- stage 3 aki (as defined by kdigo criteria) - chronic kidney disease stage 4 or 5 - contraindications to nahco3 therapy (e.g. risk of serious drug interaction, systemic metabolic alkalosis, congestive heart failure) - urine ph > 7.0 - serum sodium >150mmol/l - blood pressure >180/100mghg - severe hypokalaemia (k<3.0mmol/l) - inability to grant informed consent - severe hypocalcaemia (cai <0.8 mmol/l) - pregnant or lactating and breast-feeding women - unwilling to use contraception - patient is on a medication that may interact with sodium bicarbonate

- stage 3 aki (as defined by kdigo criteria) - chronic kidney disease stage 4 or 5 - contraindications to nahco3 therapy (e.g. risk of serious drug interaction, systemic metabolic alkalosis, congestive heart failure) - urine ph > 7.0 - serum sodium >150mmol/l - blood pressure >180/100mghg - severe hypokalaemia (k<3.0mmol/l) - inability to grant informed consent - severe hypocalcaemia (cai <0.8 mmol/l) - pregnant or lactating and breast-feeding women - unwilling to use contraception - patient is on a medication that may interact with sodium bicarbonate