Balanced Crystalloids or Normal Saline? A Historical and Evidence-Based Perspective

Intravenous crystalloid solutions are among the most common medical interventions applied and have supplanted colloid-based solutions as the standard of care for volume resuscitation in most settings. Despite their widespread use, debate has existed over the optimal composition of these solutions and their differential effects on patient outcomes. In this review, we will describe the pre-clinical studies that identified physiological differences when 'balanced crystalloids' and 'normal saline' are administered, the experimental studies that confirmed these differences in humans, the observational studies that indicated the level of concern, and the subsequent clinical trials that provide evidence to guide therapy in current practice.