FX Swift Mask & Being Awoken by the Blasts of Air Pressure

[fullrun]

I'm now on my 6th or 7th week of CPAP with the FX Swift Mask and the ResMed S9 AutoSet. I've been diagnosed with "mild" apnea. I'm definitely sleep better... or a better description would be more "solidly".. even tho I am still awakening in the night... but the intervals have shifted from 2 to 3 hours after initially falling asleep to 4 to 5 hours. I've become accustomed to the mask.... or having to keep awakening in the middle of the night to adjust it. But, what continues to be a sleep interruption is when the air pressure increases to deal with an event... there is this blast of excess air that comes rushing out of the mask's vents (not leakage) which seems to continue on long after the apnea blockage has been dealt with. The only way to remedy it... is to shut-off the machine and restart it. The max air pressure to alleviate the blockage is 10... The night's sleep begins at 4. My thought is "why doesn't it resume to the appropriate air pressure.. why is it continuing as if the blockage is still happening?"

I guess what I am looking for is feedback from those who have had similar experiences with the effects of the increased air pressure flow and have some insight on how to deal with it. It seems that what is awakening me now is not the event, but the air pressure... and, perhaps, both.

[mayondair]

Fulrun, are you using straight CPAP with a pressure of 10 and ramp from 4 or an APAP set to a range from 4 to 10? In either case, 4 is very low, a lot of people would feel they were suffocating at that pressure, and it would most likely not be therapeutic to prevent apnea. Some people are woken by changes in pressure, so if you are using an Auto that is set to wide it may disturb your sleep. Or the exhaust air ( normal flow) may be waking you, in which case a hose hangar may help. This all takes a bit of getting used to. It would be helpful if you filled out your machine and settings in text, you'll get more specific advice that way. good luck. kathy

[robysue]

But, what continues to be a sleep interruption is when the air pressure increases to deal with an event... there is this blast of excess air that comes rushing out of the mask's vents (not leakage) which seems to continue on long after the apnea blockage has been dealt with. The only way to remedy it... is to shut-off the machine and restart it. The max air pressure to alleviate the blockage is 10... The night's sleep begins at 4. My thought is "why doesn't it resume to the appropriate air pressure.. why is it continuing as if the blockage is still happening?"

Each company's APAP has a different, proprietary algorithm that is used both to determine events and to determine how to respond to events. There's much interesting information about APAP algorithms for increasing/decreasing pressure in the thread at viewtopic/t60337/About-APAP-and-algorit ... lbiss.html by the way. The thread even includes a chart that compares the various APAP machines' responses to a canned set of input flow data that mimics a real hypopnea. The Resmed machine in the chart is the S8 and while Resmed did make changes in the algorithm between the S8 Auto and the S9 AutoSet, the general shape of the increase and decrease in pressure is similar on both machines.

The S9's autoset algorithm is quick to respond to events (obstructive apneas, snores, flow limitations, hypopneas(?)) by increasing pressure and is slow to reduce the pressure back down once the triggering event has cleared up. My patient-level understaning of the rationale behind the slow decrease in pressure is that events often occur in clusters and so if a cluster is starting to happen, there's much less increase in pressure needed to prevent or clear the subsequent events.

As to how to deal with the fact that you are awakening because of the change in pressure (or perhaps the change in pressure combined with the event that triggered the increase in pressure), I understand what you're talking about. Back last fall when I was still using the S9, I would occasionally have that problem myself. If it's the increase in the blast of air that's coming out of the exhaust flow vent holes on the Swift FX that's waking you up, an alternate hose management system might solve or partially solve the problem. How do you run the hose from the machine to your nose? If you aren't hanging it overhead, then quite likely that jet stream from the exhaust flow is blowing somewhere on you. So if you can find a way to arrange the hose where the exhaust flow doesn't hit you, that might help. Or figure out a way of "protecting" the part of your body that's being hit by the flow. For me, sleeping in a heavy fleece robe that I can wrap around my chest seems to take care of the exhaust flow problem hitting my chest. Don't know what I'll do in the summer

[KThund2]

I am probably not the best person to answer this issue, since I just had my second night of CPAP therapy. I have the Swift FX for her. The first night was fine - but last night, I kept getting what I thought were leaks and my husband complained it was "much noisier" than the night before. My mask leak alarm, however, did not go off. I can see some similarities between your problem and mine and I'm not sure how to solve it, but you're sure not alone!

Kelly

[Slartybartfast]

What robysue said. Events usuallly occur during REM sleep, which you can see as periods of disordered breathing on your flow chart, if you have the software. So when one event happens, it's "precautious," as my immigrant ex-wife used to say, to maintain the pressure at an elevated level for a while.

Your problem perhaps has more to do with your mask than the machine. One gripe I have against my Swift FX is that the exhaust vents direct air exiting the mask nearly parallel to the hose. I understand they chose to do that in order to minimize blowing cold air on a bed partner. However, the exhaust stream is fairly concentrated, so anything the blast of air touches is going to make noise. Synthetic fabrics such as used on filled comforters, bedspreads, blanket selvedges can make lots of noise. Were the exhaust directed straight out from the mask, like the Opus 360 mask that I prefer, the air generally doesn't impinge on anything, so that mask is (for me, at least) quieter than my Swift FX.

I haven't tried this yet, but something you might try: Affix a piece of gauze bandage or a piece of cotton ball over the exhaust vents with a piece of tape to diffuse the exhaust air. That should make it quieter.

[fullrun]

Both Robyuse and Slartybartfast are on the mark with me. Since I'm just beginning with CPAP and the S9.... the Air Pressure they have started with me is pre-set ramp with a min of 4 to a max of 20. So I start out at 4. My AHI.... varies between 2 and 3 a night And the Air Pressure has never maxed over 10... averaging between 8 and 9... Leakage read is mostly under 10 ml

I think it's most likely the placement of the vents on the FX (from u 2 are saying)... where the air flow is almost at times blowing back into my face.... keep in mind that I am a side sleeper.
And I also appreciate... thanks to you all... the reason for the slow return of the air pressure...

I actually had come up with a great device to guide the movement of the hose while I shift from side to side in my sleep... the ResMed S9 in on a table level to my bedside... I take the tube that runs from the machine and tie my front pajama strings at mid waist loosely around it allowing it to move freely - like a guideline. It guides the hosing so it runs up from mid-waist to my face. It connects to the masks hosing just about where it passes through the pajama string loop. This set-up has allowed me great freedom and movement when turning side to side without wrapping my shoulders or getting caught under an arm. I thought it was pretty ingenious, but I am beginning to see it's drawbacks.

[paulw]

I haven't tried this yet, but something you might try: Affix a piece of gauze bandage or a piece of cotton ball over the exhaust vents with a piece of tape to diffuse the exhaust air. That should make it quieter.

I just did this with my Swift FX using a spare foam air filter rubber banded over the exhaust ports. Seems to work great - quieter and no jet stream blowing on me (or Norma).

[Janknitz]

Fullrun,

Are you being titrated at home, or is there some other reason your machine is running "wide open" (4 to 20)? Hopefully your doctor has plans to determine your ideal pressure range and narrow that pressure range down. When it is set wide open like that, the machine has to "chase" the events, so it goes higher than it needs to and is slower to respond reduce the pressure when the event is handled. A tighter pressure range (usually only 5 - 6 cm difference between your bottom and top pressures) will eliminate a lot of that sleep disturbance from big pressure changes. Some professionals mistakenly think that a wide open pressure range is good because it will take care of all events, but it's actually very uncomfortable, and it's possible to have really good therapy with a much more narrow range.

A hanger to hold the hose over your head really helps. The holes on the swift FX are set to blow down at a 45 degree angle, and when the hose is hanging down toward your belly the vent is almost inescapable. If it's not blowing directly on you, it is certainly bouncing off the bedding and back at you. When it's hanging from overhead, it's blowing up toward the ceiling instead. The hanger also helps stabilize the pillows so they aren't being pulled out of your nose from the weight of the hose--so less waking to reposition them. Finally, a strip of velcro hook tape (the stiff side) sewn inside the back strap will keep the headgear from slipping around when you move your head on the bed pillow--and that will further stabilize the pillows so that you don't have to come slightly awake to readjust every time you move.

[fullrun]

Are you being titrated at home, or is there some other reason your machine is running "wide open" (4 to 20)? Hopefully your doctor has plans to determine your ideal pressure range and narrow that pressure range down. When it is set wide open like that, the machine has to "chase" the events, so it goes higher than it needs to and is slower to respond reduce the pressure when the event is handled. A tighter pressure range (usually only 5 - 6 cm difference between your bottom and top pressures) will eliminate a lot of that sleep disturbance from big pressure changes. Some professionals mistakenly think that a wide open pressure range is good because it will take care of all events, but it's actually very uncomfortable, and it's possible to have really good therapy with a much more narrow range.

Yes, from my conservations with my clinician the 4 to 20 ramp is only temporary... until a more accurate air pressure can beg determined. I just sent my SD card into the clinician who will then pass on the reports to my doctor at the Mt. Sinai Sleep Study Center. But your inform above is very helpful. And I expect a change in the ramp setting to more closely hone in.

I'm trying to minimize a hospital look or feel of our bedroom and our bed.. so I've been resistant to a hanger mechanism lingering above or to the side. I do use a long bobby pin that effectively secures the back band of the FX to my head... the vinyl strap that secures the pillow upward in the nostrils and lies on top of one's head is more difficult to secure as I have little or no hair to secure it's movement

I will definitely try the gauze or cotton to deflect the air... As I said in my initial statement it's hard to determine whether it's the air rush alone or a combination of the air and the event that is the predominant disturbance to my sleep. During the first month of use average air pressure (according to the machine's data) was 8.7; Leaks 7.5L/min; AHI 2.8; Total AI 1.5; Central AI .2 . What I have notice in the start of the second month as I begin to sleep more solidly and deep the AHI has gone over 3 and the leaks have been more erratic going over 10 at times.

[Kahfree]

I am probably not the best person to answer this issue, since I just had my second night of CPAP therapy. I have the Swift FX for her. The first night was fine - but last night, I kept getting what I thought were leaks and my husband complained it was "much noisier" than the night before. My mask leak alarm, however, did not go off. I can see some similarities between your problem and mine and I'm not sure how to solve it, but you're sure not alone!

Kelly

I too have just started using a CPAP and on Monday they gave me the Swift FX for her. The first night was great, I slept 6 hours without waking. The second night I used it one hour. Last night it was 5.6 hours...but I am hearing air leak from my nose now. The first night there was none, but now there is and my machine recorded a leak of 80 last night but my AHI was 2.8. I guess the leak did not interfere with a low AHI. All of this is so new and to learn what is and is not good is a task.

I just want to get to the point where I never wake up with it and sleep soundly. Someday all this will be worked out...I hope. LOL

Kelly

[HoseCrusher]

Fullrun, CAUTION...

WARNING...

And all that other stuff...

I believe it was Gregg, or something close to that, that suggested putting a diffuser on the vent of the Swift FX exhaust port. If you search on "air diffuser" you should come up with his thread on this.

I made a diffuser out of foam. Actually I made 7 of them before I got the shape down and was able to make it thick enough to get rid of any noise. It works GREAT!!!

However, when the noise is completely eliminated, the flow rate through the exhaust vent is cut about in half.

The purpose of the exhaust vent is to flush your exhaled breath out so that you don't re-breathe it. Re-breathing can load you up on carbon dioxide and cause problems.

I did some testing in this, and as long as the pressure is 6 cm H2O or higher, and as long as your respiration rate is below 12 breaths a minute, there is enough flow to eliminate your exhaled breath. I slept with mine for 6 days and wore a pulse oximeter to check for O2 levels each night. I observed no drop on O2 levels.

It was great to plop the covers up to your chin, or over your head, and have no noise at all. My wife seemed to snuggle a little bit closer too...

I ended up tearing my diffuser during cleaning, and haven't made another one. I was thinking of seeing if different foams would react differently.

Keep in mind that my testing is not exclusive, and I certainly did not cover every possibility, but I think it makes sense that covering the exhaust port to reduce noise will reduce air flow through the vent. I was surprised that it was cut about in half. I did not try a range of pressures, but concentrated on the pressure that I use. I did look at the lower pressures. At 4 cm H20 with 10 breaths per minute I was at about break even, but when I increased the breaths to 15 per minute, the exhaled breath was not being completely cleared out. At 6 cm H2O with 12 breaths per minute it worked great. Since I start my ramp at 8, I figured that would give me some cushion in the event I got really excited by a dream in the middle of the night.

I don't know what cutting the exhaust rate in half does to the reporting statistics of the machine, but it may make your leak rates look exceptionally good.

My personal feeling is that it is a good modification to try, but you need to be aware of the consequences of what you are doing. If you do this make sure to test your system out to make sure you aren't re-breathing your exhaled air, and pay close attention to your data after you attach the diffuser to make sure it isn't throwing other numbers off.

[fullrun]

The purpose of the exhaust vent is to flush your exhaled breath out so that you don't re-breathe it. Re-breathing can load you up on carbon dioxide and cause problems.

HoseCrusher... thank you!

I was looking at the vent tonight.. and playing around with placing a piece of gauze over it... and then I reflected on what you and my clinician initially said about the purpose of the vent releasing and blowing off the CO2. And, thought it best to hold off on any adaptions until my new air pressure setting is determined. Right now - I think - it's not the noise that's awakening me as much as the gush of air against my nose and face. It would be cool if ResMed came out with diffuser or a vent that was directionally adjustable...

thanks again for warning.. and heads up..

[greg-g]

I've been using this air diffuser for about 7 months. It's a very open fibre filter and I can't detect any reduction in air flow through the vent, but is does stop all the air blast.
I'm a front sleeper and use a hose hanger with a head strap on my Swift FX
It's critical not to block the vents as you would be re-breathing your expelled air.

viewtopic.php?f=1&t=54961&p=514706#p514706

[Lizistired]

The air blast is my biggest problem too now that my others have been eliminated. I want to get this sorted out before it warms up and I can't sleep in long sleeves. The cold air always blows on my forearms and wakes me up. And I like to burrow down in the covers or just pull them up over my head.
I had wondered what effect modifying the vent would have on the ResScan numbers. I may wait till I know my numbers are stable. I was about to dremel out the vent holes!

[Slartybartfast]

You have a Dremel tool? Geez, a woman after my own heart! And a Hoosier, to boot! I think I'm in love!

Take care, though, before you go modding your mask because the vent holes are carefully sized to provide just enough flow to ensure that you don't re-breathe very much of your exhaled air. If you hog out the holes the machine will just ramp up and blow more air to compensate for the reduced back pressure. The problem with the FX mask is the direction the holes are bored, not their size.

Some of the suggestions I read above indicate that others misunderstood what I suggested re: the gauze or cotton ball. The idea was to take a piece of gauze, perhaps only one or two layers, that is loosely woven enough that you can see through it, and loosely tape it over the mask vent. Only so much that the blast of air leaving the mask is directed into the gauze. Back pressure won't be affected if you tape it on loosely. But the gauze should be sufficient to diffuse the air blast.

[Edit: The wind is screaming off the ocean here in SoCal. If y'all don't hear from me again, it's because I've been blown off the hill the house is perched on.]