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Request for definitions not yet found in glossaries - 2SleepBetta - 12-11-2015
Please, would one of you experts give me or point me to definitions/meanings for these expressions from a home sleep study diagnostic company? I understand or have found all elements and characters in each expression, but can't do better than guess at the meanings of each expression.
My related sleep-data values are included if you care to comment on significance of the fragmentary information.
Total number of hypopneas (4%): 63
Apnea Max. Dens. Index (>10 Min.): 80.0
RDI(AHI) 4%: 41.6
RDI(AHI) Max Dens. Index (>10 Min.): 80.0
RDI(AHI): 51.6
The study recorded for 355 minutes and 329 minutes of sleep were analyzed. Other reported values, for the same session.
Total number of apneas (obs and cen), 165
Apnea index (obs and cen), 73
Total number of hypopneas, 118
Hypopnea index, 21.5
Central apnea index, 13.3
204 desaturations
O2 level below 88% for 12% of time (39 minutes)
Lowest O2 66%
Aside from the numbers, percentage and inequalities: As I understand RDI includes RERA's but AHI doesn't so what does RDI(AHI) mean? Is it a unique breed of cat or a confused or redundant conflation?
Thanks for considering this request.
RE: Request for definitions not yet found in glossaries - DeepBreathing - 12-11-2015
I don't know what all the numbers mean, but a few are reasonably obvious.
You slept for 329 minutes = 5.48 hours.
Your total apneas were 165. Divide that by 5.48 to give your apnea index AI = 30.09
Your total hypopneas were 118. Divide that by 5.48 to give your hypopnea index HI = 21.52 (which agrees with the report).
Add the AI and HI to get AHI: AHI = AI + HI = 30.09 + 21.52 = 51.61, which is what the report states as your "RDI(AHI)".
An AHI of 51.6 is classed as severe - it's pretty bad but not highly unusual (mine was 62 for instance). The red flag I see is the central apnea index of 13.3. You may have some difficulty getting that down to an acceptable level and might end up with an ASV machine. These are really quite wonderful but very expensive. You will normally go through a progression from CPAP / APAP through bilevel then (if all else fails) ASV.
RE: Request for definitions not yet found in glossaries - justMongo - 12-11-2015
His profile says he's down to about 1. Not bad.
RE: Request for definitions not yet found in glossaries - Sleeprider - 12-11-2015
All of the terms and acronyms are available through the Wiki Link at the top of the page. See List of Acronyms.
RE: Request for definitions not yet found in glossaries - PaulaO2 - 12-11-2015
http://www.apneaboard.com/wiki/index.php?title=Respiratory_disturbance_index
Quote: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. (TST is "total sleep time".)
RE: Request for definitions not yet found in glossaries - 2SleepBetta - 12-12-2015
Wow! Thank you Sleeprider, justMongo, PaulaO2 and DeepBreathing. Great, helpful answers. Answers like those pointers here on the Board that have brought my RDI down from over 50 to about 1. My most beneficial takeaways from the Board--for which my "desaturated" memory can't give credit by name:
1. Mask fit. Paraphrasing one most helpful post I can't find again: Struggling newbies should lie supine with prescribed pressure supplied to cushion, use hand to find and determine feel of just-leak-free cushion-to-face pressure. Apply and adjust straps accordingly to use as baseline for finding fit--a place to begin tiny equal left-right strap adjustments. Get a different mask if this test is painful.
2. If (essential!) sleep software shows a bad trend try to get timely, competent MD help, but, lacking that, make minor adjustments to prescribed pressure. After 6 weeks of rising RDI's using a 7 cmH20 CPAP Rx I got DME supplier help getting a 5-20 APAP Rx. With only slight improvement, I used Board help to change to 7.6-20 pressure range. That change and then leaving the recliner (its back comfort) to sleep on my side in bed have made all the difference. The 95% pressure ranges 10-12, median is about 8, and it rarely goes above 15 cmH2O. My high sleep-test "Centrals" {noted above) are reduced to 3 or 4 in a week--except for a few at start or end of sleep period when I am awake or if a large leak developed.
The only remaining questions from my post--for which I've not found (have overlooked?) answers, after reviewing the Wiki again and not finding answers elsewhere--are centered on how to interpret the items that are preceded by four asterisks:
Total number of hypopneas ****(4%): 63
Apnea ****Max. Dens. Index (>10 Min.): 80.0
RDI(AHI) ****4%: 41.6
RDI(AHI) ****Max Dens. Index (>10 Min.): 80.0.... (if different from use in second item abov)
As PaulaO2 shows, RDI includes RERA. Maybe I'm dense in asking what the term "RDI(AHI)" is intended to convey that distinguishes it from "RDI"? Are the two simply identical in meaning?
In my first readings about CPAP and disturbed sleep, I think I saw the "4%" and "(>10 Min.)" items along the way in some sleep medicine papers, but I was too new to the topic to grasp and retain the meanings....lost back along my CPAP trail to here.
RE: Request for definitions not yet found in glossaries - DeepBreathing - 12-12-2015
(12-11-2015, 08:40 AM)justMongo Wrote: His profile says he's down to about 1. Not bad.
I missed that. So ignore what I said about an ASV - you are obviously doing fine with the Autoset.
RE: Request for definitions not yet found in glossaries - DeepBreathing - 12-12-2015
Quote:In my first readings about CPAP and disturbed sleep, I think I saw the "4%" and "(>10 Min.)" items along the way in some sleep medicine papers, but I was too new to the topic to grasp and retain the meanings....lost back along my CPAP trail to here.
The 4% relates to the oxygen desaturation required to define an hypopnea, which varies according to which particular protocol is applied (ie some use 3%, some use 4%). I'm not an expert in this, but there is a discussion here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2635578/
Regarding the 10 minutes, I am guessing that this refers to clusters of events. They would look at the worst clusters, see how many events you had in 10 minutes then convert that to an hourly rate to get the maximum density index. Perhaps somebody could confirm my interpretation?
RE: Request for definitions not yet found in glossaries - vsheline - 12-12-2015
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(12-12-2015, 05:11 AM)DeepBreathing Wrote: Regarding the 10 minutes, I am guessing that this refers to clusters of events. They would look at the worst clusters, see how many events you had in 10 minutes then convert that to an hourly rate to get the maximum density index. Perhaps somebody could confirm my interpretation?
I would guess it means that not less than a 10 minute period should be used when calculating the "max density" of the events. In other words, if a cluster of 10 apneas were spread out across 5 minutes and no other events occurred during a total of 5 hours of sleep, the Apnea Index was 10 apneas / 5 hrs = 2 apneas per hour and the max density of these events would have been 60 per hour, because 10 divided by one sixth of an hour is 60. I think if the 10 apneas in 5 hrs of sleep had been spread out across 15 minutes the Apnea Index would be still be 2 but the max density of these events would be 40, because 10 divided by a quarter of an hour is 40.
RE: Request for definitions not yet found in glossaries - PaulaO2 - 12-12-2015
RDI and AHI are not the same thing. RDI includes all events that cause arousals from sleep. AHI only includes events (central, obstructive, and hypopnea) that last 10 seconds or longer.