Question about RDI

Just a quick question about RDI for all the veterans out there - what is a high RDI? The RDI from my sleep study was 32 and I'm trying to interpret that result.

Sorry if this is covered in other threads - I searched for "RDI" and after looking through quite a few threads I gave up.

Thanks in advance for the help!

i found it very quickly by simply typing sleep study rdi in my browser.

An index used to assess the severity of sleep apnea based on the total number of complete cessations (apnea) and partial obstructions (hypopnea) of breathing occurring per hour of sleep. These pauses in breathing must last for 10 seconds and are associated with a decrease in oxygenation of the blood. In general, the RDI can be used to classify the severity of disease (mild 5-15, moderate 15-30, and severe greater than 30).

http://en.wikipedia.org/wiki/Respirator ... ance_index

The respiratory disturbance index (RDI) — or respiratory distress Index — is an formula used in reporting polysomnography (sleep study) findings. Like the apnea-hypopnea index (AHI), it reports on respiratory events during sleep, but unlike the AHI, it also includes respiratory-effort related arousals (RERAs).[1] RERAs are arousals from sleep that do not technically meet the definitions of apneas or hypopneas, but do disrupt sleep. They are abrupt transitions from a deeper stage of sleep to a shallower.

A RERA is characterized by increasing respiratory effort for 10 seconds or more leading to an arousal from sleep, but one that does not fulfill the criteria for a hypopnea or apnea. The gold standard for measuring RERAs is esophageal manometry, as recommended by the American Academy of Sleep Medicine (AASM). However, esophageal manometry is uncomfortable for patients and impractical to use in most sleep centers.

Some research studies have found that a high RDI was significantly correlated with excessive daytime sleepiness, and that this correlation was stronger than that for the frequency of oxygen saturation decreases below 85%, but other studies have found only a weak correlation.[2]
Formula

RDI = (RERAs + Hypopneas + apneas) / TST (in hours). That is, RDI means the average number of episodes of apnea, hypopnea, and respiratory event-related arousal per hour of sleep.[3] (TST is "total sleep time".)

Thank you both very much for this. What I'm particularly curious about is what other people who have a high RDI (mine was 32) and a low AHI (mine was 3.7) experience when they go on CPAP machines - do they feel significantly better?

So much of the information I read is focused on AHI that it's hard to evaluate the impact of RDI (I understand AHI is a subset of RDI) on sleep disturbance.

I can't help you with a comparison. I don't think RDI was mentioned in my sleep study...my AHI was over 50 per hour in REM sleep so RDI sort of became a moot point.

Pugsy wrote:I can't help you with a comparison. I don't think RDI was mentioned in my sleep study...my AHI was over 50 per hour in REM sleep so RDI sort of became a moot point.

Wow - you must have been having absolutely terrible sleep before CPAP. I hope you're feeling a lot better now!

Yeah, it was pretty crappy sleep. Oxygen levels dropped to 73% I think it was.
My first symptoms to go away....nocturia and killer morning headaches. Pretty much immediately once I got the pressures tweaked a little. Took me quite a while to get in the habit of getting more than 4 hours of sleep and all that stuff. Never had the brain fog people talk about. It wasn't an overnight total miracle that some people experience. I had other issues that were unrelated to sleep apnea that impacted how I felt. The machine does a great job of fixing the sleep apnea issues. It doesn't do such a good job fixing stuff that messes with our sleep that is unrelated to sleep apnea and there is a ton of stuff out there that messes with the restorative powers of good sleep that are totally unrelated to sleep apnea.

If you have RDI much higher than AHI it means that you have lots of Flow Limitation (synonymous with Upper Airway Resistance (UAR) and RERA). Check "Flow Limitation" in the above search box.

Pugsy wrote:The machine does a great job of fixing the sleep apnea issues. It doesn't do such a good job fixing stuff that messes with our sleep that is unrelated to sleep apnea and there is a ton of stuff out there that messes with the restorative powers of good sleep that are totally unrelated to sleep apnea.

That makes perfect sense, and is unfortunate. So far my CPAP seems to be working well, although I think some of the outflow of air from the mask was drying out my right eye a bit. Also, my friend noticed that I breathed through my mouth at least once during the night because she walked by my room and heard it. From browsing through the forum for the last couple of days it seems like a lot of the work with CPAP is optimizing all of the little details.

avi123 wrote:If you have RDI much higher than AHI it means that you have lots of Flow Limitation (synonymous with Upper Airway Resistance (UAR) and RERA). Check "Flow Limitation" in the above search box.

Thanks a lot - will do!

Still curious if anyone on the forum has a high RDI and low AHI and if so what the effects of using the CPAP have been for them. Thanks in advance!

My AHI never qualified me for insurance coverage per my sleep studies. In my last in-home study, apparently my RDI did.

lazer wrote:In my last in-home study, apparently my RDI did.

That's one definite advantage of a high RDI!

SleeplessInOttawa wrote:

lazer wrote:In my last in-home study, apparently my RDI did.

That's one definite advantage of a high RDI!

True but I barely squeaked in at 5 I believe. I seem to fall more into line with the UARS crowd and disruptive sleep than actual OSA. But I suppose my continued heavy snoring and father (whom also snored and gasped for breath) passing away of a sudden heart attack at age 56 twenty-four years ago would line me up for this developing into OSA at some point if left untreated.

lazer wrote: I seem to fall more into line with the UARS crowd and disruptive sleep than actual OSA.

Have you experienced improvements in energy, mood or other areas after going on the CPAP?