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Leak on Resmed Devices

PostPosted: Tue Dec 02, 2014 6:18 pm
by pdeyoung
Hey Guys

Quick question. I have a lab that I am running a small research study out of (not my site). They have Resmed Titration units and Sandman software. The leak for all the masks are VERY low. Almost unbelievable low (ranges from 0 most of the night up to about 15l/m, MULTIPLE Pts, Multiple masks, and Multiple Nights and Rooms). How can i check that the leak is accurate.

Re: Leak on Resmed Devices

PostPosted: Tue Dec 02, 2014 10:54 pm
by somnonaut
Are you reading the leak on the machine faceplate or what is in te PSG display?

Re: Leak on Resmed Devices

PostPosted: Wed Dec 03, 2014 7:56 am
by linuxgeek
Resmed only reports unintentional leak (attempts to subtract expected leak).

You have to have the correct mask type selected for this to work ok. If you have a FFM selected, but you actually used a Nasal mask, then you'll likely get zero all night.
It won't report a negative leak value, so it will be zero. In those cases, you can never go back and figure out in the psg signals what the leak actually was.

I prefer the reporting of actual leak: (uninentional leak + intentional leak)

Re: Leak on Resmed Devices

PostPosted: Wed Dec 03, 2014 9:15 am
by bduce
I think the recording of total leak or unintentional leak fine (we use the ResMed system). Either system you use, you will still need to know the intentional leak characteristics across the pressure range for the mask you are using. In fact in some labs and hospital wards, I have a single leak value as the threshold regardless of what pressure is being used. Does not make sense!

Re: Leak on Resmed Devices

PostPosted: Wed Dec 03, 2014 12:32 pm
by somnonaut
Again,
Is what you are reading from the PSG, or from the EasycareTx software report (face plate values recorded internally in the software)? Do you use the internal reporting function to capture every setting change within the system and not just rely on gross pressure changes as shown in the PSG?

If the former, make sure your calibration into the PSG is correct. (There is a means from within the Easycare software to test the hi and lo values. It is called DC output test in the Menu pulldown. See graphic attached.
If the latter, then use a known leak valve to check the operation of the machine and test the leak values at the full range of pressures, and corroborate that the face plate values match the PSG values.
I used to have a plastic end cap with a hole (approx 7mm) that would fit into the CPAP tubing providing a calibrated leak. It was from Resmed. Does anyone know the name of, or where to obtain said known leak caps/plugs?

Re: Leak on Resmed Devices

PostPosted: Wed Dec 03, 2014 12:39 pm
by bduce
ResMed used to provide those leak caps. Still got 6 and not giving any away!

Re: Leak on Resmed Devices

PostPosted: Fri Dec 05, 2014 6:53 am
by linuxgeek
You mean they produce the same leak rate regardless of pressure?

Re: Leak on Resmed Devices

PostPosted: Fri Dec 05, 2014 6:58 am
by bduce
No. Unfortunately they use the same leak threshold (ie for when to intervene/ not intervene) regardless of the set pressure! One ward uses the magical leak threshold of 50 L/min total leak for good vs bad leak!!! Go figure :shock:

Re: Leak on Resmed Devices

PostPosted: Tue Dec 09, 2014 7:53 pm
by dream police
The way it was explained to me (by our ResMed sales rep) is that after you select which type of mask is being used, the leak value is "x" lpm above and beyond the acceptable leak at that pressure for that mask. Groovy if you're using a ResMed mask. If it's another co's, you would need to do some figuring. (i.e. Use the set pressure and mask selected to get the acceptable leak, then add the displayed leak to get the actual leak.)