This week, the two heavyweight medical journals, JAMA and the New England Journal of Medicine, featured papers describing the effect of certain intravenous fluids on the incidence of renal failure in critically ill ICU patients.
The JAMA paper  compared normal saline (relative to human plasma, a high chloride-containing solution) administration to more physiologic, low chloride-containing IV fluids such as Hartmann’s solution (very similar to Ringer’s lactate) or Plasma-Lyte 148. It showed that using the low chloride intravenous infusions led to a statistically significant decrease in the incidence of acute kidney injury and the need for renal replacement therapy.
The NEJM paper  compared the use of intravenous hydroxyethyl starch (HES) fluid resuscitation to normal saline and found that patients given HES had significantly more acute kidney injury and needed more renal replacement therapy. Bear in mind that HES is actually a solution of 6% HES in normal saline.