BiPAP - Question about Inhale and Exhale

I know there are 2 settings, IPAP(Inhaling) and EPAP(Exhaling). My question is how can this help when I stop breathing? When I stop breathing, I stop inhaling so how would the IPAP help me? If I stop breathing only the EPAP is at work and its too weak. My IPAP is 16 and EPAP is 13, how can it give me the air pressure I need when I don't inhale when I stop breathing?

PAP machines are NOT non-invasive ventilators. In other words, CPAP, APAP, BiPAP/VPAP and BiPAP/VPAP Auto machines simply do NOT have the ability to trigger an inhalation when you quit breathing. They work by stenting the airway open with slightly pressurized air. This treats the OSA by preventing the vast majority of events from happening, but the system is not perfect: Even at a proper therapeutic pressure, some events will still happen. When they do, the machine the machine does not try to force you to inhale; it simply waits for your body to restart the breathing on its own. The Auto machines do have an algorithm that takes detected apneas and hypopneas into account: Typically, if an auto machine detects two events close together, it will start to increase the pressure at the end of the second event. The rationale is NOT to "fix" the current event (by forcing an inhalation), but rather the pressure is raised in order to better prevent further events from occurring. And this is why it's typically a bad idea to run an auto wide open: For most people, running in a 4--20cm starts you out a a pressure that is substantially below your therapeutic setting. And when that happens, your airway is not properly stented, and this allows the airway to continue to collapse at frequent intervals. Eventually, after you've experienced enough events, the pressure is raised to close to your therapeutic setting, and at that point, the number of events should drop rather sharply.
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On the other hand, the ASV machines and the BiPAP ST and VPAP ST machines are capable of acting as non-invasive ventilators. When set in T or ST mode these machines have a back up breaths per minute rate and also measure the volume of each breath and compare it to a running average of some sort. And under the appropriate circumstances, these machines will indeed try to trigger an inhalation by rather quickly and rather substantially increasing the pressure during the expected "inhalation" stage of the breath.

And how is a regular old BiPAP supposed to work? Ideally, the prescribed EPAP should be high enough to prevent most of the OAs---the idea is that the OAs tend to occur when the airway completely collapses during (or immediately following) an exhalation. If the EPAP is high enough, the airway should have enough support to prevent it from collapsing almost all of the time. The higher IPAP is designed to hypopneas and RERAs from occurring since they often are the result of attempting to inhale through a slightly collapsed airway. The idea is that as soon as you start to inhale, the machine switches to IPAP and that should provide enough additional support to prevent a slightly compromised airway from further collapsing enough to trigger a hypopnea or RERA.

So does that mean that my EPAP is too low when I stopped breathing 6 days in a row since I got the BiPAP(had CPAP before)?

Also, I wanted an Auto BiPAP because my pressure changes every week or so(done LOTS of sleep study...) but apparently for some reason I wasn't "qualified", whatever that meant.

Maxman190 wrote:So does that mean that my EPAP is too low

EPAP does control some of the events, so yes it could be too low. But w/o seeing your graph it's just a WAG.

Maxman190 wrote:So does that mean that my EPAP is too low when I stopped breathing 6 days in a row since I got the BiPAP(had CPAP before)?

The question is how many times you stopped breathing and for how long?

If your treated AHI is < 5 night after night, then the sleep docs would say your pressures are sufficiently controlling your apnea. From a more practical point of view, most posters here seem to feel best when the AHI < 2 or 2.5. But it is unrealistic to expect an AHI = 0.0 night after night.

But if your treated AHI is consistently greater than 5 and most of your events are apneas, then it is likely that your EPAP might not be high enough. In this case, I'd strongly recommend contacting the doc's office and report the problem to him/her.

And if your AHI is consistently running between 3 and 5 and you still feel bad, then that may be also be an indication that it's time to get back in touch with the doc's office and ask for some advice.

Also, I wanted an Auto BiPAP because my pressure chan'ges every week or so(done LOTS of sleep study...) but apparently for some reason I wasn't "qualified", whatever that meant.

Here in the states a prescription for a BiPAP will let you get a BiPAP Auto---if you find a cooperative DME that will set you up with the BiPAP Auto instead of a plain BiPAP.

It would be unusual for a doc to change someones pressure every week- they usually like to see at least a months data. Are you self titrating? Certainly you're not having a sleep study every week. You did not give enough information for anyone to really help you. If you are serious about this you will answer Robysue's question about AHI.
You may not need an AUTO machine, a Bilevel may be just fine. AUTO is not the superior machine. What is superior is 100% compliance night after night and nap after nap.

Maxman190 wrote:So does that mean that my EPAP is too low when I stopped breathing 6 days in a row since I got the BiPAP(had CPAP before)?

Also, I wanted an Auto BiPAP because my pressure changes every week or so(done LOTS of sleep study...) but apparently for some reason I wasn't "qualified", whatever that meant.

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my doctor did not want to write a prescription for Auto BiPap. However, I insisted that I wanted one due to its flexibility of air pressure. He wrote the prescription.

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