Sodium Bicarbonate Therapy in Patients with Metabolic Acidosis

Abstract

Metabolic acidosis occurs when a relative accumulation of plasma anions in excess of cations reduces plasma pH. Replacement of sodium bicarbonate to patients with sodium bicarbonate loss due to diarrhea or renal proximal tubular acidosis is useful, but there is no definite evidence that sodium bicarbonate administration to patients with acute metabolic acidosis, including diabetic ketoacidosis, lactic acidosis, septic shock, intraoperative metabolic acidosis, or cardiac arrest, is beneficial regarding clinical outcomes or mortality rate. Patients with advanced chronic kidney disease usually show metabolic acidosis due to increased unmeasured anions and hyperchloremia. It has been suggested that metabolic acidosis might have a negative impact on progression of kidney dysfunction and that sodium bicarbonate administration might attenuate this effect, but further evaluation is required to validate such a renoprotective strategy. Sodium bicarbonate is the predominant buffer used in dialysis fluids and patients on maintenance dialysis are subjected to a load of sodium bicarbonate during the sessions, suffering a transient metabolic alkalosis of variable severity. Side effects associated with sodium bicarbonate therapy include hypercapnia, hypokalemia, ionized hypocalcemia, and QTc interval prolongation. The potential impact of regular sodium bicarbonate therapy on worsening vascular calcifications in patients with chronic kidney disease has been insufficiently investigated.

Clinical use of plasma lactate concentration. Part 2: Prognostic and diagnostic utility and the clinical management of hyperlactatemia

“…Sodium bicarbonate has the potential to cause hypernatremia, hyperosmolality, ionized hypocalcemia, overshoot alkalosis, and hypercarbia, as well as intracellular and CSF acidosis. [184][185][186][187][188][189][190] Sodium bicarbonate can also promote lactate production by upregulating the glycolytic enzyme phosphofructokinase. [191][192][193][194][195][196] A number of experimental animal studies have documented bicarbonate therapy to be of no benefit or detrimental in the management of hyperlactatemia, 191,194 and the administration of bicarbonate in people with hyperlactatemia is associated with increased mortality without significant improvement in hemodynamic variables.…”

Use of Bicarbonate in Patients With Metabolic Acidosis

“…5 Other side effects of bicarbonate therapy are potassium shifts resulting in hypokalemia, ionized calcium shifts resulting in hypocalcemia, volume expansion and hypernatremia (with sodium bicarbonate), acidosis of cerebrospinal fl uid, hypoxia due to left shift of the oxyhemoglobin curve (which increases the affi nity of hemoglobin for oxygen), rebound alkalosis, and prolongation of the QTc interval. 5,8 Despite the pathologic conditions present in metabolic acidosis, bicarbonate therapy does not improve cellular or hemodynamic functions and is associated with an increase in mortality. 3,4,8 Two randomized controlled trials and retrospective studies 5,6,9 have failed to fi nd the benefi t of bicarbonate therapy in critically ill patients with lactic acidosis and a pH exceeding 7.1.…”

“…5,8 Despite the pathologic conditions present in metabolic acidosis, bicarbonate therapy does not improve cellular or hemodynamic functions and is associated with an increase in mortality. 3,4,8 Two randomized controlled trials and retrospective studies 5,6,9 have failed to fi nd the benefi t of bicarbonate therapy in critically ill patients with lactic acidosis and a pH exceeding 7.1. The lack of benefi t is most likely related to 2 adverse effects that occur with bicarbonate administration: intracellular acidifi cation due to the accumulation of carbon dioxide after bicarbonate administration and a pH-dependent decrease in ionized calcium that decreases contractility.…”

“…The lack of benefi t is most likely related to 2 adverse effects that occur with bicarbonate administration: intracellular acidifi cation due to the accumulation of carbon dioxide after bicarbonate administration and a pH-dependent decrease in ionized calcium that decreases contractility. 4,5,8 The potential harmful effects of sodium bicarbonate therapy are listed in the Table. Lactic acidosis may develop in cardiac surgery patients owing to inadequate delivery of oxygen to tissues to meet metabolic demand. The effects of the acidosis make it tempting to try to improve the acidosis with administration of bicarbonate, but the effects of treatment are the same as in other critically ill patients.…”

Comment on “Sodium Bicarbonate Therapy in Patients with Metabolic Acidosis”

“…In the paper of Adeva-Andany et al [1] there are some discrepancies with the literature.The authors write “Evidence that significant harmful effects are derived from metabolic acidosis by itself has not been provided in human beings and therefore the successful management of metabolic acidosis require the therapy of the underlying causative disorder.” According to Edge et al [2] and Nyenwe et al [3] metabolic acidosis (= low blood-pH = high concentration of hydrogen ions H + ) is the immediate cause of decreased level of consciousness including coma: the glycolytic enzyme phosphofructokinase is pH-dependent, as its activity is decreasing with decreasing pH. The consequence is impaired utilisation of glucose in brain cells.…”