**6. Clinical signs and symptoms**

**4. Theories**

be affected.

tory effect on the nervous system.

**Figure 3.** Dopamine-induced thalamus and cortex.

disrupts neural transmission.

**5. Pathophysiology**

• *Myer-Overton:* when inert gas is dissolved in the nervous system, the inert gas has an inhibi-

114 Hyperbaric Oxygen Treatment in Research and Clinical Practice - Mechanisms of Action in Focus

• *Quastel-Metabolic:* at high pressure, inert gas disrupts cell metabolism. These sensitive cells are mostly found in the brain. The cells, which are consciousness formation, are the first to

• *Clathrate:* under pressure nitrogen creates clathrate with protein and water. This formation

• *Iceberg:* when nitrogen gas dissolves in water, it creates molecules called icebergs. The ice-

There are many variables that affect the susceptibility of the person to nitrogen narcosis. Diving health, deep diving experience, working conditions, environmental conditions are some of these. As the depth increases, the diver starts sign of the suppressing. Thinking problems, deterioration of time perception, deterioration of decision-making, memory problems, motor and mental functions, and the prolongation of reaction time are some of these [5].

When the diver starts to exit, the symptoms disappear quickly; sometimes, it does not remem-

ber what you are doing underwater during nitrogen narcosis.

berg also prevents the transmission of the nervous system like the same clathrate [4].

The mechanism of CNS oxygen poisoning is not fully known. Oxygen is believed to have evolved by the increase of pO2 and the free oxygen derivatives affecting the CNS metabolism. As a rule, poisoning is seen when exposed to pO2 pressure on 2 ATA and above [6].

Oxygen poisoning occurs more rapidly as the pO2 pressure increases. According to Clark and Lambertsen's work; pO<sup>2</sup> 1.7 ATA for 7 h, 1.8 ATA for 3 h, 2 ATA for 50 min and 3 ATA for 30 min showed signs of MSS poisoning [7].

Signs and findings are described in a wide range of fans. Nausea, vomiting, dizziness, ringing in the ears, incoordination, tunnel vision, irritability, pallor, sweating, heart rate slowing (bradycardia), lips, and hands twitching, eyes widening of the baby, hiccups, to remember the recent past, hallucination, confusion (confusion) are chief of the signs and findings. However, the most dramatic of these is the seizure, namely the convulsion. It is typical that consciousness is closed during convulsion [7].

The most common finding is a face twenty in the oxygen pressure on 2 ATA. The sign of paleness in the face is due to hyperoxia-induced vasoconstriction. Similarly, the loss of sensation in the fingers is the result of vasoconstriction [9].

Even though the depth is the same, being in the water reduces the resistance to oxygen poisoning considerably compared to being in dry air in the pressure chamber. Water and diving stress increase the susceptibility to oxygen poisoning. Also underwater, the signs mentioned above cannot be noticed, but the divers are noticed that they are poisoned when they have convulsions. Convulsions underwater are dangerous because they can lead to suffocation or barotrauma. Therefore, many authorities have determined the maximum depth of pure oxygen diving underwater to be 10 m. Other causes that reduce the threshold value of CNS poisoning are exercise, hypothermia, increased calm carbon dioxide levels [10].

Facial twitch usually results in convulsions. During convulsion, all body stimuli develop and the tonic phase called full contraction begins. During this time, breathing is interrupted. The tonic phase usually lasts 30 s and is accompanied by loss of consciousness. This period approximately takes 1 min, followed by the head, neck, trunk, and legs in large contraction followed by clonic phase. After the clonic phase, the contractures decrease and the respiration starts with hyperventilation, and after a while consciousness comes back. The diver does not remember any part of the event. The concentration of carbon dioxide has increased because of being held breath during the convulsion. However, contrary to normal epilepsy patients, there is no reduction in oxygen reaching the CNS during respiration, as oxygen breathes at high pressure before the diver seizure [11].

pay attention to the other factors, which increase the influence of nitrogen narcosis mentioned in the previous paragraph. The effects of nitrogen narcosis are roughly measured by two methods. First of these, the behavioral approach measures the fulfillment of the assigned task, which measures arithmetic, memory, and handicraft. The other is a measure of some

Toxic Effects of Hyperbaric Conditions http://dx.doi.org/10.5772/intechopen.78392 117

The behavioral approach is examined in three main categories: cognitive ability, reaction time, and skill. Cognitive competence is the most frequently affected by nitrogen narcosis,

In this study, conducted on open water divers, anxiety, and a decrease in the success of the task were observed. The anxiety status was determined by measuring plasma cortisol and urine noradrenaline. The intellectual function, arithmetic, and memory capacity of open dives were found lower than the coastal diving in open sea diving. The cause of this decline is

The effect of nitrogen narcosis on behavior has been studied by psychologists. They defined this as a slow process model. In this model, they saw slowed activation with anesthesia, increased reactivation duration. The least affected hand is skill because less cognitive function

Neurophysiological tests are needed to evaluate some subjective values, to achieve low performance and to provide objective evidence. These are the information that is obtained by drawing the electroencephalogram of the brain after diving with compressed air in the cabin. First, findings of high stimulation in the cortex of the brain have been reached. This situation

The measurement of the functions of the central nervous system can be done by examining the cortical potentials, evoked from the exposed inert gases in the brain. The low response to

When acute poisoning statements are made during treatment in the pressure chamber, the patient should be given air to breathe deeply. If necessary, the treatment table can be changed by the underwater physician. In case of unconsciousness, stomach contents should be pre-

The first goal during convulsion is to prevent trauma [7]. The tongue should prevent the patient from biting the tongue during the seizure. It should be known that naturally depends on the dive, the lack of oxygen (hypoxia) does not occur. It is necessary to wait until the tonic phase of the convulsion is finished. Otherwise, the diver may be exposed to

neurophysiological parameters [5].

but skill competence is least affected.

depending on stress of the open sea diving.

includes voltage increases in the basal rhythm of the brain.

vented from escaping to the lungs (aspiration).

stimulus is an experimental measure of the effect of nitrogen narcosis.

(A) Behavioral approach

is needed for skill.

**7. Treatment**

lung barotrauma.

(B) Neurophysiological changes

When toxic effects of oxygen occur, it is necessary to reduce the partial pressure of oxygen inhaled immediately. In the pressure chamber, it is necessary to remove the oxygen mask or reduce the pressure. Diving depth must be reduced during diving. The diver must be brought to the surface safely. Reducing the pressure in the pressure chamber or rising in the dive is accompanied by lung barotrauma risk because it is kept breath during the seizure. After first aid, barotrauma should be controlled by drawing a chest radiograph [8].

Although the sensitivity of nitrogen narcosis is quite different from person to person, all the divers who dive at depths of 60–70 m demonstrate clinical signs of nitrogen narcosis. Firstly, high cognitive functions are affected. The main symptoms of these are judgments, decisionmaking, close memory, learning, concentration, and attention. The diver may feel very good and can over-confidence himself as a light alcohol drinker. Along with increased nitrogen partial pressure at higher pressures, diminished hand strength and progressive deterioration of mental performance, intellectual fixation, hallucinations, and finally lethargy/blunting and coma. Some divers may experience a disorder in the form of tunnel vision, but they cannot be aware of the danger because of the perception disorder [1].

Tension, cold, tiredness, soothing medicines, alcohol and medications that affect the central nervous system may cause exacerbated narcosis. The effects of nitrogen narcosis are likened to the intake of alcohol. Alcohol and nitrogen narcosis symptoms are often associated, especially as enthusiasm and motor coordination develop. Even with a somewhat sarcastic approach, the nitrogen narcosis is assessed with a criterion called the Martini law. According to this law, every 50 feet of depth leads to equivalent effects on a glass of martin. Enthusiasm, joy, laughter at 10–30 m; increased self-confidence, fixed idea at 30–50 m; loquaciousness, dizziness, hysterical seizures at 50–70 m; delayed response to stimuli, loss of concentration, mood swings at 70–90 m; hallucinations, and loss of consciousness develop over 90 m [3].

The nitrogen narcosis effect is affected within a few minutes when you descend into depth and is not related to the dive time. Initially, fast diving increases the anesthetic effect, but this effect is rapidly returned when ascending to surface [3].

Other causes that increase the degree of nitrogen narcosis need to be considered. Alcohol, fatigue, tension, cold, oxygen, and carbon dioxide changes increase the effect of narcosis, limiting the diver's ability in underwater. Experimental studies have shown that alcohol and underwater exercises increase the effect of narcosis. Increased carbon dioxide and nitrogen pressurized diver have been shown to reduce performance. In certain periods and long dives, divers can develop some adaptations against to the narcotic effect of nitrogen [4].

Despite the fact that it is not a realistic and appropriate guide for the formation of nitrogen narcosis, scientific studies are carrying out. It is useful to monitor the performance of the diver in simple tasks, tests that can be reached to narcotic sensitive individuals, the use of low narcotic gas mixtures during diving and reduction of other factors affecting narcosis in depth, achieve a safe dive operation without encountering this effect. Since these tests are not used in the selection of the sportive diver or mixed gas is not used in sportive diving, the depth of the dive is reduced or terminated when anesthesia develops. It is also necessary to pay attention to the other factors, which increase the influence of nitrogen narcosis mentioned in the previous paragraph. The effects of nitrogen narcosis are roughly measured by two methods. First of these, the behavioral approach measures the fulfillment of the assigned task, which measures arithmetic, memory, and handicraft. The other is a measure of some neurophysiological parameters [5].

#### (A) Behavioral approach

there is no reduction in oxygen reaching the CNS during respiration, as oxygen breathes at

When toxic effects of oxygen occur, it is necessary to reduce the partial pressure of oxygen inhaled immediately. In the pressure chamber, it is necessary to remove the oxygen mask or reduce the pressure. Diving depth must be reduced during diving. The diver must be brought to the surface safely. Reducing the pressure in the pressure chamber or rising in the dive is accompanied by lung barotrauma risk because it is kept breath during the seizure. After first

Although the sensitivity of nitrogen narcosis is quite different from person to person, all the divers who dive at depths of 60–70 m demonstrate clinical signs of nitrogen narcosis. Firstly, high cognitive functions are affected. The main symptoms of these are judgments, decisionmaking, close memory, learning, concentration, and attention. The diver may feel very good and can over-confidence himself as a light alcohol drinker. Along with increased nitrogen partial pressure at higher pressures, diminished hand strength and progressive deterioration of mental performance, intellectual fixation, hallucinations, and finally lethargy/blunting and coma. Some divers may experience a disorder in the form of tunnel vision, but they cannot be

Tension, cold, tiredness, soothing medicines, alcohol and medications that affect the central nervous system may cause exacerbated narcosis. The effects of nitrogen narcosis are likened to the intake of alcohol. Alcohol and nitrogen narcosis symptoms are often associated, especially as enthusiasm and motor coordination develop. Even with a somewhat sarcastic approach, the nitrogen narcosis is assessed with a criterion called the Martini law. According to this law, every 50 feet of depth leads to equivalent effects on a glass of martin. Enthusiasm, joy, laughter at 10–30 m; increased self-confidence, fixed idea at 30–50 m; loquaciousness, dizziness, hysterical seizures at 50–70 m; delayed response to stimuli, loss of concentration, mood

The nitrogen narcosis effect is affected within a few minutes when you descend into depth and is not related to the dive time. Initially, fast diving increases the anesthetic effect, but this

Other causes that increase the degree of nitrogen narcosis need to be considered. Alcohol, fatigue, tension, cold, oxygen, and carbon dioxide changes increase the effect of narcosis, limiting the diver's ability in underwater. Experimental studies have shown that alcohol and underwater exercises increase the effect of narcosis. Increased carbon dioxide and nitrogen pressurized diver have been shown to reduce performance. In certain periods and long dives,

Despite the fact that it is not a realistic and appropriate guide for the formation of nitrogen narcosis, scientific studies are carrying out. It is useful to monitor the performance of the diver in simple tasks, tests that can be reached to narcotic sensitive individuals, the use of low narcotic gas mixtures during diving and reduction of other factors affecting narcosis in depth, achieve a safe dive operation without encountering this effect. Since these tests are not used in the selection of the sportive diver or mixed gas is not used in sportive diving, the depth of the dive is reduced or terminated when anesthesia develops. It is also necessary to

swings at 70–90 m; hallucinations, and loss of consciousness develop over 90 m [3].

divers can develop some adaptations against to the narcotic effect of nitrogen [4].

aid, barotrauma should be controlled by drawing a chest radiograph [8].

116 Hyperbaric Oxygen Treatment in Research and Clinical Practice - Mechanisms of Action in Focus

aware of the danger because of the perception disorder [1].

effect is rapidly returned when ascending to surface [3].

high pressure before the diver seizure [11].

The behavioral approach is examined in three main categories: cognitive ability, reaction time, and skill. Cognitive competence is the most frequently affected by nitrogen narcosis, but skill competence is least affected.

In this study, conducted on open water divers, anxiety, and a decrease in the success of the task were observed. The anxiety status was determined by measuring plasma cortisol and urine noradrenaline. The intellectual function, arithmetic, and memory capacity of open dives were found lower than the coastal diving in open sea diving. The cause of this decline is depending on stress of the open sea diving.

The effect of nitrogen narcosis on behavior has been studied by psychologists. They defined this as a slow process model. In this model, they saw slowed activation with anesthesia, increased reactivation duration. The least affected hand is skill because less cognitive function is needed for skill.

(B) Neurophysiological changes

Neurophysiological tests are needed to evaluate some subjective values, to achieve low performance and to provide objective evidence. These are the information that is obtained by drawing the electroencephalogram of the brain after diving with compressed air in the cabin. First, findings of high stimulation in the cortex of the brain have been reached. This situation includes voltage increases in the basal rhythm of the brain.

The measurement of the functions of the central nervous system can be done by examining the cortical potentials, evoked from the exposed inert gases in the brain. The low response to stimulus is an experimental measure of the effect of nitrogen narcosis.
