- Design
- pragmatic, adaptive, double-blind, placebo-controlled randomised trial across 55 ICUs in seven countries (SODa-BIC)
- Population
- 500 adults with metabolic acidosis (pH below 7.30, base excess no more than -4 mmol/L) receiving vasopressors in the ICU
- 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); renal-replacement therapy 16.8% vs 20.9%; 30-day in-hospital mortality 25.4% vs 24.0%
SODa-BIC randomised 500 adults across 55 ICUs in seven countries who had metabolic acidosis — pH below 7.30, base excess no more than -4 mmol/L, with controlled carbon dioxide — and were receiving vasopressors, to sodium bicarbonate or 5% dextrose placebo. The infusion ran for up to five hours, titrated to a pH of at least 7.30 and a base excess of at least zero, so the acidosis was genuinely corrected.
Major adverse kidney events within 30 days — death, renal-replacement therapy or persistent renal dysfunction — occurred in 40.2% of the bicarbonate group and 39.4% of placebo. In-hospital mortality by day 30 was 25.4% against 24.0%.
This is the trial the practice has been waiting for. Bicarbonate in this setting has been given for decades on the reasoning that acidaemia impairs catecholamine responsiveness and cardiac function, and the earlier randomised evidence was small and subgroup-driven. Here the intervention was delivered properly, blinded, to the population in whom the case was strongest, and produced nothing.
For a nephrology service the action is in the order sets and in the referrals. A request for bicarbonate to correct a pH in a shocked patient is a request to treat a number, and the clinical work is elsewhere — the source of the acidosis, the perfusion, and the decision about whether and when renal replacement therapy is actually indicated.
- Do not give sodium bicarbonate to correct pH in vasopressor-dependent metabolic acidosis
- Keep the separate indications where bicarbonate has its own grounds — severe hyperkalaemia, sodium-channel-blocker toxicity, some poisonings
- Base the renal replacement therapy decision on the established indications rather than on pH alone
- Remove standing 'correct the acidosis' orders from ICU and nephrology protocols that still carry them
- Note the entry criteria: pH below 7.30 with a controlled PaCO2, so this does not apply to respiratory acidosis
The statistics, in plain English
The adjusted difference of 1.2 percentage points with a 95% confidence interval of -7.1 to 9.4 and P = 0.78 is a clear null on the primary outcome; with 500 patients the interval still admits a benefit or harm of up to about 7 to 9 percentage points, so this excludes a large effect rather than every effect. Renal-replacement therapy was numerically lower with bicarbonate, -3.9 percentage points (95% CI -10.6 to 2.7), but that interval crosses zero and it was one of several secondary outcomes — reading a trend into it is exactly the error the null primary result should discourage.
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