When is a sodium bicarbonate (bicarb) drip initiated?

From the Guidelines

A sodium bicarbonate (bicarb) drip is typically initiated when a patient has severe metabolic acidosis with a pH less than 6.9, as bicarbonate may be beneficial in these patients, but is not necessary if the pH is greater than 7.0 1.

Key Considerations

• The decision to start a bicarb drip should be based on the severity of the metabolic acidosis and the patient's overall clinical condition.
• The standard preparation is 150 mEq of sodium bicarbonate in 1 liter of D5W, infused at 1-1.5 mEq/kg over 1-2 hours, with the rate adjusted based on serial blood gas measurements.
• Before starting a bicarb drip, ensure adequate ventilation as the correction of acidosis produces carbon dioxide that must be exhaled.
• Potassium levels should be monitored closely as bicarbonate therapy can lower serum potassium.

Clinical Scenarios

• Diabetic ketoacidosis with severe acidosis (pH < 6.9) is a common scenario where bicarb drip may be considered 1.
• Other scenarios include lactic acidosis, renal tubular acidosis, or certain drug overdoses, where severe metabolic acidosis is present.

Important Notes

• Bicarb drips are used judiciously due to potential complications including fluid overload, hypernatremia, and paradoxical intracellular acidosis.
• The rationale for bicarbonate therapy is to increase blood pH by providing additional buffer capacity, which helps normalize cellular function, improve cardiac contractility, and enhance the effectiveness of vasopressors in critically ill patients 1.

From the FDA Drug Label

In cardiac arrest, a rapid intravenous dose of one to two 50 mL vials (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 (as indicated by arterial pH and blood gas monitoring) to reverse the acidosis. In metabolic acidosis associated with shock, therapy should be monitored by measuring blood gases, plasma osmolarity, arterial blood lactate, hemodynamics and cardiac rhythm. 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.

A sodium bicarbonate (bicarb) drip is initiated:

• In cardiac arrest: immediately with a rapid intravenous dose of 44.6 to 100 mEq
• In metabolic acidosis associated with shock: as determined by blood gas monitoring and clinical condition of the patient, with an initial infusion of 2 to 5 mEq/kg body weight over 4 to 8 hours 2
• In less urgent forms of metabolic acidosis: as judged by the lowering of total CO2 content, blood pH, and clinical condition of the patient, with an initial infusion of 2 to 5 mEq/kg body weight over 4 to 8 hours 2

From the Research

Initiation of Sodium Bicarbonate Drip

• A sodium bicarbonate (bicarb) drip is initiated in patients with severe metabolic acidosis, defined by a pH < 7.2 with HCO3- < 8 mE- q/L in plasma 3.
• In patients with diabetic ketoacidosis (DKA), sodium bicarbonate administration should be individualized and considered in a subset of patients with moderately severe acidemia (pH<7.20 and plasma bicarbonate level < 12mmol/L) who are at risk for worsening acidemia, particularly if hemodynamically unstable 4.
• Sodium bicarbonate should not be administered to children with DKA, except if acidemia is very severe and hemodynamic instability is refractory to saline administration 4.
• The use of sodium bicarbonate in patients with lactic acidosis and cardiac arrest is not recommended, unless there are specific circumstances such as patients with concomitant acute kidney injury and lactic acidosis, or patients with cardiac arrest secondary to sodium channel blockade or hyperkalemia 5.
• In patients with severe metabolic acidaemia in the intensive care unit, sodium bicarbonate infusion had no effect on the primary composite outcome, but decreased the primary composite outcome and day 28 mortality in the a-priori defined stratum of patients with acute kidney injury 6.

Key Considerations

• The decision to initiate a sodium bicarbonate drip should be based on a risk-benefit assessment, considering the potential complications of therapy, such as hypernatremia, hypokalemia, ionic hypocalcemia, rebound alkalosis, and intracellular acidosis 3.
• Patients receiving sodium bicarbonate therapy require monitoring with serial evaluation of the internal environment, especially arterial blood gases, plasma electrolytes, and ionized calcium 3.
• Isotonic solutions should be preferred instead of hypertonic bicarbonate, and the development of hypernatremia must be prevented 3.