How is sodium bicarbonate dosed in the treatment of lactic acidosis?

Updated: Oct 02, 2018
  • Author: Bret A Nicks, MD, MHA; Chief Editor: Romesh Khardori, MD, PhD, FACP  more...
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Answer

Answer

The starting dose of sodium bicarbonate (NaHCO3-) is one third to one half of the calculated extracellular bicarbonate (HCO3-) deficit, as illustrated by the following formula:

HCO3 deficit (in mEq) = 0.5 × (Wt in kg) × (Desired HCO3 – Measured HCO3)

Metabolic alkalosis can ensue after bicarbonate administration if the correction is complete rather than partial. This result can be avoided by titration of the bicarbonate dose to modest therapeutic end points (eg, arterial pH of 7.20). In severe hypoxemia, sodium bicarbonate should be administered by slow infusion to minimize any increase in central venous carbon dioxide tension (PvCO2). Minute ventilation must be increased in order to expel carbon dioxide (CO2) generated by bicarbonate administration. Because of increased CO2 production, sodium bicarbonate may precipitate ventilatory failure and, as such, must be given with caution.

Toxic etiologies of lactic acidosis, such as methanol, ethylene glycol, and cyanide poisoning, may justify administration of bicarbonate (See Cyanide Toxicity, Ethylene Glycol Toxicity, and Toxicity, Alcohols). These are unique circumstances that require bicarbonate therapy to facilitate the detoxification processes.


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