Bicarbonate Therapy in Severe Metabolic Acidosis

Abstract

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.

Coronary Sinus Lactate as Marker of Myocardial Ischemia in Cardiac Surgery: Correlation with Morbidity and Mortality after Cardiac Surgery / Lactatul din sinusul coronarian - marker al ischemiei miocardice în chirurgia cardiacă: corelaţii cu morbiditatea şi mortalitatea postoperatorie

“…Metabolic acidosis occurs due to the anaerobic metabolism during ischemia and may induce an inflammatory response following reperfusion, which may contribute to the development of hemodynamic disorders in the postoperative period. Acidosis itself decreases myocardial contractility and cardiac response to exogenous catecholamines and is a risk factor for arrythmia development (18)(19)(20).…”

Use of Bicarbonate in Patients With Metabolic Acidosis

“…In addition, acidemia decreases the binding of norepinephrine to its receptors and is associated with hyporesponsiveness to endogenous and infused catecholamines. [2][3][4][5] Patients in severe acidosis have a predisposition to cardiac arrhythmias such as ventricular fibrillation, which can contribute to sudden death. 2,5 Acidosis adversely affects cell functions such as enzymatic reactions, generation of adenosine triphosphate, fatty acid biosynthesis, and bone formation and restoration.…”

“…2,5 Acidosis adversely affects cell functions such as enzymatic reactions, generation of adenosine triphosphate, fatty acid biosynthesis, and bone formation and restoration. 3 Patients are more susceptible to infection because of the suppressed immune response and leukocyte function. 2 It seems logical that if acidosis causes multiple cellular dysfunctions, correcting pH with alkaline Bicarbonate therapy is sometimes prescribed to treat acute metabolic acidosis, an acid-base disorder that is characterized by a primary decrease in the concentration of bicarbonate ions (HCO 3 -), a compensatory decrease in the partial pressure of carbon dioxide (PaCO 2 ), and a decrease in serum pH.…”

“…1 Acidosis is considered severe when the pH is less than 7.20. Assuming an appropriate ventilatory response, this blood pH would be associated with a serum HCO 3 -concentration of less than 10 mEq/L. 2 Two general mechanisms cause metabolic acidosis: a true HCO 3 -deficit (such as renal or gastrointestinal losses) or a net addition of strong acids (such as toxins, diabetic ketoacidosis, or lactic acid production).…”

“…Assuming an appropriate ventilatory response, this blood pH would be associated with a serum HCO 3 -concentration of less than 10 mEq/L. 2 Two general mechanisms cause metabolic acidosis: a true HCO 3 -deficit (such as renal or gastrointestinal losses) or a net addition of strong acids (such as toxins, diabetic ketoacidosis, or lactic acid production). 1,3 Bicarbonate replacement is beneficial for patients with true bicarbonate deficits, but not in patients with metabolic acidosis caused by an increase in acid production.…”