How does respiratory acidosis affect arterial blood gas values, particularly pH and PaCO2?

Respiratory acidosis leads to a decrease in arterial blood pH (less than 7.35) and an increase in the partial pressure of arterial carbon dioxide (PaCO2), which is elevated due to CO2 retention. The low pH results from the increased levels of free hydrogen ions in the blood, while the high PaCO2 reflects impaired gas exchange.

In respiratory acidosis, the arterial blood gas values show a low pH, indicating acidosis, and a high PaCO2 due to the retention of carbon dioxide. The increase in free hydrogen ions from CO2 retention causes the pH to drop below the normal range of 7.35. If the condition persists, the kidneys may begin to compensate by increasing bicarbonate levels, but initially, the bicarbonate level may remain normal.