The BASE trial was a pragmatic, cluster-randomized, multiple-crossover trial conducted at an academic medical center comparing two commonly used balanced crystalloids—Normosol-R vs lactated Ringers—for IV fluid therapy in critically ill adults. Between June 2018 and January 2019, 2,084 patients were enrolled, and the primary outcome was plasma bicarbonate concentration through 7 days. Plasma bicarbonate values were similar between groups, and there were no meaningful differences in clinical outcomes including new kidney replacement therapy or 30-day mortality. These findings suggest that among balanced crystalloids, choosing Normosol-R rather than lactated Ringers does not improve acid-base status or patient-centered outcomes in critically ill adults.  

Qian ET, Brown RM, Jackson KE, Wang L, Stollings JL, Freundlich RE, Wanderer JP, Siew ED, Bernard GR, Self WH, Casey JD, Rice TW, Semler MW; Pragmatic Critical Care Research Group. Normosol-R vs Lactated Ringers in the Critically Ill: A Randomized Trial. Chest. 2025 Aug;168(2):336-345. doi: 10.1016/j.chest.2025.02.008. Epub 2025 Feb 17.  PMID: 39971001

BASE Trial (Normosol-R vs Lactated Ringers in Critical Illness)

Critically ill patients often receive intravenous fluids to support blood pressure, circulation, and organ perfusion. Two commonly used balanced crystalloid solutions are Normosol-R and lactated Ringers, which differ slightly in electrolyte composition and buffering agents. The BASE trial compared these fluids to determine whether the choice between balanced crystalloids affects acid-base status, kidney outcomes, or survival.

Importance

Balanced crystalloid solutions have been associated with improved outcomes compared with saline in some critically ill populations, but it is unclear whether clinically important differences exist between balanced crystalloids. Before the BASE Trial, whether choosing Normosol-R rather than lactated Ringers affects outcomes for critically ill adults was uncertain.

Objective

To determine whether use of Normosol-R compared with lactated Ringers affects plasma bicarbonate concentration through 7 days and clinical outcomes among critically ill adults.

Interventions

In a pragmatic, cluster-randomized, multiple-crossover trial at an academic medical center in the United States, critically ill adults were assigned to receive Normosol-R or lactated Ringers for IV fluid therapy. The primary outcome was the plasma bicarbonate concentration between enrollment and 7 days. Secondary outcomes included new receipt of kidney replacement therapy and death by day 30.

Results

Between June 2018 and January 2019, 2,084 patients were enrolled. Plasma bicarbonate concentration through 7 days did not differ between groups (mean difference, –0.12 mmol/dL; 95% CI, –0.61 to 0.36; P = .61). New kidney replacement therapy occurred in 6.0% of patients in the Normosol-R group and 5.0% in the lactated Ringers group (absolute risk difference, 1.0%; 95% CI, –1.2% to 3.1%). Death by day 30 occurred in 16.3% of patients in the Normosol-R group and 16.0% in the lactated Ringers group (absolute risk difference, 0.3%; 95% CI, –2.9% to 3.6%).

Conclusions and Relevance

Among critically ill adults, use of Normosol-R did not improve plasma bicarbonate concentration or clinical outcomes compared with lactated Ringers. These findings suggest that among balanced crystalloids, the choice between these two solutions does not meaningfully change patient-centered outcomes.