You likely know this already, but future readers might not: There are a couple potential gotchas about using pulse oximetry on its own to rule out a trip to urgent care. Both are edge cases of the fact that it’s actually measuring the ratio of bound to unbound hemoglobin in the blood as a proxy for blood oxygenation. Both can be pretty confidently ruled out by an additional gadget.
First, carbon monoxide binds to hemoglobin even more readily than oxygen does. Someone who’s been breathing CO may read 100% on a pulse oximeter, because 100% of their hemoglobin is bound to something, but it’s bound to CO instead of O2 so they’re not getting properly oxygenated. This can be addressed by having working carbon monoxide detectors in your home.
Second, if there’s not enough hemoglobin going around your system due to internal bleeding, you can have 100% of the available hemoglobin bound to oxygen and yet not be getting enough total number of oxygen molecules delivered to your body in the time frame that the tissues need it. This edge case can be addressed by monitoring your blood pressure, as it’ll often (but not always, at first!) change as your body tries to compensate for blood loss. Monitoring for any signs of GI bleeding or unusual bruising can also help make sure you seek care at an appropriate time even if the pulse oximeter reads 100% saturation.
Those are the major situations in which a pulse oximeter will claim you’re OK when you actually aren’t. When you’re confident that you’ve got an appropriate amount of hemoglobin going around in your blood and there’s no CO in your environment for it to bind to instead of oxygen, the device will be a pretty accurate proxy for whether your breathing is adequately oxygenating your blood.
Edited to add—there’s another gadget that someone who cares a lot about measuring their respiration might want to know exists, and it looks like they’re available for a couple hundred bucks for home use. It’s called an end-tidal CO2, or etco2, monitor. I don’t have the training/background to explain that like pulse oximetry, but it could be good to look into if you often find yourself in the situation of “breathing feels different from usual, I wonder what changed” and enjoy data.
You likely know this already, but future readers might not: There are a couple potential gotchas about using pulse oximetry on its own to rule out a trip to urgent care. Both are edge cases of the fact that it’s actually measuring the ratio of bound to unbound hemoglobin in the blood as a proxy for blood oxygenation. Both can be pretty confidently ruled out by an additional gadget.
First, carbon monoxide binds to hemoglobin even more readily than oxygen does. Someone who’s been breathing CO may read 100% on a pulse oximeter, because 100% of their hemoglobin is bound to something, but it’s bound to CO instead of O2 so they’re not getting properly oxygenated. This can be addressed by having working carbon monoxide detectors in your home.
Second, if there’s not enough hemoglobin going around your system due to internal bleeding, you can have 100% of the available hemoglobin bound to oxygen and yet not be getting enough total number of oxygen molecules delivered to your body in the time frame that the tissues need it. This edge case can be addressed by monitoring your blood pressure, as it’ll often (but not always, at first!) change as your body tries to compensate for blood loss. Monitoring for any signs of GI bleeding or unusual bruising can also help make sure you seek care at an appropriate time even if the pulse oximeter reads 100% saturation.
Those are the major situations in which a pulse oximeter will claim you’re OK when you actually aren’t. When you’re confident that you’ve got an appropriate amount of hemoglobin going around in your blood and there’s no CO in your environment for it to bind to instead of oxygen, the device will be a pretty accurate proxy for whether your breathing is adequately oxygenating your blood.
Edited to add—there’s another gadget that someone who cares a lot about measuring their respiration might want to know exists, and it looks like they’re available for a couple hundred bucks for home use. It’s called an end-tidal CO2, or etco2, monitor. I don’t have the training/background to explain that like pulse oximetry, but it could be good to look into if you often find yourself in the situation of “breathing feels different from usual, I wonder what changed” and enjoy data.