2L 02, CPAP, Leak Rate & AHI

Slinky · Post by **Slinky** » Fri Feb 09, 2007 7:41 pm

Hmmm, I know what I want to know. I'm just not sure how to phrase the question.

Does there have to be any adjustment to a CPAP (Resmed S8 Elite) currently set at 8 cms w/a Start pressure of 5 cms and EPR of 2 Always On w/no Ramp time when 2L of 02 are added just out of the Humidaire 3i before the mask hose??? Smart Start is turned On.

The mask being used is the Respironics ComfortLite 2 nasal cushion.

What effect, if any, would one expect the 2L of 02 to have on the Leak rate?
What effect, if any, would one expect the 2L of 02 to have on the Pressure?

The 02 concentrator is in an adjoining room. The manual states the 02 should be turned off BEFORE the CPAP is turned off.

Obviously, this is not too convenient to do so when one gets up to go to the bathroom and returns to bed. Nor even when one gets up for the day. The Smart Start is VERY slow to turn off the Elite when the mask is taken off and does give one time to go to the other room to turn the 02 off but what does that do to the Pressure, Leak and AHI data? Out of habit I've just pushed the button to turn the Elite off rather than wait for the Smart Start.

I'm a little uncomfortable w/this 02/Elite "shut off" bit as things are set up now. Sleep doctor and 02 DME both say its nothing to worry about.

Goofproof · Post by **Goofproof** » Fri Feb 09, 2007 8:34 pm

The O2 will not have any effect on anything, O2 added to the stream would just lower the output of the XPAP.

The pressure will remain the same because the XPAP controls it,

One thing you do need and should be supplyed, is a checkvalve to keep the O2 from flowing into the XPAP if it is shut off first. With my type it vents the hose at the HH output, So autostart won't work when using that kind of check valve.

I have thought 2L of O2 was worthless, due to the added air stream of XPAP venting out the mask most of the output, so I cranked mine up to 4L on XPAP, and 2L in the day straight. I questioned the Dr. but he didn't do well in math, and couldn't see why it would make a difference. Jim

dsm · Post by **dsm** » Fri Feb 09, 2007 8:58 pm

Slinky,

Jim has it nailed re the cpap setting the pressure.

I have often wondered how the O2 gets efectively mixed in as the cpap output pressure of 8 or 10 or whatever cms would be pushing back into the oxygen concentrator line.

I assume there is a oneway valve in the O2 concentrator output line (to stop blow back from devices like cpaps) and the other question I would have is how does the O2 concentrator handle the back pressure from the cpap.

I can imagine a venturi effect coupling that might somehow allow the O2 to be sucked into the cpap airflow. ?.

Question to Jim, does the O2 concentrator deliver its supply under a set pressure ?

Interesting challenges

DSM

Slinky · Post by **Slinky** » Fri Feb 09, 2007 10:22 pm

Duh. You are asking me questions I don't have the slightest clue about.

The "thingie" they gave me and showed me how to put on, is just a plastic "tube", one end of which fits on the HH and the hose to the mask fits on the other end. In the middle of the plastic "thingie tube" is a small outlet (or nipple, if you prefer) which the tubing from the concentrator slips onto. If I use the Elite w/o 02 it has a little cap to put on the "nipple" outlet for the 02 tubing. I wouldn't call this plastic "thingie tube" a check valve, but what do I know?

Nothing was done to or put on the 02 concentrator. They didn't even bypass or remove the humidifier from the concentrator. Matter of fact they didn't even look at the concentrator or go in the room the concentrator is in.

My concentrator is a DeVillBiss 5 L (Sunrise) and it is set at 2. There is a little "guage", like a ball in a vertical tube that "floats" up to the pressure desired. You just turn a knob to turn the "output" level higher or lower so that the ball "floats" at the line on the vertical tube indicating the level of 02 output.

Slinky · Post by **Slinky** » Fri Feb 09, 2007 10:28 pm

Smart Start "is" working w/the 02 added.

I'm hoping SAG, MattMan or KansasRT will jump in here and can answer our questions. I sure can't answer your questions any better than what I posted above.

Goofproof · Post by **Goofproof** » Sat Feb 10, 2007 11:37 am

dsm wrote:Slinky,

Jim has it nailed re the cpap setting the pressure.

I have often wondered how the O2 gets efectively mixed in as the cpap output pressure of 8 or 10 or whatever cms would be pushing back into the oxygen concentrator line.

I assume there is a oneway valve in the O2 concentrator output line (to stop blow back from devices like cpaps) and the other question I would have is how does the O2 concentrator handle the back pressure from the cpap.

I can imagine a venturi effect coupling that might somehow allow the O2 to be sucked into the cpap airflow. ?.

Question to Jim, does the O2 concentrator deliver its supply under a set pressure ?

Interesting challenges

DSM

I don't have O2 now, but when you are in hospital they have a flow guage hooked up (with a ball that floats in the O2 stream) and a knob to control the flow.

I would say the O2 concentrator pressure is higher than XPAP pressure and the O2 concentrator has a flow regulator built into the unit. I don't think XPAP could be higher than the O2 concentrator could overcome.

My O2 concentrator was smarter than I was, I used a 50 foot O2 line, (The MAX) To keep the unit out of the bedroom. The hose got kinked and formed a restriction, the bells and whistles went off on the O2 concentrator, Not knowing how they worked, I called Lincare. (I thought it had broke down), they had me check the line and I had it trapped under the recliner. Jim

Goofproof · Post by **Goofproof** » Sat Feb 10, 2007 11:47 am

Slinky wrote:Smart Start "is" working w/the 02 added.

I'm hoping SAG, MattMan or KansasRT will jump in here and can answer our questions. I sure can't answer your questions any better than what I posted above.

If the smartstart works with the O2 check valve, it means your O2 check valve doesn't vent the O2 at the valve. The one Lincare gave me does, so autostart won't work, it vents the O2 at the valve, and also vents your breathing pulse. My second valve isn't a valve at all it's just a tap for the O2, it was used in the OR, to hook O2 up to me XPAP, it will start the machine, but it will not protect the XPAP.

If your smartstart works with your O2 connector, you don't have a correct check valve, once the XPAP shuts off the output is blocked to the hose. Jim

Slinky · Post by **Slinky** » Sat Feb 10, 2007 11:51 am

Yeah, well all of a sudden my 02 concentrator wasn't putting out hardly any air no matter how high I turned it. I called my "johnny on the spot" 02 DME and they had a driver out w/in an hour.

Talk about a red-face!!! I didn't have the humidifier bottle on correctly. Duh. I never thought to check that. It "looked" like the cap was screwed on straight.

Oh, how I wish my xPAP DME was a good and as conscientious. Snort. Like that will never happen!

Goofproof · Post by **Goofproof** » Sat Feb 10, 2007 12:11 pm

Slinky wrote: Yeah, well all of a sudden my 02 concentrator wasn't putting out hardly any air no matter how high I turned it. I called my "johnny on the spot" 02 DME and they had a driver out w/in an hour.

Talk about a red-face!!! I didn't have the humidifier bottle on correctly. Duh. I never thought to check that. It "looked" like the cap was screwed on straight.

Oh, how I wish my xPAP DME was a good and as conscientious. Snort. Like that will never happen!

My O2 concentrator at home didn't have a humidifier on it the Hospital line used one, I guess they thought I had toughened up. You should check for that check valve, with it in the mounted position it should block air flow into the HH. (Just blow into the outlet, if air comes out of the connection to the HH, it's not working. Jim

Slinky · Post by **Slinky** » Sat Feb 10, 2007 1:16 pm

That happened several months ago. Long before the 02 was added to the CPAP. In fact, before I started on CPAP. Just sharing an embarrassing moment w/you since you 'fessed up to one.

Goofproof · Post by **Goofproof** » Sat Feb 10, 2007 8:26 pm

I embarrass myself at regular intervals, that's how I get my best exercise. Jim