During an oxygen shortage (like with Covid), could hospitals use a lower concentration, maybe 70-80%? From what I understand, the 99% gets diluted by different apparatuses, such as nasal cannulas (more dilution) and face masks (less dilution). I know quality control and having a reliable baseline is important too, but why is 95-99% the needed concentration?
In: Biology
I think you are talking about two different things. The oxygen saturation of the air we breathe is 21% and if you are healthy, this is fine – and this should correlate to 95-99% oxygen saturation of your blood. If your blood oxygen saturation (Sp02) goes below 90-95%, we start to get worried that you are either not taking in oxygen effectively, or you are not delivering it effectively.
When we give you oxygen in the hospital there are various ways to do this, and they correspond with different oxygen saturations. The nasal cannula, depending on oxygen flow/min usually ranges from 21-40% oxygen saturation. A nonrebreather mask or face tent can do higher amounts like up to 60-80%. When someone is on a ventilator, you can more precisely control what oxygen level they should be getting. You are right that it is difficult to get 100% oxygen delivery because of pressure losses the way the apparatuses are set up. However if necessary, there is a device called high-flow nasal cannula that can achieve this level.
So a healthy person could have an Sp02 of 99% even though they are breathing 21% oxygen – meanwhile, someone with lung disease may need a nasal cannula with flow that delivers 28% oxygen to maintain that same Sp02 of 99% because without it, their Sp02 might fall to 90%. Hope this makes sense
Latest Answers