APAP or BiPAP

I've started talking with my RT about a new machine and need to know from all of you experienced users....Should I push for APAP or BiPAP?

A bipap requires a specific order for it. If you have a cpap order (script) you can get an apap or cpap.

Depends on your order (script) which machine you can get.

Generally it depends on your disorder and current pressure and how well you tolerate it. If your pressure is at or over 15 cm you are a good candidate for Bipap out of the gate. If the majority of your SDB is from Hypopnea (vs Apnea) you may benefit from Bipap use.

Bipap has two pressures, one for inhale, one for exhale, each address different aspects of SDB. Both can address Vibratory Snore (VS) and Flow Limitation (FL), but individually they address:

IPAP (Inhale pressure) addresses the above and Hypopnea (HI)
EPAP (Exhale pressure) addresses the above and Apnea (AI or OA)

So if your Apnea is eliminated at a pressure of 8.0, EPAP can be set at 8. If you continue to have Hypopnea those can be eliminated with higher IPAP such as 12. So you end up with a pressure of 12/8 which can be a lot more comfortable than a CPAP pressure of straight 12.

So if your machine has reporting ability, you can nail down OSA with a microscope. If AI remains higher than wanted you increase EPAP. IF HI remains higher you increase IPAP. Since there is a differential change in pressure and we can tolerate a higher pressure on inhale than exhale it seems easier to breathe against a Bipap.

There are exceptions to the above but in general that is the short of it. There are different types of bilevel machines for different disorders such as CSDB, CSR etc. In some cases Bilevel can adversely impact therapy in a negative way if you have central apnea.

In more recent years there have been many new types of bilevel come out to treat those specific disorders such as with the Adapt SV, ST etc. They are finding if you can stabilize breathing that some of these events like centrals go away on their own.

oops, think the site is a bit slow today.

Snoredog has nailed it succinctly but there is an additional aspect to using a Bilevel that appeals to many people who try them.

This is the psychological benefit of feeling you are breathing more normally than happens with a fixed pressure deliver machine (by fixed pressre delivery I am meaning machines that deliver a single pressure for both inhale & ehale these being cpap & apap)

Most new cpap & apap machines do have added pressure relief mechanisms and they do help some people but they just don't compare to two levels of pressure for the full breathing cycle.

What I found from my own titrations was that the pressure allocated could be taken as a simple baseline for setting up a bilevel using a simple formula. Lets say the titration was for 13 CMs then this means the clinic set the pressure high enough to eliminate all AI & HI events (apneas & hypopneas). That actually means it is running higher than is really needed most of the time. An apap can help here in that it can be set to a lower pressure and can adjust as needed during the night but there is still the matter of the single pressure being delivered.

The rule I use for myself is titration -2 for epap and +1 for ipap. This creates a gap of 3 which is an accepted optimal gap for the most effective results and good feeling.

With an Auto, I would set them using this formula (as a general rule) titration - 3 for the lower range and titration + 3 for the upper range. The approach of leaving the higher apap range at maximum is flawed in that too often due to leaks of some other defect in the machines detection, they can 'runaway' that is go to max pressure & stay there. The newer models seem less prone to doing this but why let it even try.

Good luck

DSM