Oxygen toxicity symptoms
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Oxygen Toxicity Symptoms: Pulmonary and Central Nervous System Effects
Pulmonary Oxygen Toxicity Symptoms
Pulmonary oxygen toxicity mainly affects the lungs and airways. Early symptoms include substernal distress or chest discomfort, which can develop after several hours of breathing high concentrations of oxygen. This is often accompanied by signs of tracheobronchitis, such as inflammation of the trachea and reduced tracheal mucus velocity, which can be detected within a few hours of exposure to high oxygen levels 6. As exposure continues, people may experience decreased lung function, including reduced vital capacity, diffusing capacity, and lung compliance. These changes can resemble those seen in adult respiratory distress syndrome 17.
Central Nervous System (CNS) Oxygen Toxicity Symptoms
CNS oxygen toxicity is a major concern, especially in situations like diving or hyperbaric oxygen therapy. The most dangerous symptom is the sudden onset of seizures, which can lead to loss of consciousness and, in underwater settings, drowning 3410. Other CNS symptoms reported include:
- Headache
- Nausea
- Dizziness
- Hyperventilation or heavy breathing
- Facial muscle twitching
- Disorientation
- Tinnitus (ringing in the ears)
- Difficulty maintaining balance or depth (in divers)
- Tingling in the limbs
- Hearing disturbances
- Amnesia
- Loss of consciousness 34510
The risk and severity of these symptoms increase with higher oxygen pressures and longer exposure times. Some individuals are more sensitive to oxygen toxicity than others 3.
Factors Influencing Oxygen Toxicity Symptoms
Certain factors can increase the risk or severity of oxygen toxicity symptoms. For example, elevated carbon dioxide (CO₂) levels (hypercapnia) can make CNS symptoms appear sooner and more severely, including severe headache, nausea, and facial muscle twitching 45. Some medications, such as bleomycin, nitrofurantoin, and corticosteroids, may also worsen lung injury caused by oxygen 1.
Early Detection and Prediction
Recent research suggests that monitoring electrodermal activity (EDA) can help predict the onset of CNS oxygen toxicity symptoms before they become severe. This could allow for early intervention, especially in divers, to prevent dangerous outcomes like seizures and loss of consciousness 2.
Cellular and Biochemical Effects
At the cellular level, oxygen toxicity is caused by the buildup of reactive oxygen species (ROS), such as hydrogen peroxide and free radicals, which can damage cells and tissues. This can lead to cell death, primarily through necrosis in the lungs, although apoptosis (programmed cell death) is also observed in some cases 178.
Conclusion
Oxygen toxicity can cause a range of symptoms, primarily affecting the lungs and central nervous system. Pulmonary symptoms include chest discomfort and reduced lung function, while CNS symptoms range from headache and nausea to seizures and loss of consciousness. The risk increases with higher oxygen levels, longer exposure, and factors like elevated CO₂. Early detection methods and awareness of risk factors are important for preventing severe outcomes, especially in high-risk settings like diving and critical care.
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