01-17-2017, 06:17 PM
(This post was last modified: 01-21-2017, 06:45 PM by esaye.)
High WatchPAT numbers compared to CPAP
I've been on CPAP for 1 month and feeling much better throughout the day. My Dr. wanted to make sure my oxygen levels were OK so they sent me home with a WatchPAT for a night.
I wore the WatchPAT and used my CPAP machine and the AHI numbers are very different for the same night.
My CPAP = 2.9 AHI
WatchPAT = 32.5 AHI
Has anyone else seen these type of results? I'm going to the Dr. tomorrow to sort this out.
EsAye
RE: High WatchPAT numbers compared to CPAP
Hi esaye,
WELCOME! to the forum.!
I'm not familiar with the device you mentioned, hang in there for answers to your question, good luck to you with your CPAP therapy.
trish6hundred
RE: High WatchPAT numbers compared to CPAP
I Googled WatchPat.
Per their web site,
Quote:WatchPAT is an FDA-approved portable diagnostic device that uniquely uses finger based physiology and innovative technology to enable simple and accurate Obstructive Sleep Apnea (OSA) testing while avoiding the complexity and discomfort associated with traditional air-flow based systems.
Note: I'm an epidemiologist, not a medical provider.
RE: High WatchPAT numbers compared to CPAP
The WatchPAT iss measuring something a lot different from what your CPAP does in order to determine apneas so it is not surprising to me that there are differences. Another source of potential differences is how hypopneas are scored. There can be a lot of difference in hypopnea scoring from CPAP to CPAP just due to some looseness in the definition. Add those differences to the ones generated by sensing different things and I can see a possibility for major scoring differences. Just my thoughts.
Best Regards,
PaytonA
RE: High WatchPAT numbers compared to CPAP
Just returned from the Dr. and they are recommending a sleep study at at their location since the numbers are dramatically different.
RE: High WatchPAT numbers compared to CPAP
I hope that this is being covered for you by insurance.
RE: High WatchPAT numbers compared to CPAP
From what I can understand on the WatchPat site, it measures apneas and hypopneas by a very indirect method. I'd suggest your CPAP is giving a more accurate report, based on actually measuring your breathing. (Plus the difference in hypopnea definitions mentioned by PaytonA).
Have a look at your SleepyHead output and see if there are disturbances which could be apneas or hypopneas but are not flagged. Examples include events lasting less than 10 seconds, or flow rate reductions not flagged as hypopneas. Your WatchPat could be picking these up and reporting them. I don't know if the WatchPat gives the exact time and duration of each event - if so it would be interesting to do a direct comparison with SleepyHead.
As for the sleep study, I agree with Payton - check your insurance coverage (with the insurance company, not the DME) before agreeing to anything.
RE: High WatchPAT numbers compared to CPAP
This is interesting. I was diagnosed 4 years ago when I was with Kaiser Permanente, and the diagnosis was based on one night with a WatchPAT. No other sleep study then or since. I always wondered if the WP over-reported my events. In the 4 years I've been on CPAP I could count on two hands the total -- Total -- number of obstructive apneas reported by my machine. And occasional but quite infrequent hypopneas. Of course this could mean my machine is doing its job very well. Maybe I'll look into an in-house sleep study...
RE: High WatchPAT numbers compared to CPAP
I have done some looking around to try to figure out what WatchPAT is and how it works. So far I have not been very successful finding out how it works nor how much it costs to buy a unit but I think that I have figured out some more possibility for the large difference in AHI between CPAP and WatchPAT. WatchPAT claims to be able to tell reliably when the user is awake and when the user is asleep. If they can do that accurately and if they count sleep/wake time as awake then there is a lot of room for difference.
The WatchPAT divides the number of apnea events by the actual time asleep. So if you put your CPAP and WatchPAT on and go to bed and then have a hard time getting to sleep and maybe laze in bed for an hour after you have awakened in the morning, the WatchPAT will igmpre this time in its calculation making the AHI look higher than the AHI form the CPAP which uses the time from on to off.
It would be useful to compare data from both in graphical form. One thing that gives me reservations about using PAT (Peripheral Arterial Tone) is that sit is not just an indirect measurement but it it is indirect, several times removed. We shall see..
Best REgards,
PaytonA
