In the case of pneumonia, why might a patient develop respiratory alkalosis?

A patient with pneumonia may develop respiratory alkalosis primarily due to hyperventilation in response to hypoxia. When the lung tissue is infected and inflammation occurs, gas exchange can become impaired, leading to decreased oxygen levels in the blood (hypoxia). To compensate for this reduced oxygenation, the respiratory drive increases, causing the patient to hyperventilate. During hyperventilation, carbon dioxide is expelled from the body at a greater rate than it is produced, resulting in a decrease in blood carbon dioxide levels (hypocapnia). This shift alters the acid-base balance, leading to respiratory alkalosis, characterized by a higher pH in the blood.

The other options describe scenarios that do not align with the physiological responses typically seen in pneumonia. For instance, hypoventilation due to fatigue would lead to respiratory acidosis rather than alkalosis, as it causes carbon dioxide retention. Increased lung compliance is not a common factor in pneumonia; in fact, lung compliance often decreases due to increased secretions and inflammation. Finally, decreased metabolic demand does not directly affect respiratory rate or pH as it pertains to gas exchange in the lungs. Thus, hyperventilation stemming from a need to improve oxygenation is the most relevant reason for the development of respiratory