Hello Guest, Welcome to Apnea Board !
As a guest, you are limited to certain areas of the board and there are some features you can't use.
To post a message, you must create a free account using a valid email address.

or Create an Account


New Posts   Today's Posts

Help understand the different machines
#1
Help understand the different machines
I thought I was beginning to grasp the basics, but today decided I might be more confused than on top of it.

So here is the question...
1. can someone briefly explain the major differences/functions of

a. Auto (Resmed Autoset an example)
b. Bi-Level (same as BiPAP?)
c. Bi-Level Auto
d. VPAP

and when does one need a. vs b. vs c. vs d.?

2. Also, My mind cannot see the difference in bi-level as opposed to the exhale pressure reduction function that is an "added" feature in many models.

3. Finally, I have an opportunity, assuming things progress, to get at a terrific price a Respironics 750p which I think is
"Respironics PR System One REMstar BiPAP Auto w/ Bi-Flex"
(does 750p automatically equal precisely and totally that? Or are some 750p's not bi-flex, or not Auto, or not BiPAP, for example?)

Thanks.


Post Reply Post Reply
#2
RE: Help understand the different machines
see above for questions

1a, auto machines raise the pressure (generally) when you snore, have an obstructive apnea, or a hypopnea, in the hopes of providing just enough pressure to keep that from happening, based on changing conditions (sleep position, level of sleep (rem, etc)) as the night goes on.

1b bipap is the PhillipsRespironics trademark name for bilevel, VPAP is the resmed name for the same thing.

1c bi-level auto is a bi-level machine that also autoadjusts as in 1a.

1d see 1b.

cpap vs apap, and bilevel vs auto bilevel are the same rational. primarily enhanced comfort and thus more likely to stick with the program.

2) in broad strokes, bilevel gives you MORE exhale relief than cpap with exhale reduction. for instance, on a resmed s9 vpap machine, the exhale reduction (epr) can go up to 3, on a bilevel machine, you can have the pressure support (difference between inhale and exhale) set to up to 10. the behavior of the bilevel pressure differences is very configurable as to timing, and aggressiveness on the changes, whereas there's just 0,1,2,3 for the pressure relief in cpap/autoset mode.

a 750 is a 750. a 760 is a 760, the defining set of what a machine does is based on it's REF code (aka, model number). you can google up what exactly is in a 750, and/or request the clinicians manual for it here.

respironics seems to like to have confusing (to me) and somewhat conflicting model names, as if to keep people guessing, the resmed lineup is easier for me, except for the vpap adapt, where the older and newer units have the same name, and the only way you can tell the difference is checking the REF number on the back.
Post Reply Post Reply
#3
RE: Help understand the different machines
(06-21-2014, 04:35 PM)jcarerra Wrote: So here is the question...
1. can someone briefly explain the major differences/functions of

a. Auto (Resmed Autoset an example)
b. Bi-Level (same as BiPAP?)
c. Bi-Level Auto
Auto PAPs have one pressure level that varies from the min pressure setting and max pressure setting in response to OAs, Hs, snoring and flow limitations. APAPs are billed under the same insurance code as plain old CPAPs are both billed under the same HCPC code, namely E0601. APAPs and CPAPs are both prescribed for plain vanilla OSA.

Bi-level machines include the Resmed S9 VPAP S and the PR System One BiPAP Pro. These machines have two distinct therapeutic pressure settings. The IPAP pressure is the pressure delivered during the inhalations. The EPAP pressure is the pressure delivered during the exhalations. The difference between the IPAP and EPAP is typically around 4-5 cm, but it can be as little as 1 cm or as much as 8-10cm (or more).

NOTE about Resmed Machines: If the PS = 0, 1, 2, or 3, a Resmed S9 VPAP S will act and behave very similarly to an S9 Elite with the EPR set to 0, 1, 2, or 3 respectively. There's a small (but potentially significant) difference in how the pressure is raised back up for the inhalations, however. The Elite will start raising the pressure just before the inhalation starts (at the very tail end of the exhalation), whereas the VPAP S will wait until it is sure the inhalation has started. Most people cannot feel this difference. So the major difference between an S9 Elite and a bi-level machine is that the difference between IPAP and EPAP can be greater than 3 cm.

Bi-level auto machines are like bi-levels in that they deliver a distinctly different pressure on inhale (IPAP) and on exhale (EPAP). But the IPAP and EPAP pressures are allowed to vary during the night in response to OAs, Hs, snoring, and flow limitations. The difference between IPAP and EPAP is called the pressure support or PS for short. Exactly how the IPAP and EPAP pressures vary depends on both the brand of bi-level used and the PS setting(s).

On a Resmed S9 VPAP Auto, there are three critical therapeutic settings:
  • min EPAP
    max IPAP
    PS
The S9 VPAP Auto increases/decreases the EPAP and IPAP at the same time all night long, and the PS setting is simply how far apart the two pressure levels are. In other words:
  • min IPAP = min EPAP + PS
    max EPAP = max IPAP - PS
And all night long, the EPAP is allowed to range from min EPAP to max IPAP - PS and the IPAP is allowed to range from min EPAP + PS to max IPAP. At all points during the night IPAP - EPAP = PS.

On a PR System One BiPAP Auto, things work a bit differently. The IPAP and EPAP are allowed to vary independently of each other. This requires four therapeutic settings:
  • min EPAP
    max IPAP
    min PS
    max PS
The minimum IPAP = min EPAP + min PS and the maximum EPAP = max IPAP - min PS. EPAP (but not IPAP) is increased for clusters of OAs and snoring. IPAP (but not EPAP) is increased for clusters of Hs, RERAs, and flow limitations. In other words, the IPAP and EPAP are allowed to vary independent of each other as long as
  • min PS < IPAP - EPAP < max PS
In other words, the difference between IPAP and EPAP must stay between the min PS and max PS settings. So if IPAP - EPAP = min PS and EPAP needs to be increased, both IPAP and EPAP will be increased. Likewise, if IPAP - EPAP = max PS and IPAP needs to be increased, both IPAP and EPAP will be increased.

NOTE 1: By setting min PS = max PS on a PR System One BiPAP Auto, you can make the BiPAP Auto behave very similarly to the Resmed S9 VPAP Auto. There is no way to make a Resmed S9 VPAP Auto behave like a System One BiPAP when min PS and max PS are different numbers.

NOTE 2 about Resmed Machines: If the PS = 0, 1, 2, or 3, a Resmed S9 VPAP Auto will act and behave very similarly to an S9 AutoSet with the EPR set to 0, 1, 2, or 3 respectively. There's a small (but potentially significant) difference in how the pressure is raised back up for the inhalations, however. The AutoSet will start raising the pressure just before the inhalation starts (at the very tail end of the exhalation), whereas the VPAP Auto will wait until it is sure the inhalation has started. Most people cannot feel this difference. So the major difference between an S9 AutoSet and a bi-level auto machine is that the difference between IPAP and EPAP can be greater than 3 cm.

Quote:and when does one need a. vs b. vs c.?
A script that specifies "CPAP at n cm" can be filled by any E0601 machine, although a DME that is willing to sell an APAP will set the APAP up in straight CPAP mode.

Bi-level and bi-level auto machines are both billed under the HCPC billing code E0470. A script that reads "CPAP at n cm" or "APAP min--max cm" is NOT enough for a DME to legally sell you a bi-levle or bi-level auto machine.

Both E0601 machines and E0470 machines are used to treat plain vanilla OSA. E0470 machines, however, are usually prescribed only when the patient is having certain kinds of difficulties with PAP therapy.
E0470 (Bi-level and bi-level auto) machines are typically prescribed for one of the following reasons:
  • Patient has failed to respond to CPAP/APAP for some reason, but moving the patient to an even more expensive ST or ASV machine is not (yet) medically warranted. In other words, the patient's AHI has not yet come down to the normal range, but it's not clear the problem is CompSA. Among other things, the bi-levels can deliver up to 25 cm of pressure, whereas APAPs can only deliver up to 20 cm of pressure.

  • Patient is unable to tolerate CPAP/APAP for some reason, and there is reason to believe the switch to bi-level may help. Typical "can't tolerate" reasons are severe aerophagia at pressures required to keep the OSA under control and inability to exhale against the pressure comfortably even though exhale relief is set at its maximum.

  • Patient needs at least 15cm of pressure to contol the OSA in an in lab titration study and the tech has reason to believe the high pressure is causing additional sleep disturbances. Techs can switch to a bi-level titration in this case, and if the patient does better on bi-level, then bi-level may be the first machine recommended.

  • Patient has central sleep apnea or complex sleep apnea, but the insurance company first requires the patient to try (and "fail") CPAP/APAP/Bi-level before the insurance company is willing to authorize a more expensive ST or ASV machine. The rationale is not quite as cruel as it sounds: Some people with CompSA don't need the full support that an ST or ASV machine provides---i.e. after using an appropriately set bi-level for several weeks, the problems with centrals resolve themselves and the person does fine on bi-level.

Quote:2. Also, My mind cannot see the difference in bi-level as opposed to the exhale pressure reduction function that is an "added" feature in many models.
It's a matter of degree. If you are using a bilevel with a PS setting of 1,2, or 3 cm, then it can be argued that a Resmed S9 AutoSet should do the job. However, I can attest that I'm that rare patient where the S9 AutoSet was not the best choice even though my typical PS on my BiPAP Auto is often right around 3cm.

In my case, the Resmed S9 AutoSet (with EPR = 3) triggered severe aerophagia when I first started in CPAP mode with my (original) titrated pressure of 9cm. (So effectively I was using a machine similar to a bi-level set with IPAP = 9 and EPAP = 6.) My AHI values were fantastic (always below 1.0) and my leak line was fabulous. But the severe aerophagia triggered a whole cascade of negative affects on my sleep and the quality of my life took a sharp nose dive in the first two weeks I was on CPAP. The PA who was in charge of my treatment ordered a switch to APAP (wide open) for a week of titration to see whether my pressure could be reduced.

APAP was less uncomfortable and at the end of the titration, the PA agreed to simply switch me to APAP with a range of 4-8 cm. EPR was still set at 3, and what this meant was that both IPAP and EPAP started at 4cm. As events or snoring or flow limitations occurred, the IPAP increased, first to 5, then to 6 and then to 7. When the IPAP = 7, the EPAP was still at 4cm. When IPAP was bumped up to 8, the EPAP increased to 5. My AHI was not quite so great, but it was still very good (AHI mostly between 1.0 and 2.5), but the aerophagia continued to be a problem on most nights and the CPAP-induced insomnia was growing fat and strong. Moreover, I was pretty constantly aware of the slight increase in pressure towards the end of my exhalations when the IPAP > 4 and I constantly felt as though the machine was rushing me to inhale before I was done exhaling.

About 2 months into my PAP nightmare, the doc and PA talked with each other (but not me), and at my next semi-emergency meeting with the PA, she said all they'd been able to come up with was the idea of seeing if I'd do any better on bi-level than APAP.

My first bi-level titration resulted in a script for bilevel at IPAP = 8; EPAP = 6. Which is a really weird bilevel script since PS = 2. For a whole lot of reasons that I don't want to get into here, I wound up with a PR System One (Series 50) BiPAP Auto set in fixed bilevel mode with IPAP = 8; EPAP = 6.

The difference in comfort was remarkable. With the BiPAP, I could tolerate being awake in the middle of the night for more than 10-15 minutes without throwing a screaming hissy-fit at hubby about how deeply uncomfortable (and unfair!!!!) all this PAP mess was.

I continued to have some problems with aerophagia and a lot of problems with generally very restless sleep, lots of bedtime insomina, and lots of sleep maintenance insomia. The PA sent me back to the lab for another bi-level titration, that resulted in a script for IPAP 7; EPAP = 4. My stomach could tolerate that without any aerophagia, and my sleep was marginally better (I was also doing hard core CBT-I for the insomnia). But, unfortunately, the titration night was a "good" night OSA-wise, and at home the AHI was bouncing all over the place with a fair number of AHI > 3.5 and 4. And the machine was scoring a lot of snoring. And hubby was confirming the snoring.

And that's when I wound up being switched to Bi-level Auto with the crazy settings that I still use: Min EPAP = 4, Max IPAP = 8, min PS = 2, max PS = 4. Most nights the IPAP is at 8 for most of the night; my EPAP usually stays between 4 and 5, but occasionally gets bumped up to 6 for 30-60 minute stretches. And the stomach can tolerate all this, and my sleep is ranges from "half-decent" to "decent" in terms of the insomnia.


Quote:3. Finally, I have an opportunity, assuming things progress, to get at a terrific price a Respironics 750p which I think is
"Respironics PR System One REMstar BiPAP Auto w/ Bi-Flex"
(does 750p automatically equal precisely and totally that? Or are some 750p's not bi-flex, or not Auto, or not BiPAP, for example?)
The 750p is the exact machine I use. It is the slightly older Series 50 System One BiPAP Auto. It has no heated hose option. The humidifer cannot be preheated. The LCD does not have 1-day data available. And the min PS = 2 in Auto mode cannot be changed. But those are really the only things different between the 750 BiPAP Auto and the 760 BiPAP Auto.

The "p" in the model name indicates it was originally bundled with a (Series 50) System One Humidifier, as I recall.

The 750p System One BiPAP Auto can be run in:
  • Fixed CPAP mode
  • Fixed bilevel mode
  • Auto bilevel mode
Because min PS = 2 there is no way to effectively turn the 750p into an APAP, although setting the (max) PS = 2 will mean that it will run very similar to the S9 AutoSet with EPR = 2.

It's also worth pointing out that the Flex systems on the PR machines are not like the Resmed EPR system. The Flex systems do drop the pressure at the beginning of each exhalation, but the drop is NOT by a fixed amount. The size of the drop depends on the forcefulness of the exhalation. And even with Flex = 3 and a very forceful exhalation, the pressure is probably only going to drop by 1.5-2.0 cm. The pressure increase starts sooner in Flex than it does for EPR.

All that said, the 750p is a really nice machine. If it's a good price and you want to see what bi-level feels like with a PS = 4 or 5, it's worth considering.


Post Reply Post Reply
#4
RE: Help understand the different machines
diamaunt meant:
"for instance, on a resmed S9 apap machine, the exhale reduction (EPR) can go up to 3, on an S9 VPAP bilevel machine you can have the pressure support (difference between inhale and exhale) set to up to 10."

EPR on ResMed machines is a basic form of bi-level, because EPAP (the pressure during exhale) ends and changes to IPAP at the start of inhale and IPAP ends and drops back to EPAP at the beginning of exhale. So it is as if EPR is based on the length of the inhalation time, the same as "Pressure Support" is on a bi-level machine. (But a full bi-level machine will have more adjustability on how soon/late and how abrupt/gradual the transitions will be when switching between the two pressures.)

Flex on Philips Respironics machines, however, is "flow based" and the reduction in pressure during exhale only lasts as long as we are actively exhaling. ("Flow" refers to the rate of airflow being inhaled or exhaled.) On a machine with Flex, when there is no Flow there is no pressure relief.

The point is: during the natural pause between the end of actively exhaling until the beginning of actively inhaling, Flex on a Philips Respironics machine provides no pressure relief, but EPR on a ResMed machine does. It is a difference which can take some time to get used to when changing between machines.

The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies.  Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment.
Post Reply Post Reply
#5
RE: Help understand the different machines
Highly informative information!
This place is amazing.

When do you need
ASV instead of Bi-Level auto instead of Bi-Level instead of APAP instead of CPAP?

Or is there no definitive answer to that? Smile
Post Reply Post Reply
#6
RE: Help understand the different machines
(06-21-2014, 06:15 PM)diamaunt Wrote: a 750 is a 750. a 760 is a 760, the defining set of what a machine does is based on it's REF code (aka, model number). you can google up what exactly is in a 750, and/or request the clinicians manual for it here.
Just want to clarify something important here.

The 750 is the PR System One BiPAP Auto from the Series 50 line of System Ones. The Series 50 machines (models 150, 250, 450, 550, 650, 750) are the first generation System One machines. They were released in around 2009 or 2010.

The 760 is the PR System One BiPAP Auto from the Series 60 line of System Ones. The Series 60 machines (models 220, 260, 460, 560, 660, 760) are the second generation System One machines. They first hit the market in 2012 as I recall.

The Auto algorithms and the central apnea detection algorithms on the Series 50 and Series 60 machines are the same. The Series 50 and Series 60 full efficacy models (450, 460, 550, 560, 650, 660, 750, 760) all record the same exact data: Detailed daily data includes full efficacy data, wave form data, pressure level data, and leak data; the efficacy data includes detection of OAs, CAs, Hs, RERAs, periodic breathing, snoring, flow limitations (only when running in Auto mode). And the Flex systems on the Series 50 and Series 60 machines work the same way.

The major difference between the Series 50 and Series 60 machines is the fact that the Series 60 machines have an optional heated hose that requires a specific version of the Series 60 humidifier and a special power cord. There is no heated hose option for the Series 50 machines.

Other differences are additional patient "comfort" features added to the Series 60 machines or differences in the software needed to examine the data:
  • The Series 60 machines have 1-day data available on the machine's LCD; the Series 50 machines do not.
  • The Series 60 machines' heated humidifier can be preheated; the Series 50 machines' heated humidifiers cannot be preheated.
  • The Series 60 machines have a so-called "silent mode". When "silent mode" is turned on, the machine will not make annoying beeps every time it is turned OFF or ON; the Series 50 machines don't have "silent mode"
  • On a Series 60 machine, the patient can control both the initial ramp pressure and the ramp time from the patient's set up menu; on a Series 60 machine changing the ramp time can only be done from inside the Clinical menu.
  • On a Series 60 machine, the patient can choose between a 15mm and 22mm hose inside the patient set up menu; on a Series 50 machine, changing the hose size can only be done from the clinical menu AND the oldest Series 50 machines cannot be used with 15mm hoses.
  • You need SleepyHead 0.9.3 or higher to read the data from a Series 60 machine; any version of SleepyHead can read a the data from a Series 50 machine.
  • The newest version of Encore Basic or Encore Pro is needed to look at the data from a Series 60 machine; Encore Viewer 2.1 will NOT be able to load the Series 60 machine data correctly. Encore Viewer 2.1, Encore Basic or Encore Pro will all read the data from a Series 50 machine.


Post Reply Post Reply
#7
RE: Help understand the different machines
(06-21-2014, 07:52 PM)robysue Wrote: The 750 is the PR System One BiPAP Auto from the Series 50 line of System Ones. The Series 50 machines (models 150, 250, 450, 550, 650, 750) are the first generation System One machines. They were released in around 2009 or 2010.

The 760 is the PR System One BiPAP Auto from the Series 60 line of System Ones. The Series 60 machines (models 220, 260, 460, 560, 660, 760) are the second generation System One machines. They first hit the market in 2012 as I recall.




For those who aren't sure which machine you have,
here's roughly what the differing series of REMstar machines look like:


[Image: which-remstar.jpg]




If you have a PR System one (either 50 or 60 series),
here's how to tell what specific machine you have:


[Image: PR-model.jpg]




On the ResMed S9 series CPAP machines, you can usually identify your machine
by the name near the start/stop button:


[Image: s9-autoset-models.jpg]



Coffee
SuperSleeper
Apnea Board Administrator
www.ApneaBoard.com


INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.


Post Reply Post Reply
#8
RE: Help understand the different machines
(06-21-2014, 07:29 PM)jcarerra Wrote: When do you need ASV instead of Bi-Level auto instead of Bi-Level instead of APAP instead of CPAP?

to quote the resmed titration guide:

Indications for ASV therapy

• Periodic breathing, both normocapnic and hypocapnic
• Other forms of central and concomitant obstructive events (mixed sleep apnea)
• Complex sleep apnea (CompSA)
Post Reply Post Reply
#9
RE: Help understand the different machines
(06-21-2014, 10:46 PM)SuperSleeper Wrote: On the ResMed S9 series CPAP machines, you can usually identify your machine
by the name near the start/stop button:[/size]

[Image: s9-autoset-models.jpg]
Coffee

it might also say: "VPAP S" "VPAP Auto" "VPAP ST" "VPAP ST-A" "VPAP Adapt" to name a few, (or even VPAP Tx if you're very lucky) it gets more fun in that there's two adapt models, the old and the new, and both say 'vpap adapt' on the top.

however, like the respironics, you can look on the label, (on the back, on the resmed machines) and check the REF number:

36000 S9 VPAP Tx lab system
36001 S9 CPAP Escape (CPAP Only)
36002 S9 APAP Escape Auto (No data)
36003 S9 CPAP Elite
36004 S9 VPAP S
36005 S9 APAP AutoSet
36006 S9 VPAP Auto
36007 S9 VPAP Adapt (older)
36009 S9 VPAP ST-A
36037 S9 VPAP Adapt
36038 S9 VPAP ST
36039 S9 VPAP ST-A
36050 S9 VPAP Tx
36065 S9 APAP/CPAP AutoSet, Pink
36150 S9 UK Autoset CS
36160 S9 france autoset cs
36170 S9 germany autoset cs
36251 S9 autoeset cs-a (Switzerland)
36211 S9 autoeset cs-a (Europe "group 1")
36231 S9 autoeset cs-a (Europe "group 2")
36271 S9 autoeset cs-a (Europe "group 3")
36995 S9 climateline tube
36996 S9 Climateline max tube
Post Reply Post Reply
#10
RE: Help understand the different machines
(06-21-2014, 07:29 PM)jcarerra Wrote: When do you need ASV instead of Bi-Level auto
instead of Bi-Level instead of APAP instead of CPAP?


Hi jcarerra,

In my view, everyone using a fixed CPAP therapy mode would benefit from a data-capable and APAP-capable machine rather than merely a fixed-pressure machine, because all APAP machines can also be operated in plain fixed-pressure mode, and everyone (and their doctor) deserves to have the option to periodically (and economically) recheck the titration pressure by turning on the Auto mode for a night (or week or whatever) to verify the pressure needs have not significantly changed. And that applies to the folks (there are quite a few!) who do better on fixed CPAP than on APAP.

Whether therapy is optimal in fixed-pressure CPAP mode rather than APAP mode, and the individual settings, varies from person to person, of course.

In general, the "Auto" function in an APAP machine refers to automatic adjustment of EPAP in order to minimize obstructive events while keeping the average EPAP pressure low (by raising EPAP only as much as recently shown to be needed).

Anyone who does better with the maximum EPR enabled or the maximum FLEX enabled, may do even better with a bi-level machine, which allows greater pressure range and controllability between the EPAP pressure versus the IPAP pressure. For some, using bi-level is needed for comfort or avoidance of aerophagia, whereas for others it may be needed to eliminate Upper Airway Resistance Syndrome (UARS).

Great article explaining UARS and Respiratory Effort Related Arousal (RERA) events, and why some patients continue to suffer excessive daytime sleepiness even though they are using PAP treatment and have low AHI numbers, and how bi-level treatment may be able to solve this:
http://www.apneaboard.com/forums/Thread-...light=UARS

A bi-level Auto machine will (like an APAP machine) automatically adjust EPAP in order to minimize obstructive events while keeping the average EPAP pressure low (by raising EPAP only as much as recently shown to be needed).

An Adaptive Servo Ventilator (ASV) machine is only needed by those who need to treat central apneas by automatically (and quickly!) increasing Pressure Support (the difference between EPAP and IPAP pressures) in order for the machine to do all the work of breathing during times when our respiratory system is not even trying to breathe.

More recent ASV models have also added the Auto function and automatically adjust EPAP in order to minimize obstructive events while keeping the average EPAP pressure low (by raising EPAP only as much as recently shown to be needed).

I think the bi-level "ST" machine is an early form of ASV machine which allows a manually-adjustable backup breathing rate during central events. Unlike ST machines, ASV machines can use an automatically-varying backup respiration rate which matches our recent breathing rate. "ST" machines (and early models of ASV machines, also) are not Auto models, since they do NOT automatically adjust EPAP in order to minimize obstructive events while keeping the average EPAP pressure low (by raising EPAP only as much as recently shown to be needed).

The bi-level "ST-A" or "AVAPS" machines are like early ASV machines which were not Auto models (do not auto-adjust EPAP) but do automatically adjust Pressure Support to treat central events, and they have two main added features: the IPAP pressure can go as high as 30 cm H2O if needed, plus these machines add a manually-adjusted lower limit for Tidal Volume (Vt, the volume of air inhaled or exhaled in each breath). Having an adjustable lower limit for the Tidal Volume is useful in two ways. First, ASV machines and ST machines have a weakness because they use an automatically-adjusting target for the Minute Volume (Minute Volume is the total volume of air either inhaled or exhaled in one minute) which targets 90% or 95% of our recent breathing, and, in some patients (like me, for example), sometimes our breathing so very gradually gets slower and more shallow, so very gradually that the ASV never notices and never kicks in, allowing very long hypopneas. Having a manually-adjusted absolute lower limit for Tidal Volume prevents this from happening. Second, in cases where the patient is weak or is taking opiate pain meds which are reducing respiratory drive, similarly, having a lower limit for Tidal Volume keeps the patient adequately ventilated even when the patient is too weak or drugged to do this on their own, thereby saving their life.

Take care,
-- Vaughn



The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies.  Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment.
Post Reply Post Reply


Possibly Related Threads...
Thread Author Replies Views Last Post
  csa machines cexer 1 73 03-20-2024, 01:43 PM
Last Post: cexer
  New to OSCAR..Please Help me understand the data. *screenshots attached* Cowboys77 0 87 03-19-2024, 05:52 AM
Last Post: Cowboys77
  Help needed to understand chart SteveC 0 97 03-11-2024, 11:54 PM
Last Post: SteveC
  Just trying to understand this stuff Domino96 5 271 03-05-2024, 11:31 AM
Last Post: Sleeprider
  [CPAP] Newby trying to understand what i am seeing WoodyV12 18 982 02-24-2024, 08:17 PM
Last Post: Macka
  Returning defective machines to Philips Respironics big_dave 5 672 02-04-2024, 02:15 PM
Last Post: big_dave
Question [CPAP] Help to understand current situation and OSCAR data 3dkid14 0 254 01-18-2024, 04:21 AM
Last Post: 3dkid14


New Posts   Today's Posts


About Apnea Board

Apnea Board is an educational web site designed to empower Sleep Apnea patients.