Rebreather or Anesthesia machine?

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Question.
for a ccr diver has an clip on o2 monitor ever been used... I was thinking it should be used for Hypoxia as an alarm... or is it to slow to react?
What about high po2 mix... would the blood stream show higher than 100%
 
Tell him that bleeding is only a problem when you can hear it...!
All bleeding stops…
Eventually.
 
Question.
for a ccr diver has an clip on o2 monitor ever been used... I was thinking it should be used for Hypoxia as an alarm... or is it to slow to react?
What about high po2 mix... would the blood stream show higher than 100%

Andy Torbet posted on IG that he was doing some post dive testing with O2 monitors. Don't know about during a dive though.

But here is something that I want to see if it has any relevance. my garmin fenix 6x has what they are calling a Pulse OX sensor that monitors O2 content in the blood...and this watch is rated to 10 ATA. Does anyone know if this kind of sensor will work during a dive? And is this the kind of O2 monitoring we are talking about here?
If so, I'm going to wear it out for a dive tomorrow to see what kind of results I get.
 
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Don't know... but would assume that its sealed. Love to know if readings change from baseline... and how it reacts...
Wonder if skip breathing or CO2 retention could be measured....
 
O2 monitors that you see clipped on to people's fingers or toes are saturation monitors, they measure how saturated the blood (hemoglobin, actually) is. That is, what percentage of hemoglobin molecules are carrying as much O2 as they can. So it can't be above 100%.

PO2 monitors on a rebreather measure the partial pressure of O2 in the loop. This is the product of the percentage of O2 in the gas (FiO2) and the ambient pressure in atmospheres. That's different from saturation.

The monitors that I show at the end of the video aren't saturation monitors. The one on the rebreather is measuring PPO2, and the one on the anesthesia machine is measuring FiO2. They are the same at sea level. I don't know what would happen if you took an anesthesia machine underwater, but I suspect it would void the warranty.

While theoretically you could measure O2 saturation during a dive, I don't think that would be helpful, since you could become hypoxic and lose consciousness before the sat monitor could react. The anesthesiologists in this threat (paging @rsingler ) can probably answer that better, as far as how tightly linked those two things are.

You can definitely see desaturation even if the PPO2 is high enough. We see SAO2 drop pretty rapidly in infants if respiration is obstructed, but that has to do with special considerations (functional residual capacity, etc..). And people with lung disease (e.g. pneumonia) will have an increased A-a gradient, which means that they might desaturate even if they are breathing supplemental O2.

The thing is that it's fairly easy to measure PPO2 in the gas, and if that's in normal range, then no need to measure SAO2 since those other physiological things aren't going to really change during a dive (maybe immersion pulmonary edema would increase your A-a gradient, but I don't see rebreathers being designed to monitor for that). Of course, that depends on the PPO2 measuring device working correctly, and a lot of rebreather training is about that...
 
Well, technically a clip-on monitor measures how red the thing they are attached to is. As the guy giving a talk on why technology might not be your friend once said, after he clipped an o2 monitor onto a raggedy ann, 86% isn’t great sat, but it’s pretty good for a doll.

So I wouldn’t trust the clip-on type under water without some studies as to how your finger reacts to pressure and cold.
 
The monitors that I show at the end of the video aren't saturation monitors. The one on the rebreather is measuring PPO2, and the one on the anesthesia machine is measuring FiO2. They are the same at sea level. I don't know what would happen if you took an anesthesia machine underwater, but I suspect it would void the warranty.

I imagine they utilize anesthesia machines in places like Santa Fe or Flagstaff, where the altitude is great enough that these differences matter.
 
I imagine they utilize anesthesia machines in places like Santa Fe or Flagstaff, where the altitude is great enough that these differences matter.

I know that some medical equipment uses other means for measuring FiO2, but I think that most anesthesia machines use galvanic sensors, just like rebreathers. Which means that they measure PPO2. So while it's true that the absolute PPO2 with air and 100% O2 would be lower at altitude than at sea level, calibrating the unit will show you FiO2 accurately. A rebreather sensor deals with changing ambient pressure, an anesthesia unit does not.

I have no idea if the PPO2 difference at altitude affects anesthesia, though. Maybe @rsingler knows? Maybe they have to run slightly higher FiO2 at Denver General?

I do know that when I was an Intern, they had a hyperbaric chamber at Mt. Sinai that they did vascular surgery in...
 
Well, technically a clip-on monitor measures how red the thing they are attached to is. As the guy giving a talk on why technology might not be your friend once said, after he clipped an o2 monitor onto a raggedy ann, 86% isn’t great sat, but it’s pretty good for a doll.

So I wouldn’t trust the clip-on type under water without some studies as to how your finger reacts to pressure and cold.

Interesting....
doesn't Poseidon solid state O2 sensor measure a color (I think its red) to read po2? I know that other solid state o2 sensors do that too. But are not rated very high in o2 percentages...
 

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