Negative Input

Negative Input

Status report:

Waking.

Reason:

Unknown

Light sensor report:

Negative.

Proximity sensor report:

Negative.

Sound recorder report:

Negative.

Pain sensor report:

Negative.

Run internal diagnostic:

Confused, dizzy, not breathing.

Command: Initiate breathing.

Status report:

Situation worsening.

Seek cause:

Breathing failed.

Command:

Breathe harder and monitor outcome.

Outcome report:

Air intake totally blocked!

Emergency:

Confusion and dizziness, darkness encroaching, must act immediately!

Urgent command:

Displace mask and chinstrap!

Status check:

Returning to normal.

Equipment check:

Mask attached and intact CPAP powered but turned off.

Cause of shutdown:

Unknown.

Turn CPAP on, test mask:

Fully operational.

Turn off, test mask:

Can't breathe.

Analysis report:

Mask failure caused when Silicone tubing closes with negative input.

Conclusion:

Unacceptable risk.

Require improved equipment and early warning systems.

It may depend on your specific mask. My wife has had failures with her ResMed S9 and has survived them for surprisingly long periods of time.

Howdy Sierra,

The mask in question is the Airfit P30

Yes both of my machines have shut down in the middle of the night from time to time and it can leave you pretty wrecked, but there is some air that can still be sucked through the machine and the outlet valve and, of course, there are often leaks which can all add up to enabling you to survive for long enough to wake up and deal with the problem, albeit with a bit of a headache.

The Airfit is different. I have tested it numerous times now and if you are lying on your back it does still allow a tiny amount of air through the two depressed tubes, if you don't suck too hard, but if you are on your side with one tube already closed the other tube closes totally due to the negative suction.

It leaves you with absolutely no air intake at all.

Most masks would only pose a serious risk to somebody who was a really heavy sleeper, or if the machine failed at a critical point in a sleep cycle, but the Airfit is a much more immediate risk to a far wider range of CPAP uses.

Other than it's lethal potential it is a very comfortable mask, and works really well for me, so what could I do to minimize the risk?

I gather that the more recent machines can be self starting which would be helpful in a very short outage.

There are also power outage alarms which might be useful although I think that both of my machines are capable of shutting down without the excuse of an outage.

Are there alarms for pressure loss?

I will attempt to adapt the existing mask to prevent the side tubes from collapsing under negative pressure but why have the manufacturers not already considered all of this?

Don't they have some obligation to make sure their products are safe?

The mask vent is above the soft tubes that suck flat.

It is on top of the head where the main hose to the machine connects.

You can breathe out quite easily with no resistance but the tubes are a one way valve.

Hence my statement that it leaves you with absolutely no air intake at all.

Wander into your nearest CPAP shop and you can test one for yourself. Pop the mask on, close the intake pipe and hold your hand or a pillow against one cheek and try to breathe.

Paradoxically it is a brilliantly conceived design for comfort and fit and effectiveness under pressure.

Perhaps the prototype used a different grade of silicone but the product that Resmed are selling is dangerously flawed.

It would not be of such a concern to me if I thought that natural reflexes would safeguard the user but they don't.

I use a chinstrap which, arguably you could negate, but that would take a positive instruction.

It would require, not just a reflex to allow the mouth to open, but a conscious choice to actively open the mouth against the tension of the chinstrap and to hold it open against the constant pressure.

It is not a natural and instinctive, unconscious response.

With other masks you have some time to muddle your way to consciousness and remedy the situation but with this mask there is no time.

The initial layout of this thread was designed to show the necessity for a number of steps from emergency wakeup to becoming fully conscious and reactive to urgent circumstances and it could be argued that normal masks do allow enough time for most CPAP users to rectify the problem and recover from the impact but only because there is still a limited airflow. It does not allow for the limitations of zero airflow and it does not allow for the added delays caused by increasing confusion and disorientation and other symptoms of oxygen deprivation nor does it allow for the added liability caused by using CPAP on patients who are already confused or irresponsive due to varying levels of disability or dementia.

I don't doubt that there are situations where SmartStart would prove useful but how many power outages would be short enough for you to hold your breath through them and what about when the shut down is initiated by the machine itself and what if something simple and common happens like the primary hose wriggles loose?

The machine is happily blowing air into infinity and you've had your last gasp.

No matter how many safeguards you put in place the risk still remains in a mask design that can totally obstruct all airflow.

It seems to me that the Resmed Airfit mask is, in itself, inherently dangerous.

I’m new to this CPAP caper but there are lots of regulations that cover selling therapeutic goods, however you are entitled to survive using a product. There’s a volume of exhaled breath called ‘dead space’ between the mouth and the great outdoors with some mouth, mask and nose appliances having perforated ports so the exhaled air is immediately dispelled. When there is zero positive pressure these perforations allow for a minimal amount of air to be drawn in while you struggle to the surface. Is the problem the machine, the side tubes or something else ? If it’s just the tubes then it is something the ‘design guys’ should be made aware of. It sounds like you’re having a terrible experience.

When you were talking about the mask I was thinking it was the minimal full face type, but I see it is just on the nose. I also see that it comes in two versions the Nasal and Pillows. Both appear to have some venting on the nasal part as well as at the top of the head. I wonder if one style may have more venting at the nose compared to the other? The drawing from the manual also seems to suggest the QuietAir vent on the pillows version is removeable. I wonder if it would provide more venting if you removed the QuietAir part? See drawing below.

I also believe there are similar DreamWear models which Resmed apparently tried to duplicate to make the P30. Perhaps they are better designed.

I have adapted this mask so that it functions within parameters that I consider essential for survival but the changes I have made are drastic and cannot be discussed or recommended in this forum.

I firmly believe that the AirFit P30 Nasal Pillows mask, in its present configuration, is dangerous and should be recalled.

I am a dentist working in dental sleep medicine. When I read all of this, I can't help, but think how much safer and less complex a simple oral sleep apnea appliance would be for most people. A real shame that the insurance companies and the sleep medical profession still pay so little attention to it. I understand that people who have severe OSA may not have the option, but the vast majority of patients do, including a portion of severe patients. Arthur B. Luisi, Jr., D.M.D.. The Naples Center for Dental sleep Medicine.

Dr.Luisi I do agree that a custom fitted oral appliance can help most mild and moderate apnea with oxygen desaturation that are within an acceptable range. We had patients that actually had both APAP and an appliance. Some used the appliance when they went on vacation or in times when PAP wasn’t convenient to use. Also had a few severe apnea patients on both as the appliance had a dual role, it helped lessen pressure and protect dentition. I also agree that cost factors and coverage come into play. If you cannot use or comply with PAP in a 90 day period the insurance will not pay for the machine or will let you have one more try. But you can give it back, comply, or pay for it out of pocket. With a dental device being fee for service in most cases, regardless of efficacy, you own it. Both therapies come with plus and minuses but absolutely believe that oral appliances should never be ruled out.