Trial of Severe Metabolic Acidosis Correction With Sodium Bicarbonate
Does pH correction with intravenous sodium bicarbonate improve outcomes in critically ill patients with metabolic acidosis?
Among consecutively screened critically ill patients, 389 meeting inclusion criteria for metabolic acidosis within 48 hours of intensive care unit (ICU) admission were randomized to standard care versus infusion of sodium bicarbonate with correction goal pH of >7.30, to a maximum of 1000 ml 4.2% sodium bicarbonate every 24 hours, with stratification by age, sepsis status, and Acute Kidney Injury Network (AKIN) score. The primary outcome was a composite of single organ failure at day 7 and all-cause mortality by day 28. Secondary outcomes included use and duration of renal replacement therapy (RRT), mechanical ventilation, and vasopressor infusion. Analysis was by intention-to-treat.
Among the overall population, no statistically significant difference in primary outcome was observed between the 194 patients in the control group versus 195 patients allocated to bicarbonate infusion (71% vs. 66%, p = 0.24), and the difference in survival to 28 days did not meet statistical significance (46% vs. 55%, p = 0.09). However, among the stratum of 182 patients with kidney injury, indicated by AKIN score 2-3, the composite outcome was more frequent (82% vs. 70%, p = 0.05), 28-day survival was significantly greater (46% vs. 63%, p = 0.03), and use of RRT was less frequent (52% vs. 35%, p < 0.01) in the bicarbonate versus control groups.
In this randomized trial (BICAR-ICU), correction of metabolic acidosis with intravenous sodium bicarbonate did not decrease the risk of organ failure within 7 days or mortality within 28 days of initiation. However, in a preselected subgroup with kidney injury, pH-correction with sodium bicarbonate increased the chance of 28-day survival.
These findings from this ICU population are consistent with previous trials in which sodium bicarbonate correction of metabolic acidosis has not proven beneficial. However, the significant outcome improvement observed among patients with renal injury warrants further in-depth investigation within this subpopulation.
Clinical Topics: Prevention
Keywords: Acidosis, Acute Kidney Injury, Bicarbonates, Critical Illness, Intensive Care Units, Primary Prevention, Renal Replacement Therapy, Respiration, Artificial, Sepsis, Sodium Bicarbonate
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