SODium BICarbonate for Metabolic Acidosis in the ICU

Inclusion Criteria: All the diagnostic criteria of metabolic acidosis below have to be fulfilled within the last 2 hours before randomisation (pH, PaCO2 and BE from the same blood gas), and a vasopressor is being infused continuously at the time of randomization. 1. Adults (≥ 18 years); 2. Receiving a continuous infusion of a vasopressor to maintain mean arterial pressure \> 65 mmHg (or a mean arterial pressure target set by the treating clinician); 3. A dedicated intravenous line (central or peripheral) is available (or insertion of such a line is planned within the next hour); and 4. Metabolic acidosis, defined as: 1. pH \< 7.30; and 2. BE ≤ -4 mEq/L; and 3. PaCO2 ≤ 45 mmHg for non-intubated patients or PaCO2 ≤ 50 mmHg for intubated patients. Exclusion Criteria: 1. Fulfilled all eligibility criteria greater than 48 hours ago; or 2. Suspected clinically significant digestive or urinary tract loss of sodium bicarbonate (e.g., diarrhoea, ileostomy losses, renal tubular acidosis, or drainage of pancreatic or bile duct); or 3. DKA; or 4. Estimated glomerular filtration rate (eGFR) \< 30 mL/min due to chronic kidney disease; or 5. Currently receiving sodium bicarbonate at the moment of randomisation (doses of sodium bicarbonate prior to randomisation are allowed); or 6. Currently receiving RRT (acute or chronic) or planned to start RRT in the next 3 hours (according to the treating clinical team); or 7. Severe dysnatraemia (serum Na ≥ 155 mEq/L or \< 120 mEq/L); or 8. Hypokalaemia (serum K \< 2.5 mEq/L); or 9. Pulmonary oedema with PaO2 / FiO2 \< 100; or 10. Hypocalcaemia (iCa \< 0.8mmol/L); or 11. Patients admitted to the ICU after a drug overdose or intoxication (including alcohol intoxication); or 12. Pregnancy or breastfeeding; or 13. Death is deemed to be inevitable as a result of the current acute illness and either the treating clinician, the patient or the substitute decision maker are not committed to full active treatment; or 14. Patients with a life expectancy \< 30 days due to a chronic or underlying medical condition; or 15. Considered to be at high risk of cerebral oedema by the treating clinician (e.g. traumatic brain injury or acute brain disease); or 16. Clinician believes that being enrolled in intervention or control arm is not in the best interest of the patient; or 17. Previous enrolment in this study.