Why is 100% oxygen not typically used for extended periods?

Using 100% oxygen for extended periods is not typically recommended because it can lead to lung damage and absorption atelectasis. When 100% oxygen is administered, it can create a situation in the lungs where the nitrogen present in the air is displaced. Nitrogen typically helps to keep the alveoli (the tiny air sacs in the lungs) open. Without nitrogen, the alveoli can collapse as oxygen is absorbed into the bloodstream, a condition known as absorption atelectasis. Prolonged exposure to high concentrations of oxygen can also be toxic to the lung tissues, leading to further complications such as oxygen toxicity, inflammatory responses, and potential pulmonary edema. Thus, while oxygen therapy is essential, it must be used judiciously and typically at lower concentrations to avoid these adverse effects.