∙ 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.

• Adults (≥ 18 years);

• 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);

• A dedicated intravenous line (central or peripheral) is available (or insertion of such a line is planned within the next hour); and

• Metabolic acidosis, defined as:

‣ pH \< 7.30; and

⁃ BE ≤ -4 mEq/L; and

⁃ PaCO2 ≤ 45 mmHg for non-intubated patients or PaCO2 ≤ 50 mmHg for intubated patients.