Leak Rates

Now that I'm getting fairly familiar with the treatment, I've been looking at what I can do to make it better. One thing I notice on the charts is Leak data. Now there seems to be a lot of information out there, but I think the issue may be my interpretation of it, or failure there of. My S9 Elite reports a leak rate of 95% at 19.2, and my Mask says it has a vent flow rate of 37 L/m at a pressure of 10. Unfortunately how the machine reports the leak rate is a mystery to me. I don't know if it reports in L/second, or L/minute

Am I right in assuming that the leak rate is fine as long as it's lower than the masks rated vent flow rate?

All these charts are going to be the end of me!

The machine calculates the mask vent. The machine's leak rate readout is the unintentional leak rate you are getting around the mask seal. The read out is in liters per minute. Many folks (including myself) can achieve a 0 l/min all right because they have found a mask that fits them properly and doesn't leak.

Sheriff

Thanks Sheriff,

So somewhere I need to find a solution for the leak I would assume? I'm fairly new to mask fitting so I guess it could be operator error? The hospital did a mask fit for both masks I've had, but they go off of the nice smiley face on the machine which says it's good so I'm not sure if there is another method to use to check.

My current mask is better as I don't wake up to the leaks like I did with the Quattro FX in medium, and I've downloaded a fitting template from Resmed for my mask so I can see I am just within the size range of my mask. I suspect I may be dislodging it when I sleep.

How does the machine know it's a mask vent and not a leak? Is there a setting anywhere which tells it as I now have a different mask. Maybe it's calculating it differently than it should (based on the old mask).

Thanks again.

SleeplessUK wrote:Now there seems to be a lot of information out there, but I think the issue may be my interpretation of it, or failure there of. My S9 Elite reports a leak rate of 95% at 19.2, and my Mask says it has a vent flow rate of 37 L/m at a pressure of 10.

You are using a Resmed S9 Elite, which reports only the excess leak rate in L/min. In other words, a perfect leak line for your machine would be 0.0 L/min all night long.

Your 95% Leak Rate = 19.2 L/min indicates that for 95% of the night your excess leaks are AT or BELOW 19.2 L/min. That also means that your excess leak rate is AT or ABOVE 19.2 L/min for 5% of the night. Resmed's official definition of a Large Leak is an excess leak rate of 24 L/min. Since 19.2 < 24, we can conclude that any official Large Leaks make up no more than 5% of the total night. In other words, Resmed's engineers would be quite happy in saying that your leaks are small enough OR short enough OR both to not adversely affect the efficacy of your CPAP therapy and the accuracy of the data recorded by your Elite.

So somewhere I need to find a solution for the leak I would assume? I'm fairly new to mask fitting so I guess it could be operator error?

Whether you really need to investigate and "fix" the leaks really depends on how much they're bothering you. If you're not waking up a lot because of the leaks and you do wake up feeling refreshed and rested in the morning, then you probably don't need to worry about tracking down the source of the leaks and fixing it. If you are waking up a lot in the night or you're waking up in the morning tired and unrefreshed, then the leaks might be affecting the quality of your sleep, even if they are not large enough or long enough to affect the effectiveness of your CPAP therapy or the accuracy of the data.

The hospital did a mask fit for both masks I've had, but they go off of the nice smiley face on the machine which says it's good so I'm not sure if there is another method to use to check.

Mr. Green Smiley Face shows up if your 70% Leak Rate is AT or BELOW 24 L/min. In other words, the Resmed engineers believe that if your leaks are in the Large Leak range for 30% or more of the night, then the efficacy of the CPAP therapy or the accuracy of the data or both is compromised. And the leaks must be addressed.

Since your 95% Leak Rate was 19.2, we can assume that your official Large Leaks make up less than 5% of the night. If you are sleeping well and your official Large Leaks make up less than 5% of the night on the vast majority of nights, then you may very well want to just not worry about eliminating the last bit of leaking.

How does the machine know it's a mask vent and not a leak? Is there a setting anywhere which tells it as I now have a different mask. Maybe it's calculating it differently than it should (based on the old mask).

Most masks of the same type have intentional leak rates that are about the same amount, so the assumption is that Resmed has programmed that information into the S9 and AirSense machines. It is worth making sure that the mask type is set correctly, particularly if you have switched to or from a full face mask. FFMs tend to have higher intentional leak rates than nasal masks and nasal pillows masks do.

SleeplessUK wrote:Thanks Sheriff,

So somewhere I need to find a solution for the leak I would assume? I'm fairly new to mask fitting so I guess it could be operator error? The hospital did a mask fit for both masks I've had, but they go off of the nice smiley face on the machine which says it's good so I'm not sure if there is another method to use to check.

My current mask is better as I don't wake up to the leaks like I did with the Quattro FX in medium, and I've downloaded a fitting template from Resmed for my mask so I can see I am just within the size range of my mask. I suspect I may be dislodging it when I sleep.

How does the machine know it's a mask vent and not a leak? Is there a setting anywhere which tells it as I now have a different mask. Maybe it's calculating it differently than it should (based on the old mask).

Thanks again.

Mask Vent rate is a Leak

Total leak rate is both the Mask Vent Rate and All Other leaks. Your leak rate changes as your treatment pressure, more pressure more leak, air vents faster. Personally I don't allow a leak rate over 38 LPM @ 14.5 C, without correcting it. Some masks vent so much, I refuse to use them, they don't meet my specs. Manufactures are more flexible with their specs, I use what works for me.

Use the Spec Sheet packed with your mask to find out the LPM it vents at your Pressure, add no more than 5 CM to that number, I keep my total leak rate under that number, if I go over I correct the problem....

Brands of machines measure the leak rate different, some like mine give you the mask vent and other leaks, others don't measure both, makes it confusing, not for me I don't use those machines. Jim

Goofproof wrote:

SleeplessUK wrote:Thanks Sheriff,

So somewhere I need to find a solution for the leak I would assume? I'm fairly new to mask fitting so I guess it could be operator error? The hospital did a mask fit for both masks I've had, but they go off of the nice smiley face on the machine which says it's good so I'm not sure if there is another method to use to check.

My current mask is better as I don't wake up to the leaks like I did with the Quattro FX in medium, and I've downloaded a fitting template from Resmed for my mask so I can see I am just within the size range of my mask. I suspect I may be dislodging it when I sleep.

How does the machine know it's a mask vent and not a leak? Is there a setting anywhere which tells it as I now have a different mask. Maybe it's calculating it differently than it should (based on the old mask).

Thanks again.

Mask Vent rate is a Leak

Total leak rare is both the Mask Vent Rate and All Other leaks. Your leak rate changes as your treatment pressure, more pressure more leak, air vents faster. Personally I don't allow a leak rate over 38 LPM @ 14.5 C, without correcting it. Some masks vent so much, I refuse to use them, they don't meet my specs. Manufactures are more flexible with their specs, I use what works for me.

Use the Spec Sheet packed with your mask to find out the LPM it vents at your Pressure, add no more than 5 CM to that number, I keep my total leak rate under that number, if I go over I correct the problem....

Brands of machines measure the leak rate different, some like mine give you the mask vent and other leaks, others don't measure both, makes it confusing, not for me I don't use those machines. Jim

Oh my... when I get a 0 L/m leak rate, the vent must be plugged... oh my!!

Sheriff

robysue wrote: FFMs tend to have higher intentional leak rates than nasal masks and nasal pillows masks do.

not by much, and less than some pillow masks

Thanks for the information. As always this group is full of great information.

Regardless of the leak it would seem the search for a new mask is still on. This new mask digs into my nose. Almost feels like it's causing bruising. Leaves my nose sore with a huge red area around it.

This therapy is going to take a lot of getting used to.