bipap

[rux1960]

how is bipap different from cpap? do you need a special diagnosis to use a bipap?

[dsm]

I'm happy to offer my perspective but will say up front, I long ago concluded Bipap was
significantly better that CPAP for a number of reasons. Some I'll add below.

1) Bipap was originally very expensive and thus they were sold as special CPAP devices for
very ill users (people with COPD or who have damaged lungs). The first versions only
offered 2 pressures, a breathing in pressure called IPAP and a lower breathing out pressure
called epap. The machine had added sensors that could detect when the users was breathing
in and when breathing out & could then adjust the delivered pressure between the two settings.

They were regarded as offering far gentler therapy (as mentioned, for people with COPD &
damaged lungs). The reason being that there was less effort by the user to breathout than
there is with a standard single pressure delivery CPAP.

Later a new feature was added called Timed mode that allowed the machine to switch
between ipap & epap at a set rate and this feature allowed Bipaps to be used for
people with predominantly Central Apnea. This further created the image of Bipaps only
being suited for special cases although they were generally better for anyone who could
afford them. Prior to Timed mode, Central Apnea could not be effectively treated by a
CPAP machine. It took special ventilators to do so.

As costs of these units dropped they spread further as other cpap users discovered how
much better they are than standard therapy. Most compliance statistics that show reasons
why people abandon CPAP therapy tend to quote the users as complaining about 1) the
difficulty of breathing out against fixed CPAP pressure & 2) the problems with their masks.

Because Bipap was always more expensive, a couple of CPAP manufacturers added some
exhale relief features to cheaper standard CPAPs in order to try to mimic the benefits of
Bipaps - the 1st big improvement in this regard was C-Flex. But the machines remain
fixed pressure.

I'll skirt around the intro of Autos but they need to be mentioned because Autos by their
nature, held very detailed statistical data on what the Auto was detecting as it needed
such information in order to do its magic pressure adjusting trick. Because this data
could be downloaded by owners of the machines, Autos triggered a self monitoring
revolution among CPAP users. In the early days of Autos, the Bipaps & Cpap machines
didn't have detailed nightly AHI stats. But in time, this capability was added first
to Bipaps then pretty close after to most CPAPs other than el-cheapo models.

Today almost all the major brands of Cpap and Bipap/Vpap support downloading of
detailed nightly data. Also Bipaps/Vpaps are not that much more expensive now and
thus in most cases represent a better therapy option.

Also, a Bipap can be run as a Cpap if someone had some reason to want to do so.

The best of all common choices today would have to be the Bipap/Vpap Auto
machines as they offer very flexible sets of choices to the user. The best Bipap Auto
would be the old Respironics Tank Bipap Auto. It is a classic and most people who own
then love them.

Re the gap between the ipap & epap pressure. Most Bipaps/Vpaps allow you to adjust
this gap and the industry optimum is generally 3 CMs difference. The Bipap Auto
starts at 2 CMs & adjusts the gap as needed & this seems to work very well for many folk.

Typically, the rule of thumb to set a Bipap is to take your titration CMs setting
(lest say 12 CMs) to add1 to get the IPAP (that is 13 CMs for Ipap) & reduce by 2
to get the Epap (thus an Epap here would be 12-2 = 10 CMs). Then by monitoring the
nightly data you can tune the Epap and Ipap settings in either 0.5 CMs increments
Respironics machines) or 0.2 increments (Resmed machines).


Good luck

DSM

[RiverDave at work]

So a bipap is basically a CPAP with full-time exhale relief that is time-based rather than pressure based?

[jnk]

dsm,

Nice summary.

I believe standard protocol is now 4 cm or above for differential:

The recommended minimum IPAP-EPAP differential is 4 cm H2O and the recommended maximum IPAP-EPAP differential is 10 cm H2O

(--1: J Clin Sleep Med. 2008 Apr 15;4(2):157-71. Kushida CA, Chediak A, Berry RB, Brown LK, Gozal D, Iber C, Parthasarathy S, Quan SF, Rowley JA; Positive Airway Pressure Titration Task Force; American Academy of Sleep Medicine. Stanford University Center of Excellence for Sleep Disorders, 401 Quarry Road, Suite 3301, Stanford, CA 94305-5730, USA.)

The way my ResMed VPAP Auto runs in auto mode is that the user/clinician sets the gap between ipap and epap, which never varies throughout the night. The two pressures (ipap and epap) are raised and lowered, in tandem, during the night as needed, so that the gap between them stays the same.

[nomoore]

So a bipap is basically a CPAP with full-time exhale relief that is time-based rather than pressure based?

The biPAP does have full-time exhale relief. It has timed-based as an option but it can work normally too. Also, the difference in pressure between inhale and exhale can be greater than the 3cm that C-Flex can do.

[dsm]

So a bipap is basically a CPAP with full-time exhale relief that is time-based rather than pressure based?

The biPAP does have full-time exhale relief. It has timed-based as an option but it can work normally too. Also, the difference in pressure between inhale and exhale can be greater than the 3cm that C-Flex can do.

Good point - but re C-Flex, it doesn't do a specific 3 CMs difference even at maximum setting. It has 3 settings that cause a momentary change in pressure between inhale and exhale (IIRC) that helps ease the breathing out against the fixed pressure the machine is set to. This dip is not measured in CMs pressure. The machine that does provide a full-time exhale relief measured in CMs is the Resmed with EPR. It offers 1 2 or 3 CMs variation and pretty accurately mimics a Bilevel. C-Flex is a brief transitional relief.

You may actually be talking about the Resmed EPR feature but the name' Bipap' is a Respironics trademark (Vpap is a Resmed trademark - both Bipap & Vpap really mean Bilevel ) so I am assuming you are talking about Respironics machines but what you said is correct if applied to EPR machines (except the comment re C-Flex).

Also re the other post mentioning 4 CMS gap - that is an interesting extract. I used to run my bilevels at 4 CMS gap but over a 2 year period I found through trial and error that 3 CMS provide a slightly better result over time so now apply that. The Respironics Bipap Auto ipap/epap gap can't be manually adjusted & it starts at 2 CMs (that seems too low to me, but when I trialled it it seemed to work very well & people who use that machine seem very satisfied with it).

I tend to think that there can be general guidelines but these are always there to be tweaked & the best settings are the ones that deliver best recorded results combined with feeling better. But, that report is accurate in advising Bilevel titration starting with a 4 CMs gap. Good find.

DSM

[SeaPappy]

I hope that the bilevel is all it's supposed to be. I'm slated to receive mine tomorrow and can't wait. I'm hoping that I can sleep a bit and finally post comprehensible thoughts. Sleep deprivation SUCKS!

[dsm]

I hope that the bilevel is all it's supposed to be. I'm slated to receive mine tomorrow and can't wait. I'm hoping that I can sleep a bit and finally post comprehensible thoughts. Sleep deprivation SUCKS!

SeaPappy,

Good luck ! - I would love to promise you it will be great but have learned over the years that there are too many factors that determine why one person likes a particular set up over another. This CPAP journey really is a road to travel & cpaptalk is one of the best coffee houses to stop and chat with fellow travelers while traveling the road.

Try running the machine in cpap at some stage so as to get a comparison of what it is like against bilevel.

There are a lot of us here who can help you fine tune your set up so please ask if you need assistance.

Cheers

DSM

[RiverDave]

Thank you for the clarification. I appreciate it.

[dsm]

Thank you for the clarification. I appreciate it.

RiverDave,

Just to expand a little. Bipaps/Vpaps (bilevels) - can be

1) S= Synchronous - driven by the users breathing, that is, switching pressure based only on the change of breath direction of the user, they can be
2) T = Timed only mode, that is, the machine is set to a BPM (breaths per minute) such as 13 & will switch between ipap & epap at that rate & ignore the users breathing, or then can be
3) S/T that is, the timed mode only takes control if the sleepers breathing rate drops below a set BPM dialled into the machine. This rate is then called the 'backup rate'. When the sleeper is breathing at a rate higher than the backup rate, the machine follows the users breathing as in S mode. So setting the machine to S/T allows for switching between Spontaneous & Timed modes based on how the users breathing is going.

Few people need T or S/T mode. T & S/T mode is mainly used for people with dominant Central Apnea. T mode is more severe & really for people who may be recovering from some respiratory condition or who may have a debilitating lung problem.

So to accurately answer your point, most Bipaps (bilevels) run in S mode. T mode is an expensive add-on & not needed for normal folk.

Cheers

DSM

[RiverDave]

DSM,

Thank you again. Now all the pieces are fitting together.