Question concerning COPD and supplemental O2

[beatsbydre]

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UWorld question 1493 says that supplementary O2 must be used carefully in COPD because hypoxia drives their respiratory function (as opposed to CO2 in normal people). Why is that?

 

[chettybangbang]

Just saying this from the top of my head, but I think its because the central chemoreceptors become desensitized to CO2 levels from chronic hypoxia. Therefore, high CO2 levels will not stimulate the respiratory centers. So if you supplement O2 to these individuals, their low O2 (hypoxia) will be corrected and therefore the respiratory centers of the brain will no longer be stimulated to breath as O2 levels will not be below 50. Not completely sure.

 

[Suncrusher]

Just saying this from the top of my head, but I think its because the central chemoreceptors become desensitized to CO2 levels from chronic hypoxia. Therefore, high CO2 levels will not stimulate the respiratory centers. So if you supplement O2 to these individuals, their low O2 (hypoxia) will be corrected and therefore the respiratory centers of the brain will no longer be stimulated to breath as O2 levels will not be below 50. Not completely sure.

That's basically correct. In normal people, hypercapnia stimulates the respiratory drive more than hypoxia, and that is an important point to know. However, COPD patients are chronically hypercapnic, so they become desensitized to hypercapnia; the only thing left stimulating their respiratory drive is hypoxia. Giving them too much O2 will correct the hypoxia, which (since it is the only thing left stimulating their respiratory drive) makes their respiratory rate extremely low.

 

[theTruth_97]

i love it when I find a thread with a person asking literally the exact same question that I came onto SDN to ask haha