Respiratory acidosis is typically a result of what physiological imbalance?

Respiratory acidosis occurs when the lungs cannot remove enough carbon dioxide (CO2) from the body, leading to an accumulation of CO2 in the bloodstream. This accumulation results in increased levels of carbonic acid, ultimately causing a decrease in blood pH and leading to a state of acidosis. The underlying physiological imbalance that primarily contributes to respiratory acidosis is decreased alveolar ventilation.

When alveolar ventilation is decreased, the efficiency of gas exchange in the lungs is compromised, and CO2 is not expelled adequately. Conditions that can lead to decreased alveolar ventilation include respiratory depression from drugs, neuromuscular diseases, chronic obstructive pulmonary disease (COPD), and severe asthma exacerbations.

In contrast, increased alveolar ventilation would result in more effective removal of CO2, thereby preventing respiratory acidosis. Decreased blood flow affects the delivery of oxygen and can complicate other conditions, but it does not directly cause respiratory acidosis. Metabolic alkalosis represents a completely different primary disturbance in acid-base balance, where there is an increase in blood pH typically due to excess bicarbonate or loss of hydrogen ions, and thus it is not relevant in the context of respiratory acidosis.