AHI vs RDI?

[lvillanueva5]

I have an AHI of 1.5 and an RDI of 18.5 and my doctor has diagnosed me with moderate OSA for which I am now on a CPAP. All the information that I've been reading focuses on the AHI and that if it's below 5, it's normal.

Do cpap machines keep track of RDIs? Is that something that will transmit to sleepyhead? (I've been reading the forum post on it.)

I guess, am I really suffering from moderate OSA if my AHI is normal. I'm not 100% happy with the doctor that I'm seeing and I'm worried that maybe he is pushing the CPAP therapy on me when it doesn't need to be.

[AshSF]

Remstar Auto w/ Aflex will track RDI. You can view it in Sleepyhead s/w. You will need to go to Preferences in sleepyhead menu and change the metric from AHI to RDI. It will then display RDI instead of AHI in your stats.

[Crimson Nape]

I'm a newbie too and hadn't known or noticed the RDI designation until you mentioned it. Upon Googling it, I found this definition:

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).

Also Known As: Respiratory Disturbance Index, Apnea-Hypopnea Index or AHI

I went back an looked at my Sleep study report, It had my AHI and RDI as the same number, 86.2. I too would like a better explanation.

My bad! Right after I posted this I came across the actual difference between the two, RDI includes respiratory-effort related arousals (RERAs).

[retired_guy]

I don't see anything in those numbers that would make me say you have "moderate" osa. But sometimes the numbers do not contain all the answers. So let's look to the symptoms. What about snoring? Have the neighbors constructed a sound-proof wall between your houses, and they live a quarter of a mile away? Do your cats move out at night preferring to live at the train station?

Then there's daytime sleepiness. Do you find yourself waking up in a cow pasture just south of Lincoln Nebraska when your original destination was your office in Atlanta? Do your fellow workers make caustic comments about the corn flakes on your nose where you didn't get them all washed off after falling into your breakfast?

Sometimes the apnea therapy is as much about improving quality of sleep, hence quality of life as it is about stopping any specific obstructive apnea.

But I'm suspicious with the numbers you post. So more information would be helpful please.

[zonk]

RDI is always than AHI as it include RERAs plus apnea and hypopnea
RERAs do not meet the scoring criteria of apnea and hypopnea but nevertheless are as worrisome as apnea and hypopnea

By using AHI alone would not qualify you for CPAP under insurance rules but RDI does

Prof Colin E. Sullivan inventor of CPAP siad the following:
Probably the best indicator of SDB, however, is simply the response to continuous positive airway pressure (CPAP) treatment. "It really is a no-brainer," Dr. Sullivan remarked, pointing out that CPAP administration is especially easy with the newer devices that automatically set the appropriate amount of positive pressure.
http://www.apneaboard.com/forums/Thread-...or-Useless

[lvillanueva5]

I don't see anything in those numbers that would make me say you have "moderate" osa. But sometimes the numbers do not contain all the answers. So let's look to the symptoms. What about snoring? Have the neighbors constructed a sound-proof wall between your houses, and they live a quarter of a mile away? Do your cats move out at night preferring to live at the train station?

Then there's daytime sleepiness. Do you find yourself waking up in a cow pasture just south of Lincoln Nebraska when your original destination was your office in Atlanta? Do your fellow workers make caustic comments about the corn flakes on your nose where you didn't get them all washed off after falling into your breakfast?

Sometimes the apnea therapy is as much about improving quality of sleep, hence quality of life as it is about stopping any specific obstructive apnea.

But I'm suspicious with the numbers you post. So more information would be helpful please.

I need to download the sleepyhead software and figure that all out. I have no idea what all my numbers are, but as soon as I do, I'll post it.

[Crimson Nape]

lvillanueva5, The ultimate question is; "Do you feel better when you wake up?"

[lvillanueva5]

lvillanueva5, The ultimate question is; "Do you feel better when you wake up?"

No But again, this is day 7 that I am using the cpap. I didn't have a problem sleeping on my side with the simplus mask, but as soon as I moved to my back, it felt like too much pressure.

I downloaded the sleepyhead app and imported my data. My data is:

RDI .32
Hypopnea .11
Obstuctive Apnea .00
Clear airway Apnea .21
Vibratory Snore .11
Periodic Breathing .00

Is this good?

[Crimson Nape]

I'm envious of your numbers. I'm down to a AHI of 2.8 and walking around like it's a birthday.

[PsychoMike]

LV, it could be that rather than a "pure" apnea, you're more in the upper airway resistive syndrome (UARS) category like me.

In my study, I only had an AHI of 6 which would have placed me in a very mild apnea category. My RDI, on the other hand, was over 50 and considered severe. The issue is that when my airway collapsed (i.e. for an apnea event), my brain was waking up too quickly for it to score the drop in blood oxygen saturation associated with a "real" apnea event....still felt like crap in the morning from not sleeping, but not getting the AHI numbers that would traditionally explain it.

UARS is a form of obstructive sleep breathing, like apneas, but not all docs will diagnose UARS....they just lump it all into OSA and be done with it. An RDI of 18 with an AHI of 1.5, to me at least, suggests moderate UARS, which is real and just as much an issue as OSA. Sure, you don't have an 18 AHI...but for what an RDI of 18 does to your sleep, you may as well have...at its most simple level, the differences are the length of events and what's happening to your blood O2 levels.