Sodium bicarbonate in metabolic acidosis on vasopressors did not reduce major kidney events

Design

Pragmatic, adaptive, double-blind, randomised placebo-controlled trial in 55 ICUs

Population

500 adults with metabolic acidosis (pH below 7.30) receiving vasopressors

Primary outcome

Major adverse kidney event (death, renal replacement therapy or persistent renal dysfunction) within 30 days

Effect

40.2% vs 39.4%; adjusted difference 1.2 percentage points (95% CI -7.1 to 9.4; P = 0.78)

SODa-BIC was a pragmatic, adaptive, double-blind trial in 55 ICUs across seven countries, published in June. It randomised 500 adults who had metabolic acidosis (pH below 7.30, base excess of -4 mmol/L or lower, and limited carbon dioxide) and were receiving vasopressors. Patients received sodium bicarbonate or 5% dextrose placebo for up to 5 hours, with the rate adjusted toward a pH of at least 7.30 and a base excess of at least 0.

A major adverse kidney event within 30 days (death, renal replacement therapy or persistent renal dysfunction) occurred in 98 of 244 patients (40.2%) given bicarbonate and 100 of 254 (39.4%) given placebo (adjusted difference 1.2 percentage points, 95% CI -7.1 to 9.4; P = 0.78). Renal replacement therapy was used in 16.8% and 20.9%, and 30-day in-hospital mortality was 25.4% and 24.0%. Four patients (1.6%) on bicarbonate had an adverse effect, against none on placebo.

The interval is wide enough that a modest benefit or harm on kidney events cannot be ruled out, and the trial was not designed to answer whether bicarbonate helps in specific subgroups such as severe acidosis or kidney injury. It does not support using bicarbonate routinely to correct acidosis in patients on vasopressors.

• Do not give bicarbonate routinely to correct acidosis in patients on vasopressors on the basis of this trial.
• Major adverse kidney events were 40.2% with bicarbonate and 39.4% with placebo.
• Treat the cause of the acidosis and the shock first.
• The trial does not address bicarbonate in other settings, such as severe acidosis with acute kidney injury.

Why it matters

Correcting a blood gas value is not the same as improving the patient, and this trial found no kidney benefit from doing it.

Don't overread it

The trial's population and dosing limit what it can say about severe acidosis, kidney injury subgroups or non-vasopressor patients.

The statistics, in plain English

An adjusted difference of 1.2 points with an interval of -7.1 to 9.4 means the data are compatible with a seven-point advantage for placebo through a nine-point advantage for bicarbonate. The trial excludes a very large effect, not a modest one.

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