0 Recommendations

How long can one use a disposable personal respiratory protection (masks)

By Michael Rich, MD MPH | 25 Jul, 2008

Can we recommend to facilities in resource poor areas that disposable respirators (masks) be used as long as they are in good condition, including the seal intact? They obviously should be kept outside the ward or clinic in a place where the inside is unlikely to get contaminated with bacilli on the inside of the mask. In our clinics in Peru and Rwanda we recommend the masks be kept on pegs hanging outside the wards, labeled with with providers name, and used for 1 to 2 weeks. Do others agree this is an acceptable practice?

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Pia Siff Josefsen, MHS Replied at 9:34 AM, 29 Jul 2008

What kind of disosable respirators are you talking about? Is it 3M or N95 or?

Edward Nardell, MD Moderator Replied at 12:38 PM, 29 Jul 2008

First, in response to Pia's question, I believe you are referring to disposable N95 respirators or the European standard equivalent.

Paul Jensen, one of the 3 moderators of the group, will make an more "official" response soon, taking into account manufacturer recommendations, etc. I will make some preliminary personal comments here that may or may not be consistent with what he says later, and as always, we should discuss differences in this forum.

The reality is that disposable respirators are expensive and must be reused in resource limited settings - and should be reused to some degree in resource-rich settings too in order not to needlessly waste resources. The question Michael Rich and many others ask is how long can they be reused and under what conditions should they be stored?

My two concerns are: 1) the integrity of the respirator with regard to protection, and 2) the contamination of the respirator - not with TB which cannot be transmitted by contact - but with common hospital pathogens that can easily be transmitted by touch. Michael alludes to both of these concerns.

1) Integrity and function of the respirator. Although the filtering face piece of the respirator (the part that covers the mouth and nose) could be damaged by sitting on it, folding it if not meant to be folded, or crushing it, by far the most vulnerable parts of the respirator are the elastic bands (usually 2) and the nose clip (which can break or become displaced). The latter two problems can lead to face-seal leak, the biggest problem with all respirators other than positive pressure devices. How long the elastic bands remain tight enough to produce a good seal depend on their original quality and thickness and how much they are stretched. In theory they could be replaced, but there are other reasons not to use the respirator much longer than the elastic bands remain able to produce a good face seal.

If the nose clip is broken or displaced the respirator cannot be used.

My personal recommendation, therefore, is to stop using the respirator when the elastic bands cannot produce a tight seal against the face. In the absence of repeat fit testing, this is a qualitative judgment. However, this may be superseded by the next recommendation, below.

2) Contamination of the respirator. Michael implies that TB contamination of respirators may be an issue, but I don’t think that is the case. TB must be inhaled to reach the alveolar macrophage, the only site infection can start unless the skin is punctured with a contaminated object. I am not worried about TB getting on the inside or outside of the respirator. However, I am worried that the filtering face piece is usually touched by potentially contaminated hands every time the respirator is put on or taken off. These porous surfaces are not cleanable, so in my opinion (I have see no data if it exists) they will definitely become increasingly contaminated with use and increasingly important fomites for spreading MSRA, C. difficile, E.coli, and other potentially nasty organisms in the hospital. For that reason we probably need to recommend attention to hand washing before and after touching the respirator, which should be done anyway. Likewise, contaminated gloves should be removed before removing a respirator that is to be reused. Ideally, in intensive care or isolation settings, respirators should not be worn from one patient to another patient because of the risk of cross contamination by direct hand contact. In ward settings, however, this would not be practical.
My personal recommendation, therefore, from a contamination perspective is to use a respirator no more than a week if it is used every day – but longer if it is used less often, using common sense as a guide. Bad contact precautions could make using a respirator just one day worse than using one a week with good technique, so hard and fast rules are hard to generate.

3) Storage.
Paul will likely comment on all of these points, but the storage solution Michael raises seems reasonable to me if these pegs are protected from other sources of contamination. Putting moist respirators into sealed (or unsealed) plastic bags will definitely encourage bacterial or fungal growth. By hanging them exhaled breath moisture can dry between uses. I have heard of respirators being stored or “decontaminated” under UV lamps, but would not recommend this practice since UV is not a good decontamination method for irregular surfaces since UV rays travel in straight lines and it will cause more rapid deterioration of elastic bands, etc.

4) Need for a better respirator for medical use in resource poor and resource rich settings.
In industry there are “elastomeric” respirators designed for reuse that have flexible smooth surfaced (cleanable) face pieces with one or two removable and replaceable filtration canisters that stick out a bit. These give the respirator a bit of a “Darth Vader” look, unfortunately. Some canisters are porous and exposed and others are somewhat protected from touch by plastic perforated covers. Elastic straps are much thicker as well for a tighter more reliable face seal. These respirators interfere with voice communication more than disposable respirators do.

Such respirators are not extraordinarily expensive – perhaps $25 to $50, but should outlast many boxes of disposable respirators. However, my concerns about contamination remain and handling would require even greater care if they are used for a long time. There would need to be a good cleaning routine, ideally at the end of each day, using some form of surface disinfectant that would be compatible with the respirator component parts. Finally, current versions of these respirators are bulky and look “industrial” rather than “clinical”. With use, they could be accepted on the ward, but Lew Radonovich from U. Florida has a project to come up with better reusable respirator designs for use in both resource-rich (pandemic flu) and resource-limited (TB, flu) settings. This will take some time, however, to design and test these products. I will update the group as this project progresses.

Please respond positively or negatively to these personal reflections and recommendations. As I said, I expect Paul Jensen to weigh in soon with perhaps somewhat different recommendations based on his experience and what the respirator manufactures say about reuse.

Ed Nardell, MD

Andra Cirule, MD Replied at 5:35 AM, 31 Jul 2008

Dear Edward Nardell,

I am sending my coments and opinion about respirators and how long time we
are using them.
In our hospital we use respirators FFP3.
TB doctors use respirators every day and several times per day, in this
situation they change them sometimes after 3 days, but sometimes after 2
weeks, it depends on many factors.
We recomend to wear respirators while they ensure good fit and fist off all,
as you said, problems with elastic bands and the nose clip.
Some years ago I was in Uzbekistan MDR-TB hospital and they changed
respirators every day, because climat was very hot and faces swet under
respirator, which after short time was humid.
But we could do some tests in our hospital, because we have respirators and
we perform fit test with Bitrex for HCW, and we can perform fit test in
different periods of time, when HCW sart to use respirator, then after some
days, 1 week, 2 weeks and after them to compare results.

About contamination, I am also thinking, that it is not possible to get TB
from respirator, but nosocomial infections, which transmitted by touching
may be possible, but it is very important only in some cases, when you have
patient with infectious TB and nosocomial infection at the same time. And
then most important protective activity is hand washing.
In cases, when patient have only nosocomial infection (not TB) respirators
for HCW are not necesary.

About storage, we recomend to put respirator into paper or material tissue
or towel, not in plastic bag. UV light damage elastic bands and dont't kill
bacilly, located inside respirator.

With best regards,
Andra Cirule

Paul A. Jensen, PhD, PE, CIH Moderator Replied at 2:07 PM, 11 Sep 2008

Excellent question and responses from Ed Nardell and Andra Cirule!

First, I would like to address the terms "respirator" and "mask." Generally, we refer to a device that protects the wearer from small particles (e.g., droplet nuclei), a particulate respirator. A filtering face-piece respirator is a respirator in which the filter interfaces with the face; hence the name. Slang for these respirators is "disposable respirator." Are they disposable? Yes. Are they re-usable? It depends!!! Most filtering facepiece particulate respirators meet either the CEN EN149 standard or the US CDC/NIOSH 42 CFR 84 standard. Some countries have adopted these standards in total or in principle.

That said, we must think of re-use in terms of general infection control and in terms of liability. In terms of general infection control, we must ask the following: Would/could re-use of the respirator lead to transmission of an infectious microorganism to a susceptible host? This could be HCW to patient, HCW to self, HCW to others, etc. For instance, one would not re-use a respirator after exposure to a known or suspect pandemic influenza patient. Why? They may be fomites! As you know, fomites are associated with hospital acquired infections (HAI). What are other examples? How about stethoscopes, neckties, basic hospital equipment, IV drip tubes, catheters, life support equipment, and many, many other "things"? How do we stop cross-infection or HAI? When was the last time your doctor changed his/her tie between before and after attending to your needs? BBP regulations deal with most medical equipment. So, we must come up with a reasonable and safe program for re-use of respirators. Common sense can go very far . . .

Now let's talk about liability. Do the respirator certifying bodies or the respirator manufacturers want to recommend anything other than the most conservative (and expensive) approach? While I do not endorse any particular respirator, the following is a direct quotation from the User Instructions for 3M 9210/37021, 9211/37022 Particulate Respirator N95: "Time Use Limitation If respirator becomes damaged, soiled, or breathing becomes difficult, leave the contaminated area immediately and replace the respirator." Please note that there is much more information on the User Instructions. So, what does 3M recommend? It is not clear to this reader!

What is practical for re-use of "disposable" respirators? Andra Cirule has a very practical program in Latvia. In the respiratory training, one must ensure wearers understand what may affect their fit. For instance, some respirators have extremely thin rubber bands as straps. After wearing these respirators a few times (e.g., stretching the bands), the respirator may not be held on the face a tightly as it did when "fresh out of the box." Some respirators have substantial straps or straps that are adjustable; hence, their fit on the face may be conserved over time. One must remember, however, that if there is any doubt regarding the fit of a re-used respirator, it should be replaced. Finally, and you all know this, do not share disposable respirators with others!!!

Please let all know your thoughts regarding this topic as well as what re-use policies and practices you have implemented in your facility/country.

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