Ti Min question

[DreadPirateRawburts]

Hi All,

I see a lot of talk about TI max, but little about TI min. What is the benefit or side effect of increasing this setting. When should it be used?

[Jay51]

Ti Min sets the minimum limit on time spent in IPAP (inspiratory positive airway pressure).  

One advantage of increasing it would be to prevent the premature cycling back to EPAP for people with weak inspiratory pressure.  They would be able to inhale more air and increase tidal volume more this way.

[DreadPirateRawburts]

Ti Min sets the minimum limit on time spent in IPAP (inspiratory positive airway pressure).  

One advantage of increasing it would be to prevent the premature cycling back to EPAP for people with weak inspiratory pressure.  They would be able to inhale more air and increase tidal volume more this way.

So all things considered equal, increasing to say .8 would Be a good thing to try and supplement a low tidal volume ?

[Jay51]

It should.  You can even try a bit higher and see what happens to your tidal volume median in OSCAR.  Once your find your highest Ti Min setting that gives you the highest tidal volume median, that would probably be ideal.  It has to be balanced against comfort also (the sweet spot inhale time of yours so it doesn't feel too short or too long).

[DreadPirateRawburts]

It should.  You can even try a bit higher and see what happens to your tidal volume median in OSCAR.  Once your find your highest Ti Min setting that gives you the highest tidal volume median, that would probably be ideal.  It has to be balanced against comfort also (the sweet spot inhale time of yours so it doesn't feel too short or too long).

What is the best way to figure out what is the best min, Trial and error?

I have low tidal volume. Adding PS makes centrals appear, and increasing pressure gives me awful aerophagia, so looking at other options

[Jay51]

Probably trial and error with your current machine. 

I have had similar experiences with pressure as you have:  lower natural tidal volume, increased Centrals with added pressure(s), and some aerophagia with very high pressures.  

It seems like the natural progression is:  cpap 1st.  If that doesn't work - too many flow limitations,  increased centrals, etc. then on to a bilevel (bipap).  When the bipap in my sleep study caused an explosion of centrals, I was put on a machine with a back up rate.  The back up rate solved the Central's problem.  ASV is for central apneas and has a dynamic back up rate based on your own personal respiratory rate - it uses a 3 minute rolling average to determine it.  ST and ST(A) are both machine with back up rates, but they are intended for patient's with COPD, etc.  

You have the VAUTO.  One timing control you can change to help would be to increase "trigger" setting to high (or better yet very high - to help stop centrals).  It changes the sensitivity so that the slightest attempt at inhaling on your part triggers the VAUTO to respond with Pressure support (IPAP).

Hopefully you can get optimized better by tweaking both Ti Min and Trigger settings.