Oxygen can be toxic to the central nervous system when the partial pressure of oxygen exceeds 1.6 atmospheres. The risk of oxygen toxicity is one of the main limiting factors in the use of nitrogen-oxygen (NITROX) breathing mixtures.
number of atmospheres experienced at a given depth in sea water =
= ((depth in feet salt water) + 33) / 33
partial pressure of oxygen in atmospheres =
= (decimal fraction of oxygen in the breathing mixture) * (atmospheres at depth)
If the partial pressure of oxygen is > 1.6 atmospheres, then the patient is at risk for oxygen toxicity. It is rare if the partial pressure of oxygen is < 1.4 atmospheres.
The maximum depth that a diver can go on a given oxygen mixture is:
