Does Respironics calculate AHI the same as ResMed?

[Shaky]

I used Resmed CPAP machines for almost 20 years, but got a Respironics Dreamstation (APAP) last fall. From the research I did prior to deciding on the Dreamstation, I know they use different algorithms to determine how much pressure to use during the night, but I figured they would probably be pretty close to what I was used to.

The one thing I noticed about my data was that my AHI rate was much lower than it had ever been with the Resmed machines. Since switching to the Dreamstation three months ago, my AHI has averaged 1.38. I don't know my exact average on the Resmed machines, but it was almost always between 2.5 and 3.5. I haven't noticed any difference in quality of sleep, and I'm not even sure it would be noticeable when the events were already pretty low.

I guess the Respironics machine could be that much better at reducing apneas and hypopneas, but I'm skeptical. Has anyone switched between the two companies and noticed a similar change in their data?

[Wulfman...]

I used Resmed CPAP machines for almost 20 years, but got a Respironics Dreamstation (APAP) last fall. From the research I did prior to deciding on the Dreamstation, I know they use different algorithms to determine how much pressure to use during the night, but I figured they would probably be pretty close to what I was used to.

The one thing I noticed about my data was that my AHI rate was much lower than it had ever been with the Resmed machines. Since switching to the Dreamstation three months ago, my AHI has averaged 1.38. I don't know my exact average on the Resmed machines, but it was almost always between 2.5 and 3.5. I haven't noticed any difference in quality of sleep, and I'm not even sure it would be noticeable when the events were already pretty low.

I guess the Respironics machine could be that much better at reducing apneas and hypopneas, but I'm skeptical. Has anyone switched between the two companies and noticed a similar change in their data?

To answer the question posed in the Subject line........Probably not.
For one thing, over various periods, a person's AHI and other events can vary. So, unless you could wear the two identically configured machines simultaneously, there would be differences.
Their algorithms are probably somewhat different along with their response times. That could account for differences.
Even in the ResMed machines, the algorithms have changed between the S7/S8 to S9 and (maybe) AirSense 10 machines.

If both machines were configured to identical straight pressure CPAP with no exhale relief, then there would be some comparison of "apples to apples". But, there are still some variations in events over time.

These machines aren't perfect, but if used over extended periods of time, the monitored results can help the users to improve their therapy.


Den

.

[Shaky]

To answer the question posed in the Subject line........Probably not.
For one thing, over various periods, a person's AHI and other events can vary. So, unless you could wear the two identically configured machines simultaneously, there would be differences.
Their algorithms are probably somewhat different along with their response times. That could account for differences.
Even in the ResMed machines, the algorithms have changed between the S7/S8 to S9 and (maybe) AirSense 10 machines.

If both machines were configured to identical straight pressure CPAP with no exhale relief, then there would be some comparison of "apples to apples". But, there are still some variations in events over time.

These machines aren't perfect, but if used over extended periods of time, the monitored results can help the users to improve their therapy.


Den

.

Thanks for the reply.

The min/max on the machines is programmed identically and I have used my old Resmed machine a few nights when travelling, and my AHI was higher those nights. I think the only difference could be actual improvement or a calculation difference.

And yes, I'm a big believer in CPAP/APAP therapy. It's made a big difference in my life.

[LSAT]

Machines have improved over the years....the detection is better now than it was years ago. Even if you went from ResMed to ResMed a
you would find improvements.....Several years ago I was using a ResMed S8 and my AHI ranged from 3-5. When I upgraded to the S9 my AHI immediately dropped to a 1.5-2.5 range. I'm guessing that the AirSense 10 is even more sensitive in detecting events.

[Shaky]

Machines have improved over the years....the detection is better now than it was years ago. Even if you went from ResMed to ResMed a
you would find improvements.....Several years ago I was using a ResMed S8 and my AHI ranged from 3-5. When I upgraded to the S9 my AHI immediately dropped to a 1.5-2.5 range. I'm guessing that the AirSense 10 is even more sensitive in detecting events.

Thanks. I went from an S8 to an Airsense 10, so that makes a lot of sense.

[palerider]

Machines have improved over the years....the detection is better now than it was years ago. Even if you went from ResMed to ResMed a
you would find improvements.....Several years ago I was using a ResMed S8 and my AHI ranged from 3-5. When I upgraded to the S9 my AHI immediately dropped to a 1.5-2.5 range. I'm guessing that the AirSense 10 is even more sensitive in detecting events.

Thanks. I went from an S8 to an Airsense 10, so that makes a lot of sense.

iirc S8 machines were known to overreport hypopneas, resulting in inflated AHI.

[Goofproof]

To answer the question posed in the Subject line........Probably not.
For one thing, over various periods, a person's AHI and other events can vary. So, unless you could wear the two identically configured machines simultaneously, there would be differences.
Their algorithms are probably somewhat different along with their response times. That could account for differences.
Even in the ResMed machines, the algorithms have changed between the S7/S8 to S9 and (maybe) AirSense 10 machines.

If both machines were configured to identical straight pressure CPAP with no exhale relief, then there would be some comparison of "apples to apples". But, there are still some variations in events over time.

These machines aren't perfect, but if used over extended periods of time, the monitored results can help the users to improve their therapy.


Den

.

Thanks for the reply.

The min/max on the machines is programmed identically and I have used my old Resmed machine a few nights when travelling, and my AHI was higher those nights. I think the only difference could be actual improvement or a calculation difference.

And yes, I'm a big believer in CPAP/APAP therapy. It's made a big difference in my life.

Even if you used two like machines the results wouldn't match. Also every time we sleep the results are different. It comes down to the three states of matter theory, usually don't matter is the correct answer. Nothing is set in stone, life is a game of averages. Jim

[D.H.]

Newer machines are better regardless of the make. This is because of more advance design, and also because of the "wear and tear" on an older machine.

BTW, you didn't say exactly what model your old machine is. One poster stated that a particular ResMed model over-reported events.

Obviously, if the newer machine were more sensitive about recording events (without being more sensitive about responding to them) your stats would be worse, not better. Also, Dream Station machines have pretty good filters, so you might be breathing cleaner air. Also, are you using a heated hose? Were you using one before? Can you think of anything else that might be different?

Note that my AHI on the DreamStation Auto (min 13.5 - max 20) is almost always lower than 1. My prior machine was so old that it did not keep stats.

Also, back in September, 2016 I had a few bad nights, so I changed from a fixed 13 to a variable 13.5 to 20. Since then, I've never gone above 2 and rarely go above 1.

Further, note that I changed both filters last week, and don't even seem to go above 0.5!

[LSAT]

Newer machines are better regardless of the make. This is because of more advance design, and also because of the "wear and tear" on an older machine.

BTW, you didn't say exactly what model your old machine is. One poster stated that a particular ResMed model over-reported events.

Obviously, if the newer machine were more sensitive about recording events (without being more sensitive about responding to them) your stats would be worse, not better. Also, Dream Station machines have pretty good filters, so you might be breathing cleaner air. Also, are you using a heated hose? Were you using one before? Can you think of anything else that might be different?

Note that my AHI on the DreamStation Auto (min 13.5 - max 20) is almost always lower than 1. My prior machine was so old that it did not keep stats.

Also, back in September, 2016 I had a few bad nights, so I changed from a fixed 13 to a variable 13.5 to 20. Since then, I've never gone above 2 and rarely go above 1.


Further, note that I changed both filters last week, and don't even seem to go above 0.5!

He said he had a ResMed S8