04-04-2015, 04:02 PM
(This post was last modified: 04-04-2015, 06:04 PM by vsheline.)
(04-04-2015, 11:46 AM)BobF Wrote: My AHI's have jumped all of a sudden from an years average of around 2.0 to a startling 8-17.0 for two nights straight. I run 12.0 cm of H20. Can the REsMed S9 Elite machine have stopped supplying the 12 cm of H20?
Yes. Or maybe you are having mouth leaking? Or maybe your hose has a leak and needs to be replaced, or maybe your mask has an oxygen port cap which has fallen off. Or maybe "normal" mask leaks are higher. Or maybe your sleep position has changed. Or maybe there have been changes in your diet or over-the-counter nonprescription medicines, or prescription meds. Or maybe you have moved to a higher elevation, increasing the number of central apneas.
Are all the additional apnea events obstructive in type? Has the amount of Leak changed much? Are you sleeping flat on your back more often?
Quote:What is the cheapest and best water manometer available. I have seen some but don't see how they connect to the hose or the machine. They all seem to have a small diameter port on them.
12 cm H2O is very small (0.17 psi), so you can simply use tape (if needed) between the hose and the manometer.
Quote:Can the pressure be measured at the oxygen port of the Respironics mask?
The small O2 port could used if the manometer was one which did not require airflow through the manometer. Without airflow through the manometer (and through the narrow tube to manometer) there would be no pressure drop between the mask and the manometer, so the manometer would accurately report the mask pressure.
Quote:Is the 12 cm H2O the static pressure when the hose is deadheaded or is it the pressure that is at the actual mask oxygen port when there is flow?
If the hose type is correctly set in the machine settings, the machine will correctly compensate for the pressure drops caused by airflow in the humidifier and hose, and the pressure the CPAP machine reports will be mask pressure.
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. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
04-04-2015, 04:40 PM
(This post was last modified: 04-04-2015, 04:41 PM by archangle.)
Please put your machine type in your profile. i.e. ResMed S9 Elite instead of just ResMed.
Download SleepyHead if you haven't already. One of the things it reports is "Mask Pressure." I believe mask pressure is a report of the actual pressure delivered and it will spot SOME possible failures where the machine won't be delivering the correct pressure.
Note that it is possible that the pressure sensor is working poorly and that's causing the machine to deliver the wrong pressure, but if the mask pressure graph is reporting the wrong pressure, you DO have a problem.
One really poor "manometer" is to get a big pot of water, and stick the hose down deeply into the water. Turn the machine on, then slowly pull the hose up until it starts blowing bubbles. The depth below the surface where it starts blowing bubbles is your pressure in cmH2O.
It's a really crude measurement, but might be useful. It can also spray water around when it bubbles if you aren't careful, especially if you use something narrow like a water glass. It could show you if the pressure is seriously wrong.
It also suffers from the problem that you're measuring pressure at zero flow rate. Pressure might be OK at no flow, but then be wrong when you have air flowing.
The "right" way to use a manometer is to put a "t-fitting" inline with the hose, and run a smaller tube off of the t-fitting to the manometer while you're using the machine. Some of the sellers include a t-fitting and a hose with the manometer.
Get the free SleepyHead software here
for information on the main alternative to CPAP.
If it's midnight and a DME tells you it's dark outside, go and check it yourself.