BRITTANY HOWARD: This is Dr. Brittany Howard from the Department of Otolaryngology at the Mayo Clinic. I'm the chair of the facial plastic and reconstructive surgery division. And the subject matter expert for us regarding respiratory personal protective equipment. We're going to be talking today about some of the various respiratory options for health care workers in the current COVID environment.

The first things we're going to talk about are the CDC stratification of respiratory personal protective equipment. Then we'll be talking about the types of respiratory protective equipment available to health care workers. And ultimately, we'll be looking at each of those pieces as well as the pros and cons as they apply specifically to an otolaryngologist, and throughout all health care teams.

The CDC stratifies respiratory protective equipment strategies into conventional contingency and crisis management plans. Our conventional plans are the ones that we would do on your daily best practice care, specifically providing patient care without any change in daily contemporary practices. This is what we do when all things are normal and we have unlimited access to personal protective equipment.

Currently throughout much of the country, however, we are in a contingency model. This is a point where we have to modify our operations and protocols based on the external environment to preserve what is potentially a dwindling supply of protective equipment. What we have also certainly heard talk about is the potential of reaching a crisis level. This is when of the strategies that are used in health care are no longer commensurate with the US standards of care. And we've heard discussions of everything from bandannas to no mask at all for personal protection.

We're going to talk about where each of the masks that we will talk about today falls in line with these. Looking at types of respiratory protective equipment, the four most common categories are your surgical masks, disposable N95s, a elastomeric respirators, PAPRs and CAPRs which are each either a powered air purifying respirator or a controlled air purifying respirator.

All four of these are included in the CDC's conventional respiratory protection algorithm, and each one with specifics about how it should be used. So our first example is a standard surgical mask. These are regulated and certified by the FDA. They protect the provider from droplet level respiratory products and protect both the surgeon and the patient in a surgical field. They are appropriate when droplet precautions are needed and where we're worried about respiratory molecules down to approximately 3 microns in size, which most of those, as we heard earlier, are approximately five. And these are appropriate in those droplet settings.

When we start talking about diseases, it can potentially be aerosolized. Then we start talking about a higher level of protection. The CDC minimum level of recommended protection in a conventional environment is an N95 respirator. This is one example. There are different types that come differentials shapes, sizes, and colors. And they need to be fit tested to the individual.

These are intended as single use items. However, that's in our conventional algorithm. Once we start hitting contingency and we're worried about dwindling supplies, we start talking about reusing what's supposed to be a single use item and specifically trying to protect it for longer periods of time behind things like a surgical mask to prevent it getting contaminated.

These masks are rated N95. And one thing that should come to mind is what exactly does N95 mean. N stands for not resistant to oil, which is one of the reasons it's so important that you don't touch these with your hands. Because you actually will degrade the filter particles of the mask and why many of them have a cage, as you can see on this one, protecting the underlying filter from your skin.

Other levels are R, which is partially resistant to oil and P which means oil proof or largely oil proof. Disposal masks do come in those types and styles. But they're much harder to find and not conventionally available. In general what you'll see in hospital settings are N95s. Again, these are considered to be of good use in aerosolizing environments. However, they are also considered the minimum protection because they are that N95.

The 95 in that moniker stands for the fact that this protects you from 95% of respiratory molecules down to 3 microns in size-- sorry. Not three microns. 0.3 microns in size. And you have at least that much protection. There are additional respirators that are graded N, R, P depending on the type of filter. 99, which means that they will protect you from 99% of the respiratory particles down to that 0.3 micron size.

And then the highest level of filter available is something that is graded at 100. And it protects the wearer from 99.97% of respiratory molecules. It is considered to be commensurate and equivalent to wearing that powered or controlled air purifying respirator. It's equivalent to a Hepa filter.

So once you move out of single use or intended for single use items, what we move into are things called a elastomeric respirators. These respirators can be used multiple times by a single or various individual. Or they need to be fully disinfected between wearers' use. They, in and of themselves, are not the protective equipment. The protective component are disposable but multi-use cartridges that fit on them.

In this example, this is a Drager Explorer elastomeric respirator. And many, many companies make these. The CDC has a list of all approved respirators of this type easily available. This is a half mast style meaning that your eyes are still exposed. When you're worried about aerosolized viruses or diseases, in addition to protecting your lungs with these respirators, you must also protect all the rest of the mucous membranes. And that includes your eyes wearing some form of high level protective gear, goggles, glasses, or a full face mask.

Once on, these can be at a level equivalent to your N95 or higher depending on the cartridge selected. The cartridge selected here is a P100 filter. These are, again, reusable for a single individual. The duration of their life varies from manufacturer and the environment they're brought in to. But they certainly have well documented by up to six months in a well cared for and health care environment.

These, again, are P100s which then makes them equivalent to your actual powered option, which is the PAPR. These powered air purifying respirators are meant to be used for a long period time by a health care worker. Their downsides in the health care surgical world is that anyone is interacting with a sterile field cannot use these because they blow the air from the individual out onto the surgical field. And so they must be carefully selected.

When they are full hoods like this that come down onto the shoulders, they are considered better in the surgical field. Because you can still put a surgical gown across this and therefore vent the air coming off of you down and away from the surgical field. But it's still not ideal, necessarily.

CAPRs or other forms of PAPRs in which only the face is enclosed do carry a higher risk to the surgical field. But they do have the added positive of protecting your eyes immediately. And with that, we're just going to see if there's any other questions. Anything that you can think of?