* stage 3 aki (as defined by kidney disease improving global outcome 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 \> 7.5 * serum sodium \>150mmol/l * blood pressure \>180/100mghg * severe hypokalaemia (k\<3.0mmol/l) * severe hypocalcaemia (cai \<0.8 mmol/l) * pregnant or lactating and breast-feeding women * patient is on a medication that may interact with sodium bicarbonate

* stage 3 aki (as defined by kidney disease improving global outcome 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 \> 7.5 * serum sodium \>150mmol/l * blood pressure \>180/100mghg * severe hypokalaemia (k\<3.0mmol/l) * severe hypocalcaemia (cai \<0.8 mmol/l) * pregnant or lactating and breast-feeding women * patient is on a medication that may interact with sodium bicarbonate

- stage 3 aki (as defined by kidney disease improving global outcome 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 > 7.5 - serum sodium >150mmol/l - blood pressure >180/100mghg - severe hypokalaemia (k<3.0mmol/l) - severe hypocalcaemia (cai <0.8 mmol/l) - pregnant or lactating and breast-feeding women - patient is on a medication that may interact with sodium bicarbonate

- stage 3 aki (as defined by kidney disease improving global outcome 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 > 7.5 - serum sodium >150mmol/l - blood pressure >180/100mghg - severe hypokalaemia (k<3.0mmol/l) - severe hypocalcaemia (cai <0.8 mmol/l) - pregnant or lactating and breast-feeding women - patient is on a medication that may interact with sodium bicarbonate