Hello Guest, Welcome to Apnea Board !
As a guest, you are limited to certain areas of the board and there are some features you can't use.
To post a message, you must create a free account using a valid email address.

or Create an Account


New Posts   Today's Posts

CAHI [How to determine the number of Central Hypopneas]
#1
CAHI [How to determine the number of Central Hypopneas]
I need to calculate CAHI and determine the number of Central Hypopneas. Is that something OSCAR can tell me?
Post Reply Post Reply



Donate to Apnea Board  
#2
RE: CAHI
Yes. As well as total AHI, OSCAR provides a breakdown of CA, OA, hypopnea, and RERA events per hour and shows each event flag chart.
Download OSCAR

Organize Charts
Attaching Charts

Mask Primer
Soft Cervical Collar

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.

Post Reply Post Reply
#3
RE: CAHI
I need to know Central Hypopneas. I only see hyponeas in OSCAR.
Post Reply Post Reply
#4
RE: CAHI
Central Hypopneas are not scored by vendors so OSCAR does not report them.
Fred Bonjour - Project Manager and Lead Tester for OSCAR - Open Source CPAP Analysis Reporter 
OSCAR

Download OSCAR
New to Apnea? Helpful tips to ensure success
Soft Cervical Collar
Mask Primer
Dealing with a DME
Organize Charts
Attaching Charts

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
Post Reply Post Reply



Donate to Apnea Board  
#5
RE: CAHI
Please Bonjour, can you tell me how I determine my CAHI number, for the purpose of justifying an ASV?
Post Reply Post Reply
#6
RE: CAHI
it's a great question. I'd like to know the answer too. the machine doesn't distinguish obstructive from central hypopnea. the cpap industry came up in response to oa. much less is known about ca. I suspect the best you can do is use your ca index unless you can figure out how to identify a central hypopnea in your flow and show some examples to your provider. if you do figure it out, please share. some folks seem to be able to identify central apnea in the flow rate graph but as often as I've asked, no one has explained how.

edit: in taking your interests / concerns to your provider, emphasize how you feel. it's my understanding a doc can work around some strict rules or protocols with additional factors like "the patient continues to feel awful".
Post Reply Post Reply
#7
RE: CAHI
It is very difficult to easily differentiate a central hypopnea from an obstructive one, however if you look at the events individually and can interpret whether there is flow limitation associated with the event, then hypopnea events with flow limitations or that have irregular large breaths before the event will generally be obstructive or related to sleep transition. Hypopnea that occurs cyclically without flow limitation is likely to be central. Everything else is "not determined".
Sleeprider
Apnea Board Moderator
www.ApneaBoard.com

____________________________________________
Download OSCAR Software
Soft Cervical Collar
Optimizing Therapy
Organize your OSCAR Charts
Attaching Files

How To Deal With Equipment Supplier


INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
Post Reply Post Reply



Donate to Apnea Board  
#8
RE: CAHI [How to determine the number of Central Hypopneas]
My CPAP reports in Clinical Mode AHI, Total AI, and Central AI.  The Clinical Setup manual for the machine discusses a mechanism for identifying an event as a Central event.  It involves imposing a small oscillation in the pressure setting during the last portion of the suspected apnea event.  The resulting pressure changes indicate whether or not the air passage is open.  If not, the event is obstructive.  If open, then the event is classified as a central event.  This detection system seems reasonable to me.  But since this is my first post to this board and since I'm responding to Croweater's original question, I offer this information somewhat tentatively.  Even in the form of a question.  Is this technique NOT a valid way to distinguish between obstructive and central events.    

Then I have my own question:  Can I assume that the Central AI events reported are part of the AHI and/or Total AI.  I observe that for my case, the number of Central AI events is almost as large as, but never larger than, the AHI or Total AI.  Also, I observe that AHI is sometimes just slightly larger than Total AI.  That doesn't make sense to me as the word Total means for me every event is counted.  I want to understand these numbers because I would like to know if most of my events are indeed central implying that my treatment is working and keeping the number of obstructive events below 5.  If I can do the simple subtraction: AHI - Central AI = obstructive apenea hypopnea events, then I'm in pretty good shape with my treatment.  

Before suggesting to me to download Oscar, I'm in the process of getting set up to do that.  My CPAP was supplied without a memory card. My nightly data is supplied to an online account over WiFi connection, but only in a very limited format.  Only recently have I learned that there is a great deal more information to be had from the machine using the Clinical Mode and stillm more with a SD Memory Card. I'm getting said card and the accessory to adapt it to my computer and will begin using OSCAR as soon as I accumulate and transfer some data.  I'm excited to see just how much information I can retrieve.   Smile
Post Reply Post Reply
#9
RE: CAHI [How to determine the number of Central Hypopneas]
G'day sherwoga. Welcome to Apnea Board.

The pressure oscillation you described is used on some Resmed machines to determine if an apnea is central or obstructive. It's called the Focal Oscillation Technique (FOT). It works with apneas but not with hypopneas. I think the only ways to classify an hypopnea are 1) look at the waveform and see what's happening (takes an experienced eye), and 2) have a sleep test that specifically has a chest strap to determine breathing effort and is calibrated to report central v obstructive hypopneas.

Quote:Can I assume that the Central AI events reported are part of the AHI and/or Total AI.

Yes.

Quote: I observe that for my case, the number of Central AI events is almost as large as, but never larger than, the AHI or Total AI. Also, I observe that AHI is sometimes just slightly larger than Total AI. That doesn't make sense to me as the word Total means for me every event is counted. I want to understand these numbers because I would like to know if most of my events are indeed central implying that my treatment is working and keeping the number of obstructive events below 5. If I can do the simple subtraction: AHI - Central AI = obstructive apenea hypopnea events, then I'm in pretty good shape with my treatment.

AHI is the sum of apnea index (both obstructive and central) plus the hypopnea index (again, central and obstructive, though the machine doesn't differentiate). So yes the AHI will always be the same as or larger than the AI. It will in fact be the sum of AI + HI. If the central apnea index is nearly as large as the AI or AHI that means you're mainly having central events. Once we see your charts we'll have a better basis of discussion.

Quote:I want to understand these numbers because I would like to know if most of my events are indeed central implying that my treatment is working and keeping the number of obstructive events below 5. If I can do the simple subtraction: AHI - Central AI = obstructive apenea hypopnea events, then I'm in pretty good shape with my treatment.

I think this is a false premise. Central apneas are still apneas. You stop breathing for ten seconds or more. They put stress on your body and heart. You can't just exclude them from consideration and say that because your obstructives are under control then everything is hunky dory.

Can I suggest you start your own thread when you post your charts, so that this one doesn't go too far off topic? Thanks.
DeepBreathing
Apnea Board Moderator
www.ApneaBoard.com


Bed

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
Post Reply Post Reply
#10
RE: CAHI [How to determine the number of Central Hypopneas]
Will make this my last entry in this thread.  I felt it was pertainent to Croweater's thread because several entries seemed to indicate that it is not possible to distinguish obstructive and central events.  That contradicted both how I interpreted my Clinician manual and, now your confirmation of that interpretation.  Adding the questions was more or less an afterthought.  Sorry to create confusion. I do understand the value of the guideline you suggest.   

Your point about stress on my body is well noted.  I guess where my new thread will take up will be a discussion of what can be done to treat central events.  If my treatment is minimizing obstructive events, then where do I go from here?  You don't need to answer now.  I'll start a thread of my own after my thoughts mature a bit more on this subject.  

In the meantime, thanks for the answers you have provided.
Post Reply Post Reply



Donate to Apnea Board  


Possibly Related Threads...
Thread Author Replies Views Last Post
  Central Sleep Apnea Treated But Still Feeling Bad Chequebook 20 412 Yesterday, 12:16 PM
Last Post: 70sSanO
Question [Diagnosis] Do you have central sleep apnea? DeepBreathing 19 840 12-02-2019, 04:31 PM
Last Post: Osiris357
Question Hypopneas Dogjudge 1 144 12-01-2019, 06:41 PM
Last Post: OpalRose
  New CPAP User ready to quit - Central Apnea, ASV tntfrahm 54 1,622 11-25-2019, 02:03 AM
Last Post: jaswilliams
Ohmy Help refining CPAP settings to control Obstructive Events and Central Events/Are Cent sherwoga 44 976 11-21-2019, 10:27 PM
Last Post: bonjour
  [CPAP] Trying to identify whether these are real central apneas dogfish1977 22 395 11-20-2019, 09:13 PM
Last Post: SarcasticDave94
  Still central apnea after using CPAP for 3 weeks kevinpz 4 165 11-17-2019, 01:15 PM
Last Post: Sleeprider


New Posts   Today's Posts






About Apnea Board

Apnea Board is an educational web site designed to empower Sleep Apnea patients.