How does a patient with COPD and therefore chronically Hypercapnia not have a respiratory acidosis (acute decompensation due to respiratory infection can cause respiratory acidosis)....but why not normally? I'm assuming because of their kidneys compensation with bicarbonate?
Jul 19, '15
Careful, not all COPD'ers are chronically hypercapneic! Many of them have normal range PCo2, it has a lot to do with the severity of their disease and the amount of time they've been at that level of severity. If a patient has a chronically high PCo2 the kidneys will compensate by excreting more HCO3- to make the pH more alkalotic to bring it back into 7.35-7.45 range, so yes you are correct on that. It doesn't happen overnight, it takes a good amount of time for the kidneys to react in this manner. The kidney's reabsorb more bicarbonate if it senses a low pH (acidic), instead of excreting it into the urine. It's all apart of homeostasis.