Manometer

Guest · Post by **Guest** » Thu Apr 10, 2014 6:53 pm

Guest wrote:
Guest wrote:
Stevoreno_55 wrote:Well that's what 3 labs told me yesterday; I'm in Mississippi and we always seem to be in last place as well as behind the times.
could that be cuz you asked them about a 2 nite study

fact is if your doc orders a split nite
that is what you will get
a split nite

time to insist to the doc that is what you want
Not necessarily - if the insurance does not cover split night studies and only covers full night diagnostics followed by full night titrations, then fact is your split night could cost you the full price out of pocket, to the tune of several thousands of dollars.
Oh - and also, even if a split night is ordered, if you don't exhibit enough respiratory events to meet criteria to initiate PAP therapy, or if you don't have sufficient sleep time during the first portion of the night, you might not be split anyway. (This is to ensure that the insurance company will pay for your PAP machine as well as to ensure that you are not put on PAP unnecessarily.)

he's on medicare who does approve of the split nites

but why dont you give an example of an insurance plan that wont

and with all that bs about insurance needing time for dx
did you forget this person was dx'd yrs ago and is currently cpap compliant
so there is a danger in allowing this person to go all nite w/o cpap therapy

and you must be aware that any reputable lab would have sop's which would require
that therapy begin when things like low o2, etc are encountered
ask this op what his low o2 level was in his earlier psg's

fact is even medicare allows the dx portion to terminate before 120 min
when the criteria is met

so why would medicare want to pay for 2 nites

stevo i would check on that before you end up with that bill

Stevoreno_55 · Post by **Stevoreno_55** » Sat Apr 12, 2014 1:27 am

What exactly is a "split night" study compared to a "2 night" study? The doctor told me this week when I went to see him and I asked him to write me a Rx for a new CPAP machine; he said he would not agree to do that but he did say he would agree to write me an order for a new sleep study; a new 2 night sleep study since it will soon be 7 years since I had my last 2 night sleep study. He did not mention anything to me about writing an order for a "split night" study.

Stevoreno_55
MS Gulf Coast
04/12/14

Bama Rambler · Post by **Bama Rambler** » Sat Apr 12, 2014 7:47 am

A 2 night study is just what it sounds like. The first night is spent on the sleep study and the second night is spent on pressure titration. Where they figure out what pressure or pressures work for you and then fine tune it.

A split night study is where they spend the first part of the night in sleep study and the second part in titration. So you only spend one night in the lab.

Wulfman... · Post by **Wulfman...** » Sat Apr 12, 2014 4:36 pm

Stevoreno_55 wrote:What exactly is a "split night" study compared to a "2 night" study? The doctor told me this week when I went to see him and I asked him to write me a Rx for a new CPAP machine; he said he would not agree to do that but he did say he would agree to write me an order for a new sleep study; a new 2 night sleep study since it will soon be 7 years since I had my last 2 night sleep study. He did not mention anything to me about writing an order for a "split night" study.

Stevoreno_55
MS Gulf Coast
04/12/14

Sounds like a money-sucking scumbag to me.
If you have your previous prescription (and you should), you could buy a new one from an online seller.......and probably be money ahead on deductibles and co-pays.

Does he have an interest (financial) in the sleep lab?
They make far more money on 2-night studies than on split-night studies.
I had a split-night study, nine years ago. I wouldn't even consider a 2-night one.

Last December, I asked my new GP/PCP to sign a new CPAP prescription that I had filed out (copied from the form on CPAP-dot-COM), and she did......no questions asked. My original sleep doctor had done a horrible job filling out my first one.......but it was good enough to buy equipment and supplies with. I just wanted one that was more accurate and complete, even though I may never need it.

Den

.

Guest · Post by **Guest** » Sat Apr 12, 2014 5:09 pm

Wulfman... wrote:Sounds like a money-sucking scumbag to me.
If you have your previous prescription (and you should), you could buy a new one from an online seller.......and probably be money ahead on deductibles and co-pays.

Does he have an interest (financial) in the sleep lab?
They make far more money on 2-night studies than on split-night studies.
I had a split-night study, nine years ago. I wouldn't even consider a 2-night one.

I couldn't agree more. Also many labs and DMEs will insist you need a new study every 5 yrs. esp if changing over to Medicare. That is not true and is where the money sucking begins.

Fact is, if you have the paperwork and a script from a study you took before being Medicare eligible, they will honor it as long as it meets the Medicare requirements.

So for those who do NOT want to be subject to the dx portion of the study, etc. be forewarned if your doc, lab, or dme starts talking that way that you are part of a money mill operation.

biker · Post by **biker** » Mon Aug 25, 2014 6:00 pm

I'm not seeing how this method tests to ensure the CPAP can deliver the set pressure in the presence of the normal amount of air "leak". This is just measuring the unit's ability to maintain pressure while losing no air whatsoever.

Jay Aitchsee wrote:This sounds pretty easy : viewtopic.php?f=1&t=95316&p=883884&hili ... er#p883884
levman wrote:
If you want to test it, you could rig up a simple home made water manometer. Just tape or rubber band the end of your hose to a centimeter scaled ruler, making sure the end of the hose exactly lines up with zero.

Fill a large glass or pitcher with water. Lower the ruler/hose contraption into the water, making sure to lower it deep enough that the ruler measurement breaking the surface of the water is well larger than your CPAP prescription setting. For example, if your prescription is 10cm, you want to make sure that the 10cm mark (and then some) is submerged.

Now, turn on your CPAP, and SLOWLY start raising the ruler out of the water. The ruler reading at the surface of the water, just when bubbles start to emerge from the hose, is the setting your machine is calibrated to.

I should warn you that the difference between "bubbles start to appear" and "water splashing everywhere" is pretty small, so raise the device out of the water SLOWLY and stop as soon as you see bubbles.

This trick was originally posted by another cpaptalk member, I can't take credit for it, but it's pretty brilliant.

The reason I suggest doing this is because I had a similar problem when I first got my Transcend - I felt like it was blowing me up like a balloon! I was sure that they must have set it wrong. Only they didn't, both the Transcend and my REMstar were reading exactly 10cm. I think these travel machines are just a little funky, maybe it has something to do with the size and type of motor they have to use on such a small device?

At least this way you'll know whether the machine has been set properly.

Minok · Post by **Minok** » Mon Apr 03, 2017 2:20 pm

biker wrote:I'm not seeing how this method tests to ensure the CPAP can deliver the set pressure in the presence of the normal amount of air "leak". This is just measuring the unit's ability to maintain pressure while losing no air whatsoever.

The CPAP machine has internal air bypass(controlled leak) as well, it needs that to maintain the pressure its set to. Otherwise it could cause you harm if it ran too high, or the electric motor would have to stall when it got a blockage.

What you are measuring is the ability of the machine to produce the pressure at the hose end. Yes, what part of that pressure ends up in your body, vs leaks out at the vent at the mask does divide the pressure you receive from off of what the machine puts out, but the machine doesn't know about the masks design. For the purposes of the tests being done its good enough.

palerider · Post by **palerider** » Mon Apr 03, 2017 2:43 pm

Minok wrote:
biker wrote:I'm not seeing how this method tests to ensure the CPAP can deliver the set pressure in the presence of the normal amount of air "leak". This is just measuring the unit's ability to maintain pressure while losing no air whatsoever.

The CPAP machine has internal air bypass(controlled leak) as well, it needs that to maintain the pressure its set to. Otherwise it could cause you harm if it ran too high, or the electric motor would have to stall when it got a blockage.

What you are measuring is the ability of the machine to produce the pressure at the hose end. Yes, what part of that pressure ends up in your body, vs leaks out at the vent at the mask does divide the pressure you receive from off of what the machine puts out, but the machine doesn't know about the masks design. For the purposes of the tests being done its good enough.

No, it doesn't, this is all wrong.

biomed · Post by **biomed** » Fri Sep 13, 2019 11:54 pm

I impatiently built my first quicky, cheapo DIY U-tube manometer a week ago and it was highly underdamped. When hit with a sudden pressure change, like a mouth puff, it overshot 50% and rang for at least a half dozen cycles. Not good for dynamic pressure measurements. I tried the simplest solution of covering the fill end with electrical tape and used a pin hole to provide controlled, slightly-less-than-critical pneumatic damping with about 5% overshoot. 5% wasn't enough to significantly affect observing APAP blower spool-up-or-down.

I was considering hydraulic damping by stuffing small pieces of open-cell foam into the bottom of the U, but if I applied to much damping, it would be a pain fishing out the excess foam.

If I hadn't had so much fun, I could have purchased a nice U-tube manometer for $11.99 on ebay.

I'll have to model the problem in SPICE or look for data on liquid Dirac Delta Functions.

I still have a beautiful, odorific 1964 book "Introduction to Automatic Controls", written by Howard Harrison and John Bollinger. Cost me 25 cents, used, in 1976. After going through the basics, it models a number of ship's hydraulic controls, linear and nonlinear, first using the fluid dynamics model, then the mechanical equivalent, then the electrical equivalent, using Bode, Nyquist and Root Locus plots.

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Additional Comments: Newly diagnosed pressures as of June 05, 2014 are 22cmIPAP and 18cmEPAP; first diagnosed with OSA in 1999.