For END calculations then yes, a higher END is calculated for a specific gas at a specific depth if you assume oxygen is narcotic. However, when talking about theoretical methods for reducing narcosis, I would argue that dismissing the posibility that it might not be narcotic, and therefore dismissing it as a method for reducing narcosis, is a little bit different, and not entirely justified. Not that the idea of breathing oxygen before a deep air dive to reduce narcosis makes any sort of sense either way though...
Perhaps, but I'm a diver not a scientist. I knew someone that reckoned if he headbutted a wall repeatedly before a fight then the fight would be less disorientating. Theoretically, I could see a logic behind this. It didn't stop us pissing ourselves laughing when he knocked himself out.
At the time the question was asked it was to see if there was any evidence that raised Oxygen levels in the blood may reduce the impact of narcosis. Why I wondered this at the time I have no idea, possibly because I was bored and wanted to cause a ruck 13 months later...
