In ICU patients with acute kidney injury and metabolic acidosis, sodium bicarbonate therapy reduces the incidence of bloodstream infections by 54% (risk ratio 0.46, 95% CI 0.26–0.80), an effect not attributable to reduced catheter use or dialysis need, indicating an unexplained immunomodulatory or antimicrobial mechanism.

When the blood becomes too acidic, white blood cells called neutrophils cannot move well or kill bacteria effectively, and the lining of blood vessels becomes leaky. Giving sodium bicarbonate raises the blood's pH, which lets neutrophils move to infection sites, swallow bacteria, and destroy them more efficiently. It also tightens the blood vessel walls, making it harder for bacteria to enter the bloodstream from the gut or other tissues.