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September 26, 2020  |  Breathing easy with technology  |  6561 hit(s)

In an effort to improve my sleep regimen, I was recently prescribed a CPAP machine. This device helps with obstructive sleep apnea, where your throat closes during sleep. The CPAP machine basically pushes air into your nose and/or mouth to keep things open.

The concept is relatively simple, but it involves technology. You wear a mask; the mask is connected via a hose to the device itself, which blows air and has sensors to adjust the pressure and temperature. There's a water reservoir so the machine can humidify the air it's blowing at you. There are air filters that need to be changed periodically. The mask, hose, and water reservoirs need to be washed regularly.

So how does the manufacturer (Philips) make and distribute a machine that's a this complex but is intended for a wide variety of people? I count four ways, and am wondering about a fifth.

First, before you can take home your CPAP machine, you get a 20-minute training session slash demo. The trainer walks you how to assemble and use the machine, and they give you the schedule and some tips for cleaning.

I read once that people retain 10% of what they hear during a presentation. The exact number (10%) isn't that important; the idea is just that people don't retain everything you tell them.[1] And I think about all the people who use a CPAP machine. Is a 20-minute demo going to be enough to train this wide range of people? My guess is no.

So second, the machine comes with a manual—two, in fact, a quickstart and a detailed manual. These reiterate a lot of what you learn in the presentation, so you have at least the possibility of hearing it all twice. The quickstart has a lot of pictures. (The manual, a few line drawings.) For me, it was an interesting case of reading documentation for something that I felt I kind of already knew but that I needed some refreshing on.

A third way that Philips tries to help their users is through design. For example, when things connect, they go together in only one way. There's only one way to plug in the machine. The hose goes into the machine only one way. The filters and water reservoir go into the machine only one way; you can't close it if they're not right. The nosepiece in the mask has clear markings right on it for how to put it together. These are all versions of self-documenting features: you literally do not need to read the manual to understand how to put together the components.

As another example, there are very few controls on the machine. For basic use, you need to press only a single button to turn the machine on and the same button again to turn it off. There's a second button if you want to adjust the "ramp"—that is, to set the air pressure to increase gradually when you start up the machine.[2]

And there is a fourth way in which Philips can help people. The machine phones home to report a bunch of statistics about the user's sleep. (That part of the machine required no setup at all, which was great.) This feature has several purposes (some of them a little uncomfortable to contemplate), but at least if the distributor is getting odd reports or no reports from the patient, they know something went wrong. Perhaps they contact you if that's the case.

I imagine that with these efforts on Philips's part, most people can manage to put on their mask and get the machine running. But how well Philips does attempt to help users with ongoing maintenance? It's easy to forget to fill the reservoir. Similarly, the training emphasized that you should wash the hose every week. Is everyone really going to do that? I mean, we're all supposed to floss every day, but how many people really do that?

So I wonder. Does the machine stop and display a message if the water reservoir is empty? Does it tell you when it's time to change an air filter? Does it (somehow) figure out that it's time to wash the hose? I don't know, and I'm reluctant to get into a situation where the machine has to tell me these things. But given the many ways in which the machine, once running, can go wrong, I hope that the manufacturer has taken steps to try to keep it going.

All in all, giving out a complex piece of technology to people and expecting them to all use it right is a hard problem. It's clear that the folks at Philips have thought a lot about this and come up with different ways to try to handle it. Still, I am curious how many people fail when trying to use the machine—they never figure out how to use it, they use it wrong, or they don't maintain it and the machine itself fails. As someone with a professional interest in communicating complex concepts, I find this to be an interesting challenge.

[1] Someone on my team at work has a variant on this idea: you need to hear something 7 times before you learn it. ^

[2] There is also a dial that you can use to make a bunch of other settings, and the dial is multi-modal: turn left for one mode, turn right for another mode, and push for a third mode. Arg. I hate multi-modal controls. But at least this one is optional after you've done the initial setup. ^





Jerry Kindall   26 Sep 20 - 7:58 PM

My wife and I both have that same CPAP. No, it does not warn you when the water reservoir is low or when you need to replace the filters or clean the hose.

If you Google around a bit you can find information on how to access the hidden clinician menu and what the settings there do. It's pretty hackable.