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].