PB 420E Stops - maybe?

LastBreathe · Post by **LastBreathe** » Tue Jan 03, 2006 8:12 pm

I have been on CPAP for 2 years. I got a PB420E roughly 6 months ago.

I think in the last month that I have woken up 5 times where I believe the PB420 is no longer blowing air - at all. My mask is still on, nothing noticable for leaks, power still on, etc. Then all of a sudden without me doing anything the PB420E starts up again. Is there a situation that would cause this?

Here is my problem - I live alone and when I am sleeping I am dead to the world. I am pretty sure what I described above actually happened but I do know I wasn't not cognizant enough to say I am certain. I remember waking up unable to breathe, chacking my mask, looking at the clock for power, and then just as I reach to check the machine - woosh, the air starts flowing again. I thought nothing of it the first few times but this is no about 10 times. The data doesn't seem to show anything out of the ordinary though. Am I dreaming, nutz, or could this happen for some reason? Ie, certain levels of apneas shut the machine down until normal breathing is restored or something?

dsm · Post by **dsm** » Tue Jan 03, 2006 9:38 pm

Can you add your thoughts to this thread below - I started it because I was experiencing the same phenomenon & have done with every xPAP I have tried.
Even my current PB330 BiLevel.

I noticed it with my 1st machine running in CPAP mode. I still see this effect now. The downloaded data says the machine continued as normal all night.

To date noone has stepped forward with a really good explanation of the effect.

viewtopic.php?t=6301&highlight=

Cheers DSM

Old Firehorse · Post by **Old Firehorse** » Tue Jan 03, 2006 10:30 pm

Don't know for sure. But I suspect this temporary-off feature is a safety mechanism that kicks in when the machine thinks it detects hyperventilation. That instant off-feature would result in CO2 being temporarily elevated, which in turn would counteract hyperventilation.

Just a waaay-out-on-the-limb guess. I wouldn't take that guess to the bank, though, unless the clerks there were hyperventilating.

Darth Vader Look · Post by **Darth Vader Look** » Tue Jan 03, 2006 11:19 pm

How about an educated stab in the dark at this. I have to ask, do you know for sure that the unit is off (no pressure) when this happens?

I have heard of some machines having an auto on, auto off circuit. Not sure why but I have heard it can be defeated on some machines (maybe this was on older models). The one case I heard about the owner just had to blow into the mask and the unit would sense it and turn on. Not sure how the auto off worked, likely because it didn't work right. My thought here is a large leak of some kind (ie. mask, hose, etc.) would shut the unit down and sound an alarm but then again that should show up on the data.

I wouldn't think that this was a case of defective equipment or intermittent faults with it because it would tend to get worse over time until it completely failed. Possible that it had an automatically resetable thermostat in the motor circuit that was/is tripping out and turning back on?

Could your body just have assimilated to the pressure thus giving you the impression/feeling that the unit was off. If that was the case you should still feel the air coming out of the vent holes in the mask and at your pressure that would be easily verifiable by placing your hand or even a tissue in front of these vent holes.

If the power is removed from the machine is all data lost? Since the Respironics unit dumps data to card that would not be the case for those types of units. Possible firmware problem? Have all possible logic states been taken into consideration in the algorithm with no open ends. The more complex the machine is the more chance of a glitch or intermittent connection. In order to see this a tech would have to be monitoring with logic analyzers and meters and hope that it occurs. A Murphy law - when you are set up to monitor for a fault that fault will never happen.

Just a few of my thoughts.

rested gal · Post by **rested gal** » Wed Jan 04, 2006 12:02 am

LastBreathe wrote:I remember waking up unable to breathe, chacking my mask, looking at the clock for power, and then just as I reach to check the machine - woosh, the air starts flowing again.

When you say you check your mask, do you hold your hand near the exhaust vent to check it, or do you mean you're just touching your mask to see if the mask is still on your face? If you can feel air flow from the mask vent with your hand, treatment is happening. If you don't feel any air blowing out of the mask vent with your hand close to it, then yes, something did shut off the machine.

If treatment air actually is flowing unbeknownst to you because you didn't feel specifically for air flow from the mask's exhaust vent, my guess is that when you reach for your machine, perhaps your body and head movement change the position of the mask just enough that a small leak makes you suddenly feel and/or hear air that had been moving just fine within the mask all along.

When I wake up during the night, breathing at pressure seems so natural and effortless, it feels like there's no air flowing. There's rarely ever a feeling of air movement at all within a mask, not even a full face mask, or from nasal pillows. Most people have to put their fingers up to feel the exhaust air to realize the air flow is "on".

You might want to check the electrical connections to your machine, both at the wall and at the back of the machine. Be sure all plugs are firmly seated in the sockets.

ozij · Post by **ozij** » Wed Jan 04, 2006 12:09 am

Ie, certain levels of apneas shut the machine down until normal breathing is restored or something?

That doesn't make sense to me. Nor does a CO2 "safety feature" make sense - the machine can't measure it, and is meant for treating obstructive apneas.

I would do a very very thorough check of all the electric connections, paying special attention to where the little inlet where power supply enters the machine. I had a slight problem there once with a plug that wasn't snug enough - and yes, the machine stops for a moment, without recording the stop (I was wide awake and fumbling for the humidifer switch, more than once, when I touched the power cord, and apparently nudged the plug just enough to disconnect the power)..

Could anything by touching that little round plug?
Or snagging on the cable or power supply where it connects to the electric outlet?

If all those things checked out perfect, I would consider buying a new power supply for the machine, or taking it to the DME to be checked.

Another possibility: Could you be waking up because you covered the mask's vent with the covers or something?

I recenetly seem to have stopped my Breeze's vent with my hand!

Are you sure the sensor tube is plugged in properly, and isn't getting pulled out?
O.

dsm · Post by **dsm** » Wed Jan 04, 2006 1:17 am

RG has a good point in suggesting you check the air vents. This is what I have been doing & always there is air.

The other part of this phenomenon is the machine seeming to be very quiet. I have put this down to our hearing adjusting to it.

I agree with you re the feeling that suddenly air flows again.

***************

The only theory I can come up with is that if we (perhaps some of us) go into very shallow breathing & then wake up, it may well seem like there is little air. Then we start increasing our breathing & the machine delivers & we feel that suddenly the air flow has increased but in actuality it is our breathing that has increased due to waking up. - Just a thought.

Cheers

DSM

John M · Post by **John M** » Wed Jan 04, 2006 4:02 am

I have a 420E. Something similar happened to me fairly recently. Later when I got up, I found out that the power had gone out intermittently (as evidenced by VCR clocks blinking at 12:00 AM).

One of the shortcomings of the 420E (in my opinion) is that if the power is off for more than a few seconds, the unit turns off and will not turn back on when the power comes back on. As I recall, my Respironics REMstar did not do this (one of the few good things about the REMstar in my opinion, given the quality problems I've had with multiple REMstar Pro w/CFlex units).

This is also a good argument for the "auto on" feature of some machines.

The best solution would be to have a battery backup and/or an alarm (loud enough to be heard). . .

Regards,
-John

Guest · Post by **Guest** » Wed Jan 04, 2006 8:04 am

I also have a 420 E, and have had it shut down also. You state your machine is only 6 months old, it should still be under warrantty..call your supplier and request another unit. My machine was only a few weeks old, I would sit and watch it power up, then watch it lose power,(hint: the read-out may have a single line that dips lower than your minimum pressure setting, then straight back up-study carefuly)
It would shut down, but restart as I wiggled to reach for it, as stated earlier, it seemed to be in the power supply. It was under warranty, and I received a replacement.
If you will search back on this site, using the piggyback heated hose connection also results in power shutdowns for some 420E users, depending on which power supploy your machine came with, there is more than one supply-.if you have a heated hose, use seperate power supplies, not the piggyback.
The 420E only measure air-flow...it does NOT sample O2 or CO2.
Wouldn't it be a wonderful service if a large DME supplier would maintain and publish stats on the defectiver return rate of various brands and models of machines!! Like a cpap consumer reports! That would be a TRUE patient service!!

PhillyPat · Post by **PhillyPat** » Wed Jan 04, 2006 12:03 pm

Being new to CPAP, only a little over a month, I was amazed to discover how my body has adapted to having air blown down my throat! I have a PB 420G. I still wake up thinking the machine is not working, because 1) it's quiet; 2) I can't sense any air moving in the mask. As soon as I put my hand up by the air vents, or in a panic loosen my mask or open my mouth, I feel the whoosh of air and realize that I have gotten so used to it already that it feels normal. I still don't understand it. I am claustrophobic, and I have fought masks in surgery to the dismay of the anesthesiologists, yet my CPAP mask doesn't bother me at all. Most of the time when I wake up, which is rarely now, I think at first that I have again fallen asleep with my glasses on. (I guess that happens when you have been so sleep deprived in the past that it's a common occurrence to fall asleep when you are not supposed to!) I would have to go with RG's explanation if there is nothing to show that the power actually went off.

WillSucceed · Post by **WillSucceed** » Wed Jan 04, 2006 1:18 pm

One of the shortcomings of the 420E (in my opinion) is that if the power is off for more than a few seconds, the unit turns off and will not turn back on when the power comes back on.

I've wondered about this as well and have solved this problem by having my 420E plugged into a UPS-battery backup.

LastBreath wrote:

I think in the last month that I have woken up 5 times where I believe the PB420 is no longer blowing air - at all. My mask is still on, nothing noticable for leaks, power still on, etc. Then all of a sudden without me doing anything the PB420E starts up again. Is there a situation that would cause this?

When you look at the screen, is it showing a pressure or, is it showing FL1?
If you have a HUGE leak, it might have reduced its' airflow significantly and would be showing FL1, then, as soon as you correct the leak, it would rev back up to correct pressure.
If you were having a central apnea of a long duration, you would have an arousal, but the machine should still be blowing at the default command-on-apena of 10 (or whatever you have it set to) [hope I am getting my terms correct here, it might be 1FL rather than FL1] and should not have shut down.

I'm hopeful that what is happening is that the machine is blowing and you are just so accustomed to it, you don't notice the blow. I wake up at times thinking that the machine has shut down but when I put my hand in front of the exhaust hole on the Breeze, I feel the air blowing and go back to sleep.

gailzee · Post by **gailzee** » Wed Jan 04, 2006 10:06 pm

Check the air venting holes in your mask/nasal pillow. If you feel the rush of air, then your machine is working. I have not had it ''shut off'' because if it did, or my mask pulls away from my face, I instantly wake up and know something's not right. I too, have had to raise my pressure, and am now set at autopap 8 - 14. Funny part is using the Silverlining software, NO matter what setting I'm at, I have exactly the same # of ap's, hypop's, no matter WHAT.

If PB is watching this msg. board, can an alarm sound be built into the machine (for the price I'm sure they can do this), that would sound when machine goes off.

Do you notice your breathing feels wrong when your machine goes off?

I've been using my 420E for a year now. It's fine and I have no desire to change, except to buy new nasal pillows/ hoses, things like that. I bought a back up set up for travel.......

Good luck to you...

LastBreathe · Post by **LastBreathe** » Sat Mar 18, 2006 7:40 am

A late reply to this, but it I have witnessed it several more times since my original post and what happens is that the machine instantaneously stops air flow then just as quickly statrts the air flow from the machine again.

The machine is still on and I can see the display. My next challenge is to read the display but its quick and without my glasses I can only see that it is on so its not a power issue.

I also can hear that air flow from the machine has stopped and yes, there is nothing flowing out of the exhalation port on the mask.

I'm thinking its some kind of safety feture or response feature because its happening wakes me up then the machine goes back to normal operation.

However, in the Silverlining software there is nothin recorded out of the ordinary. I would think it should reflect this somehow.

NightHawkeye · Post by **NightHawkeye** » Sat Mar 18, 2006 8:07 am

LastBreathe wrote:I'm thinking its some kind of safety feture or response feature because its happening wakes me up then the machine goes back to normal operation.

Wrong! You could always write PB to see if there is such a safety feature, but I seriously doubt it. Doesn't sound like a good thing at all to me.

Regards,
Bill

ozij · Post by **ozij** » Sat Mar 18, 2006 12:53 pm

I agree with Bill. If indeed the machine has stopped supplying air, the machine has failed, and you are waking up because a the saftey features of the human brain.

O.