Sodium bicarbonate therapy for metabolic acidosis in critically ill patients: a Bayesian systematic review and meta-analysis of randomised controlled trials

To evaluate the effects of sodium bicarbonate therapy on mortality and renal outcomes in critically ill adults with metabolic acidosis. We performed a systematic review and Bayesian random-effects meta-analysis of randomised controlled trials (RCTs) comparing intravenous sodium bicarbonate with placebo or usual care in adult intensive care unit patients with metabolic acidosis. MEDLINE, Embase and CENTRAL were searched from inception to December 2025, with an updated search on 2 April 2026. The primary outcome was short-term all-cause mortality. Secondary outcomes included renal replacement therapy (RRT) initiation, 90-day mortality, RRT-free days, vasopressor-free days, intensive care unit and hospital length of stay and adverse events. Four RCTs including 1544 patients were analysed. Sodium bicarbonate did not show a clear short-term mortality benefit (RR 0.94, 95% CrI 0.73–1.22), with a posterior probability of benefit of 72.1%. For RRT initiation, sodium bicarbonate was associated with a lower risk (RR 0.74, 95% CrI 0.59–0.98), with a posterior probability of benefit of 97.2%. Effects on other outcomes were small or imprecise, and no consistent safety signal was identified. Current randomised evidence does not demonstrate a clear survival benefit from sodium bicarbonate therapy in critically ill adults with metabolic acidosis, but suggests a high probability of reducing RRT initiation. Further trials should define the patients most likely to benefit. PROSPERO registration: CRD420251246519.