Background. Both balanced crystalloids and saline are used for intravenous fluid administration in critically ill adults, but it is not known which results in better clinical outcomes.
Methods
In a pragmatic, cluster-randomized, multiple-crossover trial conducted in five intensive care units at an academic center, we assigned 15,802 adults to receive saline (0. 9% sodium chloride) or balanced crystalloids (lactated Ringer’s solution or Plasma-Lyte A) according to the randomization of the unit to which they were admitted.
The primary outcome was a major adverse kidney event within 30 days – a composite of death from any cause, new renal-replacement therapy, or persistent renal dysfunction (defined as an elevation of the creatinine level to ≥200% of baseline) – all censored at hospital discharge or 30 days, whichever occurred first.
Results
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).
Conclusions
Among critically ill adults, the use of balanced crystalloids for intravenous fluid administration resulted in a lower rate of the composite outcome of death from any cause, new renal-replacement therapy, or persistent renal dysfunction than the use of saline. (Funded by the Vanderbilt Institute for Clinical and Translational Research and others; SMART-MED and SMART-SURG ClinicalTrials. gov numbers, NCT02444988 and NCT02547779. )