In this episode, I’ll discuss when using IV bicarb in the ICU is actually helpful.
If used to attempt to normalize pH without correcting the underlying problem, sodium bicarbonate use is essentially pointless as its effects will be short-lived. In addition, indiscriminate bicarb use should be avoided due to potential adverse effects including:
- Increased production of lactate (by altering pH and interfering the feedback loop on lactate production normally created by acidemia).
- Decreased left ventricular contractility (due to a decrease in free ionized calcium).
There are at least 3 scenarios where routine bicarb use in the ICU is considered to have little to no clinically relevant effect:
- Coagulopathy (correction of the pH with sodium bicarbonate does not seem to be enough to reverse the adverse effects of acidemia coagulation)
- Respiratory acidosis with inadequate ventilation (The elevated PCO2 that results from inadequate ventilation puts a stop to the generation of H2O and CO2 that normally results from -HCO3 administration)
- Cardiac arrest (many studies have shown little/no benefit and perhaps harm from administration of sodium bicarbonate for rapid correction of acidemia accompanying cardiac arrest, and the latest ACLS guidelines published by the AHA do not recommend routine administration)
But when is sodium bicarb use actually indicated? I can come up with 4 general indications where I believe bicarb is routinely indicated for use in ICU patients:
- Drug toxicity (Quinidine-induced torsades and tricyclic toxicity to alkalinize the serum, and aspirin toxicity to alkalinize the urine)
- Diabetic ketoacidosis and pH < 7 (Prevent the decrease in myocardial contractility that accompanies severe acidosis)
- Hyperkalemia (After 4-6 hours, if the patient with hyperkalemia also had metabolic acidosis, the serum potassium will decrease by just over 0.5 mEq/L)
- Initial treatment of severe lactic or metabolic acidosis to allow time for the underlying condition to be treated (While this is using bicarb as a ‘bandage’ it could allow time to correct the underlying cause by reversing reduced responsiveness to catecholamine vasopressors or arrhythmias)
What do you think about these indications? Is there a scenario I missed where IV sodium bicarb could routinely be given in the ICU and a benefit be expected? Let me know in the comment section below or by tweeting @pharmacyjoe.
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