**8. Prevention**

When medications that prevent convulsions are used before the dive, the convulsion is under control, but cell damage is still present. This causes the diver to reach uncontrolled depths and be exposed to more toxic effects. The only safe approach is to make diving plans at depth limits. This limit depends on the partial pressure of the oxygen, the duration of the dive and environmental factors.

Underwater physicians test the candidates who are susceptible to CNS oxygen poisoning. The oxygen tolerance test can be done by oxygen breathing in the hyperbaric oxygen therapy device at 2.8 ATM for 30 min. Although this test is susceptible to positive ones, there is no clinical validity of the "oxygen tolerance test." Tolerance can vary from person to person or from day to day in the same person [9].

In the simplest case, it is necessary to avoid high partial pressures of inert gases during diving. It is important to be aware of the circumstances of air diving and know that performance and decision-making authority will be affected at depths of over 40 m. In professional diving, it is necessary to use less narcotic gases such as helium to increase the depth of safe diving. It is known that the adaptation of the dive with the daily dives against nitrogen narcosis. Some studies have shown that although some personal adaptations can occur, reaction times do not benefit from repeated dives.

To prevent nitrogen narcosis, some mixed gases are used in professional dives. Diving is planned here by creating a mixture of oxygen with nitrogen, helium or helium/nitrogen. The aim here is to reduce the narcotic effect by reducing the partial pressure of the nitrogen. However, it is necessary to pay careful attention to oxygen poisoning since oxygen increases partial pressure in such diving. As helium increases heat transfer, divers must be careful against the hypothermic effect. Due to such effects, only professional divers are allowed to mix gas dives.

Amphetamines reduce the narcotic effect that causes the prolongation of the reaction period, so they are not used in diving. The diver should be aware of the risks in the underwater environment. Also, increase narcotic efficacy, drugs that suppress the central nervous system, such as alcohol and antihistamines. These drugs create a synergistic effect with nitrogen, accelerating the reduction of performance and decision-making.
