Recent International Trial Finds Sodium Bicarbonate Does Not Improve Outcomes in Critically Ill Patients with Metabolic Acidosis and Shock

A major international clinical trial published in The New England Journal of Medicine has found that intravenous sodium bicarbonate does not reduce the risk of death, serious kidney complications, or the need for dialysis in critically ill patients with severe metabolic acidosis and shock requiring medication to support blood pressure.

Led in New Zealand by Professor Paul Young, Co-Clinical Leader of the Wellington Intensive Care Unit and Deputy Director of MRINZ, the SODa-BIC trial enrolled 500 patients across 55 intensive care units in seven countries. It is the largest placebo-controlled trial to examine whether sodium bicarbonate improves outcomes in this high-risk group of critically ill patients.

Participants were randomly assigned to receive either intravenous sodium bicarbonate or placebo. Serious kidney-related complications within 30 days occurred in 40.2% of patients who received sodium bicarbonate compared with 39.4% of those who received placebo, with no meaningful difference between the groups. Mortality, persistent kidney complications and the need for ongoing dialysis were also similar.

Professor Ary Serpa Neto, Chief Investigator of SODa-BIC, said:

“Sodium bicarbonate clearly changed the acid levels in the blood, but this did not translate into better outcomes for patients. The important message is that correcting an abnormal laboratory value does not necessarily mean we are improving the patient's chances of recovery.”

Sodium bicarbonate did have a clear effect on blood pH, the laboratory abnormality it was intended to treat. Treatment rapidly corrected blood acidity and reduced the recurrence of metabolic acidosis. However, these improvements did not translate into better overall clinical outcomes.

Professor Paul Young, the New Zealand Lead Investigator, said:

“Sodium bicarbonate has been used in intensive care for decades, despite surprisingly limited evidence that it improves outcomes. SODa-BIC provides the strongest evidence to date that routinely correcting metabolic acidosis with bicarbonate in patients with shock does not improve outcomes that matter to patients. However, the results also suggested there may be an important role for bicarbonate in selected patients with the most severe acidosis.  In this group of patients, correcting acidosis may reduce the risk of death. This is an area that deserves further investigation.”

The findings challenge a common treatment approach in intensive care and provide important evidence to guide the management of patients with severe metabolic acidosis and shock. They suggest that routine administration of sodium bicarbonate for this indication is unlikely to improve outcomes that matter to patients, while highlighting the potential for more targeted use in patients in whom correction of acidosis may reduce mortality.

The SODa-BIC trial was led by the Australian and New Zealand Intensive Care Research Centre and conducted through the Australian and New Zealand Intensive Care Society Clinical Trials Group. The study involved investigators from Australia, New Zealand, Japan, Oman, Saudi Arabia, India and Brazil and was funded by the Australian National Health and Medical Research Council.