Modified "Rise Time" on Luna G3 B25A BiPAP

[Cape67]

I'm about seven months into this precarious yet moderately illuminating adventure with my new-ish Luna G3 B25A bipap. Sadly I cannot provide OSCAR data as this particular device is not supported. And yes, I know it's not a preferred device, but I was desperate as my lovely insurance would not approve it, and I had to buy a bipap out of pocket, and this was about all I could afford. 

I recently thought I would try and change the Rise Time setting on the clinical menu, a setting previously overlooked, as I had not yet altered that value. The Rise Time range of values is 0 to 4, with a higher value representing, apparently, a longer inspiratory time. I was hesitant to even try this since I read that the ideal I to E ratio for a patient without interstitial pulmonary compromise is somewhere about 1 to 3, thirty-three percent, or thereabouts.  

The default factory setting is 2 of 4.  I simply tried a conservative bump to 3 of 4 to see what would happen.  Presently, after a few days, I do not see any changes in my AHI or minute volumes on PAP Link, but I can report that, strangely enough it indeed does feel quite a bit more comfortable on setting 3 versus the original 2.  I have no idea why this is, but I guess I will just park the Rise Time there for now.

For some reason, I thought that Rise Time was synonymous with Ramp Time, but as I'm sure most of you reading this are aware, these are two completely different parameters (duh, lol) 

Now if I can just get back my Wellvue O2 ring from a relative who borrowed it a few weeks ago.

Finally, I have no idea if this matters or will be helpful to anyone, but just wanted to share my findings. 

   
Current settings, after much experimentation and reading.
   

[Deborah K.]

I don't understand enough about the Luna to address much else, but you would benefit from turning your ramp off.  You get virtually no treatment during ramp, and if you get up for a bathroom break you go right back into another 1/2 hour of ramp, making your therapy extremely weak.

[PeaceLoveAndPizza]

An I:E ratio of 1:3 or 1:4 is typical for awake breathing, not sleep breathing. During sleep an I:E of 1:1 to 1:3 is more typical. During sleep your I:E ratio is a subconscious action. To change it would require some kind of ventilator like an ASV.

Here is an excellent wiki page on this topic.

https://www.apneaboard.com/wiki/index.ph...I:E)_Ratio

[Jay51]

What is Rise Time?

"The speed at which inspiratory pressure increases to the set target pressure is known as the rise time on most BiPAPs. Adjustments in rise time can improve patient comfort/tolerability with BiPAP. Rise times generally go from 100ms to 600ms, with settings of 1 through 5. A setting of 1 is the fastest while a setting of 5 is the slowest. Adjustments in the rise time change the waveform delivery of the pressure, furthermore, affecting your I:E ratio."

Basically, increasing rise time give a person more time to inhale.  Decreasing it gives less time to complete inhalation.  For instance, if a person needed 500ml for a breath, with a short rise time, it would occur very quickly (kind of "punchy").  If the same person took a 500ml breath with a longer rise time, it would give more time in seconds and fractions of a second to complete the breath.  

Why is this important?

"Adjusting the length of time needed to cycle from EPAP to IPAP can be very useful. BiPAP waveforms can be altered with the rise time by changing the angle of the pressure delivery. A faster rise time, setting 1, can result in a square waveform, where a slower rise time, setting 5, will be more sinusoidal.

This slope change allows the patient to get more or less inspiratory flow to reach the target pressure. Setting this will vary with different patient populations. COPD patients tend to need a faster inhalation and prolonged exhalation. A shorter rise time will aid in this style of breathing for this patient population. A restrictive or neuromuscular patient may need a longer rise time to allow for adequate gas exchange. Patients in acute respiratory failure may be flow starved, therefore, needing a shorter rise time to meet their inspiratory demands."

Probably the more rounded your respiratory wave tops look, the better (and with an appropriate I:E ratio like PeaceLoveAndPizza recommends above).  Comfort is important, too, in choosing rise time.  

I hope that this helps.  

[Cape67]

Thanks guys!  All great information, appreciate it.