Metabolic acidosis in acute kidney injury: bicarbonate or not?

Question

6-year-old dog with non-oliguric acute kidney injury. After 12 hours of fluid therapy, the venous blood gas is as follows:

Parameter	Result	Reference
pH	7.12	7.35–7.45
Bicarbonate	9 mmol/L	20–26
pCO2	29 mmHg	33–45
Potassium	4.9 mmol/L	3.5–5.5
Ionised calcium	1.15 mmol/L	1.12–1.40

Which statement about sodium bicarbonate is correct in this case?

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A. The whole bicarbonate deficit should be corrected with a rapid intravenous bolus

Rapid correction can cause ionised hypocalcaemia, hypokalaemia, hypernatraemia and paradoxical cerebrospinal fluid acidosis.

B. It may be considered because the acidosis is severe and persists despite fluids: give a fraction of the deficit slowly, monitoring ionised calcium and potassium

Correct. With pH < 7.1–7.2 and bicarbonate < 12 mmol/L that do not improve after perfusion is corrected, a quarter to a third of the calculated deficit is usually given over several hours, followed by reassessment.

C. It is indicated in all acute kidney injury, even if the pH is above 7.3

Mild to moderate acidosis usually corrects with fluid therapy and better perfusion. Bicarbonate carries risks and is only considered in severe, persistent acidosis.

D. It can be given through the same line as lactated Ringer's or calcium gluconate

Bicarbonate precipitates with calcium to form calcium carbonate: it must not be mixed with calcium-containing solutions.

lightbulb Key takeaway

The deficit is estimated as 0.3 × body weight (kg) × base deficit. The patient must be able to eliminate the CO2 generated; in anuria with overload, the sodium and volume load of bicarbonate is another argument for dialysis.

Which statement about sodium bicarbonate is correct in this case?

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