Difference between ASV and BiPap ST

Hi I am new to this and need help understanding difference between ASV and BiPap ST. My second sleep study was done with ASV as I have central sleep apneas as well as obstructive apnea. I tolerated it much better than the CPAP or Bilevel as I would wake up at pressure changes of Bilevel. My doctor ordered ASV I saw the script. Medical equipment supplier is ordering BiPap St and insist it is the same as ASV and I should relax they have been doing this a long time and know what they are doing. It is just different companies use different names. Is any of this correct? Please advise I want to start this off correctly!

Staying within the Respironics brand because that is what a BiPap ST is
They aren't the same and they go about things a little differently. I don't understand the differences well enough to explain but other ASV users may be able to help.

BiPap ST
https://www.cpap.com/productpage/respir ... ap-st.html

BiPap Auto SV Advanced
https://www.cpap.com/productpage/PR-Sys ... anced.html

While I am not able to explain the differences either, Pugsy is correct. ASV & Bipap ST are different and if you are supposed to get an ASV, don't let them give you a bipap ST.

Read and print the information from the links Pugsy provided you. Show the DME. Let them know you will NOT be fooled into taking the wrong machine.

From the descriptions of the two machines it appears that the BiPAP ST uses a simpler algorithm to support breathing where it will initiate inhalation (by triggering the IPAP) at fixed, preprogrammed time intervals. In contrast, the ASV uses an advanced "servo-ventilation" algorithm that uses target peak airflow as a goal (as opposed to fixed timing). It seems like the latter is being overly protected by Respironics and they don't give much details but it should be much more natural to the patient than forcing fixed-timing breathing.

If you want to go by the ability of both machines to assist individuals with impaired spontaneous breathing abilities, yes, they both are supposed to be doing it; however, the ASV seems to be taking a much more advanced approach, which appears to be mostly about the comfort of the patient, but to me, that is a large part of the efficacy of the device.

I would not accept the BiPAP ST when the prescription is for an ASV.

McSleepy

You might call your Doctor and tell them there trying to make a change from his script. If they don't want to give you an ASV find another DME that deals with your insurance. Call your insurance and find out what DME'S are available to you that you can deal with. I trust a DME about as far as I can throw my house. It's your health get what your suppose to get. There's quite a price difference between those to machines.

I'd find a different DME, since the two machines are prescribed for different conditions and substitution can be outright dangerous.

The S/T units are for patients with central apnea. They are basically ventilators, using either a pressure increase or outright backup rate to force patients to breathe when their central nervous system doesn't believe it's necessary to do so.

ASV units are primarily for patients with complex apnea, which combines central and obstructive conditions. The backup rate function of the S/T units is included to deal with the central apnea component of complex SA, but it also uses a fairly complex algorithm to determine whether a patient is meeting flow targets.

If you've been through an ASV study and prescribed an ASV, the latter diagnosis is quite likely and an ASV is indicated. In addition to finding another DME, I'd report this to the doctor; they'll want to know not to recommend them in the future.

BiPAP/VPAP is where the machine can vary the inhale and exhale pressure (IPAP and EPAP). An auto-BiPAP/VPAP can vary the IPAP and EPAP over time, for example, if it notices you "need" more pressure because you're having events. Importantly, this adjustment happens over time - it notices you having events, so it decides the IPAP is too lower, for example. In this way, it functions a lot like an Auto-PAP but it can adjust both IPAP and EPAP. If you *stop* breathing, it won't do anything except flag an event and possibly adjust the pressure down the line.

A BiPAP ST is like a regular bipap, but it has a backup breathing timer. If it notices you are not breathing, it will kick in a pressure rise to encourage you to breathe. It won't breathe for you - that's a ventilator - but it will often cause a breathe to happen.

An ASV is a different beast. It adjusts pressures, but instead of watching events like an auto machine to decide what pressure levels, it watches the breathing pattern and volumes. It adjusts pressures each breath as it happens. It doesn't have to wait for an event to happen and then down the road increase it - it'll increase it as it notices your breath isn't "deep" enough, or an abnormal breath pattern is happening. It also has a backup rate like the ST for if you stop breathing, like the BiPAP ST.

That's what makes the ASV kind of a beast to use for many people, because the pressures are different on every breath potentially. But it's also what makes it so effective, as it's "fixing" the breathing immediately.

Despite the advanced tech, the ASV isn't a ventilator either - it won't breathe for you. But it's sort of like a passive ventilator.

Thanks. Just went through asv titration last night. It did feel different than st. The explanation here helps a bit.

One thing that doesn't fit though is where you said it doesn't breath for you. Asv has a backup rate same as st. I thought the backup rate was acting like a ventilator?

Nooblakahn wrote: One thing that doesn't fit though is where you said it doesn't breath for you. Asv has a backup rate same as st. I thought the backup rate was acting like a ventilator?

At least the BiPAP ST does (i.e., act that way), its description says it is for patients "who need Non-Invasive (NIV) Ventilatory Support". Although one difference I can think of from an invasive ventilator (with intubation) is that even 25cm H2O is not going to force your lungs full of air if you are completely limp. But if need that much, you should consider the ER, instead.
McSleepy

Yeah. I was flat out wrong... he said that the backup function of st is included with asv... my reading comprehension is failing today...

Sorry about that... not sure how I misread....

No problem. A ventilator will actually breathe "for" you, inflating your lungs. the xPAP treatments with a backup timer (bipap ST, ASV) will simply increase pressure. The increased pressure will trigger a breath (usually).

The advantage of the ASV is in the changing pressure on the fly, it can (usually) better manage the central events and combinations of obstructive and central events. It does make it pretty odd to use at first.

BiPAP ST is NOT ASV. Find a competent DME, and report the old DME to your doctor so he can steer other patients away from that guy. Even if the doctor browbeats the DME into ordering an ASV, I'd recommend a different DME. Find one who's in network.

Sometimes, insurance will insist on you trying bilevel/BiPAP before they'll pay for ASV.

They keep making the various CPAP/BiPAP devices more complicated and blurring the boundaries, but here's a rough idea.

BiPAP/VPAP/Bilevel machines give you a lower pressure when you exhale, but they wait for you to start inhaling before they go to the "inhale" pressure.

BiPAP ST machines have an option of a "timed" mode. In this timed mode, if you don't start inhaling within a certain number of seconds, it will go to the inhale pressure to try and make you start the next breath.

An ASV machines uses more complicated processes, but it will not only automatically try to start the next breath, it will quickly adjust the pressure upwards to make you breathe.

The ASV machine is sort of a "bigger hammer" and may be rough to adjust to at first, but it's often more effective on tough central apnea cases.

Currently, I have Respironic auto and Resmed autoset II but non of them provide
fast pressure response to Apnea event. Finally I have to switch back to the basic
CPAP mode and sometime can not tolerate with continues high pressure.

Resmed autoset responds fast but when the airway closed as OSA the pressure will not
increase until termination of apnea ?

My question: In order to looking for a more comfortable pap beside cpap, can I choose a
bilevel/vpap
vpap auto
vpap s/t
vpap adapt sv

...not to mention the ASV is an expensive machine

The ASV for me was easy to adjust to. Couple of days. Learns your breathing pattern. I really like it!
Don't settle for something that may not help you. Especially if your prescription is for an ASV.