What action should be taken if a diver exhibits signs of CNS O2 Toxicity?

When a diver shows signs of CNS (central nervous system) oxygen toxicity, the appropriate response is to immediately ascend to a safer depth. CNS O2 toxicity can occur when divers breathe high partial pressures of oxygen, which can lead to symptoms such as visual disturbances, seizures, or altered levels of consciousness. These symptoms indicate that the diver is experiencing a dangerous condition that requires prompt action to prevent severe complications.

Ascending to a shallower depth reduces the pressure of the surrounding water, which in turn decreases the partial pressure of oxygen that the diver is exposed to. This can alleviate the symptoms of CNS O2 toxicity and provide a safer environment for the diver’s recovery.

Continuing the dive or increasing descent in this situation would exacerbate the diver's condition due to increasing pressures and oxygen levels, which could lead to more severe symptoms or even loss of consciousness. Simply notifying support staff without taking immediate action would not address the urgent medical need and could put the diver at greater risk. Therefore, the correct approach is to promptly ascend to a safer depth to mitigate the dangers of CNS O2 toxicity.