Clinical question: Does a balanced crystalloid solution lead to better outcomes than does normal saline when used in critically sick adults?
Background: Balanced crystalloids are considered more physiological, with a composition closer to plasma. Observational studies have shown lower rates of hyperchloremic acidosis, renal failure, and death with use of balanced crystalloids. In spite of this, normal saline has been the most commonly used fluid. Differences in effects on important patient-related outcomes of safety and efficacy between these two interventions remain unknown.
Study design: Pragmatic, unblinded, cluster-randomized, multiple-crossover trial.
Setting: Vanderbilt University Health Center, Nashville, Tenn.
Synopsis: This study comprised 15,802 adults with mean age of 58 admitted to ICU who were cluster randomized to receive either balanced crystalloid or normal saline. Primary outcome was a composite of death from any cause, renal replacement therapy, or persistent renal dysfunction at 30 days and was observed less frequently in the balanced crystalloid group (adjusted odds ratio, 0.90; 95% confidence interval, 0.82-0.99; P = .04).
Since the trial was cluster randomized, prognostic imbalance between the groups caused by confounding factors was a big risk. Results could not be generalized because the study was done in a university health center. Mean fluid amount received was modest in both groups. Questions still remain about the efficacy and safety of balanced fluids, and hospitalists should weigh their decisions in light of this new information.
Bottom line: Balanced crystalloid solution decreased 30-day composite outcome of death, renal replacement therapy, or persistent renal dysfunction.
Citation: Semler MW et al. Balanced crystalloids versus saline in critically ill adults. N Engl J Med. 2018 Mar 1;378(9):829-39.
Dr. Parasramka is an assistant professor in the division of hospital medicine at the University of Kentucky, Lexington.