SpO2 does NOT measure how much oxygen is being delivered to tissues & organs. Hyperventilating decreases CO₂. As CO₂ decreases hemoglobin holds onto oxygen too strongly. Increase CO₂ to increase oxygen delivery from hemoglobin to tissues & organs. Don't hyperventilate \r
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Patrick McKeown: \"[…] and your SpO2 is 99, which is normal. Here's another thing. If Jakob started hyperventilating, are you going to really bring in that much more oxygen into your blood? You can't, because you're already 99% saturated. \r
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\"Now say, for example, if you were doing hyperventilation. Now your blood oxygen saturation will go from 99% to 100%. So even though you're bringing in a lot more air your blood oxygen saturation is only going to increase by 1%. […] \r
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\"In the blood 98.5% of your oxygen is carried bound by hemoglobin. So what you're measuring there is your SpO2: of your hemoglobin, what's the fraction of it that's actually carrying oxygen. \r
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\"Now if you were to hyperventilate as I said, it will increase it by 1%. But in the interim the hyperventilation will get rid of too much carbon dioxide. […] The hyperventilation will actually increase the SpO2, and this will be down to two reasons. One is that you're taking more air into your lungs. But the second reason is that as you hyperventilate, not only is your oxygen increasing but your carbon dioxide is decreasing. \r
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\"And as your carbon dioxide decreases, there is a curve called the oxygen dissociation curve. That shifts to the left. And as carbon dioxide decreases hemoglobin holds onto oxygen too strongly. And because hemoglobin is not releasing oxygen readily that's going to further cause your SpO2 to increase. […] \r
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\"What is our breathing all about? It's really to get oxygen to be delivered to the tissues and organs. We're not going to be breathing in air for that oxygen to do a round trip and then we breathe it back out again. But if we hyperventilate, that's more of what happens. If we want our blood to release oxygen to the tissues and organs, we need carbon dioxide. And who made that discovery? Christian Bohr. […] The Bohr effect. […] He said that as carbon dioxide increases in the blood, blood pH drops, and the affinity of hemoglobin for oxygen reduces. So if I want to increase oxygen delivery throughout my body, don't hyperventilate. […] Gently slow down your breathing to the point that you are underbreathing […]\" \r
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Patrick McKeown with Mads Tömörkènyi & Jakob @ 59:58–01:03:24 (posted 2024-07-21) https://youtu.be/-nCm8c_hVJA&t=3598