UMEM Educational Pearls

Title: Acidotic with AKI - Will Bicarb Help?

Keywords: bicarbonate, metabolic acidosis, renal replacement therapy, acute kidney injury (PubMed Search)

Posted: 11/25/2025 by Jessica Downing, MD
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The role of sodium bicarbonate in the treatment of severe acidemia has been controversial, with some studies suggesting no benefit, and others indicating that it may help reduce need for renal replacement therapy (RRT) and even improve mortality. The BICARICU-2 Trial was an open-label multicenter RCT conducted in France that evaluated the impact of a bicarb infusion among patients with metabolic acidosis and moderate to severe AKI.

There was no difference in 90 day mortality, but patients in the bicarb group were less likely to be started on RRT (38% vs 47% in the control group) using pre-defined criteria for RRT initiation, and had a 50% lower rate of bloodstream infections. Patients in the bicarb group who were started on RRT met criteria for RRT later than those in the control group (median 31h vs 15.5h).

Study Details:

Patient Population:

SOFA score >4 OR arterial lactate > 2mmol/L within 48h of ICU admission
Metabolic acidosis, defined by pH < 7.2, HCO3- < 20mEq/L, and PaCO2 < 45mmHg
Moderate to severe AKI, defined as Cr >2.0 x baseline or UOP < 0.5 mL/kg/h for >12h.
Patients with severe baseline CKD, ketoacidosis, intoxication with exogenous acids (metformin, salicylate, methanol, ethylene glycol), or ongoing bicarb losses via GI or urinary tracts were excluded.
The presumed etiology of acidemia was septic shock in over half of included patients, and over 75% were on vasopressors.

Intervention:

4.2% bicarb infusion administered in 125-250 aliquots with a target pH >7.3, though not to exceed 1L/500mEq within 24h.
The intervention continued for a maximum of 28d or until ICU DC.
Patients in the intervention group received a median of 750mL in the first 48h.

RRT Triggers:

Immediate: K > 6.5mEq/L with EKG changes or cardiogenic pulmonary edema with no UOP and hypoxia
24h after enrollment: UOP <0.3 Ml/kg/h over 24h, pH <7.2 despite resuscitation, K > 6.5 MEq/L.

References

Jung B, Jabaudon M, De Jong A, Bitker L, Audard J, Klouche K, Sarton B, Guitton C, Lasocki S, Rieu B, Canet E, Jeantrelle C, Roquilly A, Mayaux J, Verdonk F, Pottecher J, Ferrandiere M, Riu B, Garcon P, Assefi M, Detouche P, Forel JM, Roger C, Bourenne J, Jacquier S, Bougon D, Rolle A, Corne P, Benchabane N, Richard JC, Asehnoune K, Chanques G, Reignier J, Belafia F, Fosset M, Huguet H, Futier E, Molinari N, Jaber S; BICARICU-2 Study Group. Sodium Bicarbonate for Severe Metabolic Acidemia and Acute Kidney Injury: The BICARICU-2 Randomized Clinical Trial. JAMA. 2025 Oct 29:e2520231. doi: 10.1001/jama.2025.20231. Epub ahead of print. PMID: 41159812; PMCID: PMC12573113.