Hypoxia and Medicine

What blood oxygen saturation is normal?

Now for some reason this question was deleted before because i asked "what O2 sat would someone pass out at" and i honestly asked it in the most medical meaning possible. My grandmother is currently dying of pulmonary anemia and her oxygen level is somewhere between 75 and 85. My question is what happens at different O2 sats. What level is normal, what causes confusion, fainting, coma, and death... I honestly hope this question wont be deleted, because i feel that i have done nothing wrong in posting it, i am just wondering about anatomy.

Public Comments

1. Normal is 99. At 95 I feel like I'm suffocating. At 89 I am very lightheaded. At 85 I need to keep laying down or I will pass out. Some people can tolerate lower levels if they have been breathing lower levels for some time.
2. Anything above 97% is good. 85% is hospitalized I was at 79% once time with pneumonia and I was barely coherent. I did know where I was but extremal tired feeling. The doc's office I was at called an ambulance. The Hospital would not release me until my Oxy was above 95%
3. Your grandmother is suffering from Pulmonary Edema, not "anemia". I know they sound alike but there is no such thing as "pulmonary anemia". Anyway, 97% is considered normal saturation but doctors accept 96-98 because the device used to measure O2 saturation has a accuracy range of +/- 2%. Defining a saturation that will cause the symptoms you describe is difficult because there are people walking around with 85% because it happened gradually and their bodies had a chance to adjust to the lower levels. But if your sat were to drop from 97% to 85% rapidly then you would experience all the symptoms you described. You see there is a physiologic curve that describes the relationship of the Oxygen levels in your blood with the saturations. At 97% you are in a safe area whereas at 85% the situation changes dramatically.At that level you are on a "slippery slope" which could result in your grandmothers condition deteriorating rapidly. She must be in an ICU at this point or at the very least on very high concentrations of oxygen with or without a respirator helping her. You usually only see this unresponsiveness to high oxygen levels when the heart is failing. What's called Congestive Heart Failure. I've seen many, many patients recover and do just fine but just as often they don't do well. Let her doctor be your guide on that. Since I don't know anything but what you've said in your question I can't give you anymore information. All I can do is keep her in my prayers and hope for her recovery. And God bless you for caring enough to ask about her here.
4. anywhere from 90% to 100% is considered normal. however, the older a person gets, a lower spo2 can be acceptable. Depending on her age 85 may be okay for her. people can adjust to lower sats. Now i must say this, you cannot base oxygenation absolutely on Spo2 analysis. An arterial blood gas is a very good indicator as to how well someone is breathing. the two tests should be correlated to accurately see where she is at lung wise. If she isn't turning blue when it says 75%, i would be hesitant to believe the number. Usually at that level you will see increased respiratory rate and cyanosis (which is blue coloring of lips, fingertips, etc) when you get down to it though every single person is different when it comes to how their body reacts. I urge you to talk to her doctors and pray for her to get better. I also second the fact that it is "Pulmonary edema" and not anemia...(fluid build up on the lungs)