CPAP and SCUBA

[chunkyfrog]

Oh, Davey! (sob)

[ClayL]

Let me qualify by saying I'm not a diver, but my understanding of nitrogen absorption while diving comes not from the pressurized air one is breathing, but from the pressure of the water around you the deeper you go. I wouldn't think they are related.

They are closely related.
As you go underwater and the ambient pressure increases, the regulator changes the pressure of the air you are breathing to match it. That allows your lungs to expand which they couldn't do otherwise because your muscles are not strong enough to fight the ambient pressure.

Since the pressure of the air you are breathing is the same as the ambient pressure, the increased pressure causes more nitrogen to be absorbed into your bloodstream. That is why coming back up too quickly can cause decompression sickness ("bends") which is nitrogen bubbles forming in your blood that can cause death or several types of damage - paralysis being a common type. (It is not common to have decompression sickness but some damage is common if you do experience it. Sometimes reversible sometimes not)

I agree with the others that the small amount of nitrogen absorption due to CPAP will be negligible .

DAN (Divers Alert Network) can always be called to get an expert answer though.

(20 year diver with PADI Rescue Diver certification)

[Otter]

It seems to me that wading would have more effect than CPAP. Ignoring the point that DreamDiver just brought up CPAP, would at most create the effect of the equivalent depth of water, usually not more than 20cm h20. We're talking less than 8 inches! You can get deeper in a good bathtub.

[CanuckDiver]

Hey,

Very experienced Diver here who had never dived while using CPAP until recently. Here are my experiences.

1. Agree with all the above comments about CPAP and pressure. This is all right on the mark.

2. There are however issues you need to be aware of. None of them are serious enough to outright kill you but you should be cognizant of them. They are:

Gulping : I often wake up bloated and with signs of gas. This happens when your body has issues when you sleep and you "gulp" air into your stomach. This also aggravates my Esophagus to the point where my system wants to dry heave, especially in the mornings. My pressure is only 11 but even still, after a night at the pub and a long sleep, this happens every now and then. It is not an issue after I have been awake for awhile but it could potentially be a problem at depth.

Aerophagia and Air in Digestive system: This is the big one. I have had to add extra weight (a lot!) to keep me down. Until I had read these and other forum postings, I had not realized why this had occurred. Now I know it is the extra air in my digestive system from the gulping, gas etc that has created the extra buoyancy. It took about 4 dives to realize I needed to just bite the bullet and add extra weight. This also becomes a problem with consistency as most of us like to dive with as little weight as possible but with the extra air, it is a problem to figure out what you need. At about half a tank I have trouble at about 30ft which is wear the pressure start to thin your suit and make you heavier. Above that I was starting to rocket to the surface no matter what I did.

I will end by saying that it took me awhile to correlate some of the diving issues I was having with the CPAP and potentially with GERD, which also has an effect on the amount of gas in your system. When I realised that my GERD and my Aerophagia were the causes of the problems, it had been relatively easy to adjust but there is a big difference in the way you think of things when planning activity. The same could be said about your stomach and abdomen muscles: Those with a real 6 pack do not appear to have as much of an issue with my problems diving and CPAP. So my goal is to get those muscles back into play more than they are presently and hope this will reduce the Aerophagia content.

Hope this helped.

[icemanbryan]

But what if you do CPAP in a water-bed?

Too Funny

[pauldw]

CPAP air is not "pressurized" to the point where it inflates the lungs or forces air into the lungs. It is merely enough to splint the airway (nasal and/or throat) to allow one to breathe normally.

True of CPAP for obstructive sleep apnea. Not true of ASV for central sleep apnea.

At any rate, is there any substantive difference for ASV users instead of CPAP? I haven't been doing ASV long, but it just gives me an odd feeling in my airway, like it has been hollowed out or changed in some way.