Is it possible to increase overall tidal volume?

[IUsedToSnore]

I seems to be a generally "shallow breather" and my 95% tidal volume is around 360.00 usually (I'm 5'4" and 125 lbs). That seems kinda low from stuff I've read.

Is there a way to increase this through respiratory exercises or general cardio like running? Is this something I should even be concerned about?

[Sleeprider]

I don't agree your tidal volume mL is particularly low, and looking at tidal volume alone is a very incomplete picture. Your respiratory volume is better represented by your minute vent (L/min), and is a product of the tidal volume and respiration rate in breaths per minute. In my experience, efforts to influence tidal volume, usually with pressure support in bilevel therapy, results in suppression of the respiration rate, resulting is no net change in the minute vent. In other words, it is common to see higher tidal volume and lower respiration rate, or lower tidal volume and higher respiraton rate in any individual, result in a canceling out of any meaningful differences. It is possible to increase respiratory drive to increase both tidal volume and respiration rate by actually providing more re-breathed carbon dioxide using an Enhanced Expiratory Rebreathing Space (EERS), but that is not somethine we would suggest to someone with normal respiration and a lack of central apnea events The only control you have with your current machine that might increase tidal volume is the EPR which offers you up to 3-cm of pressure support. It's unlikely to make much of a change. What is your current EPR setting?

[IUsedToSnore]

Thank you for such a complete response. I do have central apnea (that was my diagnosis) and have been playing around with my EPR to try to reduce my flow limits. My current EPR setting is one.

[SarcasticDave94]

If the diagnosis is CA, EPR turned off may be a good idea to lower these. It may be good to post a chart as well. If the CA are responding poorly, the standard CPAP may not be the right machine. It does depend on the data in the sleep study. If these CA events are pre-existing you need the ASV, but let's first see the data before considering things of this nature.

[IUsedToSnore]

Thank you. Here is last two night's data!

[SarcasticDave94]

Not many CA or other events. Tidal Volume doesn't seem too bad, it does get into the 500's as Max. Any areas of discomfort? Events that disrupt sleep? Other things of that nature? Example is that if these bit of CA events are a concern or a disturbance, EPR could be dropped to 0 and see if it helps. I'm guessing exhale comfort may then be compromised a bit though.

I think the bottom line with charts like these is to only adjust things if comfort has been compromised.

[Sleeprider]

You do have random central apnea events and I suspect the suppressed tidal volume is related to being at or near an apneic threshold. To understand this, you have to understand what drives respiration is not the need for oxygen, but the presence of carbon dioxide in the blood stream that subtly changes the blood chemistry, which is picked up by chemoreceptors that in turn tell you to breathe or not. In some sensitive individuals, the increased ventilation from CPAP or bilevel PAP causes a lowering of the normal CO2 level resulting in hypocapnea or hypocarbia (https://www.ncbi.nlm.nih.gov/books/NBK493167/ ) This has a suppressing effect on respiraton and can reslt in central apnea ranging from mild, like yours, or more severe forms that was likely present when your EPR or pressure was higher.

If you're still following this and I haven't driven you off with a technical explanation, just wait, it gets better. In my first response I mentioned EERS. Well, here is the wiki link http://www.apneaboard.com/wiki/index.php...ace_(EERS) EERS is an effective way to maintain a higher carbon dioxide level while providing the PAP therapy that resolves obstructive sleep apnea. This inreases tidal volume and respiratory drive to prevent the variable breathing and central apnea events, and make you more tolerant of pressure and pressure support or EPR. So as I said, we don't recommend this as something to simply increase tidal volume, we do have some members that use this technique to control CA with the side-benefit of improving respiration volume and rate. It is a viable alternative to ASV therapy for complex apnea, but it is not in common use, and it is unlikely your doctor is aware of it. These are pretty big draw-backs to it being adopted as a mainstream therapy approach.

You are managing your CA by limiting EPR or pressure support and using lower pressure, sufficient to control OSA but less than your apneic threshold. Short of moving to EERS or ASV, that is probably the best we can do for now. The good news is that your body will slowly adjust to the increased ventilation and lower CO2 levels of CPAP, and eventually these events will diminish, and a more normal tidal volume return. This is a normal process that just takes time for the body to adjust to its new normal with CPAP.

[SarcasticDave94]

If these CA are going to resolve on their own, I would think we'd see data of their decrease at or before month 3 of machine use.

[IUsedToSnore]

Thank you everyone. I've been using my machine nightly for seven months now. It doesn't seem like those centrals are going to go away....

[SarcasticDave94]

In that case, you should build a case with the Doc. to discuss ASV as maybe idiopathic CA. Idiopathic means unknown cause basically. Even so, CA can only be beaten back consistently with ASV. A step further, best results are with a ResMed AirCurve 10 ASV, unless you need manual timing controls which this does not have.