results from increased alveolar
) leading to decreased plasma carbon dioxide
concentration. This leads to decreased hydrogen ion and freely ionized blood calcium
There are two types of respiratory alkalosis: chronic and acute.
- In acute respiratory alkalosis, increased levels of carbon dioxide are "blown off" by the lungs, which are hyperventilating. During acute respiratory alkalosis, the person may lose consciousness where the rate of ventilation will resume to normal.
- In chronic respiratory alkalosis, for every 10 mM drop in pCO2 in blood, there is a corresponding 5 mM of bicarbonate ion drop. The drop of 5 mM of bicarbonate ion is a compensation effect which reduces the alkalosis effect of the drop in pCO2 in blood. This is termed metabolic compensation.
Causes of the alveolar hyperventilation seen in respiratory alkalosis include:
In addition, a respiratory alkalosis is often produced accidentally by doctors (iatrogenically) during mechanical ventilation of patients.
Symptoms of respiratory alkalosis are related to the decreased blood carbon dioxide levels, and include peripheral paraesthesiae
. In addition, the alkalosis may disrupt calcium ion balance, and cause the symptoms of hypocalcaemia
(such as tetany
) with no fall in total serum calcium levels.