An Exchange With My Kaiser Doctor

Weezer · Post by **Weezer** » Thu Jan 03, 2008 9:32 pm

I had a question for my doctor which I'm not sure he fully answered.

In short, I did a take-home test with the Vantage and was titrated at 11. Did a follow-up test in the Kaiser lab and the tech titrated me at 6!

Here is my question:

Hi, Dr. xxx. Been using the CPAP at 6 and still struggling with it, but have decided to forego the surgery for now. The machine I'm using is the Resmed Autoset Vantage. Each morning, I monitor my progress and my AHI is significantly higher than it was at the higher pressure. I know you said to basically ignore these numbers, but this is the same machine that Kaiser used for my take-home test, which titrated me at 11. I'm confused. Can you explain the discrepancy? Thanks.

His response:

The autoset is data is based on an algorithm based on resistance (can be affected by leak, etc.). Cpap of 6 should be enough for you based on a manual titration which is always more accurate then an auto reading

Anybody know what to make of this? Is he right? Should I ignore the data I'm getting from the Vantage? And if so, what is up with this machine? I'm baffled.

tomjax · Post by **tomjax** » Thu Jan 03, 2008 10:22 pm

I would simply adjust my pressure to a range- 4-12 and get a weeks data and when you get the 90 pct number, simply manally set it to that pressure- probably about 11 and get another week or so data with printouts.

If your ahi is down at this pressure, go back and show him the data and ask him why yourAHI is down to, say 1, at the higher pressure than his suggested 6.

Then ask him why he thinks a lab titrated is more accurate than an APAP generated number.

Be prepared for more BS, which is what you got the last visit.

Slinky · Post by **Slinky** » Thu Jan 03, 2008 10:30 pm

Well, first off, did you feel better at 11 cms of pressure than you are doing at 6 cms of pressure?

Are you still using a Vantage or did they drop you down to a Resmed S8 Elite w/EPR straight CPAP?

And, no, you don't always get a more accurate titration w/an in-lab study. Too much depends on how experience the tech is and how comfortable you were sleeping in strange surroundings all wired up vs a titration over multiple nights in the comfort of your own bed and surroundings. How much experience you had w/the mask(s) you used during both the in-lab and home auto titrations also enters strongly into it.

What you may be running into, tho, is, if you are running in straight CPAP mode, EPR may be turned off or maybe turned too high. EPR does not work in auto mode on the Resmeds. Using EPR reduces the LED reported pressure because you are at a lower pressure than your set pressure each time you exhale.

Did you use the Settling option whilst in auto mode? That reduces the reported pressure. Did or are you using Ramp in straight CPAP mode? That can also reduce the reported pressure.

Mask leak also affects the reported pressure. The xPAP has to produce more pressure to compensate for the high leak rate.

In addition, the pressure reported on the LED screen is the pressure AT OR BELOW WHICH you spent 95% of the night. Same for the reported Leak rate.

You might do very well at 6 cms of pressure in straight CPAP mode if you turn off the EPR or turn it down to 1 if it is on 3. At 6 cms of pressure and EPR of 3 you are only getting 3 cms of pressure on exhale. At 11 cms of set pressure you would be getting 8 cms of pressure on exhale w/EPR set at 3.

Also, in auto mode if the pressure range is set too wide (many sleep docs make the mistake of ordering the wide open range of 4 cms to 20 cms) it takes the auto PAP too long to build up to the set pressure or to run up the pressure high enough to stop an apnea or hypopnea.

If you still have the Vantage I'd be inclined to use it in auto mode and set the lower pressure at 6 cms and the upper pressure at 11 cms and check my data for a full week to see what the data says AND how I felt.

Ask your sleep doctor what he thinks of that idea. Hopefully he will go along w/you and order that pressure range for a week.

Goofproof · Post by **Goofproof** » Thu Jan 03, 2008 10:32 pm

He sounds like a AFAC Doctor to me. (Quack) Jim

ozij · Post by **ozij** » Thu Jan 03, 2008 11:29 pm

From your September and October letters:

Weezer wrote:With my machine set "wide open" at 4-20, my AHI was consistently higher – over 11. I reset the parameters to 7-15. (My doctor titrated me at 11). Last night, I had it on for over 7 hrs. – and my AHI was 15.6!

My leak rate is low, under .1. And while my AI remains 5 or under, my HI is quite high – over 10.

Weezer wrote: At Kaiser, they send you home with an APAP for one night – but I couldn't fall asleep with it at all

An at home "sleep study" on the Vantage for one night has a great chance of being worthless. And from reaading you other posts I gather you weren't feeling too well with a pressure of 11 either.

Because of the fact that your HI seems to go up the closer you get to 11 (based on this thread viewtopic.php?p=214652&highlight=#214652) I would start out at a 4-7 range.

Based on what you told us of your Vantage one night titration, the discrepancy between that single night and the manual titration does make sense.

With a wide open range on my two week - and more - auto titration done by the lab, my discomfort with the mask and the whole process was sending the pressure high, and they sent me out at a fixed pressure of 7.5 - which was too high. With a different machine and a different RT I was sent home at 4-8, and I gradually raised the lower range. Whenever I check a higher top pressure, I don't sleep as well, nor do I get good numbers.

Your rising HI at higher pressure may be the appearance of flow limitations in response to trouble you have exhaling (see BarryKrakowMD's threads) and the machine may be raising the pressure in response to the flow limitations, something Resmed's algorithm is planned to do. In your case, you may be getting into a vicious cycle that raises the pressure in response to flow limitations.
By narrowing the range, and dropping the top you may avoid that.

If that doesn't work, You shoud also consider the possibility that you may just be one of those people whose breathing the Resmed algorithm doesn't analyse properly, and you may need another machine. GoofyUT, who loved the Resmed as a machine discovered he did much much better with the Respironics algorithm. WillSucceed, and apparently I too, do better with a PB auto than with the Respironics.

Most machines nowaday base their response on sophisticated calculations of your breathing flow, and its changes.

O.

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CPAPopedia Keywords Contained In This Post (Click For Definition): respironics, resmed, Titration, AHI, auto, APAP

Snoredog · Post by **Snoredog** » Fri Jan 04, 2008 2:42 am

My first guess is your doctor is FOS! Use the machine in Auto mode for a while, allow it "room" to work and do its job, set the Maximum up to about 16cm, keep the Minimum up above 6.5 cm, any lower and it won't flush out your exhaled CO2 effectively.

Since you have Kaiser (those cheap bastards) I doubt you have a copy of your PSG, but if you do, look for CA's or MA's on the report, also snoring can cause that machine to drive up pressure, it will chase those to no end.

One thing I've learned about this disorder over the past 7 years, doctors don't know squat about the machines used to treat the disorder much less about algorithm they may use for said treatment, half of them cannot figure out how to log-on to their own computer much less how an algorithm works.

Guest · Post by **Guest** » Fri Jan 04, 2008 7:35 am

Hi Weezer,

I had experienced on the resmed autoset and the algorithm retirated after an hour or so....if you have the software you can see that the AHI graph increases the pressure slowly to reach the peak, then if any no respeonses or detection of AH the autoset restart from ground zero. So, you may experience many peak falls on the AHI graphs. My personal experience tell me that that the algorithm and sensitive is not good enough. Loan another unit like Respronics M-Series Auto Cpap that has vast feature with Humidifier for your trial before committ to any type of cpap. As for the AHI & RDI grahps it tells more and you may want to ask the copy from you doctor. Good luck and you are in the right forum just learn as much as you can.

Mckooi

Weezer · Post by **Weezer** » Sat Jan 05, 2008 12:37 pm

Thanks for all your input.

I'm inclined to think the in-lab sleep test is more accurate than the take-home in that it was done manually by a tech. He showed me my chart and it was amazing to see what an apnea looks like – and how smooth my breathing was on the CPAP.

But one night in the lab is admittedly a very small sample size.

Re: the Vantage. Don't you think it has a tendency to run the pressure up? After all, it can't tell if you're awake or asleep. And might it mistake something else for an apnea? Does it even react to hypoapneas?

As far as the numbers, don't you think the Vantage is awfully sensitive to hypoapneas? I'm inclined to ignore the HI number and focus solely on the AI. But even that seems tricky.

The bottom line is that I'd love to get my AHI under five, but it ain't happening.

The great thing about a pressure of 6 at straight CPAP (with no EPR) is that it's actually comfortable to sleep with it on. I feel like the fluctuating pressure of the Auto wakes me up at night. And the EPR creates a whistling sound in the Swift.

Wulfman · Post by **Wulfman** » Sat Jan 05, 2008 1:27 pm

Weezer,

Based on what I've read, I'd be inclined to think your pressure needs to be up around 11 cm. and not at 6. You may think it's "comfortable" to sleep with, but it doesn't appear to be fully resolving your problem. That doesn't mean that this therapy has to be UNcomfortable, but you'll get used to the increased pressure.

My suggestion would be to re-set it to CPAP mode (if you haven't done so already and so you can use EPR if you like) and start with a pressure of 9 and then work upwards from there as need be.

In short, your doc is an idiot. (or what Snoredog or Goofproof said)

Den

Slinky · Post by **Slinky** » Sat Jan 05, 2008 1:30 pm

There definitely are people who don't do well in auto mode but do well in straight CPAP mode. Even minor changes in pressure can bother some people.

jskinner · Post by **jskinner** » Sat Jan 05, 2008 2:04 pm

Snoredog wrote:One thing I've learned about this disorder over the past 7 years, doctors don't know squat about the machines used to treat the disorder much less about algorithm they may use for said treatment

Amen to that!

RosemaryB · Post by **RosemaryB** » Sat Jan 05, 2008 6:22 pm

jskinner wrote:
Snoredog wrote:One thing I've learned about this disorder over the past 7 years, doctors don't know squat about the machines used to treat the disorder much less about algorithm they may use for said treatment
Amen to that!

Double amen to that. Most of the RT's at the DME's don't know squat etither. A relative I'm helping had an RN at the DME fit her with pillows that were clearly too small. Just a look at this woman's nares and you could plainly see that. She complained about leaking and I was giving her various tips. Then when I was able to see her in person and take a look at the mask, I was really shocked at the incompetence of the one who fitted her mask. No amount of tweaking can take care of leaks if you can see a gap between the nares and the pillows .

At least my doctor's honest. He openly admits I know more about this than he does. He's a GP. He knew enough to send me for a sleep study. He's willing to go over my charts with me and discuss how things are going. A rare doctor.

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CPAPopedia Keywords Contained In This Post (Click For Definition): DME

Weezer · Post by **Weezer** » Sun Jan 06, 2008 12:29 pm

I don't know.

I think I'm gonna stick with 6 for now.

I trust the results of the in-lab sleep study more than the take-home test.

The first test had my AHI at 10.2. The lab had me at 20.1. (Supine @ 33.8, Non-Supine @ 19.0).

That's a big difference.

Slinky · Post by **Slinky** » Sun Jan 06, 2008 12:38 pm

Whatever floats your boat. Keep an eye on your data if you can. As you get acclimated and become more comfortable sleeping w/CPAP you might want to try upping your pressure .5 cms for a week or even a month, and maybe even another .5 for another week or month, etc. until you find you have a great AHI "and" comfortable sleep. And it just may be that that is what your doctor is really up to, getting you compliant and acclimated before upping your pressure in small increments.

Wulfman · Post by **Wulfman** » Sun Jan 06, 2008 12:52 pm

Weezer wrote:I don't know.

I think I'm gonna stick with 6 for now.

I trust the results of the in-lab sleep study more than the take-home test.

The first test had my AHI at 10.2. The lab had me at 20.1. (Supine @ 33.8, Non-Supine @ 19.0).

That's a big difference.

Don't say you haven't been warned.

My one-night sleep study (PSG "in-lab") showed that I needed at least a pressure of 16 and my sleep doctor prescribed a pressure of 18. After I got my machine and tried 18 for less than an hour, I had a feeling he was wrong. I re-set my machine for 10 and used that for almost a year until finally moving up to 12 cm. (mainly to get rid of the snoring).
I'll trust the numbers from my machine(s) on a nightly basis rather then a one-night sleep study and a moron doctor.....

Den