11-16-2023, 09:31 AM
Difference between Vauto and S modes
Is there any difference between a ResMed AirCurve 10 Vauto running in Vauto mode with fixed pressures (e.g. EPAP 8, IPAP 12 max, PS 4) and the same machine running in S mode (EPAP 8, IPAP 12)? The manual lists a few things like:
- S mode has easy-breathe on/off
- Vauto has max IPAP, min EPAP, and PS, which S mode simulates with the bilevel pressures
- S has rise time
Other than that searches have not shown anything that jumps out as being significant.
I’ve used Vauto mode for years and it is working well, but now I’m trying to dial-in parameters to see if arousals can be handled more effectively. I’ve spent the past week using S mode with no difference in AHI or how I feel, but I have not tried to fine-tune as yet.
I have a therapy thread where I will post charts when I’ve given it more time, but wanted to check with the collective hive mind in the event I missed something regarding differences.
RE: Difference between Vauto and S modes
That is a pretty good summary of differences. In older machines, and VPAP-S, flow limitation may not be tracked in S-mode. It appears newer Vauto machines will track flow limitation in S-mode. The purpose of gathering flow limitation data is that it is a key parameter in auto-pressure algorithms and is not needed in fixed pressure modes.
RE: Difference between Vauto and S modes
Thanks. I appreciate the sanity check.
RE: Difference between Vauto and S modes
(11-16-2023, 09:41 AM)Sleeprider Wrote: That is a pretty good summary of differences. In older machines, and VPAP-S, flow limitation may not be tracked in S-mode. It appears newer Vauto machines will track flow limitation in S-mode. The purpose of gathering flow limitation data is that it is a key parameter in auto-pressure algorithms and is not needed in fixed pressure modes.
My new VAuto machine didn't seem to track flow limitations in S-mode.
RE: Difference between Vauto and S modes
A workaround to get Flow Limitations reporting, is to use the Auto mode and set the EPAP and the max IPAP to your current settings and set the PS to the difference of the two. Based on a prior post listing the S mode EPAP at 8 and the IPAP at 12, you would set the Auto mode to EPAP 8, max IPAP to 12, and the PS to 4. That will provide you the same exact pressures of the S mode, but with Flow Limitations being reported.
- Red
RE: Difference between Vauto and S modes
Thanks CR! I like to use flow limits as harbingers of bad things, so will give the fixed pressure a go with Vauto mode.
RE: Difference between Vauto and S modes
sorry, I still don't understand the differewnce between VAuto vs S mode
is there a simple way to explain the main difference?
RE: Difference between Vauto and S modes
Vauto is a mode capable of increasing EPAP and IPAP together in response to flow limitation and events, while S-mode is fixed at the set EPAP and IPAP. There are minor differences in the available settings in S-mode like the ability to turn off the EasyBreathe flow transition algorithm, resulting in a square-wave pressure change between EPAP and IPAP. as described in post #1. Functionally, Vauto and S mode are the same other than automatic pressure increases and decreased in Vauto.
RE: Difference between Vauto and S modes
I'm glad this came up. I have been very comfortable and had all but eliminated events at EPAP10 IPAP14 on Auto mode for the last year. My doctor was unhappy with my SpO2 levels at this setting. They seemed fine enough to me-24% 94-100, 75% 88-93, and less than a minute 80-87. The max was 98 and the average was 93. She moved me to 16/12 and changed me to S mode. It has not been a good experience for me.
I would like to switch back to auto setting but am curious if doing that and increasing my EPAP/IPAP could result in the old comfort along with an improved SPo2. Is it right to say that changing to 12/16 and setting the PS to 4 would do this? I don't see or understand the advantages to S mode (certainly not from my personal experience).
RE: Difference between Vauto and S modes
It really depends on the cause of the SpO2 desaturation. We could probably pick it out if you start a therapy thread and post your chart. I know how to improve oxygenation and ventilation and will be glad to help. For starters, changing to Vauto mode with a limited maximum pressure could help. Based on your current settings of 14/10, and your doctor's recommendation of 16/14, you could use mode Vauto with EPAP min 10.0, IPAP max 20.0 and PS 4, and would fully bracket your fixed settings and your doctors recommendation.
