CPAP Monitor Alerts Wearer To Malfunctions

Continuous Positive Airway Pressure machines are a common treatment tool for sleep apnea and other respiratory issues. A common problem with their use is that the mask becomes dislodged during sleep, and thus fails to provide airway pressure to the patient. [Bin Sun] decided to take a stab at solving this problem.

The project consists of an Arduino fitted with a MPXV7002DP pressure sensor. The sensor is used to monitor the pressure in the CPAP pipes. If the pressure varies regularly, it is likely the system is working. If however, the pressure remains at a roughly constant level, that suggests the mask is no longer properly fitted to the wearer, or that there is another problem. In this event, the device sounds a buzzer to wake the wearer, alerting them to check the equipment.

It’s a simple solution to the problem, and something we’re surprised isn’t built into most CPAP machines from the factory. It’s important to be careful before modifying any medical equipment, though we see plenty of hackers taking the plunge to innovate in this area.

28 thoughts on “CPAP Monitor Alerts Wearer To Malfunctions

  1. CPAP stands for constant positive airway pressure. The blower in the machine works to keep the pressure in the mask/tube constant, whether you’re inhaling or exhaling. I’m not sure monitoring the pressure is the best way to look for a dislodged mask. I think it would be better to monitor the flow- if the mask comes off, the flow will by high and in one direction. Also, the noise level will increase quite a bit if the mask comes off, so you could simply monitor the sound level.

  2. Being a CPAP pacient for 10 years, flow detection + pressure works best to detect dislodged masks.
    On the other hand, personally, I wouldn’t want something beeping at me, I already have a bad sleep thank you.
    Besides, if the CPAP has a power failure or mask failure(both extremely rare for me), I tend to wake up gasping for air. At least I haven’t died from choking yet!

  3. reading car forums across the globe CPAP machines seem fairly common in the states but nowhere else? is that just me or is my sample size just too small. used to date a girl (in the UK) who suffered BAD from sleep apnea, (she kindly neglected to tell me about it the first night she stayed over, that was plesant) and dont recall any professionals ever recommending a CPAP

    1. True apnea or just snoring? Snoring itself isn’t a problem, it’s when the person stops breathing altogether (which is completely silent) regularly during sleep, forcing the brain to keep waking up and never getting into the deeper sleep modes that it needs.

    2. Here in .fi, CPAP machines are relatively common among elderly people, but if the sleep apnea is due to obesity, doctors here usually try to just push the patient to lose some weight.

  4. This feature is built into the one I sleep with. If the mask comes off, it beeps till I wake up and reseat the mask. As others have commented, it usually isn’t the beeping that wakes me: it’s the not breathing/gasping for air.

  5. Many CPAP systems allow the user to see a report each morning if they choose to look at it. The majority seem to never even browse these more than once just to see what information is being presented.

    Physicians generally ask that you bring your CPAP with you to appointments. They read the memory card which stores a wealth of information most patients would be unlikely to know how to respond to but the physician can use to effectively provide directions to the patient., as well as determine if any settings changes are appropriate and thus reduce the number of inpatient sleep studies that are required. About all the patient can do in any event is replenish the water reservoir or tighen/replace their mask and/or chin strap, and replace air filters.

    I recognize the model shown. It is fairly current and provides more information to the patient than most can use.

    1. Perhaps there are different levels of machine. I have one that looks exactly like that and it has a built in cell modem. Apparently my insurance company requires reports indicating I’m in compliance with use or they won’t cover the rental and consumables. 21 days a month with at least 4 hours of use. I’m sure that the company that I get it and the supplies from charges them (me) a lot of money for it so I can understand why the insurance company wants me to be using it.

      I find that the quality of my sleep hasn’t improved, but I fall asleep significantly faster. It used to take me about 45 minutes to an hour, now it’s like 5 minutes.

      1. If you’re sleep isn’t improved you need to see the docs again.

        mine significantly improved, and stays improved, until the stupid tubes crack and start leaking air. Why on earth they are so flimsy, considering they get wrapped around my head, arms, neck, etc is beyond me, other than the fact when I looked at paying for a replacement myself, they are £90!.

        Fortunately the NHS works, and they replaced it for me.

      2. ” find that the quality of my sleep hasn’t improved, but I fall asleep significantly faster. It used to take me about 45 minutes to an hour, now it’s like 5 minutes.”

        Okay, my experience is just the opposite, before the CPAP, I fell asleep almost instantly ( I was SO tired!)
        Now it is 20 minutes of “getting comfortable”.

  6. It is totally common to hear that something hugging your face helps you to fall asleep quickly once you’ve grown used to it. The mask pressing on your face gives you a very positive ritual/signal that it’s beddy-bye time, and your body will quickly learn and take this cue. Completely common. But this is just “mask on face” helping you to fall asleep quickly.

    You want the positive airway pressure to keep your airway open during sleep as is the point of the machine. You should definitely feel more rested but say you are not, and this means you should inform your physician of this at this time.

  7. Interesting project.
    Which should not have to be built.

    CPAPs internally measure the pressure, and record it on the SD card.
    They should make them so they broadcast the information over bluetooth.
    Then a cell-phone (or similar) program could monitor, and
    if desired give an alarm when problems occur (such as excessive leak,
    or power outage).
    Instead of having to mess with the machine if you wanted a report in the morning,
    your cell phone should just have quick feedback – which you can tailor to
    highlight any problems (like setting what level of mask leak to alert me to).
    (Or it could send you an e-mail if there were any problems.)

    This would be especially helpful for monitoring somebody else’s CPAP
    (e.g. for a child, or somebody who is less able).

    1. A nice extension to the project would be to add remote notification ability – wifi, etc. That would help those caring for somebody who uses CPAP, but is less able/willing to adjust themselves. (Children, less able, etc.)

      It’s estimated than 1 to 4 percent of children suffer from sleep apnea. Studies have suggested that as many as 25 percent of children diagnosed with attention-deficit hyperactivity disorder may actually have symptoms of obstructive sleep apnea and that much of their learning difficulty and behavior problems can be the consequence of chronic fragmented sleep.

  8. They also should have a connector on them for an auxilary power supply.
    If main power goes out, it would draw on the auxilary supply connector would power the electronics and the blower, but not the heater.
    (One should not have to be woken up, and mess with turning off the heater
    and connecting a battery.)

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