This is a really interesting question.
I definitely ‘grew up’ being told that bicarbonate therapy was a last resort. I try to think about this in the context of some of the more common cases that we see:
In diabetic ketoacidosis (DKA). The metabolic acidosis of DKA typically resolves with fluid therapy and insulin alone. Sodium bicarbonate, is no longer recommended. The American Diabetes Association does list it as a treatment option for patients with a pH < 7.0 1 hour after onset of fluid therapy, without prospective randomized studies to demonstrate efficacy. Bicarbonate drives K into cells, potentially worsening hypokalaemia; shifts the oxyhaemoglobin curve to the left, decreasing oxygen release at the tissue level; and can contribute to paradoxical CNS acidosis, fluid overload, lactic acidosis, persistent ketosis and cerebral oedema.
Regardless of the condition, it would be rare to reach for the bicarbonate without other therapies (fluids) starting first. The only clinical situation where I have used bicarbonate was in a rare case of distal renal tubular acidosis (secondary to IMHA). These cases have significant bicarbonate wastage due to their tubular disorder.
I have also been bicarbonate used in cases of CPR when bloods have been taken during the CPR and a severe acidosis is determined.
Overall, not something I can think of many indications for.
Any other thoughts?
Scott
