One major trickle-down effect of widespread disease outbreaks can be a shortage of certain supplies. As COVID-19 has emerged and spread in humans, availability of items such as nose-and-mouth (e.g. surgical) masks rapidly decreased because of hoarding, diversion to the black market, increased unnecessary use and increased legitimate use. In such a situation, veterinary clinics are typically unable to get masks because suppliers are sold out and production will (obviously) be geared towards supplying the human medical facilities. As a result, a growing concern right now (in both human and veterinary medicine) is how to handle shortages, with scenarios where facilities run out of supplies being on the horizon.
Surgical masks are likely to be the first thing we run out of. The most apparent solution to the problem would be to start reusing surgical masks, but these masks are marketed as single-use items and under normal circumstances are not meant to be re-used. So a lot of clinics are now asking the question:
Can we re-use surgical masks?
The answer isn’t straightforward. To start, we need to clarify what types of masks we’re talking. Surgical masks are used during surgery to reduce the risk of the surgeon depositing aerosols / droplets into the surgical site. This post is focused on use of masks to protect the veterinary patient. The approach to re-use of items to protect the user (e.g. from a pathogen like the COVID-19 virus) is a different story.
The main concern with reuse of masks in a clinic scenario (i.e. to protect the patient, not the wearer) is not contamination of the masks (because they’re not sterile to start with), it’s whether they still function adequately when re-used. That hasn’t been well investigated, as there’s not much motivation to research re-use of cheap, easy-to-get (during normal times) items like masks.
Consider the potential implications of using a mask that is less effective than normal:
- In surgery, the risk is predominantly to the patient, as there may be increased risk of contamination of the surgical site.
- However, the overall risk to the patient under most circumstances is probably limited with good adherence to other standard surgical asepsis practices. Some surgeries would be higher risk, though. Limiting talking during surgery to necessary discussions can probably reduce the risk a bit more, since talking produces more aerosols.
- In veterinary medicine, the risk to the surgeon (e.g. from being sprayed in the face with infectious material during the procedure) is very low (to nil). (In human medicine, there are more risks to the surgeon because of the need for protection from bloodborne pathogens like HIV and hepatitis C. Fortunately, we don’t have the same degree of bloodborne risk from animals.)
So, a suboptimal (e.g. reused) surgical mask is better than no mask, the increased risk to the patient (that needs the procedure) is low and the increased risk to personnel is little to none.
Masks are labelled as single-use. Doesn’t that make reusing them inappropriate?
- Re-use of items marketed as single use is actually quite common, particularly in veterinary medicine. We just have to put some thought into it and be responsible about how and when this is done.
- There’s not a lot of guidance available specifically on reuse of masks (but I suspect more will come in the near future). The CDC recommends extended use of masks rather than reuse (e.g. wear the same mask for longer, rather than taking it off and putting it on again), but their discussion also includes use of N95 masks – these are meant to protect the wearer, so contamination of the outside of the mask during use and removal is more of a concern than with surgical masks.
- One reference about reuse of masks during an influenza pandemic states “If a sufficient supply of respirators is not available, NIOSH and CDC recommend that healthcare facilities may consider reuse as long as the device has not been obviously soiled or damaged (e.g. creased or torn). ” That seems reasonable.
What about autoclaving or using dry heat to disinfect masks between uses?
- This might be counterproductive. The main concern (from the patient protection standpoint) isn’t accumulation of microbes in/on the mask, it’s mask integrity. Steam, in particular, may be harmful since one of the layers of most masks is designed to absorb fluid (i.e. from the wearer’s breath). I’d be concerned that methods to sterilize masks would reduce contaminants but ultimately create more risk by damaging the mask.
What about reusable cloth masks?
- I saw a lot of these being used by people while travelling recently. How effective they are will depend a lot on the material and design.
- One study reported only marginal protection from aersols by masks made out of various common fabric materials. You can even find washable surgical masks available for sale online, but I’m not sure whether any have FDA (or equivalent) approval. Use of washable/reusable masks by human surgeons has been reported.
- A reusable cloth mask is presumably still better than no mask, but I’d have a hard time saying an untested/unapproved cloth mask is better than a reused standard surgical mask.
What about face shields?
- Face shields are designed to protect against splatters or aerosols coming at the wearer, not to prevent the wearer’s aerosols from contaminating other things. I guess I’d place them in the “better than nothing” category depending on the design, but aerosols escaping out the bottom of the shield and into the surgical site would be a particular concern if used in surgery.
If reuse of surgical masks for veterinary surgery becomes necessary, what are the most important considerations?
- Veterinary clinics should consider having personnel start saving masks they have used before the supply runs too low. I would not re-use them until needed, but better to have a stockpile of used masks than no masks at all.
- Personnel should save their own masks separately rather than pooling them, since sharing masks is 1) gross and 2) a potential way to transmit human pathogens between people.
- Before saving a mask, it should be carefully untied and inspected to see if there are any visible defects.
- Masks to be re-used should be placed somewhere they can dry, to reduce the likelihood of bacterial growth inside the mask. Masks should not be re-used when they are damp.
- After re-use, masks should not be placed back into the same reuse pile. It’s hard to say how many times a mask can be resused, but better to reuse all the available masks once before starting to reuse masks multiple times.
Does reusing masks constitute failure to meet a standard of care? Is it something owners should be informed about?
- Standards of care are often poorly defined and a bit of a moving target. Discussions with regulatory bodies are useful to get clarification of their thoughts about reuse of masks under extenuating circumstances such as this.
- I don’t think owner consent is required for procedures involving reused standard masks, but I think it would be required if we end up having to do procedures without masks.
Can surgery be done without masks?
- There is actually minimal evidence regarding how much (or if) masks protect patients from infections (it’s a difficult theory to test when wearing masks is the standard of care). That said, it makes sense that they do, so we want to avoid depositing aerosols into the surgical field as much as possible.
- Consider the cost-benefit. If I ruptured my appendix today, I’d want surgery, even if the surgeon isn’t wearing a mask or is wearing a suboptimal mask. If I need a new hip, I’ll wait until they have all the needed supplies, because the urgency for surgery is less, and the implications of a post-op infection are major. The same concept applies to veterinary surgery.
For veterinary clinics that are adequately stocked for now but are not sure when they’ll get more masks:
- Conserve masks as much as possible (i.e. use good “PPE stewardship”).
- Consider starting to save masks for reuse.
For clinics that are already running low on masks:
- Consider postponing elective procedures
- Limit non-essential personnel in surgery. Some human teaching hospitals have started keeping students out of operating rooms to save masks, and the same discussion may have to occur in veterinary teaching hospitals.
- Save masks in case they need to be reused.
Hopefully this isn’t a problem we’ll have to deal with, but I suspect it will be. I’ve talked to some clinics that are almost out, and I suspect that many clinics will soon be in that situation. We’re monitoring our supplies closely here but no one can predict the course of this outbreak and its short and longterm effects on the supply chain. It’s better to think about things in advance and be prepared, rather than walk into the clinic one day and realize “oh crap, we’re out of masks.”