What is respiratory acidosis primarily caused by?

Respiratory acidosis is primarily characterized by an accumulation of carbon dioxide (CO2) in the blood, leading to lower pH levels. This condition typically arises from inadequate ventilation, where the body's ability to exhale CO2 is compromised, causing increased levels of CO2 in circulation. Conditions such as chronic obstructive pulmonary disease (COPD), severe asthma, or respiratory muscle weakness can contribute to this impaired ventilation.

Increased CO2 levels result in a higher concentration of carbonic acid in the blood, thereby decreasing pH and causing the acidosis. Understanding that respiratory acidosis stems directly from elevated CO2 distinguishes it from other respiratory or metabolic conditions that might influence acid-base balance without the central role of carbon dioxide retention.