Differences in titration protocol - bipap versus avaps/ivaps

According to the Respironics titration protocol guide for regular bipap spontaneous and spontaneous/timed (bipap S/T), you raise EPAP to eliminate obstructive apneas and then IPAP to eliminate residual hypopneas, RERAs and flow limitations. IPAP is to blow of CO2/increase target volume/minute volume and EPAP is to maintain adequate oxygenation.

According to the same protocol guide, for AVAPS (volume controlled) you set a wide range for IPAP min - IPAP max, such as 8 - 25cmh2o and then set your target volume. The theory is that the IPAP value will automatically adjust as needed throughout the night in order to meet the set target volume.

But, since before the IPAP was used to eliminate everything but full obstructive apneas, now the AVAPS protocol says to raise EPAP to eliminate the obstructive events - including hypopneas - and maintain adequate oxygenation. Without a constant PS, the way sleep disordered breathing is treated has a different approach. I assume this is because on straight bilevel pressure the constant pressure support is what helps prevent hypopneas.

Since with AVAPS your pressure support is constantly changing, you now need to raise EPAP higher in order to deal with the obstructive events and maintain oxygen saturation.

Or, you could continuously raise the min IPAP pressure until most of the residual events are eliminated. In effect, you could take your titrated bilevel settings and then just give AVAPS room to increase if needed to maintain target volume. So, say, titrated IPAP as min and then maybe +5cmh2o as the max IPAP level. I'm not sure if this truly allows the AVAPS algorithm to work as designed.

There seem to be a lot of research articles and titration guides that support either approach (wide range of IPAP, using EPAP to eliminate all events; versus titrated IPAP/EPAP, allow IPAP to increase while sleeping to meet volume needs).

I feel at a loss and my doctor has not been able to answer my questions.

Matt00926 wrote:I feel at a loss and my doctor has not been able to answer my questions.

What questions do you have? You gave a good synopsis of the two protocols, but you haven't listed any specific questions about those protocols.

And what form of sleep disordered breathing have you been diagnosed with? That's important because the way that OSA or OSA with a very minor amount of pressure induced CAs is treated is very different from the way primary CSA or CSA with a minor amount of OSA is treated.

Regular bilevel S or auto bilevel S is usually does not adequately treat primary CSA, but it does a good job of treating ordinary OSA when the patient has trouble adjusting to CPAP/APAP for a wide number of reasons, including a small number of pressure induced central apneas.

Bilevel ST can be useful in treating CompSA, which is really nothing more than OSA complicated by the emergence of a significant number of central apneas when PAP therapy is started. It may or may not be very effective when treating someone who's primary problem is central sleep apnea, where the primary problem to begin with is central apneas.

The ASV machines and the AVAPS machines are designed to specifically treat central sleep apnea. But they are also useful in treating CompSA when bilevel S or bilevel ST do not adequately control the the patient's pressure induced central apneas.

The titration protocols for the various machines are designed with the targeted patient group's main sleep disordered breathing problems in mind.

robysue wrote:

Matt00926 wrote:I feel at a loss and my doctor has not been able to answer my questions.

What questions do you have? You gave a good synopsis of the two protocols, but you haven't listed any specific questions about those protocols.

And what form of sleep disordered breathing have you been diagnosed with? That's important because the way that OSA or OSA with a very minor amount of pressure induced CAs is treated is very different from the way primary CSA or CSA with a minor amount of OSA is treated.

Regular bilevel S or auto bilevel S is usually does not adequately treat primary CSA, but it does a good job of treating ordinary OSA when the patient has trouble adjusting to CPAP/APAP for a wide number of reasons, including a small number of pressure induced central apneas.

Bilevel ST can be useful in treating CompSA, which is really nothing more than OSA complicated by the emergence of a significant number of central apneas when PAP therapy is started. It may or may not be very effective when treating someone who's primary problem is central sleep apnea, where the primary problem to begin with is central apneas.

The ASV machines and the AVAPS machines are designed to specifically treat central sleep apnea. But they are also useful in treating CompSA when bilevel S or bilevel ST do not adequately control the the patient's pressure induced central apneas.

The titration protocols for the various machines are designed with the targeted patient group's main sleep disordered breathing problems in mind.

I have diagnosed nocturnal hypoventilation due to restrictive lung disease (chest wall disorder). My oxygen saturation goes into the 70's and my CO2 levels increase above 50 as well.

My question is which approach should I follow? According to a few guides I've read I am supposed to keep the EPAP value as low as possible because my airway never completely closes, and also it supposedly keeps the work of breathing low. When I was titrated for regular BiPAP S the sleep doc specifically told the techs to only raise EPAP in the event of complete airway obstructions (obstructive apneas). My final EPAP stayed the same at 4cmh2o and my IPAP ended up at 20cmh2o.

Unfortunately, the techs that I did a follow up AVAPS titration with (another medical facility) didn't seem familiar with the Trilogy machine and I saw on the report it was on auto-EPAP from 4-14cmh2o.

When it comes to the AVAPS protocol, as far I can understand, I would be effectively raising the EPAP value in order to eliminate all obstructive events instead of primarily using the IPAP to do it. I'm wondering if this is okay to do for restrictive patients - I have read for neuromuscular disease that you keep the EPAP at 4/5 and just keep raising the IPAP until your goals are met.