Machines which blow air at me

[becktrev]

I thought it doesn't hurt to sometimes talk a little again about accustoming yourself to CPAP.

I often see the expression here 'trying to breathe against the air blowing at me from the machine'.
You know, it does feel like that, but it would perhaps help to appreciate what is really happening.

The machine is only blowing air 'at you' for the first few seconds. Quite quickly the pressure inside you is almost the same as that in the hose and up to your machine. Afterwards, all that is happening is that you are breathing air at a higher pressure than the room you are in. There is no large volume 'coming at you'. just a relatively small amount moving along the tube, corresponding to the amount passing through the mask's vent hole.

Then why does it feel as if the air is pushing at you?
It is you that is causing this effect, not the machine. Inhale and the tube pressure drops slightly, exhale and you try increase the amount of air in the tube and in so doing push up the pressure momentarily – you feel resistance. You're trying to blow up a balloon.
You can feel this effect even without the machine running, just by blocking the vent hole and trying a few very deep breaths. The higher the operating pressure, the more pronounced it becomes - simply because the tube's walls are not intended to expand.

How to deal with it?:

The major thing is ...... relax.
You perhaps get into bed and start organising things. Your glasses here, water there. Where's the mask? Did I feed the cat? Is my pillow right? Sometimes there is more action then, than the whole evening. If you start your Darth Veda bit (my wife calls it that) straight away and switch on the machine, what happens? You are breathing like an olympic weight-lifter. No way your tube can take the exhalation pressure properly. Your mask will leak – you are fighting the machine.

Relax.
Lie there for five minutes with the machine off and think about life, about Bush, your mother-in-law, ice-cream – whatever slows you down. Having the mask already on doesn't hurt – very often it seems to warm up a bit and fit better after a few minutes anyway.
Only when your breathing has slowed right down and you have long since finished rolling about the place and playing with your pillow, do you slowly stretch out a hand and switch on the power. No big sighs – no 'oh dear what's coming next' fast breathing. Keep it as gentle as possible and it will feel normal.
And should you later wake up suddenly – panic – heavy breathing – with an 'air is pushing at me' feeling – either relax and slow it down, or hit the ramp button and start again.

As I say, remember, it is you that's making the breathing more difficult, not your machine.

(Should anyone think I'm getting it wrong, feel free to correct me. I'm delivering it as I see it)

[roster]

You said it well. Someone related 20 cm h20 pressure to normal atmospheric pressure. I don't want to find the tables and do the calculation but cpap pressure is a very small fraction of the atmospheric pressure we are already accustomed to.

[DreamStalker]

You said it well. Someone related 20 cm h2o pressure to normal atmospheric pressure. I don't want to find the tables and do the calculation but cpap pressure is a very small fraction of the atmospheric pressure we are already accustomed to.

I think 20 cm H2O is about a 2% increase over "normal" atmospheric pressure.

[Goofproof]

You said it well. Someone related 20 cm h2o pressure to normal atmospheric pressure. I don't want to find the tables and do the calculation but cpap pressure is a very small fraction of the atmospheric pressure we are already accustomed to.

I think 20 cm H2O is about a 2% increase over "normal" atmospheric pressure.

That doesn't speak well for our toughness as humans, if we have to use a ramp at 10 cm, a 1% increase. We almost need a pressurized cabin in our cars when we go on trips. Jim