Critically ill patients often require IV fluids for resuscitation but questions remain about the optimal type of IV fluid and best rate of IV fluid bolus infusion. JAMA Associate Editor Kristin Walter, MD, MS, discusses a recent clinical trial that examined the effect of 2 different crystalloid solutions and 2 IV fluid bolus infusion rates on ICU patient mortality with Alexandre B. Cavalcanti, MD, PhD, director of the Research Institute HCor in San Paulo, Brazil, and Craig M. Coopersmith, MD, professor of surgery and director of the Critical Care Center at Emory University School of Medicine in Atlanta, Georgia. Related Content: Effect of Slower vs Faster Intravenous Fluid Bolus Rates on Mortality in Critically Ill Patients: The BaSICS Randomized Clinical Trial Does Crystalloid Composition or Rate of Fluid Administration Make a Difference When Resuscitating Patients in the ICU? Effect of Intravenous Fluid Treatment With a Balanced Solution vs 0.9% Saline Solution on Mortality in Critically Ill Patients: The BaSICS Randomized Clinical Trial Effect of Intravenous Fluid Treatment With a Balanced vs Normal Saline Solution at a High vs Low Infusion Rate on Mortality in Critically Ill Patients