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Tidal Volume Yep I searched but
#21
(12-25-2014, 05:46 PM)PaytonA Wrote:
(12-25-2014, 03:50 PM)Kadenz Wrote: This exchange of posts sounds like it's very important, but was beyond my knowledge frontier (or, in plain language, I didn't quite follow it).

So please excuse what might be a stupid question. Is it better (in some sense & adjusting for size & weight) to breathe quickly or slowly; and deeply or shallowly?

My opinion is that it does not really matter as long as you are getting sufficient oxygen to your lungs. It would seem to me like the minute ventilation (the volume of air that gets to your lungs each minute) is the important thing.

Best Regards,

PaytonA



Many thanks PaytonA - very helpful.

Kadenz

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#22
(12-25-2014, 03:50 PM)Kadenz Wrote: Is it better (in some sense & adjusting for size & weight) to breathe quickly or slowly; and deeply or shallowly?

(12-25-2014, 05:46 PM)PaytonA Wrote: My opinion is that it does not really matter as long as you are getting sufficient oxygen to your lungs. It would seem to me like the minute ventilation (the volume of air that gets to your lungs each minute) is the important thing.

(12-25-2014, 11:38 PM)PaytonA Wrote: The dependence of the correct tidal volume on height and correct weight does not make much sense to me. I would think that the heavier one is the more air is needed to oxygenate all of the tissues and that also takes me back to thinking that minute ventilation is probably more important.

Only a percentage of the air in each breath (in each Tidal Volume) reaches our alveoli and participtes in getting oxygen into our blood.

The percentage of air which does not reach the alveoli is the percentage of air which reaches only the nasal cavity and throat and bronchial tubes, which represent "dead space" as far as breathing is concerned.

A few comments:

1. The more shallowly we breathe, the larger is the proportion of air which stays in the dead space. For example, if we purposely breathe very shallowly, so that the Tidal Volume is smaller than the dead space in our airway, we would feel smothered and would be getting too little oxygen no matter how quickly we breathe these too-shallow breaths, because we would be rebreathing the air in our airway rather than breathing deeply enough to bring fresh air into our alveoli. So, in view of this, it can be said that it would be better to breathe deeper breaths more slowly instead of shallower breaths more quickly, even if the Minute Ventilation were to be the same.

2. In the formula given earlier, the expected Tidal Volume is calculated using a person's "ideal weight" which is based only on a person's height. So, essentially, this means the formula uses only our height or skeletal structure, which apparently is a better predictor of airway and lung volumes than weight. When people become overweight, their airway and lung size tend to stay unchanged. Also, I think fat cells do not need ventilation, or not as much as muscles and organs do.

Some types of ventilators target a certain amount of Tidal Volume. In an earlier post I linked to a thread which mentioned that sometimes overweight patients have been severely harmed when hospital staff have set up hospital ventilators to force too large of a Tidal Volume, because mis-trained hospital staff used the patient's actual weight instead of ideal weight when calculating the target Tidal Volume.

3. The ResMed ASV machines use Minute Volume to keep track of how much ventilation the patient needs, and when a patient fails to breathe the machine targets (tries to maintain) 90% of the patient's recent Minute Ventilation. So, clearly, ResMed medical staff agree with PaytonA that Minute Vent is more important than Tidal Volume alone.



Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
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#23
(12-25-2014, 11:38 PM)PaytonA Wrote:
(12-25-2014, 06:58 PM)justMongo Wrote: Rapid breathing will blow off too much CO2. It is called hyperventilation.
That shifts the pH of the blood slightly toward basic;
The pH shift constricts blood vessels and cause dizziness or even fainting.

Hyperventilation can be caused by slower deeper breaths also. I know because I have done that. You are right, Mongo. One needs to keep the correct amount of oxygen entering the lungs so there is probably some sort of correct range for minute ventilation for each person.

The dependence of the correct tidal volume on height and correct weight does not make much sense to me. I would think that the heavier one is the more air is needed to oxygenate all of the tissues and that also takes me back to thinking that minute ventilation is probably more important.

Just my thoughts.

Best Regards,

PaytonA

perhaps you are thinking of hypoventilation? It results in not enough CO2 leaving the blood, and where hyperventilation leads to alkalosis (raise in blood pH), hypoventilation leads to acidosis which is a drop in blood pH. Hypoventilation can lead to dyspnea, which causes a person to feel short of breath or a tight feeling in their chest.

Just a thought, (sorry, Biotechnology tech in training, just learned about respiration and blood pH, lol)
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#24
SOOOOO splain this to my now twisted brain LOL. I never have a tidal volume average over 400. Ever. Sometimes down to 360 average. But my min vent ratio is right down the middle of normal according to anything I find for average adult on the net with much searching.

Resp rate is right down the middle of normal. Actually everything is right down the middle but the stupid tidal volume average.

Wife runs about the same tidal volumes i do and shes much lighter and shorter.

So how does that work that the tidal volume on SH is always low average by 100 Huh but everything else is square in the middle of normal including min vent???? Dont-know Me??? Unsure Software????Thinking-about Im a mutant???Unsure

Aint the machine cuz its same if I use my wifes machine. Color me confused.Oh-jeez

Obviously I aint dead. I feel fine. So what gives????Huh
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#25
are you maybe looking at a median instead of an average?
Dedicated to QALity sleep.
You'll note I am listed as an Advisory Member. I am honored to be listed as such. See the fine print - Advisory Members as a group provide advice and suggestions to Apnea Board administrators and staff concerning Apnea Board operation and administrative policies. Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment.
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#26
Well, you made me look at something I had not paid much attention to. I found a tidal volume average from 540 to 620 and everything in between and a 95% of 1000 to 1160. I guess that's why I float. Smile
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#27
(12-30-2014, 12:14 AM)Ghost1958 Wrote: So how does that work that the tidal volume on SH is always low average by 100 Huh but everything else is square in the middle of normal including min vent???? Dont-know Me??? Unsure Software????Thinking-about Im a mutant???Unsure

Aint the machine cuz its same if I use my wifes machine. Color me confused.Oh-jeez

Obviously I aint dead. I feel fine. So what gives????Huh

I've got it......you are an alien. Laugh-a-lot
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#28
(01-01-2015, 12:30 PM)PaytonA Wrote:
(12-30-2014, 12:14 AM)Ghost1958 Wrote: So how does that work that the tidal volume on SH is always low average by 100 Huh but everything else is square in the middle of normal including min vent???? Dont-know Me??? Unsure Software????Thinking-about Im a mutant???Unsure

Aint the machine cuz its same if I use my wifes machine. Color me confused.Oh-jeez

Obviously I aint dead. I feel fine. So what gives????Huh

I've got it......you are an alien. Laugh-a-lot

You sir I shall report to the I. C. O. E. ( Intergalactic Coalition Of Extraterrestrials) for hate speech and discrimination concerning health during breathing alien atmospheres. Sad

Howd you guess ????Laugh-a-lot



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#29
Just a SWAG.

Seriously it sounds like you are mixing median values and average values which can in some cases give one some weird results.

Best Regards,

PaytonA
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