Discussion by Dr. Timothy Sullivan and Dr. Eric Korbach
Causes of very severe acidosis (e.g. Bicarb < 4):
- Toxins/alcohols
- Lactate
- Ketones
Rule of thumb: Lactate x 1.5 = expected anion gap from lactate alone (Is the lactate sufficient to explain the anion gap acidosis?)
Bicarbonate — may consider if pH<7.1 or non-anion gap acidosis — does cause a transient acidosis
Dialysis — not a good option for metabolic acidosis related to lactate — does not clear lactate — particularly not useful for elevated lactate related to poor perfusion; need to be stable for dialysis because will cause fluid shifts which an unstable patient cannot tolerate
CRRT (continuous renal replacement therapy) — will help clear lactate — useful in hemodynamically unstable patients
Osmolal gap is a “rule-in test”, not a “rule out” test (i.e. if no gap is present, it does not completely rule out the presence of toxic alcohols)
Fulminant hepatic failure presents as a vasodilatory shock (looks like a septic shock) with many metabolic and systemic abnormalities.
emshorts 