Converting SCBA full face masks a possibility?

[Bahumat]

So, I'm a new CPAP user, in my first trial month. Played around with a few masks, definitely finding that full-face for me is just a necessity. I can't draw in enough air from just my nostrils to satisfy, so I wake up gasping in the night. However, the designs of the full-face masks I've tried, while some were good, lacked.

I have access to industrial fit-testing equipment and training therein; I'm confident I could get a good seal with a Scott full-face mask (used for Self Contained Breathing Apparatus, SCBA's). I'd have to custom make an adapter to fit the mask port to the air hose of the C-PAP, but I don't think that that is insurmountable.

Can anyone familiar with C-PAP masks chime in with my this could or couldn't work? I know that the Scott full-face masks I'm looking at (pretty much identical to the kind firefighters use, and entirely identical to the kind used in oilfield / confined space entry / H2S safety) are larger and heavier than most. They're designed for positive pressure. They have one-way valves, or those could be built into the adapter.

I'd likely have to hand-drill a few small exhaust holes into the mask. They're quite comfortable to wear and the head-netting style of headband is also great. I wonder if the injection silicone would hold up to such long-term wear though.

[Goofproof]

When trying to reinvent the wheel, start with a round shape first. it seems easier to roll uphill. What is the cost of these masks and the headgear? jim

[Bahumat]

When trying to reinvent the wheel, start with a round shape first. it seems easier to roll uphill. What is the cost of these masks and the headgear? jim

Significantly less than what I'm being quoted from my sleep provider. $70 - $200 CAD dollars. As I'm involved in the industry, I can get a scott face mask for very reasonable prices. The issue being, I don't believe that there's any existing adapter to go from C-PAP air line to the scott mask. I'd have to design and make that via rapid prototype or else hand-machining. Neither of which I particularly mind.

My primary concern is that the volume of air a Scott mask holds is considerably more than an average face-mask. The pressure can be maintained and sustained, but there's much more total air in the mask compared to the C-Pap masks I've tried so far. So my concerns are, in this order:

A) Will I be able to successfully make an adapter that will work with the air hose? (I'm fairly confident I can.)

B) Will the increased air volume in the mask require more through-put of air to avoid feeling like I'm choking on my own breath?

Etc.

Insofar as reinventing the wheel... it's more that I'm looking at a tractor tire and trying to figure out how to attach it to my Toyota. The masks are designed to work all the time with positive pressure. It's more, it seems, a matter of bringing the rest of the system up to par with it.

[Guest]

My first concern would be "How am I going to balance the exhalation ports so that the pressure remains adaquate yet at the same time washing enough CO2 out of the mask so that I don't become Hypercapnic. Furthermore, how am I going to measure that to make sure i have it right?"

[Bahumat]

My first concern would be "How am I going to balance the exhalation ports so that the pressure remains adaquate yet at the same time washing enough CO2 out of the mask so that I don't become Hypercapnic. Furthermore, how am I going to measure that to make sure i have it right?"

The diaphragms for the valves are thin plastic that is easily shaved/cut/perforated.

Measuring it, though, presents a considerable technical challenge. Hmm. Ideas for solutions?

[Guest]

Either purchase a machine that would mimic an individual breathing on the mask that would measure the amount of expired gas that is inspired...........OR....find a research facility or hospital that would allow you to wear it while you have an indwelling arterial catheter with continous Arterial blood gas monitoring.

[Bahumat]

Either purchase a machine that would mimic an individual breathing on the mask that would measure the amount of expired gas that is inspired...........OR....find a research facility or hospital that would allow you to wear it while you have an indwelling arterial catheter with continous Arterial blood gas monitoring.

I think that either of those go well beyond the technical feasibility of the idea. I don't know that any such machine exists outside of highly specialized applications, and likewise, a hospital stay for what amounts to an in-out air measurement seems a poor idea.

... I do have access to mask fit hardware and software. I could measure the usual leak rate of my present masks to get an idea of the average l/min lost through the vents. Hmm.

[LoneStar]

I can't draw in enough air from just my nostrils to satisfy, so I wake up gasping in the night.

First, fill out your equipment profile in the User Control Panel; it will enable us to help you more.

What are your pressure settings? If you are using the ramp feature or using APAP with the lower setting set too low, you could have the sensation of not being able to draw air.

While adapting a SCBA mask might be a possibility, I think working with your machine setting first might help your "drawing air in" problem.

Lisa (Texan)

[roster]

So you want to have your eyes subjected to the CPAP pressure all night long 24 x 7? That may not be such a good idea.

[Guest]

Either purchase a machine that would mimic an individual breathing on the mask that would measure the amount of expired gas that is inspired...........OR....find a research facility or hospital that would allow you to wear it while you have an indwelling arterial catheter with continous Arterial blood gas monitoring.

I think that either of those go well beyond the technical feasibility of the idea. I don't know that any such machine exists outside of highly specialized applications, and likewise, a hospital stay for what amounts to an in-out air measurement seems a poor idea.

... I do have access to mask fit hardware and software. I could measure the usual leak rate of my present masks to get an idea of the average l/min lost through the vents. Hmm.

You would still have no idea what leak rate would maintain the proper pressure level yet still flush enough of the expired CO2 out of the mask to provide a safe level.

[Bahumat]

So you want to have your eyes subjected to the CPAP pressure all night long 24 x 7? That may not be such a good idea.

It may not be, or it could even possibly be better for me, depending on how the pressure differential in the sinuses would work.

Bear in mind there's already work duties out there where individuals have to wear these masks and are subject to positive pressure, and in those occupations they're spending eight hours or so a day in those masks. Asbestos and mould remediation sees a lot of guys pulling ten hour shifts with these on all the time.

Not that I'm discounting your concern; I'm wondering what equivalent titration level, now, that an SCBA ordinarily runs at.

[Bahumat]

Either purchase a machine that would mimic an individual breathing on the mask that would measure the amount of expired gas that is inspired...........OR....find a research facility or hospital that would allow you to wear it while you have an indwelling arterial catheter with continous Arterial blood gas monitoring.

I think that either of those go well beyond the technical feasibility of the idea. I don't know that any such machine exists outside of highly specialized applications, and likewise, a hospital stay for what amounts to an in-out air measurement seems a poor idea.

... I do have access to mask fit hardware and software. I could measure the usual leak rate of my present masks to get an idea of the average l/min lost through the vents. Hmm.

You would still have no idea what leak rate would maintain the proper pressure level yet still flush enough of the expired CO2 out of the mask to provide a safe level.

True. So. Any ideas how one might evaluate this with confidence, without resorting to arterial catheterization? A fingertip O2 monitor with alarm?

[Bahumat]

You would still have no idea what leak rate would maintain the proper pressure level yet still flush enough of the expired CO2 out of the mask to provide a safe level.

Hmm. Actually, now that I think about it, I do have access to portable O2 monitors with incredibly screechy loud alarms. It might be complicated, but I could probably actually fit one inside the mask. Hmm.

[Guest]

You also need to consider the fact that SCBA systems work the same as a SCUBA system. There is a positive pressure cutoff in the regulator that cuts the positive flow when the individual exhales. I am not aware of what that pressure would be, but I would bet that it is fairly low. So this begs the question, what level of positive pressure can the SCBA seal withstand. Remember that it is designed facing outward so that it works on a negative pressure principal. Put a regular SCBA on and plug the exhalation ports and see how hard you have to bloe out to create a leak and still be wearing the mask comfortably.

[Guest]

You would still have no idea what leak rate would maintain the proper pressure level yet still flush enough of the expired CO2 out of the mask to provide a safe level.

Hmm. Actually, now that I think about it, I do have access to portable O2 monitors with incredibly screechy loud alarms. It might be complicated, but I could probably actually fit one inside the mask. Hmm.

O2 would not be your problem, CO2 buildup in the blood would be your problem.