Some Victorian anaesthetists are sensing a pending shortage of disposable respirators and are exploring reusable alternatives like elastomerics.
They are quiet, effective, comfortable, fit more reliably, no electronics/batteries, and are reusable.
Short review of some below

They are often perceived incorrectly as a way of elevating precautions. They should be seen as a means of preserving stock of disposables, as well as providing a better fit in some staff who do not fit the available disposables and whose supply chain is currently very unreliable.

They are in use in many healthcare settings around the world for this purpose.
This is Guys St Thomas MERIT in London https://twitter.com/amit_pawa/status/1245490684972486659

This is a hospital in Texas. Interesting story. https://elemental.medium.com/a-tiny-hospital-in-texas-might-help-solve-the-mask-shortage-9ad3c0a7a861

This is in Canada
https://www.cbc.ca/amp/1.5549297?__twitter_impression=true

Choice is initially between a half face or full face respirator.
Usually a half if you need glasses, or full if you don’t need glasses and want additional sustainably condensation free eye protection.
Either way they look like gas masks, and we just need to get used to it.

The two main brands available in Australia are Sundstrom & 3M. Sundstrom make a half face (SR100) respirator that has one inspiratory filter directly in front, and one expiratory valve either side. The filter does protrude forward and makes *certain* face shields less effective.

The SR200 is their full face model which has the same forward filter profile. The airflow is designed to draw fresh air into and over the inside of the visor which prevents the buildup of blinding condensation. They are slightly front heavy compared to alternatives.

The benefit of the single filter is that during the fit check, the filter opening can be occluded and on inspiration, with a good seal, the mask collapses. This means the fit check is more likely to be reliable.

Decontamination is either dismantling and washing the respirator in warm soapy water, or submerging the whole unit in 70% alcohol for 5 mins. Manufacturer advice of alcohol decontamination is below, as is the Guys St Thomas

The SR200 only comes in one size, and I have seen it fail a fit test in someone with a smaller head in which the straps could not pull the mask on securely.

The 3M half face respirators (7500) have two filters, one positioned either side of the expiratory valve in front. Expiratory breath is channeled downwards.
The shorter forward profile means these work better with most face shields.

The filters are used until they start to block, which is likely to be often, and are cleaned by wiping down externally in addition to the rest of the mask. The manufacturer’s coronovirus cleaning recommendations are here.
https://multimedia.3m.com/mws/media/1793959O/cleaning-and-disinfecting-3m-reusable-respirators-following-potential-exposure-to-coronaviruses.pdf

The 3M full face mask is comfortable, but communication may be slightly more difficult than all the others mentioned above, and comes in different sizes.
I may follow up with a video to demonstrate these differences.

As with all equipment used in hospitals there should be consultation with people who are tasked with safety when using them, and institutional buy in and integration is the best way to ensure safety.
And, as always, a reminder that PPE is only a small part of risk reduction. https://twitter.com/drpieterpeach/status/1260835115917144066

Small typo correction - the 3M enclosed filters are *unlikely* to become blocked very often