Medicine and Health · Intoxications

Oxygen (O2) Toxicity

Carbon Monoxide (CO) Toxicity

Carbon Dioxide (CO2) Toxicity

Nitrogen (N) Toxicity

Oxygen (O2) Toxicity

At certain pressures, oxygen becomes toxic for humans. The maximum pressure for pure oxygen is 1.7 atmospheres and 2 atmospheres in a combination of gases. When these levels are reached, intoxication known as hyperoxia, results.

The minimum partial pressure of oxygen is approximately 0.1 to 0.17 atm. of pressure. This can happen if the breathable air supply is interrupted or when the percentages of oxygen in the combination are very low.

The symptoms of a diver suffering O2 intoxication include: problems with vision, abnormal sounds (vibrations), dizziness, vertigo, and contractions of the lips and facial muscles, seizures and in extreme cases, death.

Treatment for O2 toxicity depends on the degree of intoxication, however it is advisable to place the diver in a ventilated room with low oxygen content. In the event that seizures begin underwater it is advisable to keep the depth the diver is at constant until the seizures cease, followed by a gradual ascent. If the diver is conscious, the air supply can be changed to one with enough O2.

Carbon Monoxide (CO) Toxicity

When filling the tanks, if a source of CO (internal motor combustion) is present nearby, carbon monoxide can accumulate within the tanks, causing air poisoning.

Carbon monoxide attaches itself to hemoglobin 100 times more than oxygen does, which leads to the following symptoms: red or irritated skin, dizziness, nausea, head aches, vomiting and unconsciousness.

It is advisable to end the dive, ascending gradually and pausing every now and then, placing the diver in a room with plenty of ventilation with low oxygen, consulting a doctor as soon as possible.

Carbon Dioxide (CO2) Toxicity

Carbon dioxide toxicity occurs for various reasons. One of them is the inadequate ventilation of the “open” scuba equipment; another is the controlled breathing (which takes place in apnea diving) or when due to psychological influence and the amount of air in the tank (stress factor), the diver diminishes his air supply without realizing it.

Once the diver resurfaces, he suffers from so-called hypercapnea or carbon dioxide toxicity whose symptoms include head aches, breathing difficulty, unconsciousness and bluish skin.

The diver himself regains composure simply by resurfacing and allowing the body to eliminate the CO2 excess from the blood. It is advisable to increase the diver’s lung ventilation, replace the breathing equipment and end the dive in the event that the failure is caused by faulty equipment.

Nitrogen (N) Toxicity

Nitrogen is a principal component of air and poses the greatest obstacle when descending and remaining on the bottom when diving.

Ninety seven percent of the air we breathe is made up of nitrogen. The body tissues have the ability to absorb this gas and then eliminate it. The amount of gas absorbed or eliminated and which does not form part of a chemical combination will depend on differences in partial pressures of the gas existing within and outside the tissue.

The bigger the differences in pressure of the gas outside the tissue, the greater the amount of gas that will enter the tissue.

Narcosis due to nitrogen begins showing effects after 15 to 18 meters, but is noticeable when the nitrogen reaches a partial pressure of 3.2 atn., which occurs at 30 meters.

Symptoms include dizziness, drowsiness, panic, hallucinations and euphoria.
In order to fight these symptoms, safety measures must be adhered to: not exceeding the 30 meter depth limit, abiding by the restrictions recommended in the decompression tables, ascending at a speed of 9 meters or less and making a safety stop before rising to the surface.