Oxygen Therapy: No Benefit for Time to Death or Time to Hospitalization IF Oxygen Saturation is Slightly Reduced
Background: A pulse oximeter is placed on the finger to measure the amount of oxygen bound to red blood cells. The measurement is simple and non-invasive. The value is called oxygen saturation and abbreviated SpO2; normal is 95 – 97%.
Based on the results of studies conducted in the 1970s, insurance companies along with Medicare/Medicaid pay for oxygen therapy IF:
REST: SpO2 is equal to or less than 88%
DURING SLEEP: SpO2 is equal to or less than 88% OR if there is a fall in SpO2 of at least 5% with evidence of restlessness, difficulty sleeping, or impaired thinking
DURING EXERCISE: SpO2 equal to less than 88% OR if the person has shortness of breath and high levels of breathing during exercise and the use of oxygen allows the person to increase exercise endurance.
Study: The National Heart, Lung, and Blood Institute (supported by your and my tax money) sponsored a study to evaluate if oxygen therapy was beneficial for those just above the 88% cut-off value. The investigators studied those with COPD who had SpO2 of 89 – 93% at rest – who were supposed to use oxygen therapy 24/7 – OR those with SpO2 less than 90% for at least 10 seconds during a 6 minute walk test – who were supposed to use oxygen therapy during exercise and sleep.
Oximeter measures the percentage of oxygen being carried by red blood cells
One-half of the subjects were treated with oxygen therapy, while the other one-half received no treatment. The study outcomes were time to death and time to first hospitalization for any cause.
The study results were published in the October 27, 2016, issue of the New England Journal of Medicine (volume 375; pages 1617-1627). DOI: 10.1056/NEJMoa1604344.
Results: A total of 738 patients at 42 different medical centers or clinics were followed for 1 – 6 years. There were no differences between the oxygen group and the no oxygen group for time to death or time to first hospitalization. Also, there were no differences in quality of life or 6 minute walking distance between the two groups.
Woman using portable oxygen system
Conclusion: The use of oxygen for those with moderately low levels of oxygen saturation did not provide any benefit.
My Comments: The investigators questioned if the benefits of oxygen might help those with reduced SpO2, but above the cut-off of 88%. They did not find a difference in time to death or time to being hospitalized.
Woman using oxygen at rest
These results will not change current practice. There is good evidence that oxygen therapy enables those who have a SpO2 of 88% or lower with activities to walk farther/longer with less shortness of breath. I and other health care providers will continue to prescribe oxygen based on current standards as listed in Background.
Portable oxygen concentrator which provides continuous flow 1-3 l/min or pulse flow 1-9 l/min