Oxygen Saturation Measurements

[charliecoutas]

I have bought a board which contains all the stuff to do oxygen saturation/pulse rate measurement: Pulse Oximeter and Heart Rate Sensor - MAX30101 & MAX32664. But the documentation says it is for finger measurements only (there are other versions for wrist and earlobe). I need it to go on a toe. My question is this: what is the difference between measurements taken from the finger or the toe?

I would guess that somebody knows all about this (Tim B?) who works in the medical arena.

Thanks
Charlie

[RGV250]

Hi,
I have just tried mine on 3 toes and it failed to register anything so I would say no go.

Regards,
Bob

[charliecoutas]

Thanks Bob, that's very useful to know.

Charlie

[top204]

I think because the foot is so far from the heart, and actually has a pumping mechanism itself to move the blood back up, the blood surge down there will be very small.

There are only a few places at the bottom of a leg that a pulse can be detected with any certainty, and one them is the ankle, so maybe an ankle strap with a slimmed down detector will work, or maybe, a more sensitive detector with a different frequency of InfraRed.

For tests of the best position, try a stethoscope in different places on a foot and see which one has the better response, this will mean the blood is closer to the surface of the skin.

[charliecoutas]

Yes I agree Les. The module I have says that it is specifically for the finger, there are other options but the toe is not one of them. I need to rethink this.

The problem is this: a young lady with Rett Syndrome is in a special home. Her blood oxygen saturation sometimes drops, sometimes to a dangerous level. She has a monitor (it uses her toe) but the staff are not always near the unit. I was going to add a monitor that linked to the main office area by radio to raise the alarm quickly. The chat about cameras suggests that maybe a video link from her existing monitor?

I can't use her finger because her hands are usually busy twisting each other and a monitor would quickly be knocked off.

[trastikata]

She has a monitor (it uses her toe) but the staff are not always near the unit.

Charlie, can't you use some signal (beep, led etc) from the current monitor as trigger for your alarm unit?

[charliecoutas]

Good idea but ideally the office should see the saturation level as well as hearing the beep. A pal of mine has written an app to solve Sudoku by showing the Sudoku puzzle to his phone. This involves working out what digits are in what boxes. There would be a camera looking at the monitor, a box to analyse the data then an HC-12 (radio link) to send a warning a PIC driven box in the office. But it sounds like a difficult thing to do (for me).

My other half (the current Mrs Coultas) spent some time on the phone to people who use these devices. There is quite a demand for a longer path between the test unit and the results unit, but nobody has yet met that demand (TimB?).

[ken_k]

options

https://www.turnermedical.com/FOREHEAD_OXIMETRY_REFLECTANCE_PULSE_OXIMETER_s/75.htm

https://www.turnermedical.com/EAR_PULSE_OXIMETER_s/74.htm

[Teo]

https://getwellue.com/pages/o2ring-oxygen-monitor
Teo

[charliecoutas]

Thanks Ken, Teo, useful input.

Charlie