Lit Matters 1: Battle of the balanced crystalloids

Balanced crystalloids outperform normal saline in many critically ill patients, but the choice between lactated Ringer's and Normosol-R appears clinically interchangeable. In ICU fluid resuscitation, differences in buffer chemistry and strong ion difference did not translate into better bicarbonate levels, kidney outcomes, or survival.

Balanced Crystalloids in Critical Illness

• Buffer chemistry differences: Lactated Ringer's uses lactate while Normosol-R uses acetate and gluconate, creating a markedly different strong ion difference without a meaningful bedside advantage.
• Primary bicarbonate outcome: Serum bicarbonate was the headline endpoint, and it was unchanged between fluids even among patients who received larger crystalloid volumes.
• Kidney and mortality endpoints: Major adverse kidney events, new renal replacement therapy, and in-hospital mortality were all similar, with mortality landing around 16% in both groups.
• Pragmatic ICU fluid strategy: The assigned balanced fluid was used for boluses, maintenance fluids, and medication carriers, making the trial feel close to real ICU practice. We get into the bedside implications in the episode.
• Generalizability limits: This was a single-center medical ICU trial with traumatic brain injury excluded, so external validity is narrower than the broad balanced-crystalloid question many clinicians care about.