Caused by alveolar hyperventilation, respiratory alkalosis is a condition marked by a decrease in partial pressure of arterial carbon dioxide (PaCO2) to below 35 mm Hg. Uncomplicated respiratory alkalosis leads to a decrease in hydrogen ion concentration, which causes elevated blood pH. Hypocapnia occurs when the elimination of carbon dioxide by the lungs exceeds the production of carbon dioxide at the cellular level.
Respiratory alkalosis can result from pulmonary or nonpulmonary causes:
Pulmonary causes include pneumonia, interstitial lung disease, pulmonary vascular disease, and acute asthma.