Fluid resuscitation is one of the most prevalent treatment in critical care. There is not definitive evidence about the best fluid for resuscitation. The aim of this review will be to asses the efficacy and safety of buffered solution versus saline. We will perform an electronic search in Medline, Embase, and Central. Studies will be eligible if they are clinical trials who including critical ill patients. Primary outcomes are mortality and renal failure. All findings will be tabulated and synthesized. We will perform a meta-analysis according to Cochrane Review standards. We will design a summary of findings table.