Study protocol for the Balanced Solution versus Saline in Intensive Care Study (BaSICS): a factorial randomised trial.

Background: The effectiveness and safety of balanced crystalloid fluids compared with saline (0.9% sodium chloride) as a fluid of choice in critically ill patients remain unclear. The effects of different fluid infusion rates on outcomes are also unknown.

Objectives: To test the hypothesis that a balanced crystalloid solution, compared with saline, decreases 90-day all-cause mortality among critically ill patients; and to test the hypothesis that slow, compared with rapid, infusion rate decreases 90-day mortality in this population of patients.

Methods: The Balanced Solution versus Saline in Intensive Care Study (BaSICS) is a pragmatic, 2 ??2 factorial, randomised controlled trial. A total of 11 000 patients will be recruited from at least 100 Brazilian intensive care units. Patients will be randomised to receive Plasma-Lyte 148 or saline, and to rapid infusion (999 mL/h) or slow infusion (333 mL/h). Study fluids will be used for resuscitation episodes (at rapid or slow infusion rates), dilution of compatible medications and maintenance solutions. Patients, health care providers and investigators will be blinded to the solutions being tested. The rate of bolus infusion will not be blinded.

Outcomes: The primary outcome is 90-day all-cause mortality. Secondary outcomes are: incidence of renal failure requiring renal replacement therapy within 90 days, incidence of acute kidney injury (Kidney Disease: Improving Global Outcomes stages 2 and 3), incidence of non-renal organ dysfunction assessed by Sepsis-related Organ Failure Assessment score at Days 3 and 7, and number of mechanical ventilationfree days within the first 28 days after randomisation.

Results And Conclusions: The BaSICS trial will provide robust evidence on whether a balanced crystalloid, compared with saline, improves important patient outcomes in critically ill patients. BaSICS will also provide relevant information on whether bolus infusion rate affects outcomes in this population.

Trial Registration: ClinicalTrials.gov NCT02875873.