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Lung diseases

Lung and oxygen levels

03/20/2008

Question:

My 3 year old has been diagnosed with Bronchiolitis Oblitrans Syndrome. He has recently had an oxygen stats test carried out. I was just wondering what the normal overnight oxygens levels should be for a child with a lung condition.

Answer:

In a child with healthy lungs, oxygen saturation (which measures how much oxygen the blood is carrying - compared to the absolute most it could hold) usually registers 95-100%. Children whose lungs are not functioning properly - either from a temporary problem like asthma or pneumonia, or from a more chronic problem like bronchiolitis obliterans - may have saturations of <95% while asleep, even if their awake oxygen levels are "normal." This is because everyone breaths with a little less effort when they sleep - for healthy lungs, that's not a problem, but in illness that decrease in effort can be just enough to allow the oxygen level to drop.

Oxygen levels that are above 88-90% generally do not require treatment, as the body can usually function well with that amount of oxygen in the blood.

Oxygen levels that are intermittently dropping below 88-90% can, however, put a strain on the body over time, and when dips into this range are frequent, usually oxygen is prescribed.

It's hard to say what a "normal overnight oxygen level" is for your child's condition without knowing how bad his bronchiolitis obliterans is. If the drop in sats seems greater than would be expected for him (based on what is seen on his chest CT, how his lungs sound, how his sats are during the day . . . ), his doctors may search for additional, fixable, reasons for the drop in oxygen levels. Such additional reasons could be problems like obstructive sleep apnea, reflux and aspiration, nocturnal bronchospasm, etc..

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Response by:

Elizabeth D Allen, MD Elizabeth D Allen, MD
Clinical Associate Professor of Pediatrics
College of Medicine
The Ohio State University