Sleep apnea and recording pulse oximeter

When you don't get enough exercise and eat and drink too much, you gain weight. This can lead to sleep apnea, a condition where the throat closes, often the tongue moves back, blocking the airway. Your body notices this and wakes you to clear the airway and go back to an interrupted sleep. Bad sleep leads to daytime sleepiness, high blood pressure, and a false sense of 'may be I'm hungry' and too tired to exercise and the condition gets worse. Sad to say that has happened to me.

After a sleep study eight years ago, I got a CPAP machine. It has a small pump, hose, and mask and increases the air pressure, 8 psi in my case, so the airway remains clear. A pain-in-the-*ss to travel, it meant getting a good nights sleep but it is bulky. But this past year, I learned I was 'grinding my teeth' and that led to a pair of caps on my lower left.

My dentist fabricated a mouth guard to prevent teeth grinding but with the CPAP machine, this became a real bother. So when I visited my sleep doctor, Dr. Brevard Haynes of Nashville TN, I asked about mouth pieces that might substitute or replace the CPAP machine. He showed me a "somnodent" mouth piece that pushes the jaw forward. So I told my dentist about it.

Sad to say, my dentist interpreted this as a snoring problem and instead fabricated a "snoreguard". This two-piece mouth piece appears to accomplish the same thing as a somnodent so we did it. An adjustable unit, my dentist has the adjustment pieces or they can be ordered from the manufacturer. But now comes the problem of finding out if it worked so I spoke with Dr. Haynes.

A normal sleep study takes all night and can easily cost $4,000. If the snoreguard needs adjustment, another sleep study can get pretty expensive. But a recording oximeter provides a functional screening sysetem:

I found this unit on eBay for $45. It uses two, AAA batteries and has the ability to record on a second-by-second interval both the blood oxygen level and pulse. Using the USB cable, the data is downloaded and saved as a CSV file.

This is what sleep apnea looks like when I take a nap without the CPAP or snoreguard:

Notice there were occasions when the blood oxygen level took a steep drive under 92%. In some cases, you'll notice the pulse increases which looks to be the signature of an apnea incident. I'm waking to clear my airway; it clears; and I'm back asleep.

Now drink some beer and the apnea is even worse:

In one case, it dropped down to 82%, not good at all.

This shows how the CPAP machine works:

Notice the absence of apnea events. My oxygen level doesn't even pass below 92%. The pulse peaks are probably just shifting around in bed, not uncommon when we sleep.

Now I have a way to measure the effectiveness of the snoreguard. Initial data suggests it needs to move the jaw further forward which I'll work with my dentist. Then we'll know if I can sleep free from the CPAP mask, hose, pump, and power outlet.

Bob Wilson