2007 Sleep Study

[littlemo]

ok please understand I am a canadian tech here given my input!!!! we under no circumstances put a pt on bi-pap unless they've had a failed CPAP, I know it's different in the states because the insurance companies are paying BUT on what you have told me their is NO WAY your pressure should be this high!!!!

We use something called a hoffstein calculation to determine a pt starting pressure which is usually not far off what the optimal pressure would be on a cpap machine. some may disagree as with anything in the health field, but personally, I do find it helpful. IM me your height/weight/neck circum. and i'll send you back your initial CPAP pressure which is equivalent to the IPAP on the BIPAP!

Mo

[pemoha]

I was diagnosed with sleep apnea in 2001, i was put on cpap, with a pressure of 12. In 2003 results of another sleep study I was put on bipap, pressure of 17/14. Weight gain of about 20 lbs between 2001 and 2003.

[rested gal]

you have a legal right to a copy of the printout from the bi-PAP auto as it is a part of your medical records. Just ask them for a copy.

SAG asked a good question.."did you get the download"... and I agree with Slinky's statement that you have a legal right to a copy of it.

pemoha, if you do go back to the DME to ask for a printout of the download, be SURE to ask for the printout to be the "full details" report. Explain that you don't want just the Summary report. And you don't want just a Trend report.

You want the full details report -- which will contain quite a few pages of graphs called "Sleep Therapy Daily Details" and tables called "Daily Events per Hour."

If the printout they give you of the BiPAP Auto's download consists of only three pages or less, that will not be the Full report.

[SWK]

sometimes when a person is titrated in the lab, they are over titrated. when they get home and use such a high pressure for awhile, studies show they really dont need to be titrated that high. This can be the reasoon the pressure dropped.

i had my first patient the other day come off CPAP for good. She had lost 80 lbs.

I have never changed someone's pressure down before. I have only seen people get worse, until i met the lady who lost the weight.

[littlemo]

HI SWK, I've brought peoples pressure's down as much as 4cm when they've switched from a full face mask to a nasal

[pemoha]

Rested Gal, I got a 11 page report, what are we looking for?

[rested gal]

Rested Gal, I got a 11 page report, what are we looking for?

Peggy, I like to look at the "Daily Details" graph for each night. I don't bother to even glance at the first 3 pages of the report. I go straight to page 4 to start looking at what went on for each individual session.

I look first to see what my AHI was for that night. I want to see the AHI be under 5.0.

Then I look at the leak rate on the graph. I want to see the leak rate be below 40 L/m (Liters per minute.) Since I'm a mouth-breather when I sleep, and I use tape to prevent that, I'm always curious to see if the tape held well and mask stayed in place well. If the leak stayed down where I want it... usually down in the twenties, and no more than mid-thirties. Hybrid mask users would probably see higher rates.

Finally I look at the pressure line to see if it stayed fairly steady or did a lot of climbing. I like to see it stay pretty steady, but I'm not alarmed if it has to move up occasionally. That's what auto-titrating is for...to vary the pressures "as needed." Might need more during the night, or on some nights. Most of the time mine stays rather steady since I have the lower pressure set high enough ( 8 ) that it prevents apneas.

I don't pay any attention to the table that shows "time spent" at pressures and what events sneaked through at those pressures. I look just at the graph itself.

Since I'm always using autopap and BiPAP auto machines, I don't worry about what the "90th" percent pressure says. That's useful if a person needs to get an idea what number they should set for the single pressure of a straight cpap machine.

The 90th percentile number is of interest to doctors and DMEs when they are giving someone an auto-titrating trial with the intention of taking the autopap away in a few weeks and putting the person on straight CPAP at a single pressure. However, I'll always use autopap or BiPAP auto, so that number doesn't matter to me.

[pemoha]

My AHI:
Wed 4.2
Thur 5.2
Fri 3.0
Sat 3.5
Sun 2.4-5.5 (2.4 being a 2 hr nap)

Total AHI 4.1

Leak rate for all 5 days are over 40, in the range of 49 t0 60.

I use a UM full face mask.

[StillAnotherGuest]

Do you have a scanner to post the graph pages? Or alternatively, can you get the actual download from the BiPAP (they could e-mail the file to you).
SAG

[pemoha]

No, scanner, but is there anything that I can read off of the graphs>

[Slinky]

... We use something called a hoffstein calculation to determine a pt starting pressure which is usually not far off what the optimal pressure would be on a cpap machine. some may disagree as with anything in the health field, but personally, I do find it helpful. IM me your height/weight/neck circum. and i'll send you back your initial CPAP pressure which is equivalent to the IPAP on the BIPAP!

As I understand it, LittleMo, the Hoffstein Calculation was studied w/overweight and obese patients. How accurate is it for normal weight individuals?

For instance: I am 5'4", weigh 115 lbs, with a neck circumference of 13" and my sleep evaluation AHI was 23.9. I am on a CPAP w/EPR and will be switching any day now to an AutoPAP.

[StillAnotherGuest]

...is there anything that I can read off of the graphs?

Perhaps, but if you believe that something is askew in your therapy (which is suggested by a couple of posters here already), we're gonna have to look in the places that people haven't looked at yet (or looked at but didn't "see" anything). The BiPAP graphs, as well as the sleep study graphs, will be essential to have any chance of figuring out where you need to be, if, of course, any changes are indeed required.

If you get the *.xml file from the DME for the BiPAP Auto, that'll work. The sleep study stuff'll need to be scanned somehow, maybe try Staples.

... We use something called a hoffstein calculation to determine a pt starting pressure which is usually not far off what the optimal pressure would be on a cpap machine. some may disagree as with anything in the health field, but personally, I do find it helpful.

As I understand it, LittleMo, the Hoffstein Calculation was studied w/overweight and obese patients. How accurate is it for normal weight individuals?

Cpap Pressure Cannot Be Accurately Predicted By The Hoffstein Equation
CHEST, Oct, 1999 by Thomas M Kilkenny, A Gottesman
Purpose: Many companies that administer home sleep studies provide the ordering physician with predicted CPAP pressures based upon the published Hoffstein equation. This equation uses BMI, neck circumference and the apnea-hypopnea index to predict CPAP levels (Ppred = 0.16 x BMI + 0.13 x neck + -0.04 x AHI- 5.12). We have seen many patients who have been started on CPAP according to this method but have failed to improve clinically. We sought to compare CPAP pressures attained via the Hoffstein equation with those pressures derived during formal in-lab titrations.

Methods: A prospective study was conducted that compared the Hoffstein derived CPAP pressure to those actually attained in-lab during either full night or split night studies. All patients had documented evidence of significant sleep apnea (OSA). CPAP was titrated to alleviate all abnormal respiratory events as well as snoring. Data was attained from all patients undergoing nocturnal polysomnography from Oct 1998 to April 1999.

Results: One hundred twenty eight patients had complete data points and were evaluated by this method. The Hoffstein equation correctly predicted CPAP pressures in only 11 out of 128 cases (8.6 %). The pressure derived from the equation was within 2 cm H2O of actual pressure attained in only 56 out the 128 patients (43. 8 %) and varied greater than 4 cm H2O in 40 out of the 128 patients (31.3 %). The actual CPAP pressures attained in-lab deviated from the equation predicted pressure from + 8 cm H2O to -9 cm H2O.

You're right, you can find anything to prove anything.
SAG

[littlemo]

we use the hoffstein as a starting pressure and titrate from there. usually it's not far out. but positional and REM related increases need to be taken into consideration. we find that people that end up needing a higher pressure acclimatize better starting at their Hoffstein rather than wasting time at a lower pressure and spending too much time ramping.
On occasion, I figure out 3 hoffstein's when AHI various from REM and supine.

[rested gal]

pemoha, please look on pages 1 and 3 the Encore Pro printout you were given and let us know what your report says for the areas where I drew red arrows on one of my reports:

Page 1


Page 3


pemoha, your report will have many green blocks on page 1. My example was a download from one night, so that's why it has only one green block.

[pemoha]

Rested Gal, the green bar goes up to pass the 10 at about 13.
Avg 90% Ipap pressure 19.8
Avg 90% Epap pressure 16.9
Avg non-resp apnea/hypopnea index 0.0
Avg Obstr Apnea index 1.7
Avg Hypopnea index 2.3
Avg AHI 4.0
Avg flow limit. index 1.7
Avg Vibra snore index 20.1
Avg max leak 112.0
Avg 90% leak 61.3
Avg leak 54.6
Avg lg leak 0 mins
Are those the numbers you're talking about?