorite is often the liquid solution known as bleach. Calcium hypochlorite is often found as granules.

This procedure is based on 3M’s guidelines on cleaning respirators specifically for corona virus:

• Clean your respirator at the end of each shift, when grossly contaminated, when involved in an aerosolizing procedure, or when you are concerned
• Nitrile or vinyl gloves should be worn during cleaning as well as other personal protective equipment (PPE) as indicated
• Remove any filters or cartridges and hold in a clean ziploc-type plastic bag
• Facepiece may be further disassembled as necessary
• Inspect facepiece per the User Instructions to identify any damage or excessive wear. Repair or replace facepiece as necessary
• Clean facepiece (excluding filters or cartridges) by immersing it in a warm cleaning solution, water temperature not to exceed 49 °C (120 °F), and scrub with soft brush until clean
• Add neutral detergent if necessary. Do not use cleaners containing lanolin or other oils
• Disinfect by soaking the facepiece in 5 000 ppm free chlorine solution for 1 minute
• Rinse thoroughly with fresh warm water
• Air dry in non-contaminated area
• Inspect and reassemble respirator as described in the User Instructions

Disinfecting your filters with heat

Effect of heat treatment on the infectivity of SARS-CoV. Virus aliquots (400 μl) were incubated at 56°C, 65°C and 75°C. Samples were removed at the designated time, frozen, and titrated in Vero E6 cells in triplicate. The dotted line denotes the limit of detection of the assay. (Source: Darnell et al.)

UV disinfection is probably the best method for larger organizations with a good capacity to ensure continuous availability and effectiveness of devices and lights necessary for the technique. If UV is not available, heat treatment at 70–75°C for a period of 60 minutes will inactivate viruses completely. In Darnell’s study on the SARS virus of 2004, 45 minutes at 75°C was sufficient. We’ve extended the time in this protocol to allow for heat at 70°C as well.

This temperature can be achieved with a rice cooker on the ‘keep warm’ setting. The ‘cook’ setting will melt the filter.

Caring for your filters

As per guidelines from the CDC on extended use of N95 filters, here is some guidance.

Discard N95 filters in these scenarios:

• Obviously damaged
• Difficult to breathe through
• When notably/visibly contaminated (blood, secretions, bodily fluids)

How to protect your respirator from contamination:

• Use a cleanable face shield
• Give the patient a regular surgical mask
• Hand hygiene before and after touching N95 respirator (if needed for improved fit/comfort)

How to help

If you either need or have reusable 3M respirators or filters, please fill out this survey.