ResMed S9 Pulsing on Exhale

Hello Everyone,

I read on a few places others with a ResMed S9 is experiencing pulsing on exhale. My unit is doing the same thing and I find it very annoying.

I just returned back from a sleep test and the Restronics unit they had at the clinic did not pulse.

Is the pulsing a "feature" of the ResMed or is it truly a defect?

The pulsing of airflow only occurs during long exhales.

I have used both models now and prefer PR 560. And it is mainly because of the way it senses apner. ResMed sends a series of air puffs too fast in my opinion. Respironics sends a larger air puff but waiting a little longer before sending it. As I breathe very slowly so disturbed me by ResMed's puffs.

I haven't noticed that, but do notice that my mask, the Activa LT, expands and contracts a bit with exhale and inhale - could it be your mask rather than the machine?

Coolspot,

Which S9 are you using? The model name should appear right above the ON/OFF button to the left of the LCD on the blower unit. The machine should say one of the following:

• Escape
  Elite
  Escape Auto
  AutoSet

If the machine is an Elite or an AutoSet, then the pulsing may indeed be the FOT algorithm that Lazer1234 describes. When you don't start inhaling within about 4-6 seconds after the last exhale ended, the S9 Elite and S9 AutoSet start sending out the FOTs in order to determine whether your airway appears to be CLEAR (open) or OBSTRUCTED (closed), and if you don't take an inhalation within 10 seconds of the end of the last exhalation, the machine will score the appropriate kind of apnea: a CA if the airway is CLEAR and an OA if the airway is OBSTRUCTED.

The Escape and the Escape Auto do not have the FOT algorithm because they're much dumber machines than the Elite and the AutoSet. The Escape records nothing but usage, and while the Escape Auto does record apneas and hypopneas, it does NOT try to classify the apneas into CAs and OAs. So if you have an Escape or an Escape Auto, then the problem is something other than FOTs.

robysue wrote:Coolspot,

Which S9 are you using? The model name should appear right above the ON/OFF button to the left of the LCD on the blower unit. The machine should say one of the following:

• Escape
  Elite
  Escape Auto
  AutoSet

It is an Elite.

I just find the puffing to be very annoying ... I like how the Philips Machine at the clinic was "smoother".

I assume there is no user/admin adjustable setting to delay the puffs?

cooslpot wrote: I just find the puffing to be very annoying ... I like how the Philips Machine at the clinic was "smoother".

I assume there is no user/admin adjustable setting to delay the puffs?

Is the puffing on every single exhalation? Or only on the longest of them?

Is the puffing a series of tiny puffs or one larger puff?

Are you using EPR and if so, what is it set to?

I'm wondering if the "puff" is the FOT algorthim kicking in or if it's that you happen to be super sensitive to how the EPR algorithm increases the pressure at the very tail end of the exhalation.

For the elite, I think you can set the EPR in two different modes except 1. 2 and 3.

robysue wrote: Is the puffing on every single exhalation? Or only on the longest of them?

Is the puffing a series of tiny puffs or one larger puff?

Are you using EPR and if so, what is it set to?

I'm wondering if the "puff" is the FOT algorthim kicking in or if it's that you happen to be super sensitive to how the EPR algorithm increases the pressure at the very tail end of the exhalation.

Only if I exhale longer than 4s as per the graph.

EPR is set, I think to medium.

cooslpot wrote:
It is an Elite.

I just find the puffing to be very annoying ... I like how the Philips Machine at the clinic was "smoother".

I assume there is no user/admin adjustable setting to delay the puffs?

I had the same problem, was disturbed by these small air puffs. It is ResMed FOT algorithm that detects apnea. I now use the Philips apap DS560 instead because I'm really happy with it.

coolspot wrote:

robysue wrote: Is the puffing on every single exhalation? Or only on the longest of them?

Only if I exhale longer than 4s as per the graph.

That sounds like the FOT algorithm kicking in.

You might find the PR System One's PP algorithm for distinguishing between OAs and CAs less disturbing.

Robysue, recently it seems I've seen a number of posts regarding the FOT of the S9 being disturbing and you've answered some. I don't recall this being an issue earlier. Has this been a problem all along, and I've missed it, or has ResMed made recent changes to their algorithm?

Jay Aitchsee wrote:Robysue, recently it seems I've seen a number of posts regarding the FOT of the S9 being disturbing and you've answered some. I don't recall this being an issue earlier. Has this been a problem all along, and I've missed it, or has ResMed made recent changes to their algorithm?

I have had my S9 AutoSet since May 2011, and it was already there when I got it. Firmware 0602