Oxygen toxicity

A condition resulting from the harmful effects of breathing molecular oxygen at increased partial pressures

Oxygen Toxicity

File:Oxygen toxicity diagram.png

Diagram illustrating the effects of oxygen toxicity on the human body.

Oxygen toxicity is a condition that occurs when the body is exposed to an excess of oxygen (O_) at elevated partial pressures. This can lead to harmful effects on the lungs, central nervous system, and other organs. Oxygen toxicity is a concern in various medical and diving scenarios where high concentrations of oxygen are used.

Pathophysiology

Oxygen toxicity primarily affects the lungs and the central nervous system. The condition is caused by the formation of reactive oxygen species (ROS) such as superoxide anions, hydrogen peroxide, and hydroxyl radicals. These ROS can damage cellular components, including lipids, proteins, and DNA.

Pulmonary Oxygen Toxicity

Pulmonary oxygen toxicity, also known as the "Lorrain Smith effect," occurs when the lungs are exposed to high concentrations of oxygen for extended periods. Symptoms include coughing, chest pain, and difficulty breathing. Prolonged exposure can lead to pulmonary edema and atelectasis.

Central Nervous System Oxygen Toxicity

Central nervous system (CNS) oxygen toxicity, also known as the "Paul Bert effect," can occur during hyperbaric oxygen therapy or scuba diving with enriched oxygen mixtures. Symptoms include seizures, visual disturbances, tinnitus, and nausea. CNS oxygen toxicity is acute and can be life-threatening if not managed promptly.

Risk Factors

Several factors can increase the risk of oxygen toxicity, including:

• High partial pressures of oxygen, typically above 0.5 atmospheres absolute (ATA).
• Prolonged exposure to elevated oxygen levels.
• Individual susceptibility, which can vary based on genetic and environmental factors.
• Use of oxygen-enriched breathing mixtures in diving or hyperbaric therapy.

Prevention

Preventing oxygen toxicity involves careful monitoring of oxygen exposure and adherence to safe limits. In medical settings, this includes:

• Using the lowest effective concentration of oxygen.
• Monitoring blood oxygen levels with pulse oximetry.
• Limiting the duration of exposure to high oxygen concentrations.

In diving, prevention strategies include:

• Adhering to established dive tables and limits for oxygen exposure.
• Using nitrox mixtures with appropriate oxygen fractions.
• Monitoring dive profiles and ascent rates to avoid exceeding safe oxygen partial pressures.

Management

Management of oxygen toxicity involves reducing oxygen exposure and treating symptoms. In cases of pulmonary toxicity, reducing the inspired oxygen concentration and providing supportive care can help alleviate symptoms. For CNS toxicity, immediate reduction of oxygen levels and supportive measures, such as anticonvulsant medications, may be necessary.

See Also

• Hyperbaric medicine
• Reactive oxygen species
• Scuba diving
• Pulmonary edema

Related Pages

• Hypoxia
• Hyperoxia
• Oxidative stress