Thanks, FDA! You've saved us from pulse oximetry!

[George K]

https://www.city-journal.org/fda-blocks-apple-watch-blood-oxygen-feature

Millions of Americans own an Apple Watch, which commands roughly a 50 percent share of the smartwatch market. Among its many features, the Apple Watch can take your pulse. It also contains hardware to measure your blood-oxygen levels, and it has been doing so since the watch was released—but the hardware is not operable by the watch’s wearer, who thus cannot obtain the results. Under current FDA regulation, the function is disabled. It’s another example of how federal regulation of the production and distribution of pharmaceuticals and medical devices in the United States is less focused on stopping viruses and other diseases than on blocking private-sector innovators from developing solutions that may not work or might have harmful side effects.

This matters in the Covid pandemic. On April 20, emergency-room doctor Richard Levitan described in the New York Times what he’d observed treating patients in Bellevue Hospital in New York. Levitan had seen many cases of “silent hypoxia,” unknown oxygen deprivation in which “patients without respiratory complaints had Covid pneumonia”—even those admitted to the hospital for non-Covid-related health concerns. By the time most patients made it to the hospital, they had “remarkably low oxygen saturations.” Levitan’s recommendation: “Widespread pulse oximetry screening [as] an early warning system.”

As is the norm in the modern administrative state, Congress left the details of regulation up to the agency, in this case the FDA, which classified “pulse oximeters” as Class II medical devices, deemed to pose “moderate” risk to people. The FDA decided not to exempt pulse oximeters from “premarket notification,” the requirement that a manufacturer submit a device for 90-day pre-review by the agency before introducing it to the market. The definition for pulse oximeter in the FDA’s regulation seems broad enough to encompass the Apple Watch device, were it operative: “An oximeter is a device used to transmit radiation at a known wavelength(s) through blood and to measure the blood oxygen saturation based on the amount of reflected or scattered radiation.”

Pulse oximetry is something I (used to) know a little about.

Hemoglobin which is carrying oxygen has a different absorption of light than hemoglobin which is NOT carrying oxygen. It's trivial to compare the level of total hemoglobins oxygen carrying and use that as the denominator. The fraction carrying oxygen is the numerator. Do the simple math, and bingo, percent saturation.

Now, things may have changed but the "radiation" the FDA is talking about is also known as "light." In this case, red and infrared.

BTW, I'm old enough to remember when pulse oximeters were only available for the sickest patients. In fact, I'm old enough to remember when they weren't available at all.

[Mik]

I looked into apps that purport to do that using your phone. None of them seem to be thought to work very well, so I'm not sure how the apple watch does.

But a Class II medical device? Risk to the patient? Please.

[jon-nyc]

I read about that, but never knew the specific reason.

[Loki]

One would think by the time you had a pulse ox issue you would have very significant other issues. It’s not like you get up cook breakfast have a nice convo put your finger in a pulse ox and say holy shit call the ambulance.

[jon-nyc]

Well, that’s sort of what people are reporting. Low oxygenation without feeling short of breath.

[George K]

@Mik said in Thanks, FDA! You've saved us from pulse oximetry!:

I looked into apps that purport to do that using your phone. None of them seem to be thought to work very well, so I'm not sure how the apple watch does.

But a Class II medical device? Risk to the patient? Please.

Those were my thoughts as well. I see no danger, other than an inaccurate reading. I suppose a false "normal" reading when the patient is in trouble would be a problem, but, c'mon.

[mark]

We bought a Pulse/OX meter a while ago. We check our temp and O2 every morning. So far, so good!

[Copper]

A lot of pilots carry a Pulse Oximeter. It can be important if you are flying regularly unpressurized at high altitude, especially at night.

Some later model planes have one built into the instrument panel.

You can find them in pilot shops, like this: https://www.sportys.com/pilotshop/oxi-plus-pro-pulse-oximeter.html

[Loki]

I wonder what a Venn diagram of Apple Watch wearers and people who had a 8-10% drop in pulse ox and didn’t notice it would look like.

[jon-nyc]

Seems like they double the price when they put the word 'pilot' on it.

[jon-nyc]

I think you're still missing the script here, Loki. What is being reported is a drop in sats without SOB. Google 'silent hypoxia'.

[Mik]

@Loki said in Thanks, FDA! You've saved us from pulse oximetry!:

One would think by the time you had a pulse ox issue you would have very significant other issues. It’s not like you get up cook breakfast have a nice convo put your finger in a pulse ox and say holy shit call the ambulance.

You can be quite short of oxygen and not necessarily notice it. When I was in the hospital last December they fluid overloaded me with IVs caused my normally 95+ SPO2 to drop to high 70's in room air. I never noticed it and was not short of breath. In this case you are short because COVID is damaging your lungs asymptomatically.

[Loki]

@jon-nyc said in Thanks, FDA! You've saved us from pulse oximetry!:

I think you're still missing the script here, Loki. What is being reported is a drop in sats without SOB. Google 'silent hypoxia'.

If it’s a matter of going from 92 to 88 without knowing it I get it...I am not buying a 98 to 88 drop silently.

[George K]

@jon-nyc said in Thanks, FDA! You've saved us from pulse oximetry!:

Seems like they double the price when they put the word 'pilot' on it.

You should see what they do for "medical" devices.

[Mik]

@Loki said in Thanks, FDA! You've saved us from pulse oximetry!:

@jon-nyc said in Thanks, FDA! You've saved us from pulse oximetry!:

I think you're still missing the script here, Loki. What is being reported is a drop in sats without SOB. Google 'silent hypoxia'.

If it’s a matter of going from 92 to 88 without knowing it I get it...I am not buying a 98 to 88 drop silently.

You could easily drop from 99 to 88 and never notice.

[Axtremus]

@George-K said in Thanks, FDA! You've saved us from pulse oximetry!:

@jon-nyc said in Thanks, FDA! You've saved us from pulse oximetry!:

Seems like they double the price when they put the word 'pilot' on it.

You should see what they do for "medical" devices.

Or “MIL-SPEC”.

[George K]

@Axtremus said in Thanks, FDA! You've saved us from pulse oximetry!:

@George-K said in Thanks, FDA! You've saved us from pulse oximetry!:

@jon-nyc said in Thanks, FDA! You've saved us from pulse oximetry!:

Seems like they double the price when they put the word 'pilot' on it.

You should see what they do for "medical" devices.

Or “MIL-SPEC”.

Decades ago, heart surgeons were trying a different type of suture to close the sternum when finishing a CABG. They used a suture called "Mersiline" (not sure if I spelled it right). It was a real suture, and was meant to replace the traditional use of wires to approximate the two halves of the sternum that had been sawed apart.

I guess Mersiline was fine, but was a bitch to get that last knot down to get a nice and tight closure. You had to get that knot really down, tight, on the sternum to get it to hold.

One of the surgeons I worked with had a brilliant idea. He took a regular teaspoon, and cut a notch in the tip that would be big enough to accommodate the suture and allow him to apply good pressure while pushing down on the knot to bring the suture "home."

It worked really great, but, ultimately, it was forbidden because it was not a "medically approved device."

Merseline was eventually abandoned, and we went back to standard wires.

[jon-nyc]

Still have the wires in my chest. Occasionally the TSA guys take notice.

[George K]

Wires are forever.