Difference between RDI, AHI, and sleep/breathing effort?
Question:
"Marshall M. Thomas" wrote: > The Stanford definition of a > hypopnea is an event which: a) lasts for more than 10 seconds, > b) results in a 50% reduction in airflow and c) results in > at least a 3% drop in O2 saturation levels.
I think you have that turned backwards, Marshall. Apnea (full stopping of breathing) of 10 sec. etc., Hypopnea is when you wake without a full apnea event/ before a full apnea event. — Magesteff – "Reality is merely an illusion, albeit a very persistent one." -Albert Einstein
Response:
"Magesteff (Steffeny)" wrote: > "Marshall M. Thomas" wrote: > > The Stanford definition of a > > hypopnea is an event which: a) lasts for more than 10 seconds, > > b) results in a 50% reduction in airflow and c) results in > > at least a 3% drop in O2 saturation levels. > I think you have that turned backwards, Marshall. Apnea (full stopping of > breathing) of 10 sec. etc., Hypopnea is when you wake without a full apnea event/ > before a full apnea event.
No. A hypopnea is essentially labored breathing. The definition above is correct as used by one sleep center. Maybe your sleep center has some other definition. Hypopneas can come and go without ever progressing to a full apnea. /Marshall – Hide quoted text — Show quoted text -> — > Magesteff > – "Reality is merely an illusion, albeit a very persistent one." > -Albert Einstein
Response:
Hi, I’ve been recently diagnosed with moderate obstructive sleep apnea, and when talking with different doctors and others, the terms AHI (Apnea/Hypopnea Index), RDI, (Respiratory Disturbance Index), and the breathing effort numbers all seem to be used interchangeably. I’m confused! On one sleep study, my RDI was 26, but no mention of AHI. On another, the AHI is 21, but no mention of an RDI. The doctors have also mentioned a number for my effort to breathe, (which they say is high), but I’m not sure if it’s part of the other numbers… (A PES test was done as part of the latest study). Are these the same thing? Will be asking the question also at my next doctor visit, but it’s still a few weeks away, and couldn’t find an answer on web searches. Lots more questions for the NG to post also, and thanks in advance for any help you can offer! Annie Sent via Deja.com http://www.deja.com/ Before you buy.
Response:
AHI is Apnea/Hypopnea Index. This terminolgy was proposed by Christian Guilleminault and William Dement in 1973. I don’t know the exact history of the term RDI, Respiratory Disturbance Index. However, I think that it is similar in usage today as the AHI, i.e. AHI ~ RDI. There was some reason why the AHI was proposed, but I’m not real clear on the technical difference between that and RDI. In practical terms, as these terms are used today, 27 years after the AHI proposal, RDI and AHI are the same. If someone can explain the difference, please jump in here. An apnea is where you completely stop breathing. A hypopnea is where you are still breathing, but with reduced airflow and reduced O2 saturation levels. AHI and RDI are essentially the sum of these events normalized on a per hour basis. The exact definition of an "apnea" and a "hypopnea" seems to vary amongst sleep labs. The Stanford definition of a hypopnea is an event which: a) lasts for more than 10 seconds, b) results in a 50% reduction in airflow and c) results in at least a 3% drop in O2 saturation levels. It is quite normal to have some variation in the values of these numbers. AHI/RDI measured at 21 and then measured at 26 is completely within the measurement error band. Essentially they got the same result two times in a row. The PES measurement that you talk about is completely different tban AHI or RDI. This is measure of pressure differential within the throat. The larger the absolute value of this number, the harder your body is working to get air into your lungs. /Marshall mmth…@attglobal.net – Hide quoted text — Show quoted text -kittywam…@my-deja.com wrote: > Hi, > I’ve been recently diagnosed with moderate obstructive sleep apnea, and when > talking with different doctors and others, the terms AHI (Apnea/Hypopnea > Index), RDI, (Respiratory Disturbance Index), and the breathing effort > numbers all seem to be used interchangeably. > I’m confused! > On one sleep study, my RDI was 26, but no mention of AHI. On another, the > AHI is 21, but no mention of an RDI. The doctors have also mentioned a > number for my effort to breathe, (which they say is high), but I’m not sure > if it’s part of the other numbers… (A PES test was done as part of the > latest study). Are these the same thing? > Will be asking the question also at my next doctor visit, but it’s still a > few weeks away, and couldn’t find an answer on web searches. > Lots more questions for the NG to post also, and thanks in advance for any > help you can offer! > Annie > Sent via Deja.com http://www.deja.com/ > Before you buy.
