Can Too Much Oxygen Be Harmful?

Question: Can Too Much Oxygen Be Harmful?

Oxygen makes up the majority of the air we breathe. It is also the most widely prescribed "drug" in hospitals, with about one quarter of all patients receiving it at some point during their stay at an acute care hospital. So how can it be harmful?

Answer: Pulmonary Oxygen Toxicity occurs when a person is exposed to high oxygen levels for over 16 hours in pressures of 0.5 bar or more. It occurs in progressive, overlapping phases. During the first phase, fluid floods into the tissues of the lung that are normally filled with air. Bleeding then occurs between the alveoli, destroying capillaries and epithelial cells. Tissues begin producing in an attempt to heal the area. This causes thickening and scarring of the lungs.

Symptoms begin with a substernal irritation that becomes progressively worse and is accompanied by an increasingly uncontrollable cough. The patient may experience tracheal or bronchial burning, that worsens during inspiration. Lung damage is sometimes irreversible.

Bronchopulmonary dysplasia is a chronic lung disorder that may affect infants who have been exposed to high levels of oxygen. It primarily occurs in severely ill infants who have received prolonged oxygen support on respiratory ventilators.

Sources: Diving Medicine Online