Which of the following sets of values indicates respiratory acidosis?

Which of the following sets of values indicates respiratory acidosis?

• A. Decreased pH, Increased PCO2, Normal HCO3
• B. Increased pH, Decreased PCO2, Normal HCO3
• C. Decreased pH, Normal PCO2, Decreased HCO3
• D. Increased pH, Normal PCO2, Increased HCO3

Answer: (A)

Respiratory acidosis is characterized by an increase in carbon dioxide (PCO2) levels in the blood, which leads to a decrease in pH due to the formation of carbonic acid. This condition typically occurs when the lungs are unable to effectively remove CO2, often due to respiratory disorders such as chronic obstructive pulmonary disease (COPD), severe asthma, or any condition that affects respiratory function.

In the correct set of values, there is a decreased pH indicating acidosis, an increased PCO2 demonstrating the retention of carbon dioxide, and normal bicarbonate (HCO3) levels. The bicarbonate levels remain normal initially in acute respiratory acidosis because the kidneys have not yet had time to compensate by retaining bicarbonate to help buffer the excess acid. This alignment of values confirms that the patient is experiencing respiratory acidosis.

The values associated with other options do not reflect the conditions for respiratory acidosis accurately. They may indicate metabolic disturbances or alkalosis, which are characterized by different combinations of pH, PCO2, and HCO3 levels. Understanding these relationships helps in diagnosing and managing respiratory and metabolic disorders effectively.