[k] Acid-base Disorders

THE KIDNEY

Acid-Base Disorders In the following table, arterial pH and blood gas data are summarized for a number of patients with different acid-base disorders.

1.

Indicate the type of acid-base disorder that exists for each patient. Use as normal values: pH = 7.40 [HCO3-] = 24 mEq/L; and PCO2 = 40 mm Hg.

The first six disorders are simple acid-base disorders. Mixed metabolic and respiratory acidosis is seen during cardiopulmonary arrest. With cessation of cardiac function, the tissues are inadequately perfused and resort to anaerobic metabolism (production of lactic acid). With cessation of respiration, CO2 is retained. In the example of mixed metabolic acidosis and respiratory alkalosis, pH is normal, but both the [HCO3-] and PCO2 are abnormal. An example of a clinical condition that produces such a disorder is an overdose of aspirin. The metabolic acidosis is the result of the salicylic acid (active ingredient of aspirin), and the respiratory alkalosis is the result of hyperventilation secondary to salicylic acid stimulation of the respiratory centers.