Bicarbonate therapy in severe metabolic acidosis.

The utility of bicarbonate administration to patients with severe metabolic acidosis remains controversial. Chronic bicarbonate replacement is obviously indicated for patients who continue to lose bicarbonate in the ambulatory setting, particularly patients with renal tubular acidosis syndromes or diarrhea. In patients with acute lactic acidosis and ketoacidosis, lactate and ketone bodies can be converted back to bicarbonate if the clinical situation improves. For these patients, therapy must be individualized. In general, bicarbonate should be given at an arterial blood pH of < or =7.0. The amount given should be what is calculated to bring the pH up to 7.2. The urge to give bicarbonate to a patient with severe acidemia is apt to be all but irresistible. Intervention should be restrained, however, unless the clinical situation clearly suggests benefit. Here we discuss the pros and cons of bicarbonate therapy for patients with severe metabolic acidosis.

Metabolic alkalosis, bedside and bench.

Although significant contributions to the understanding of metabolic alkalosis have been made recently, much of our knowledge rests on data from clearance studies performed in humans and animals many years ago. This article reviews the contributions of these studies, as well as more recent work relating to the control of renal acid-base transport by mineralocorticoid hormones, angiotensin, endothelin, nitric oxide, and potassium balance. Finally, clinical aspects of metabolic alkalosis are considered.