Understanding Average AHI

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Understanding Average AHI on a Respironics Manchine Compliance Report what is a good number, mine is at 2.3

AHI is Apnea/Hypopnea Index (the sum of the Apneas and Hypopneas during the night divided by the number of
therapy hours.)

Thanks......

[rested gal]

Your 2.3 average AHI is good. AHI under 5.0 with a Respironics machine is good.

If a person wants to lower their AHI even more (not that you need to), this may often (not always) accomplish that:

With a CPAP machine, raise the pressure.

With an Autopap machine, raise the minimum pressure.

With a Bilevel machine (BiPAP or VPAP), raise the EPAP pressure.

With a BiPAP Auto or VPAP Auto, raise the "min EPAP."

Before ever trying to tweak pressures, it's a good idea to be sure leaks (from mask, or from mouth if not wearing a fullface mask) are well under control.

With a Respironics machine, the average leak rate should not be more than 40.0 L/m (liters per minute) with most masks and most of the usual prescribed pressures.

With a ResMed machine, the average leak rate should be less than .40 L/s (liters per second.) The closer the leak rate is to zero with a ResMed machine, the better, since ResMed already takes into account the expected exhaust vent flow from their own masks when calculating "leak." That is, if you choose the correct mask setting on a ResMed machine.

[cinco777]

With a Respironics machine, the average leak rate should not be more than 40.0 L/m (liters per minute) with most masks and most of the usual prescribed pressures.

A Respironics machine reports System Leak that includes both the Intentional Leak rate (to flush the CO2 that accumulates in the mask) and the Unintentional Leak rate (escaping air from mask leaks, mouth leaks, etc). The Unintentional Leak rate is the "bad" one. My F&P Flexifit 431 FullFace Mask, at my pressure of 8 cmH2O, has an intentional Leak rate of 33 LPM which, if there are no "bad" leaks, would be reported as 33 LPM by EncorePro (EP), EncoreViewer (EV), and EncorePro Analyzer (EPA). Please note that EPA reports the calculated results from EP. On a Resmed machine, assuming that the user selected the right mask re its base leak rate, an equivalent Resmed reported leak rate, in liters per second (lps), would be 0 (signifies zero or no unintentional leak). On a Resmed machine, a reported leak rate of 0.4 lps equals 24 LPM (all of the leak being unintentional). An equivalent level of system leak (0.4 lps) on a Respironics machine would be reported as 33 LPM + 24 LPM or 57 LPM.

If my pressure were 15 cmH2O, my mask has an intentional leak rate of 44 LPM. Adding an equivalent level of Resmed "bad" leak (0.4 lps) for a Respironics machine would result in a reported system leak of 44 LPM + 24 LPM or 68 LPM.

Silver Pelt provided some insight into the capability of our XPAP machines to accurately report our therapy results (OA, FL, Hypopnea, ..) and provide successful "pressure therapy" at various total leak rates. For accurate reporting, he proposed a maximum System Leak rate (intentional and unintentional) of 75 LPM. I've confirmed the accuracy of this number to my satisfaction and continue to use this 75 LPM Leak Rate in judging whether my or anyone else's therapy is suffering from sleep number mis-reporting or - much worse - from being compromised by too much pressurized air being lost to the outside world. Here is the link to his earlier post on this subject. Please note that I, unlike Silver Pelt, don't differentiate between the types of mask as I concur with Velbor that a leak is a leak is a leak and that where the leak occurs is unimportant. What is important is the size of the leak. Too big a leak (in my book, 75LPM) compromises reporting and therapy.

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[araminta]

thanks, rested gal, for the explanation. I never really understood that.