Posted by DocGreg on April 21, 1999 at 11:20:40:
In Reply to: O2 overdose? posted by Odin on April 21, 1999 at 10:18:06:
Prolonged use of oxygen IS toxic to your lungs. Using it at a high flow rate for 20-30 minutes should be fairly safe...but high flow for several hours can do damage.
Oxygen acts as a free radical (for those of you who remember your chemistry) and attacks the lining of the lungs. This goes on everyday, but the body is used to fighting 21% oxygen (the amount in the air). Higher amounts, and the body can't keep up with the antioxidents it produces. Long exposures can cause thickening of the lung walls, decreasing it's ability to function.
How much is too much? I know that people I have in the hospital on 100% oxygen can show documentable lung damage after as little as 24 hours. Now, you are not getting 100% at 7 liters (probably closer to 40-50%), so the action would not be as fast. And short exposures probably don't overwhelm the body's defenses as quickly.
But don't sleep with it on. Set a timer on your watch or whatever. I think O2 is great for clusters, and I give it to patients all the time. It is also safe if used wisely. Just avoid excessive amounts.
Greg