Sodium Bicarbonate Fails to Improve Kidney Outcomes in Critically Ill Shock Patients
A landmark 500-patient RCT finds sodium bicarbonate offers no benefit over placebo for critically ill adults with metabolic acidosis and shock.
Summary
Sodium bicarbonate is widely used in intensive care units to correct dangerous drops in blood pH, but whether it actually improves patient outcomes has been unclear. This large international trial enrolled 500 critically ill adults with metabolic acidosis who were receiving vasopressors across 55 ICUs in seven countries. Patients were randomly assigned to receive sodium bicarbonate or a placebo infusion for up to five hours. The primary outcome — a composite of death, need for dialysis, or persistent kidney dysfunction within 30 days — occurred in about 40% of patients in both groups with no meaningful difference. Mortality and dialysis rates were also similar. The findings suggest sodium bicarbonate should not be routinely administered for this indication in the ICU.
Detailed Summary
Metabolic acidosis — a dangerous drop in blood pH — is extremely common in critically ill patients and is strongly linked to organ failure and death. For decades, clinicians have infused sodium bicarbonate to chemically neutralize the acidosis, reasoning that correcting pH would protect organs, especially the kidneys. Yet evidence supporting this practice has been limited and inconsistent, making this trial both timely and important.
The SODa-BIC trial was a pragmatic, adaptive, double-blind, randomized controlled trial conducted across 55 ICUs in seven countries. Adults with confirmed metabolic acidosis (pH below 7.30) receiving vasopressors for shock were randomly assigned to receive either sodium bicarbonate or a placebo (5% dextrose) infusion, titrated over up to five hours to target a pH of at least 7.30. The primary endpoint was a major adverse kidney event within 30 days, defined as death, initiation of renal replacement therapy, or persistent kidney dysfunction.
Among 500 enrolled patients, major adverse kidney events occurred in 40.2% of the sodium bicarbonate group versus 39.4% in the placebo group — a statistically insignificant difference of 1.2 percentage points. In-hospital mortality by day 30 was 25.4% versus 24.0%, and renal replacement therapy use was 16.8% versus 20.9%, both non-significant. A small numerical trend toward less dialysis with bicarbonate was noted but did not reach significance. Adverse events were rare but slightly more frequent in the treatment group.
For clinicians, these results challenge a long-standing but insufficiently tested practice. Routine sodium bicarbonate infusion for metabolic acidosis in vasopressor-dependent ICU patients does not appear to prevent kidney injury or death.
Several caveats apply. The summary is based on the abstract only, so subgroup analyses and secondary endpoints are unavailable. The adaptive trial design and multicenter pragmatic nature add external validity but may introduce heterogeneity. The negative result does not rule out benefit in specific subpopulations.
Key Findings
- Sodium bicarbonate did not reduce major adverse kidney events versus placebo (40.2% vs 39.4%, P=0.78).
- 30-day in-hospital mortality was nearly identical: 25.4% bicarbonate vs 24.0% placebo.
- Renal replacement therapy use trended lower with bicarbonate (16.8% vs 20.9%) but was not significant.
- Adverse events were rare but occurred only in the bicarbonate group (1.6% vs 0%).
- Results challenge routine bicarbonate use in ICU patients with metabolic acidosis and shock.
Methodology
Pragmatic, adaptive, double-blind RCT enrolling 500 adults across 55 ICUs in seven countries. Patients with metabolic acidosis (pH <7.30) on vasopressors were randomized to sodium bicarbonate or 5% dextrose placebo infused for up to 5 hours. Primary endpoint was a composite major adverse kidney event at 30 days.
Study Limitations
The full paper is not available; this summary is based on the abstract only, limiting insight into subgroup analyses, secondary endpoints, and safety data. The pragmatic multicenter design improves generalizability but may introduce treatment heterogeneity across sites. The trial targeted a broad metabolic acidosis population, potentially diluting any benefit in more severely affected subgroups.
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