Respiratory Alkalosis

A primary decrease in arterial carbon dioxide partial pressure; pH is increased and total carbon dioxide content is decreased.

The hyperventilation usually present leads to an excessive loss of carbon dioxide. Common causes include mechanical overventilation, hypoxemia, sepsis, pulmonary embolism, heart failure, hepatic failure, primary central nervous system disorders, and salicylate toxicity. Anxiety can cause a mild, acute respiratory alkalosis with a characteristic hyperventilation syndrome. Physiologic consequences of respiratory alkalosis include cerebral vasoconstriction, with resulting cerebral hypoxia and decreased ionized serum calcium concentrations leading to tetany and hypophosphatemia. Treatment consists of correcting the underlying disorder or, in the case of hyperventilation syndrome, supervised breathing into a paper bag.