Questions on minute ventilation and tidal volume

General Discussion on any topic relating to CPAP and/or Sleep Apnea.
nanoni
Posts: 1
Joined: Mon Jul 13, 2015 2:30 am

Questions on minute ventilation and tidal volume

Post by nanoni » Thu Jul 30, 2015 12:52 pm

Dear Cpap community,

I am new here, but have already gained an incredible amount of information from this forum. So, thank you all for that. I have a personal question, for which I hope you guys have an answer.
Let me outline my story shortly. I am a 30 year old sporty female, 67kg, 172cm. Since approximately one year, I have been annoyed by episodes of extreme lack of energy. Several visits to the doctor did not lead to anything. Then, my boyfriend noticed some apneas. Since my mother suffered from apnea and had jaw surgery, I thought this might be my problem as well. We both have a rather small jaw. Anyhow, I got an appointment with a ENT specialist, but not sooner than three weeks later. Luckily, I found a used affordable cpap machine, the Resmed S9 with humidifier. Which I have used for a week now to gather data.
In six nights I only got one obstructive event and two hypapnea events. However, there is something else in the data that concerns me. My median tidal volume is 240ml, 95% is 300ml. I read that 500ml is normal for a female. Also, my median minute ventilation is 4.3L/m, 95% is 5.6. I read that between 5 and 8 is normal. I experimented a bit with the pressure, varying the min between 4 and 6 and the max between 6 and 8, but this did not seem to effect the median and 95% values. I had no leak.
Do you think that these values are significantly low? And, is the data reliable?

I would be very grateful for some insight!

Best, Nanoni

McSleepy
Posts: 454
Joined: Fri Nov 26, 2010 10:32 pm
Location: USA

Re: Questions on minute ventilation and tidal volume

Post by McSleepy » Thu Jul 30, 2015 9:58 pm

I wouldn't worry about it; certainly not for the short time until you can see a doctor. My median tidal volume is around 500 mL and minute ventilation - 7 L/min, and I am a large male, with vital volume (lungs) way above the average (according to the military committees that examined me year after year). Diagnosing yourself and finding your correct pressures is a daunting task for someone who's just starting; but your pressures do seem low. It's still very likely that you do not have SA, but please wait for the visit and possible sleep study. I wish you all the best.

McSleepy

_________________
Machine: AirCurve™ 10 VAuto BiLevel Machine with HumidAir™ Heated Humidifier
Additional Comments: Previous machine: ResMed S9 VPAP Auto 25 BiLevel. Mask: Breeze with dilator pillows. Software: ResScan ver. 5.1
ResMed AirCurve 10 VAuto; Puritan-Bennett Breeze nasal pillow mask; healthy, active, middle-aged man; tall, athletic build; stomach sleeper; on CPAP since 2003; lives @ 5000 ft; surgically-corrected deviated septum and turbinates; regular nasal washes

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kaiasgram
Posts: 3568
Joined: Sat Jun 02, 2012 2:08 pm
Location: Northern California

Re: Questions on minute ventilation and tidal volume

Post by kaiasgram » Thu Jul 30, 2015 10:43 pm

McSleepy wrote: It's still very likely that you do not have SA, but please wait for the visit and possible sleep study.
I would not draw that conclusion. OP is reporting very few events while she is using the machine. Even at low pressures there is treatment happening.

_________________
Machine: AirSense 10 AutoSet with Heated Humidifer + Aifit N30i Nasal Mask Bundle
Mask: Aloha Nasal Pillow CPAP Mask with Headgear
Additional Comments: SleepyHead-now-OSCAR software on Mac OSX Ventura

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Sir NoddinOff
Posts: 4190
Joined: Mon May 14, 2012 5:30 pm
Location: California

Re: Questions on minute ventilation and tidal volume

Post by Sir NoddinOff » Sun Aug 02, 2015 10:12 am

There has been a lot of back and forth discussion on that topic here at CPAPtalk. To check out those threads, rather than using the search function at the top of this page, try typing these exact phrases into your preferred internet browser's search window, you can use Google, Duckduckgo or whatever:

site: cpaptalk.com tidal volume

I got tons of hits. Also try:

site: cpaptalk.com minute ventilation

And so forth. I also like this video:

https://www.youtube.com/watch?v=QJcAJHFqXZg

_________________
Mask: AirFit™ F10 Full Face Mask with Headgear
Additional Comments: Sleepyhead software v.0.9.8.1 Open GL and Encore Pro v2.2.
I like my ResMed AirFit F10 FFM - reasonably low leaks for my ASV therapy. I'm currently using a PR S1 AutoSV 960P Advanced. I also keep a ResMed S9 Adapt as backup. I use a heated Hibernite hose. Still rockin' with Win 7 by using GWX to stop Win 10.