Central Apneas Increase After Changing to Newer BiPAP

[tanayaray4]

yes, the trigger is at high. I understand the increasing lowest EPAP part. but I would like to understand, why would you like to decrease the pressure support further. Can you please explain it for me?

[Crimson Nape]

The PS could be causing CO₂ washout, which could be triggering your CAs. A reduction in CO₂ can tell your brain not to take a breath.

[upsman]

Crimson Nape

I'm not that familiar with BiPAP therapy, so am I understanding that pressure support is much like EPR on an APAP machine?
How are the differences between BiPAP and APAP, other than BiPAP can deliver a higher than 20 cm pressure?

I'm not trying to distract from the advice being given here, I just thought this would be a good place to ask this.

[Gideon]

Read this http://www.apneaboard.com/wiki/index.php...y_Clusters
Our main drive to breathe is from having a need to flush CO2 out of our system, Not for having a 'need' for oxygen. Low Oxygen can cause us to bathe faster.
ALL PAP machines improve our breathing. This improvement typically results in better oxygen sats and increased CO2 flushing. When CO2 concentrations drop below your apneic threshold a central apnea occurs. It's no surprise that with not breathing the CO2 concentrations build up and increase past the apneic threshold and we start breathing again. The CO2 rises and your breathing volume increases resulting in greater flushing of CO2 from your system repeating the cycle. This yields the classic waxing and waning pattern of CO2 induced breathing. Reducing the PS (or EPR) decreases the efficiency of your breathing thus reducing the flushing of CO2 from your system resulting in a reduction of Central Apnea events.

[Crimson Nape]

OK, I'll try to break it down.

EPR = Expiratory Pressure Relief (a Resmed trademarked feature)

• How it's employed on the CPAP:  IPAP - EPR = EPAP (EPAP can never be lower than 4 cmH₂O)
  
• The pressure settings on a CPAP are for normally both the IPAP and EPAP pressure.   When the EPR is employed, its value will be subtracted from the pressure or pressure range set and used for the EPAP pressure.  A pressure setting of 5 cmH₂O and an EPR value of 3 will only result in your EPAP being 4cmH₂O.  The full EPR value will not be utilized until the pressure reaches a value that allows the EPAP to be at least 4cmH₂O.
  
• EPR can only be set to a whole value from 1 to 3.
  
• Allows the patient the ability to have a pseudo bi-level without the additional cost.  This feature is listed by Resmed as a "Comfort" feature.  In practice, this option has been found to aid in reducing flow limitations.
  

PS = Pressure Support

• How it's employed on a Bi-Level:  EPAP + PS = IPAP
  
• PS can be set in increments from .2 to 8 cmH₂O
  
• PS while being listed in the "S" mode reports, it is actually only used in the Auto mode*.  In the Auto mode the pressure parameters are, 1. EPAP minimum, 2. IPAP maximum, and 3. PS.  The PS sets the pressure difference between the EPAP and IPAP.  An example would be having the  EPAP set at 10, IPAP max to 18 and a PS of 3.  This means that your Bi-Level will start at an EPAP of 10 and your IPAP will be 13 cm (EPAP+PS).  The maximum that the Bi-Level can increase its pressure to, based on the settings I listed, is an EPAP of 15 cm and the IPAP maximum of 18 cm.  
  
  * - Since the "S" mode is static, the PS is the difference between the EPAP and IPAP settings.  These are the only pressure setting options in this mode.
  

Please let me know if I answered your question completely.

- Red

[tanayaray4]

SUch nice and informaive discusiion. I'm so glad that I joined here. thanks @upsman. Being educated through the struggle .
Also, tonight I will try the suggested change in setting.. PS=3 , and EPAP=8 .

[SarcasticDave94]

OK just following along. Not unexpected but all the above info is correct. The change in PS should alter the Central events amount unless these are pre-existing CA. Then ASV is really the best answer.

[Sleeprider]

The increase in EPAP pressure will stabilize the variation in pressure you experience, because your median EPAP is 7 cm based on the last chart. Actually that is probably a high enough EPAP pressure and I think I may have been looking a IPAP. The reduction in PS is what will reduce the CA events. Everyone above did a great job of explaining respiratory drive. Your results are gong to be very good once we get it fine-tuned.

[tanayaray4]

okay. so I wanted to follow a setting for 2 days to avoid rushing over the desired setting. yesterday night I only changed the trigger to very high.  however there is an 2 hour gap between the machine screen report and oscar report. OSCAR is somehow missing out at least 2 hours : in between 3.45-5.55 am. what might be the reason for that?! 
Anyway, your advices ARE helping for sure.. 
I have not yet changed my ps to 3. should I do that , or keep it 4 for a day more? what do you guys suggest?

[Sleeprider]

Looks better today, especially the second session. You may be able to recover the data by purging data from May 1, then importing again. It's in the menu under Data/Advanced/Purge Current Day.

If you will please minimize the monthly calendar by clicking on the triangle in the date line or using F9 to turn it off, that will reveal more useful data.