Is my Leak Rate acceptable?

[Wanttosleep]

Good Day all. I've been away for over a week now and am catching up with my reading of all the posts on this forum. I continue learning here day in and day out. I've downloaded the software and downloaded my card to it for data up to the end of Nov. I will be dowloading the month of Dec. shortly and posting it here for comments.

For today I have a quick question. Is 14.4L/min and acceptable leak measurement? I think it is but would like to double check.

I was in the hospital for a week following emergency hernia surgery (weird right) and the hospital supplied me with a CPAP machine since I didn't have time to pack before going there. They set the pressures as per my doctor's recommendations but I have to tell you that mask was just awful. Thank goodness for the meds which helped me ignore most of the discomforts. Now I'm back home, feeling great and using my own equipment and my just received Mirage Quatro full face mask. I slept for 8.3 hours! Yeah. Not sure I'm feeling the results of the therapy and such a good sleep because I'm still feeling the effects of the anisthesia but if this continues I'm really thinking I'll be feeling terrific shortly.

[robysue]

For today I have a quick question. Is 14.4L/min and acceptable leak measurement? I think it is but would like to double check.

Is that 14.4 L/min figure from the S9's LCD screen? If so, it represents the 95% Leak Rate. Which means that you were leaking AT or BELOW a rate of 14.4 L/min for 95% of the time the machine was run overnight. And that also means that you were leaking AT or ABOVE a rate of 14.4 L/min for 5% of the time the machine was running. In getting a handle on what this really means, it helps to realize that 5% of one hour is three minutes. Since you said that you slept for 8.3 hours, that means your leak rate was AT or ABOVE 14.5 L/min for a total of

(3 minutes per hour) * (8.3 hours) = 24.9 = 25 minutes for the entire night

Now your real question is whether this is an acceptable leak rate. Well, the ResMed engineers who designed the S9 and it's software are not overly concerned with a leak rate of this size: The Red Frowny face (clearly unacceptable leak rate) is triggered when your 75% leak rate is AT or ABOVE 24 L/min. In other words, the ResMed folks are worried that leaking AT or ABOVE 24 L/min for 25% of the total time machine is running is enough to compromise the auto-algorithm's ability to detect and respond to events, the S9's recorded data concerning the number and type of events, and your therapy! Your leak rate is obviously well below that level. But that's not the whole story: The real question is whether leaks at this rate are bothersome enough to make you uncomfortable either while you're sleeping (or trying to sleep) or in the morning/day after a night of leaks.

So the real question of whether this leak rate is acceptable is tied into several different things:

1) Were you leaking at a smaller, but still positive leak rate all night long and finding yourself fiddling with the mask off and on all night long? If so, then the leaks are a problem because they're interrupting your sleep.

2) Did you wake up with really dry eyes (from air blowing into them) or a really dry mouth (from small mouth leaks)? And if so, are these things so bothersome that they are causing you problems either dealing with therapy or during the daytime or in trying to get to sleep? If so, then the leaks are a problem because they're making you more uncomfortable than you need to be, which in turn may eventually effect your overall compliance with therapy.

3) Did you have one or two "big" leaks that were caused by the mask getting pushed around? And after you fixed the mask problem, you didn't have any other problems? In this case, that 14.4 L/min figure probably is quite acceptable.

So what I'm trying to say is that your leak rate is very acceptable to the S9 and its engineers. But whether that leak rate is really acceptable to you is determined by how much the leaks you perceived affected your ability to get a good night's sleep and feel good in the morning. The more discomfort you have, the more you need to worry about the leaks.

[KimberlyM]

Wow Robysue, your explanation couldn't have been better. I had a question along the same lines and you answered it! Thank you so much!

[cortez356]

I was going to ask a similar question this morning but Robysue's explanation answered my question. When I have a high leak rate I check my graphs and usually I see a huge leak for a short period. However I also wonder if comparing leak rates on one machine to another is valid. A Respironics might interpret a leak differently. Then too different masks and settings could change the figures. ( BTW: I am not stating this as a voice of experience. I am a newby and that is what I have learned from this forum!!) My question would be: Do leaks cause the rest of your data to be flawed. For instance if you have an APAP does it change your pressure readings? Does it affect your AHI in any way? Great explanation Robysue.

Bob

[Wanttosleep]

Thank you for the information Robysue. Very informative to know how to decipher the numbers. In answer to your questions:

1) Were you leaking at a smaller, but still positive leak rate all night long and finding yourself fiddling with the mask off and on all night long? If so, then the leaks are a problem because they're interrupting your sleep.

I remember waking a couple of times to shift positions and during these shifts I repositioned the mask for the new position I had assumed. I do remember waking at least once when, as I was about to turn over, I noticed that there was a slight leak at my chin. This is actually the reason for my question about acceptable leak rate. For the first time in approx. 3 months I was not awaken because of leaks so I was pretty surprised to see the number as high as it 'looks'.

2) Did you wake up with really dry eyes (from air blowing into them) or a really dry mouth (from small mouth leaks)? And if so, are these things so bothersome that they are causing you problems either dealing with therapy or during the daytime or in trying to get to sleep? If so, then the leaks are a problem because they're making you more uncomfortable than you need to be, which in turn may eventually effect your overall compliance with therapy.

I had no dry eyes or dry mouth. I actually turned my humidifier down from 4 to 3.5 because I prefer to get cool, rather than warm, air. I won't turn it off completely because it really does help fight the dryness.

3) Did you have one or two "big" leaks that were caused by the mask getting pushed around? And after you fixed the mask problem, you didn't have any other problems? In this case, that 14.4 L/min figure probably is quite acceptable.

I can't remember and "big" leaks but as I mentioned above I did shift position and reposition my mask a couple of times during the night. I may have actually lifted the mask off my face in doing so and that would certainly cause a big leak.