High AHI with new mask

[TooGroggy]

Two nights ago, I started using a Quattro full face mask. The mask fit much better than my ComfortGel full face, did not leak no matter how high the pressure was or what position I slept in, and I had high hopes that I had finally found the mask for me.

The first night was very uncomfortable and ended with triple the number of obstructive events I had experienced with the ComfortGel. Since the pressure had topped off at the max of the range I had set (10 cm), I figured the mask was leaking enough that the machine was not supplied the required pressure. Oddly enough, the software reported no leaks at all.

So last night, I once again checked the mask (and the hose) for leaks and upped the max pressure from 10 to 14. 5 hours after going to bed, I looked at the AHI reading was four times "normal" and switched back to the ComfortGel. Over the next 3 hours, the software recorded a single obstructive event.

Can anyone suggest an explanation for what is going on? I just don't get how a mask can have this type of effect.

[streetrodder]

did you change the settings for the correct mask?

[TooGroggy]

Both masks are full face masks so the machine is set to Full Face. Is there another setting?

[LinkC]

All the mask setting does is allow the machine to compute the leak rate using a realistic mask vent rate. The setting has nothing to do with therapy.

The Quattro does have a greater vent rate than the Comfortfull, but it's well within the limits of your machine.

It sure sounds like you are getting leaks with the new mask. Switching mask in the night clearly indicates something about the masks makes the difference. You need to clearly rule out leakage.

[TooGroggy]

It sure sounds like you are getting leaks with the new mask.

I agree. But the machine does not seem to be detecting those leaks. For the past two nights, ResScan reported 95th percentile leaks of 0.0.

Oh well... I guess I have a few more tests to run the next few nights...

[Wulfman...]

Two nights ago, I started using a Quattro full face mask. The mask fit much better than my ComfortGel full face, did not leak no matter how high the pressure was or what position I slept in, and I had high hopes that I had finally found the mask for me.

The first night was very uncomfortable and ended with triple the number of obstructive events I had experienced with the ComfortGel. Since the pressure had topped off at the max of the range I had set (10 cm), I figured the mask was leaking enough that the machine was not supplied the required pressure. Oddly enough, the software reported no leaks at all.

So last night, I once again checked the mask (and the hose) for leaks and upped the max pressure from 10 to 14. 5 hours after going to bed, I looked at the AHI reading was four times "normal" and switched back to the ComfortGel. Over the next 3 hours, the software recorded a single obstructive event.

Can anyone suggest an explanation for what is going on? I just don't get how a mask can have this type of effect.

Not all full face masks are created equal.

You didn't say what your minimum pressure has been.....only the max pressure.
I'd be willing to throw out a guess that IF the ComfortGel was leaking more, the machine was putting out more airflow to keep the pressure at the level it was supposed to be. That extra airflow was keeping you from having more events. The better fit (?) of the Quattro is lowering the airflow and may also be affecting the response time of the machine (to the events). It also may depend on whether your apnea events had preceding events like flow limitations or snores to trigger a response.
Consequently, you may need to increase your minimum pressure to head off some of those events.

I didn't particularly like the Quattro because it didn't seem like the exhaust rate was high enough to vent the CO2 and I felt "less-rested" when using it.


Den