The narrow connector hose for the Swift does appear to be a slightly larger diameter than the Breeze's. That could make some difference in how the wave shapes of flow limitation vs hypopnea would look to various autopaps, using those such masks. However no connector hose is as large as the main air hose, so there is still going to be some "Venturi Effect" difference in what the different autopaps see, compared to regular nasal masks with no extra connector hose.
I, myself, will always continue to use the more comfortable nasal pillows masks (Aura, Breeze, Swift) with my autopap, but there truly can be a difference in treatment for some patients with some mask/autopap combos. Thus, the mask manufacturers' "not recommended for use with autopap" warning that comes with some masks.
Swift Nasal Pillows Exhaust?
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rested gal
- Posts: 12881
- Joined: Thu Sep 09, 2004 10:14 pm
- Location: Tennessee
I'm the world's worst to try to explain that - I can barely grasp it myself. As best I understand it, autopaps rely on waveshapes from our breathing to decide if they are looking at a "limited flow", or a "hypopnea" or an "apnea". An autopap has to process what it sees and then decide what action to take - raise the pressure, lower the pressure or do nothing for the moment.
BiPaps and straight CPAPs, on the other hand, don't have to look at wave shapes or make those kind of decisions. They just deliver one pressure blowing at you, and that's it. Of course BiPaps can be set for two pressures - a lower one for exhalation, and there are tweaks one can make to customize some bipaps to your breathing rythym. But bottom line is neither a Bi-level machine nor a CPAP machine has to analyze waveforms and decide what to do, the way autopaps work.
It's absolutely critical to an autopap's "work" that it be able to accurately assess what a wave shape means in the first place. If a narrow diameter hose is changing the way the wave shape looks (think of pressing your thumb over the end of a garden hose - changing the way the water sprays - the Venturi Effect), that's essentially what happens to the air flow when it changes from traveling through a bigger main air hose to traveling through a narrow diameter hose before it gets to the mouth or nose - and going the other way too. Nasal pillows interfaces, in particular, have a smaller diameter connector hose - some more narrow than others.
A changed waveform pattern can give false information to the autopap about what's really going on with the patient's breathing. The autopap ends up looking at wave shapes that make it think one thing is going on (perhaps it thinks it sees a limited air flow, not as bad as a hypopnea) when actually there really IS an hypopnea occuring. Apneas are relatively cut and dried - not much mistaking about them. But the more subtle gradations between flow limitations and hypopneas can (not will..but can) cause an autopap to misread what's really happening.
IF confusion happens, then even the data one sees the next morning will not be a true picture of what "events" really happened. There might be some things marked as "limited flows" that really should have been marked as hypopneas. In that case, even the AHI will be wrong, since the machine simply adds up the apneas and hypopneas. Maybe a narrow diameter hose caused it to not recognize enough hypopneas - chalking some/many of them as limited flows instead. Limited flows are not counted when calculationg the AHI, so that could make the true AHI come out wrong.
BiPaps and straight CPAPs, on the other hand, don't have to look at wave shapes or make those kind of decisions. They just deliver one pressure blowing at you, and that's it. Of course BiPaps can be set for two pressures - a lower one for exhalation, and there are tweaks one can make to customize some bipaps to your breathing rythym. But bottom line is neither a Bi-level machine nor a CPAP machine has to analyze waveforms and decide what to do, the way autopaps work.
It's absolutely critical to an autopap's "work" that it be able to accurately assess what a wave shape means in the first place. If a narrow diameter hose is changing the way the wave shape looks (think of pressing your thumb over the end of a garden hose - changing the way the water sprays - the Venturi Effect), that's essentially what happens to the air flow when it changes from traveling through a bigger main air hose to traveling through a narrow diameter hose before it gets to the mouth or nose - and going the other way too. Nasal pillows interfaces, in particular, have a smaller diameter connector hose - some more narrow than others.
A changed waveform pattern can give false information to the autopap about what's really going on with the patient's breathing. The autopap ends up looking at wave shapes that make it think one thing is going on (perhaps it thinks it sees a limited air flow, not as bad as a hypopnea) when actually there really IS an hypopnea occuring. Apneas are relatively cut and dried - not much mistaking about them. But the more subtle gradations between flow limitations and hypopneas can (not will..but can) cause an autopap to misread what's really happening.
IF confusion happens, then even the data one sees the next morning will not be a true picture of what "events" really happened. There might be some things marked as "limited flows" that really should have been marked as hypopneas. In that case, even the AHI will be wrong, since the machine simply adds up the apneas and hypopneas. Maybe a narrow diameter hose caused it to not recognize enough hypopneas - chalking some/many of them as limited flows instead. Limited flows are not counted when calculationg the AHI, so that could make the true AHI come out wrong.