IMPORTANCE: The effect of sodium bicarbonate infusion on outcome in patients with severe metabolic acidemia and moderate to severe acute kidney injury is unknown.

OBJECTIVE: To determine whether sodium bicarbonate infusion is associated with day 90 all-cause mortality in patients with severe metabolic acidemia and moderate to severe acute kidney injury.

DESIGN, SETTING, AND PARTICIPANTS: Randomized, open-label, clinical trial conducted with 640 patients in 43 French intensive care units from October 6, 2019, to December 19, 2023, with 90-day follow-up. The last date of follow-up was June 17, 2024. Adults with severe metabolic acidemia (defined as pH =7.20) and moderate to severe acute kidney injury were enrolled.

INTERVENTION: Patients were randomized 1:1 to receive either intravenous sodium bicarbonate infusion or no sodium bicarbonate to target an arterial pH of 7.30 or higher.

MAIN OUTCOMES AND MEASURES: The primary outcome was day 90 all-cause mortality. Secondary outcomes included day 28 and day 180 all-cause mortality; use of organ support therapy, vasopressors, or invasive mechanical ventilation; intensive care unit and hospital length of stay; intensive care unit-acquired infections; fluid balance; day-7 Sequential [Sepsis-related] Organ Failure Assessment score (6 organ systems' function is evaluated and scored from 0 [no dysfunction] to 4 [failure]; total score ranges from 0 [normal] to 24 [maximum failure]); and major adverse kidney events on day 90.

RESULTS: Among 640 randomly assigned patients, 627 were analyzed (313 in the control group and 314 in the bicarbonate group). The median age was 67 years (IQR, 59-74 years); 194 of 314 patients (62%) in the bicarbonate group and 185 of 313 controls (59%) were male. In the primary analysis, day 90 all-cause mortality was 195 of 314 patients (62.1%) in the bicarbonate group and 193 of 313 (61.7%) in the control group (absolute difference, 0.4; 95% CI, -7.2 to 8.0; P = .91). There was no evidence of a group effect on day 28 or day 180 all-cause mortality. Among 18 secondary outcomes, kidney replacement therapy was used in 109 of 314 (35%) bicarbonate group patients and 157 of 313 (50%) controls (absolute difference, -15.5; 95% CI, -23.1 to -7.8). No evidence of a group effect was found on other secondary outcomes, including adverse events.

CONCLUSIONS AND RELEVANCE: For patients with severe metabolic acidemia and moderate to severe acute kidney injury, intravenous sodium bicarbonate did not affect mortality.

TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04010630.

Hospital Doctor/Hospitalists rater

As a hospitalist, the findings suggest that bicarbonate supplementation for treating acidosis in the setting of AKI does not improve survival and may delay the need for renal replacement therapy by several hours. The patients in the trial were critically ill with 62% mortality. The majority of patients had septic shock with an average lactate level of 5.8. The intervention was to administer 4.25% sodium bicarbonate solution to raise pH to 7.3. There was no blinding in the study. 15% of the patients in the control arm were administered bicarbonate and were analyzed both as part of the control and intervention arms, but the outcomes were the same.

Nephrology rater

An interesting finding from this study is the bicarbonate group received kidney replacement therapy less often compared with the no sodium bicarbonate group.