Balanced Crystalloid solutions
Balanced crystalloids are comprised of solutes that more closely resemble human plasma [59, 60]. Based on the composition of the crystalloid, the solutes will contribute to intravascular volume expansion, all while counteracting fluid shifts into the extracellular space by providing oncotic pressure[59]. While these solutions are more “physiologic” when compared to NS, balanced solutions are not perfect [59]. The benefit of resuscitation with buffered solutions compared to nonbuffered crystalloid solutions in noncardiac surgery patients remains equivocal [63, 65-69]. In a double-blinded, randomized, double-crossover and prospective cohort study in post cardiac surgery patients, Reddy et al. studied post-operative bleeding in patients resuscitated with Plasma-lyte (Baxter International Inc., Deerfield, IL) compared to NS (n=475 in Plasma-lyte group and n=479 in normal saline group) [61]. Through this analysis, authors found the transfusion rate was significantly higher in the first three days in the ICU in those receiving Plasma-Lyte compared to the control NS group (p=0.008) [61]. Moreover, investigators found individuals in the Plasma-Lyte group had significantly higher INR’s
(p=0.04) and an overall longer hospital length of stay compared to those resuscitated with NS (p=0.04) [61].
The pathophysiology of these clinical effects in buffered solutions is not well understood in-vivo [61, 70]. When further analyzing other balanced solutions, there is scarce evidence that suggests resuscitation with intravenous fluids buffered with acetate or lactate impacts inotrope usage, cumulative amount of fluids necessary, or acid base profiles [17].