Which of the following describes the values for respiratory alkalosis?

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

Answer: (B)

Respiratory alkalosis is characterized by an increase in blood pH and a decrease in the partial pressure of carbon dioxide (PCO2). This condition occurs when there is hyperventilation, leading to excessive exhalation of CO2, which consequently raises the blood's pH level.

In respiratory alkalosis, the bicarbonate (HCO3) levels may remain normal initially because the primary issue is not with bicarbonate metabolism but with the CO2 levels caused by respiratory factors. If the condition is prolonged, compensatory metabolic changes may occur, but in the acute phase or initial stages, it is common for bicarbonate to be normal.

Thus, the correct description includes an increased pH, decreased PCO2, and normal HCO3, identifying the key physiological changes that occur during respiratory alkalosis.