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

Mask Pressure reading VS Pressure reading
#1
Mask Pressure reading VS Pressure reading
I'm using a ResMed AirSense 10 Autoset with heated hose.

SleepyHead and Oscar both show graphs for both Pressure and Mask Pressure. Wondering what is the difference, and if Mask Pressure refers to the actual pressure out at the mask-end of the hose, how does it know? AFAIK there is no pressure sensor out there.

If that is not what it refers to, then can anyone tell me what it actually measures?

Thanks in advance!

Fred
Post Reply Post Reply
#2
RE: Mask Pressure reading VS Pressure reading
I believe the Mask Pressure is calculated, based on the pressure at the machine, the flow rate at the machine, and the pressure drop due to the flow in the tube between the machine and the mask. So it has to know which hose diameter you are using and its length. If you are using the ClimateLine hose, then it does know those parameters.

Just how accurate those calculations are can't be known until we can put a tiny pressure sensor right in the mask, of course.
Apnea Board Monitors are members who help oversee the smooth functioning of the Board. They are also members of the Advisory Committee which helps shape Apnea Board's rules & policies. Membership in the Advisory Members group does not imply medical expertise or qualification for advising Sleep Apnea patients concerning their treatment.
Post Reply Post Reply
#3
RE: Mask Pressure reading VS Pressure reading
Fred, the mask pressure is not available for all machines, and it is interesting to watch its subtle variations, especially when looking at a breath by breath wave form where respiratory flow rate and the mask pressure, or intended pressure delivery can be seen side by side. Mask pressure shows how Resmed shapes the airflow. While pressure shows the IPAP and EPAP, mask pressure shows how those transitions occur, and how they follow respiratory flow. You will always see mask pressure is at the lowest EPAP during an apneaThe mask pressure reflects the flow rate and mirrors flow limitations and other respiration flow anomalies. It's interesting how little time the machine is at the peak IPAP pressure, and how it drops off rapidly at first during exhale, slowing as exhale ends, then increasing to keep pace with inspiratory effort. When looking at different machines, we see the Resmed EasyBreathe pressure transitions are very different from the square wave form of a Respironics ST or SV. We have seen Philips bilevels apply mask pressure more abruptly than Resmed VPAP and CPAP with EPR.

In short, the pressure graph is the summary of pressure endpoints at any time, while the mask pressure shows a detailed wave form of how that pressure is applied.
Sleeprider
Apnea Board Moderator
www.ApneaBoard.com

____________________________________________
Download OSCAR Software
Soft Cervical Collar
Optimizing Therapy
Organize your OSCAR Charts
Attaching Files
Mask Primer
How To Deal With Equipment Supplier


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
#4
RE: Mask Pressure reading VS Pressure reading
The others can correct me if I'm wrong, and I'm new around here so I very well may be... But to me, I think a simple analogy can describe it nicely... Your household thermostat.  I believe the mask pressure is very much like the "Temperature" displayed on your thermostat... The CURRENT temperature of your house so to speak... Whereas the pressure is like your setpoint... So it might be 73 in your house, but the thermostat is set for 75... Just because your pressure is set for one thing, doesn't mean that's the pressure that's actually applied.

So for example, if you blocked off the end of the hose completely and the pressure was set for 6cm/H20, then in theory looking at a graph of the mask pressure versus pressure would be exactly the same and very steady...

On the other hand, if you quickly allowed a leak to form, then the pressure may stay set for 6cm, but the mask pressure would quickly drop below that point.  However, the machine would start outputting more air to try to build the pressure back to 6cm, and assuming your leak stayed steady, and it wasn't too large, then it would be able to... Plug that leak back up and the mask pressure would shoot way up, and the machine would reduce airflow to bring it back down to the proper level... 

In reality though, not only will the airflow change, but the pressure is going to change as well as the machine is constantly trying to respond, for example, to an exhalation where the pressure is dropped 2cm during the exhale, etc... So you're not going to see just a fixed pressure on the pressure chart either...

Hopefully that makes sense!
Post Reply Post Reply
#5
RE: Mask Pressure reading VS Pressure reading
Try this, the pressure is more of an average over time and rounds off the bumps. The mask pressure show the bumps, moment by moment. Have a look for an ASV chart, it's very easy to see it there.
mask fit http://www.apneaboard.com/wiki/index.php...ask_Primer
For auto-cpap, from machine data or software. You can set the min pressure 1 or 2cm below 95%. Or clinicians commonly use the maximum or 95% pressure for fixed pressure CPAP, this can also be used for min pressure.
https://aasm.org/resources/practiceparam...rating.pdf
Post Reply Post Reply


Possibly Related Threads...
Thread Author Replies Views Last Post
  Help reading program Aeonmed AS100A Autocpap ZaidAddenis 1 127 03-08-2024, 10:57 PM
Last Post: SuperSleeper
  Flow Rate and Mask pressure missing BuzzaJim 9 528 01-30-2024, 03:55 PM
Last Post: BuzzaJim
  OSCAR not picking up resetting of min pressure? WisNaeMe 6 536 01-17-2024, 07:55 PM
Last Post: Crimson Nape
  Stuck in previous pressure settings. ejbpesca 9 960 10-16-2023, 06:37 PM
Last Post: ejbpesca
  OSCAR Overview Pressure Plot not showing real Max sopherFellow 15 2,241 09-09-2023, 07:04 PM
Last Post: edfreeman
  OSCAR 1.5 Pressure Display Cuppa 3 648 09-05-2023, 06:29 PM
Last Post: Crimson Nape
  "Mode and pressure settings missing; yesterday's shown." manders513 5 720 08-06-2023, 06:03 PM
Last Post: manders513


New Posts   Today's Posts


About Apnea Board

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