tidal volume

[cberistain]

I see that tidal volume is shown on the daily OSCAR report .. but I don't know how to determine if the values are within an acceptable range or not..
typically mine are 0,480, 620 & 800.  does the volume of air flow depend on the size of the person, lung capacity, etc?
thanks
Charlie

[Sleeprider]

Normal or ideal tidal volume is based on your sex, height and "ideal weight" and is calculated as 7.0 mL/kg ideal body weight. Obviously there is considerable variation. Your CPAP measures the inspired flow volume from a single breath and reports that in your respiratory statistics. Your Vt falls within what is a normal range. We do not interpret tidal volume or minute vent as reported by the CPAP as a measure of respiratory health because that is something determined in a pulmonary function test (PFT), and too many variables come into play to make that interpretation. Besides, your CPAP is just measuring your Vt during sleep or rest, and that volume increases considerably when you are awake, or especially during exercise. Tidal volume on CPAP will change in response to obstruction, sleep stage, movement and arousals.

We see a lot of variation in tidal volume between individuals, and it is possible to watch changes in tidal volume, inspiration time and respiration rate to help interpret things like airway restriction or the effects of pressure support. I hope this helps with your question. The real answer on matters like lung capacity, rates of flow, and gas exchange should be based on a PFT performed by a professional, and your tidal volume on the CPAP is more useful if you use it to observe departures from normal sleeping volume.

[cberistain]

very informative... thank you,
Charlie