Can an ASV be made to perform as a BiLevel?

[Sir NoddinOff]

Just wondering if you can basically make any modern ASV machine operate functionally the same as BiLevel by changing the settings in the clinician's menu? Kinda like making an Auto machine perform as a straight CPAP? Maybe their therapy algorithms are too different... I simply don't know.

[Mary Z]

It seems that if you set the Min and Max EPAP to the value (same number) you want and the Pressure Support as a single number (Max and Min) for the IPAP you want, and enable Biflex (on Respironic System One BiPap Auto SV advanced) it would work. Set the Max pressure for EPAP + PS. If you put different values for EPAP Min and Max the IPAP would vary to EPAP +PS. Maybe someone smarter than me will have a better answer.
For example for 8/12 set Min and Max EPAP for 8, Pressure Support for 4, max pressure for 12. I believe it should work. It's a very versatile machine.
I set Min. EPAP, Max EPAP, Max Pressure and Pressure support.
8/8, 20, 4-12 are my numbers.

[Sir NoddinOff]

I believe it should work. It's a very versatile machine.

Thank you Mary, that's very helpful info and your reasoning appears to be sound (according to what little I know about AVS ). For three to six thousand bucks it should also do my dishes and mop the floors. I hope somebody else can weigh in on this.

[sleepstar]

Yes it can, but how come you want to?

ASV is prescribed for central apneas and cheyne stokes breathing. Bilevel is more for hypoventilation (when you have problems with your lungs and can't get rid of carbon dioxide)

Bilevel and ASV are completely different machines and are treating different disorders.

You really need to talk to a doctor about this. It can be dangerous.

[JohnBFisher]

Depends on the ASV:

Respironics
Set EPAP min/max to the range you want if you want the unit to adjust to changing obstructive sleep apnea. Set PSmin and PSmax to the same value. This plus EPAP should equal your IPAP value. Set Maximum Pressure to the IPAP value.

Done.

Resmed
Set EPAP to the value you need. Set PSmin and PSmax to the same value. That value plus EPAP should equal your IPAP value. Set Maximum Pressure to the IPAP value.

Done.

There may be several reasons to set up an ASV unit as if it was a BiLevel unit. It is not dangerous to do so. To use an ASV unit without a sleep study is not a good idea, since it can cause breathing problems if not properly set. However, doing something like this is not dangerous.

Of course, I offer this caution. If you have central apneas, then only a BiLevel setting will not address the central apneas. That could lead to serious health consequences (uncontrolled high blood pressure, high glucose values, etc).

Hope that helps.

[sleepstar]

Hi,

Changing your machine to bilevel when your doctor has indicated you need ASV can be dangerous.
Bilevel can worsen central sleep apnea and can influence your respiratory drive inducing hypocapnia.

"Bilevel positive airway pressure may be deleterious to certain CSA patients by inducing hypocapnia" http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2287191/



"IPAP, especially when used with a high IPAP-to-EPAP differential, has the potential to worsen central sleep apnea by lowering the PaCO2" https://journal.publications.chestnet.o ... 2/2141.pdf

"Patients with complex disease are sensitive to positive airway pressure, and usually flow limitation cannot be eliminated without worsening periodic breathing or inducing central apneas. An immediate worsening with bilevel ventilation may be seen, consistent with an effect of induced hypocapnia on the peripheral chemoreceptors" http://emedicine.medscape.com/article/304967-treatment

I'm just saying talk to your doctor. If you have an ASV, they have prescribed it for a reason, otherwise you would be on bilevel to begin with

[JohnBFisher]

... Changing your machine to bilevel when your doctor has indicated you need ASV can be dangerous. ...

I think you'll find we are in agreement. However, I would caution that an absolute ("such-and-such can be dangerous") does not come across as well as the additional information you provided. There may well be reasons which you and I do not know that would warrant making this type of change. For example, what if the OP required BiLevel - not ASV therapy - but had been able to purchase an ASV at a reasonable price. In that case making the ASV act as a BiLevel unit would make perfect sense.

So, I would caution against absolute statements, but definitely provide the detailed information (which you did do).

Just some food for thought ...