Respiratory alkalosis is defined as a primary decreasein Paco2. The mechanism is usually an inappropriate increase in alveolar ventilation relative to CO2 pro-duction. Table 50–5 lists the most common causes of respiratory alkalosis. Plasma [HCO 3−] usually
decreases 2 mEq/L for each 10 mm Hg acute decrease in Paco2 below 40 mm Hg. The distinction between acute and chronic respiratory alkalosisis not always made, because the compensatory response to chronic respiratory alkalosis is quite variable: plasma [HCO3−] decreases 2–5 mEq/L for each 10 mm Hg decrease in Paco2 below 40 mm Hg.
Correction of the underlying process is the only treatment for respiratory alkalosis. For severe alka-lemia (arterial pH >7.60), intravenous hydrochloric acid, arginine chloride, or ammonium chloride may be indicated .