OBJECTIVES: 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.

DATA SOURCES: 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.

STUDY SELECTION: Only RCTs were selected.

DATA EXTRACTION: Primary outcome was RRT; secondary outcomes were mortality, ICU length of stay, ventilator-free days, and vasopressor-free days.

DATA SYNTHESIS: 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.

CONCLUSIONS: 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.

Intensivist/Critical Care rater

The effect of administering bicarbonate to patients with metabolic acidosis has been inconclusive. This meta-analysis of randomized trials suggests there is a benefit of avoiding renal replacement therapy. The analysis was good, so there might be a benefit and a role for bicarbonate administration. However, the study was underpowered for the outcome of mortality, so more studies are still needed.

Nephrology rater

A careful analysis of the impact of sodium bicarbonate in critically ill patients with metabolic acidosis. Unfortunately, available trials are small and uncertainty remains.