When should a diver be removed from oxygen due to CNS toxicity symptoms?

A diver should be removed from oxygen at the first symptom of CNS toxicity because early recognition and intervention are critical in preventing more severe symptoms and complications. Central nervous system (CNS) toxicity is associated with exposure to high partial pressures of oxygen, and symptoms can escalate rapidly. Symptoms such as visual disturbances, irritability, or changes in behavior can indicate the onset of a toxic reaction. Prompt removal from oxygen therapy can mitigate the risk of progressing to more serious conditions, such as convulsions or loss of consciousness.

Recognizing symptoms early enables swift action to ensure the safety of the diver. This approach aligns with standard protocols in dive medicine, which emphasize that intervention at the first sign of distress can be crucial for maintaining the diver's health and safety. In the case of CNS toxicity, waiting for convulsions to occur or remaining on oxygen for a set time frame would significantly increase the risks associated with severe CNS complications. Therefore, moving the diver away from the oxygen source as soon as the first symptoms present themselves is the safest protocol.