The Impact of Leaks

I’ve often wondered why I should think or worry about leaks if my AHI was around 1.0 or so. At last night’s lab sleep test, in a conversation with the generally unhelpful respiratory therapist, something she said while admonishing me for changing my own Cpap settings, made me think that maybe leaks might impact the AHI results. My question here is, do leaks affect the results?

Certainly I would expect that being awake for quite a while would also “dilute” the AHI simply because one would presumably have no events during that time.

Phil

pdeli wrote:I’ve often wondered why I should think or worry about leaks if my AHI was around 1.0 or so. At last night’s lab sleep test, in a conversation with the generally unhelpful respiratory therapist, something she said while admonishing me for changing my own Cpap settings, made me think that maybe leaks might impact the AHI results. My question here is, do leaks affect the results?

Certainly I would expect that being awake for quite a while would also “dilute” the AHI simply because one would presumably have no events during that time.

Phil

Hi Phil,

If you have excess leaks a majority of the night, it impacts therapy because the machine can't adequately tell when you are having breathing events. Someone will come along who can provide a better explanation but at least I thought I would respond to your question since the answer is yes.

Regarding the unhelpful RT, the one who worked with my former sleep doc essentially said because I changed my own settings, it caused my problems with pap therapy. That is funny because the sleep doc alway noted that my apneas were well controlled.

Anyway, admonishing patients for changing the settings must be part of the training of many RTs.

The problem with leaks...big leaks over the large leak red line in the sand...is that we don't know if that nice low AHI is low because no apnea events happened or because the machine was clueless as to the apnea events happening because the leaks were so bad it couldn't sense what was maybe going on.

Small leaks the machine can compensate for and we can trust the data that is delivered.
Large leaks...well it depends on just how large and how long they lasted as to whether it makes the data unreliable or not. A small amount of time in large leak isn't going to invalidate the rest of the night's data and is unlikely to impact the AHI all that much. Now half the night in a huge large leak means that the validity of the data comes under scrutiny.

For the Respironics machines...leaks over 100 l/min will impact the machines ability to sense and record.
So a person could still probably rely on the data with large leaks in the 80 to 90 L/min range.
For ResMed machines...leaks over 35 L/min will make the machine pretty much clueless. I found that for leaks between the magic 24 L/min and 30 L/min range didn't seem to impact the data all that much.
Between 30 and 35 the machine started having trouble identifying what kind of apnea event I was having and I got a lot of "unknown apneas" flagged. Over 35 L/min and I got a big blank space where immediately before I was having "unknowns" and I suspect I was still having them but the machine was clueless.

So there is a little wiggle room when it comes to large leaks beyond the line in the sand for large leak territory before things go completely to hell. I still wouldn't want to be up there for very long but I don't worry about short infrequent excursions into really big leak territory as long as I sleep well.

What I do is just look at the time spent in large leak and how into large leak territory I went.
10 minutes out of 7 or 8 hours isn't going to impact much of anything all that much.
Now half the night is a totally different story if someone is deep into large leak territory.

pdeli wrote:My question here is, do leaks affect the results?

Philosophical answer: "It depends on whether the CPAP loop is able to maintain the therapeutic pressure."

pdeli wrote:I’ve often wondered why I should think or worry about leaks if my AHI was around 1.0 or so. At last night’s lab sleep test, in a conversation with the generally unhelpful respiratory therapist, something she said while admonishing me for changing my own Cpap settings, made me think that maybe leaks might impact the AHI results. My question here is, do leaks affect the results?

Certainly I would expect that being awake for quite a while would also “dilute” the AHI simply because one would presumably have no events during that time.

Phil

Good question. Also, what I'd like to know is how mouth breathing affects AHI and OSA in general. It seems if you are mouth breathing, the airway is open unless the blockage is below the uvula?

Too tall wrote:

pdeli wrote:I’ve often wondered why I should think or worry about leaks if my AHI was around 1.0 or so. At last night’s lab sleep test, in a conversation with the generally unhelpful respiratory therapist, something she said while admonishing me for changing my own Cpap settings, made me think that maybe leaks might impact the AHI results. My question here is, do leaks affect the results?

Certainly I would expect that being awake for quite a while would also “dilute” the AHI simply because one would presumably have no events during that time.

Phil

Good question. Also, what I'd like to know is how mouth breathing affects AHI and OSA in general. It seems if you are mouth breathing, the airway is open unless the blockage is below the uvula?

If the user wears a full face mask, the answer is......"not at all". If the user wears a nasal-type mask, the answer could be quite different........from "somewhat" to "significantly".
In theory, if you're mouth-breathing, you're still "breathing". However, the mouth-breathing can/will nullify the therapy and collected data with a nasal-type mask (without taping or some other way of keeping the mouth shut).
If mouth-breathing results in a circumstance like the tongue falling back into the throat and stopping the airflow, then it's likely that apneas will result if it's 10 seconds or longer.

Sort of like saying......."It depends on what the definition of IS is". (in this case it's "mouth-breathing")


Den

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pdeli wrote:I’ve often wondered why I should think or worry about leaks if my AHI was around 1.0 or so. At last night’s lab sleep test, in a conversation with the generally unhelpful respiratory therapist, something she said while admonishing me for changing my own Cpap settings, made me think that maybe leaks might impact the AHI results. My question here is, do leaks affect the results?

Certainly I would expect that being awake for quite a while would also “dilute” the AHI simply because one would presumably have no events during that time.

Phil

Phil,

Remind her whose therapy it is.
She's not the one sleeping with YOUR equipment all night, every night.


Den

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Pugsy,

By “red line” I’m thinking that you mean the Sleepyhead LL red line. In looking back on SH I see that my leaks mostly spike and they run between .15 hours to .45 hours. Sometimes none at all. I’m guessing that most leaks may be times when I lift the mask to re-adjust it.

Interestingly enough, the RT last night said that my mask leak was around "4" (while getting set up), which was OK, “but we don’t want to go above 6” whatever that means.

BTW, although the RT wanted to know “who told you to do that?” about my machine myself, I replied “Oh I just figured it out.” Actually it was one of the sleep docs who first suggested that I go online for the info, but last night I had decided to be as unhelpful as she was. Efficient, knowledgeable, hyper-focused, but inflexible and unhelpful.

The doc;s also didn’t care that I used tape on my mouth either, although I no longer need to do that.

Phil

Wulfman... wrote:

Too tall wrote:

pdeli wrote:I’ve often wondered why I should think or worry about leaks if my AHI was around 1.0 or so. At last night’s lab sleep test, in a conversation with the generally unhelpful respiratory therapist, something she said while admonishing me for changing my own Cpap settings, made me think that maybe leaks might impact the AHI results. My question here is, do leaks affect the results?

Certainly I would expect that being awake for quite a while would also “dilute” the AHI simply because one would presumably have no events during that time.

Phil

Good question. Also, what I'd like to know is how mouth breathing affects AHI and OSA in general. It seems if you are mouth breathing, the airway is open unless the blockage is below the uvula?

If the user wears a full face mask, the answer is......"not at all". If the user wears a nasal-type mask, the answer could be quite different........from "somewhat" to "significantly".
In theory, if you're mouth-breathing, you're still "breathing". However, the mouth-breathing can/will nullify the therapy and collected data with a nasal-type mask (without taping or some other way of keeping the mouth shut).
If mouth-breathing results in a circumstance like the tongue falling back into the throat and stopping the airflow, then it's likely that apneas will result if it's 10 seconds or longer.

Sort of like saying......."It depends on what the definition of IS is". (in this case it's "mouth-breathing")


Den

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Yea, Thanks. About the only thing that works for me is tape. Chin straps are uncomfortable and don't usually work completely. This is my biggest issue.

I totally agree on the chin strap, and I’ve used the mouth tape routine for quite a while.
It’s interesting what we can actually adjust to however.

At one time I thought I absolutely needed a wrist watch, and then mine broke. Guess I didn’t need that after all. Now I’m trying to get used to one of those Wrist Activity Trackers, and it’s a PIA.

More to the subject here, taping my mouth worked for a while. Then as time passed, the tape would start to split open during the night or move off of my mouth. Then the tape would somehow come completely off during the night and ended up somewhere on the floor or in the bedding.

And then I noticed that even during the day, my tongue always seem to rest forward on the roof of my mouth, so I stopped using tape. That was maybe 6 months ago, and I believe my mouth is pretty much closed all night and my tongue seems to stay put up top and forward. The machine says “no large leaks”, but it has always said that. Sleepyhead only indicates occasional brief spikes, so I’m thinking all is well. Except now AHI is just a little higher, and I’m still much more tired than I think I should be.

Still waiting for the results of a sleep test earlier this week.

Phil

Yea, When smart phones came about, I ditched the watch and didn't miss it. I use an app called, "Map My Walk". I walk every other day and I use it to log miles, time and GPS route. It has the ability to plug Oximeter and heart rate into it but I don't do any of that. I did walk with my Oximeter a few times and it scared me how high my heart rate was getting. I was walking with a younger guy who pushed me to keep up. We walk for 1 hour and shoot for 4 mph but usually get 3.7. My walk friend has a Garmin wrist watch that's made specifically for walking running etc... Does pretty much the same thing as the app only the pulse rate is there all the time.

I use the tape and it stays in place but lately I'm have like a 30 min session of OSA's. I think my nose is plugging off, Im not sure. Could be rem. Some people cut a small slit in the tape. I've tried that with some success. Still stuggling to get everything right as I'm usually below a 1 AHI when I do. But tht hasn't been the case lately. The 30 mins of OSA's jacks up the total AHI to about 4 or so. I use the cloth 3M tape, it just about pulls the skin off when you remove it.