What is the recommended dose of sodium bicarbonate (NaHCO3) for treating metabolic acidosis?

From the Guidelines

The recommended dose of sodium bicarbonate for treating metabolic acidosis is 1 to 2 mEq/kg intravenous boluses until arterial pH is >7.45, as stated in the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1.

Key Considerations

• The dose should be individualized based on the severity of acidosis and the patient's clinical condition.
• For less severe cases, calculating the bicarbonate deficit using the formula: HCO3 deficit = 0.5 × weight (kg) × (desired HCO3 - measured HCO3) can be helpful, with only half of the calculated deficit given initially.
• Continuous infusions may be used at rates of 37.5-50 mEq/hour in critical situations, as mentioned in the context of treating metabolic acidosis.
• Sodium bicarbonate administration should be accompanied by close monitoring of arterial blood gases, serum electrolytes, and clinical status, with repeat measurements every 2-4 hours during treatment.

Monitoring and Goals

• The goal is to gradually increase serum bicarbonate to safe levels (>12-15 mEq/L) rather than completely normalizing pH immediately.
• Overly rapid correction can cause complications including metabolic alkalosis, hypernatremia, hyperosmolality, and paradoxical cerebrospinal fluid acidosis.

Additional Context

• The 2000 clinical practice guidelines for nutrition in chronic renal failure by the National Kidney Foundation suggest that oral supplementation with bicarbonate salts, usually about 2 to 4 g/d or 25 to 50 mEq/d, can be used to effectively increase serum bicarbonate concentrations in patients with chronic renal failure 1.
• However, for acute severe acidosis, the intravenous route is preferred, and the dose should be guided by the most recent and highest quality evidence, which in this case is the 2010 American Heart Association guidelines 1.

From the FDA Drug Label

In cardiac arrest, a rapid intravenous dose of one to two 50 mL syringes (44.6 to 100 mEq) may be given initially and continued at a rate of 50 mL (44. 6 to 50 mEq) every 5 to 10 minutes if necessary In less urgent forms of metabolic acidosis, ... approximately 2 to 5 mEq/kg of body weight – depending upon the severity of the acidosis Initially an infusion of 2 to 5 mEq/kg body weight over a period of 4 to 8 hours will produce a measurable improvement in the abnormal acid-base status of the blood.

The recommended dose of sodium bicarbonate for treating metabolic acidosis is:

• 2 to 5 mEq/kg of body weight over a period of 4 to 8 hours in less urgent forms of metabolic acidosis.
• 1 to 2 50 mL syringes (44.6 to 100 mEq) initially in cardiac arrest, and continued at a rate of 50 mL (44.6 to 50 mEq) every 5 to 10 minutes if necessary. 2

From the Research

Sodium Bicarbonate Dose for Metabolic Acidosis

• The recommended dose of sodium bicarbonate (NaHCO3) for treating metabolic acidosis varies depending on the severity of the condition and the patient's response to treatment 3, 4.
• In general, bicarbonate should be given at an arterial blood pH of ≤7.0, and the amount given should be calculated to bring the pH up to 7.2 3.
• The dose of sodium bicarbonate can be estimated based on the patient's bicarbonate deficit, but the calculations are only for reference, and the treatment should be individualized 4.
• A study published in 2018 found that sodium bicarbonate infusion had no effect on the primary composite outcome of death from any cause by day 28 and the presence of at least one organ failure at day 7 in patients with severe metabolic acidaemia 5.
• However, another study suggested that hypertonic sodium bicarbonate can be effective in treating sodium channel blocker poisoning, but the dose should be limited to 1-2 mmol/kg, and repeated bolus doses should be administered with caution to avoid excessive sodium bicarbonate therapy and severe adverse effects 6.

Administration and Monitoring

• Sodium bicarbonate should be administered judiciously, and the patient's internal environment should be monitored closely, especially arterial blood gases, plasma electrolytes, and ionized calcium 4.
• Isotonic solutions should be preferred instead of hypertonic bicarbonate to prevent hypernatremia, and calcium should be provided for hypocalcemia to improve cardiovascular function 4.
• In mechanically ventilated patients, a respiratory response similar to the one that would develop physiologically should be established to extract excess CO2 and avoid intracellular acidosis 4.

Potential Complications

• Sodium bicarbonate therapy can cause electrolyte abnormalities such as hypokalemia and hypocalcemia, leading to QT interval prolongation and torsade de pointes in poisonings with drugs that have mixed sodium and potassium cardiac channel properties 6.
• Excessive doses of hypertonic sodium bicarbonate can cause hypernatremia, fluid overload, metabolic alkalosis, and cerebral edema, and can be potentially lethal 6.