wunat:
During some conversation with some of my diving friends, one of them raises the fact that he once heard from others that if one dives enriched air alot, there are some long-term physical side-effects.
Is it true?
:huh: :huh: :huh:
Long term? That depends on what you mean. It is supposedly, theorectically possible to suffer pulmonary O2 toxicity (as opposed to CNS) from long term high oxygen percentage breathing.
I don't know that it ever happens to anyone who isn't in a hospital on pure o2 for days.
And from what i gather, its not all that serious. Just irritation of the lungs from the effects of O2.
Thats one of the "it might happen to you if you're the 1 in 1000000000000" they teach in class, anyway
Some info
http://members.tripod.com/tjaartdb0/html/oxygen_toxicity.html#PO
Pulmonary Oxygen Toxicity(PO)
PO toxicity occurs when the diver is exposed to elevated levels oxygen for several hours. This causes damage to the cell lining of the lungs, the lung walls, the formation of fluid in the lungs and causes a feeling of shortness of breath combined with a burning throat and chest. This causes breathing to become very painful.
PO toxicity manifests itself after the diver is exposed (12 hours or more) to relatively low levels of partial oxygen pressures (pO2), 0.6 ATA (atmospheres absolute) and up.
The lungs are lined with a viscous fluid almost acting like a surfactant which helps in gas exchange and helps to lower the surface tension of the alveoli(lung sacs). When the alveoli are exposed to elevated pO2, the oxygen starts to attack the surfactant and breaks it down. This causes a shortness of breath. Normally this surfactant is regenerated if the exposure is only a few hours but on continued exposure the alveoli walls start to swell, filling the lung sacs with fluid and and decreasing the oxygen supply to the alveoli cells.
Thus too much oxygen results in not enough oxygen reaching the blood resulting in hypoxia (oxygen shortage)! That is why diving on 100% oxygen is only safe up to 20 ft or 7m.
PO toxicity is not a serious problem since it is difficult to expose oneself to oxygen long enough for this to become a real problem.
