Sunday, December 21, 2014
Pulmonary Fibrosis Oxygen Therapy
My grandpa is in the hospital for dizziness as a result of forgetting to take his blood pressure medication. He has previously been diagnosed with idiopathic pulmonary fibrosis. The nurses just called and said they were surprised to see that he was on a 100 percent oxygen feed, so they moved him to intensive care.
From what I’ve read, oxygen can cause carbon dioxide retention for people with COPD. The last time I saw him he was hyperventilating. He is still on a 100 percent oxygen feed. Is this dangerous?
High concentrations of oxygen can both be life saving and can be hazardous.
If a patient's blood oxygen level is low, then high concentrations of inhaled oxygen can help to restore dangerously low blood oxygen levels to prevent damage to the brain, liver, heart, etc.
In patients with COPD, giving too much inhaled oxygen can sometimes cause the carbon dioxide to rise. Therefore, as physicians, we measure the amount of inhaled oxygen so that we give as much as is required to get the blood oxygen into the normal range but we try to not give more than that amount.
Some patients may even require 100% inhaled oxygen to keep their blood oxygen in the low-normal range. In general, the danger of low blood oxygen is as great or greater than the danger of a high carbon dioxide level; therefore, we give as much oxygen as it takes to get the blood oxygen saturation above 90%.
Patients with pulmonary fibrosis usually do not have the same problem with rising carbon dioxide levels that patients with COPD have.
The other risk of high concentrations of inhaled oxygen is "oxygen toxicity". Even though supplemental oxygen can be life saving, it can also be toxic to the lung and can cause inflammation or fibrosis in the lung. Usually this does not happen unless the inhaled oxygen concentration is more than 60% for at least a few days.
Unfortunately, in patients who have low blood oxygen, there really are no alternatives to high concentrations of inhaled oxygen and so we have to balance the risks of oxygen with the benefits of oxygen. If the blood oxygen level is low, then the benefits of supplemental oxygen almost always outweigh the risks of supplemental oxygen.
James N Allen, Jr, MD
Clinical Professor of Pulmonary, Allergy, Critical Care & Sleep Medicine
College of Medicine
The Ohio State University