Oxygen therapy is used in both acute and chronic conditions such as asthma exacerbation, pneumonia, trauma and chronic obstructive pulmonary disorder. When used appropriately, oxygen can help relieve symptoms and even save lives. However, oxygen therapy is not without harm. Under certain cases such as with premature infants, oxygen therapy can cause harm to the patient.
Oxygen Toxicity
Oxygen therapy can cause cellular injury, absorptive atelectasis, airway injury and tissue injury. Hyperoxia, which is excessive oxygen in the blood, increases the production of reactive oxygen species such as hydrogen peroxide, which adversely affects the antioxidant defense mechanism in the body and promotes inflammation in the lungs. On the other hand, too much supplemental oxygen can wash out nitrogen in the lungs and cause absorptive atelectasis, or collapsing lung units, reducing the body's absorption of oxygen.
Premature Infants
Too much oxygen can damage the eyes of an premature infant. In a termed infant, the retina is fully developed, whereas in a premature infant, the retina is not fully vascularized. When too much oxygen is given to these premature infants, the vessels in the eyes may burst and scar, damaging the eyes, which can lead to blindness. This condition is called retinopathy of prematurity. Although excessive oxygen can cause damage to their eyes, oxygen is always given to premature infants, since their lungs are still developing and therefore need oxygen therapy to assist with ventilation. Therefore, the level of supplemental oxygen must be carefully monitored.
Respiratory Drive Suppression
Excess oxygen therapy can suppress the respiratory drive in patients with chronic obstructive pulmonary disorder. Normally, when the brain detects an increased level of carbon dioxide in the blood, it will respond by increasing respiration to compensate. However, because the carbon dioxide level in patients with chronic obstructive pulmonary disorder are chronically high, the brain monitors these patients' respiration by their oxygen level. In this case, when the oxygen level in the blood is low, the brain will increase the respiratory drive. If excess oxygen therapy is given to these patients, the brain responds by suppressing the respiratory drive. The suppressed respiratory drive is especially dangerous in these patients because their lung function is reduced. In extreme cases, prolonged excessive oxygen therapy can cause death in these patients.
Fire Hazards
When oxygen is exposed to fire, heat or fuel, it can cause combustion and even explosion. The amount of oxygen controls the rate the fire burns. The more oxygen there is, the more quickly that the fire will burn out of control. Therefore oxygen must be handled appropriately, and must be stored in a cool and shaded area and away from fuel and fire.
