Sodium Bicarbonate for Acute Metabolic Acidosis in Critically Ill Adults: A Meta-Analysis of Randomized Clinical Trials.

Abstract

Acute metabolic acidosis is frequent in critical illness and may be managed with volume replacement therapy, sodium bicarbonate, and renal replacement therapy (RRT). BICARICU-1 and BICARICU-2 trials provided new evidence on bicarbonate therapy. We aimed to systematically evaluate the effects of sodium bicarbonate in critically ill patients. We systematically searched PubMed, Embase, Medline, and the Cochrane Library for randomized controlled trials (RCTs) evaluating sodium bicarbonate vs. placebo in critically ill adults with acute metabolic acidosis. Only RCTs were selected. Primary outcome was RRT; secondary outcomes were mortality, ICU length of stay, ventilator-free days, and vasopressor-free days. We performed Hartung-Knapp random-effects meta-analyses and trial sequential analysis (TSA) for primary outcomes. Bayesian random-effects meta-analyses with noninformative and weakly informative priors were used for sensitivity analysis. Four trials enrolling 1,111 patients were included. Sodium bicarbonate showed a nonsignificant trend toward lower mortality (risk ratio [RR], 0.84; 95% CI, 0.55-1.30); TSA indicated that the cumulative sample size remained far below the required information size, and the mortality effect is inconclusive. Sodium bicarbonate significantly reduced RRT use (RR, 0.69; 95% CI, 0.61-0.78), and TSA supported firm evidence of benefit. Bayesian analyses estimated posterior probabilities of any mortality reduction (RR < 1) and reduced RRT use of 90.4% and 94.6%, respectively. Secondary outcomes remained imprecise, with a trend of toward more vasopressor-free days. In critically ill adults with acute metabolic acidosis, sodium bicarbonate significantly reduces RRT requirement, with Bayesian analyses suggesting a possibility of mortality benefit, although current evidence remains inconclusive. Larger RCTs or high-quality real-world studies are needed to confirm efficacy of sodium bicarbonate for mortality.