One discussion this week included the question of balanced crystalloids vs saline in ICU and non-ICU patients.

Reference: Semler MW, et al. Balanced crystalloids versus saline in critically ill adults. NEJM. 2018 Mar 1;378:829-839. doi:10.1056/NEJMoa1711584

Summary: Although both saline and balanced crystalloids have been administered to patients in clinical practice for decades, few trials have addressed the effects of crystalloid composition on clinical outcomes.

The authors conducted an unblinded, cluster-randomized, multiple-crossover trial in which the use of balanced crystalloids was compared with saline for intravenous fluid administration among critically ill adults admitted to five ICUs at Vanderbilt University Medical Center between June 1, 2015, and April 30, 2017. A total of 15,802 patients were enrolled. The median age was 58, and 57.6% of patients were men.

The primary outcome was the proportion of patients who met one or more criteria for a major adverse kidney event within 30 days — the composite of death, new receipt of renal-replacement therapy, or persistent renal dysfunction (defined as a final inpatient creatinine value ≥200% of the baseline value) — all censored at hospital discharge or 30 days after enrollment, whichever came first.

Among the 7942 patients in the balanced-crystalloids group, 1139 (14.3%) had a major adverse kidney event, as compared with 1211 of 7860 patients (15.4%) in the saline group (marginal odds ratio, 0.91; 95% confidence interval [CI], 0.84 to 0.99; conditional odds ratio, 0.90; 95% CI, 0.82 to 0.99; P=0.04). In-hospital mortality at 30 days was 10.3% in the balanced-crystalloids group and 11.1% in the saline group (P=0.06). The incidence of new renal-replacement therapy was 2.5% and 2.9%, respectively (P=0.08), and the incidence of persistent renal dysfunction was 6.4% and 6.6%, respectively (P=0.60).

In this trial of critically ill adults, the intravenous administration of balanced crystalloids rather than saline had a favorable effect on the composite outcome of death, new renal-replacement therapy, or persistent renal dysfunction.

Additional Reading: Hammond DA, et al. Balanced crystalloids versus saline in critically ill adults: a systematic review and meta-analysis. Annals of Pharmacotherapy. 2019 Jul 31:1060028019866420. doi: 10.1177/1060028019866420.