Average Apnea Duration

mommaw · Post by **mommaw** » Sat May 28, 2005 7:31 am

I just downloaded my data for the week and my daily report for Thursday shows my average apnea duration to be 34 seconds. My question is why would an apnea event last that long? How long does it take the auto to respond and start raising pressure to end the event? I did not notice any dramatic pressure increases for that night. Is 34 seconds a long time? My average duration is usually around 12 seconds.

Thanks
Gilda

Newsgrouper · Post by **Newsgrouper** » Sat May 28, 2005 8:29 am

Mommaw:
Where in the EncorePro does it show length of apneas. I can find the number of apneas but not the duration.

Guest · Post by **Guest** » Sat May 28, 2005 10:18 am

It's in Derek's new MyEncore program. Hopefully due out next week per Derek.

Guest · Post by **Guest** » Mon May 30, 2005 11:08 am

Mommaw I don't have the answer to your question since I don't have Derek program but I thougjt I would kick this back to the top so maybe someone will answer your question. I am curious as to what the answer is.

neversleeps · Post by **neversleeps** » Mon May 30, 2005 10:17 pm

I browsed through some sleep apnea sites on the internet and came across this:

A cessation of breathing must last 10 seconds or more to be called an apnea. Obstructive apnea episodes can last as long as two minutes and are almost always associated with a reduction in the level of oxygen in the blood. When an individual is in the midst of an obstructive sleep apnea episode, as long as sleep continues, the apnea continues. It is only terminated and the victim's life is saved by waking up. This arousal instantly increases the activity of the muscles of the tongue and throat muscles that enlarge the airway. The victim will be able to breathe and to once again fill the lungs with life-giving oxygen. This cycle may be repeated hundreds of times a night while the sufferer has no idea it is happening.

from http://www.sleepquest.com

So, compared to 120 seconds, 34 doesn't seem that long!

neversleeps · Post by **neversleeps** » Mon May 30, 2005 10:38 pm

In response to your question of how long it takes an APAP to respond to an event, I don't know. But within the definition of an APAP on the forum it states:

An AutoPAP differs from a CPAP in that an AutoPAP uses algorithms to sense subtle changes in the user's breathing and deliver only the amount of pressure necessary to keep the airway open.

An AutoPAP automatically varies the pressure to prevent and/or correct sleep disordered breathing events - apneas, hypopneas, air flow restrictions, and snores.
____________________________________________________________
It seems the APAP doesn't just respond, it is also preemptive. My rudimentary understanding is that the particular algorithms used by the given manufacturer determine if/when preventative/corrective action takes place based on how it senses the individual's particular breathing patterns, and there is no set amount of time b4 this occurs.

But I don't know for sure..... anyone ??????

derek · Post by **derek** » Tue May 31, 2005 4:22 am

Gilda,
What the Auto does when it detects an apnea is quite complicated, and is not guaranteed to "cure" it. For example, it has a different strategy if the pressure is below 8 cm than if it is higher (when central apneas are more likely). The concern is apparently not to elevate the pressure too high in case this is a central apnea - and in some cases it reduces the pressure.

In other words, the Auto makes an attempt to stop the apnea, but has limits on what it will do.
derek

neversleeps · Post by **neversleeps** » Tue May 31, 2005 6:07 pm

Ummmmm..... yeah..... That's what I meant to say......

mommaw · Post by **mommaw** » Tue May 31, 2005 9:54 pm

Thanks for all the info. After reading the article neversleeps referenced, I guess 34 seconds is not that bad. It just seems like a long time to not breath. Since my AHI is good, I will not worry. derek, what you said regarding the auto makes sense to me.

Gilda

DTeal · Post by **DTeal** » Sun Jun 26, 2011 5:52 am

A constant pressure machine tries to PREVENT an apnea by maintaining a pressure that splints the airway open.

An auto machine has 2 functions. It tries to INTERVENE during an apnea by increasing pressure to splint the airway, and it also tries to PREDICT an apnea by detecting breathing abnormalities and increase the pressure in anticipation.

I have a Resmed auto machine. It seems slow to intervene as there does not seem to be all that much pressure increase during an apnea. It seems to increase pressure more during the predicting functionality.

During a normal exhalation the flow rate should smoothly increase to a maximum and then smoothly decrease to the end of the exhalation. The predicting functionality seems to work by detecting if the exhalation does not smoothly increase and decrease ie is abnormal and restricted.

Obviously its better to prevent than to intervene, but constant pressure is not as comfortable. Also the predicting functionality has limitations, particularly with small diameter tubes and pillow masks as these have more flow restriction and make measurement of whats happening in your throat more difficult.

Its a comfort/performance trade-off. I suggest increasing the minimum pressure on the auto setting such that its still comfortable and there is less pressure increase needed during an intervention.

deerslayer · Post by **deerslayer** » Sun Jun 26, 2011 7:54 am

mommaw wrote:I just downloaded my data for the week and my daily report for Thursday shows my average apnea duration to be 34 seconds. My question is why would an apnea event last that long? How long does it take the auto to respond and start raising pressure to end the event? I did not notice any dramatic pressure increases for that night. Is 34 seconds a long time? My average duration is usually around 12 seconds.

Thanks
Gilda

hi Gilda
i am no health professional , however if my apnea durations were 34 sec. i would take note. first i would make my pcp aware of this & would want to know what my o2 sats were during these events.
i have not been able to see my episode durations since using the sd card which does not work with James analyzer program .
Please let us know what you find out.
tim

Pugsy · Post by **Pugsy** » Sun Jun 26, 2011 8:51 am

This thread was started in 2005 and Gilda "mommaw" has not posted on this forum since March 09.

Wulfman... · Post by **Wulfman...** » Sun Jun 26, 2011 1:45 pm

DTeal wrote:A constant pressure machine tries to PREVENT an apnea by maintaining a pressure that splints the airway open.

An auto machine has 2 functions. It tries to INTERVENE during an apnea by increasing pressure to splint the airway, and it also tries to PREDICT an apnea by detecting breathing abnormalities and increase the pressure in anticipation.

I have a Resmed auto machine. It seems slow to intervene as there does not seem to be all that much pressure increase during an apnea. It seems to increase pressure more during the predicting functionality.

During a normal exhalation the flow rate should smoothly increase to a maximum and then smoothly decrease to the end of the exhalation. The predicting functionality seems to work by detecting if the exhalation does not smoothly increase and decrease ie is abnormal and restricted.

Obviously its better to prevent than to intervene, but constant pressure is not as comfortable. Also the predicting functionality has limitations, particularly with small diameter tubes and pillow masks as these have more flow restriction and make measurement of whats happening in your throat more difficult.

Its a comfort/performance trade-off. I suggest increasing the minimum pressure on the auto setting such that its still comfortable and there is less pressure increase needed during an intervention.

WRONG!!!

There are NO APAP machines that will attempt to stop an apnea once it's in process. For one thing, it takes at least 10 seconds (minimum duration) for the machine to actually determine whether there is an apnea occurring. By the time it makes that determination, the apnea may be over with. APAPs only raise pressures on Snores or Flow Limitations......not Apneas.

Den

avi123 · Post by **avi123** » Sun Jun 26, 2011 2:25 pm

mommaw wrote:Thanks for all the info. After reading the article neversleeps referenced, I guess 34 seconds is not that bad. It just seems like a long time to not breath. Since my AHI is good, I will not worry. derek, what you said regarding the auto makes sense to me.

Gilda

Gilda, routinly, I have apneas that last almost a full minute. It's either the CPAP supresses them or I get awaken or I sleep thru them. Most of the times sleep thru them.

Here is one obstructive 44 sec long:

IMO, you can have AHI = 0 and be sicker than a dog while another person with AHI = 7 to 15 who feels fine. It has to do with underlying medical conditions. CPAP are not meant to treat medical conditions but only sleep issues.

pollyanna40 · Post by **pollyanna40** » Sun Jun 26, 2011 4:27 pm

Hi,i dont understand all the tecnical stuff,had my mask a 2 wks ,but during my sleep study my results my breathe was holding for 30 seconds plus and the longest was 1min 30 seconds..iv been classed as servere OSA ,i feel no better for wearing the mask! hope fully will do soon x

Average Apnea Duration

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Mask	Humidifier

Additional Comments: Pur~Sleep Oils (Love Them) Aussie Heated Hose, Encore Analyzer, Pad-A-Cheek Guards (Work Great!)

Machine	Mask

Additional Comments: straight cpap 12.20 AHI avg.0.79