Are CO2 levels higher in respiratory acidosis or respiratory alkalosis?

In respiratory acidosis, CO2 levels are elevated due to inadequate ventilation, leading to an accumulation of carbon dioxide in the bloodstream. This increase in CO2 results in a lower pH, making the blood more acidic. When ventilation is compromised—whether due to obstructive lung diseases, central respiratory depression, or other factors—CO2 is not effectively removed from the body, causing its levels to rise and resulting in respiratory acidosis.

Conversely, in respiratory alkalosis, CO2 levels are decreased because the patient is hyperventilating, which leads to excessive expulsion of carbon dioxide. This drop in CO2 raises the blood pH, making it more alkaline.

Therefore, since respiratory acidosis is defined by elevated CO2 levels, it confirms that CO2 levels are indeed higher in this condition compared to respiratory alkalosis, where CO2 is lower.