Shock Syndromes I

Crystalloids vs. colloids

The Saline versus Albumin Fluid Evaluation (SAFE) study, which enrolled almost 7000 patients

with varied shock types requiring fluid resuscitation, with 90% power, found no difference in

28-day mortality between treatment with 0.9% sodium chloride and 4% albumin (20.9% vs.

21.1%, p=0.87). However, this was not a study of strictly initial fluid resuscitation because the

allocated study fluid was used for all fluid resuscitation in the ICU until death, discharge, or 28

days after randomization. Because of this study, crystalloids are usually preferred to albumin

for the initial resuscitation of patients with shock because of their lower cost.

ii.

A pragmatic, open-label, randomized study of crystalloids compared with colloids for

resuscitation found no difference between groups in 28-day mortality (27.0% vs. 25.4%,

p=0.26) but did find a difference in 90-day mortality favoring the colloid group (34.2% vs.

30.2%, p=0.03). However, because 90-day mortality was a secondary (not primary) outcome,

the results must be interpreted with caution. In addition, the study’s open-label nature (which

may bias toward finding a difference between groups) and use of many different resuscitation

fluids within each study group make this study challenging to implement into practice.

Balanced (chloride-poor) vs. unbalanced (chloride-rich) crystalloids

Administration of chloride-rich fluids may lead to afferent renal arteriole vasoconstriction,

leading to a decrease in renal perfusion and kidney injury, and may cause a metabolic acidosis

by lowering the strong ion difference. As such, crystalloids that better approximate the

electrolyte composition of plasma (“chloride-poor,” “balanced salt,” or “balanced crystalloid”

solutions) have been evaluated.

Fluid

Sodium (mmol/L)

Chloride (mmol/L)

“Chloride-rich”a

0.9% sodium chloride

5% albumin

130–160b

0–128b

Hydroxyethyl starch 6% (130/0.4)

“Chloride-poor”a

25% albumin

130–160b

0–19b

Lactated Ringer’s solution

Plasma-Lyte A and Plasma-Lyte 148

Normosol-R

aDistinction between “chloride rich” and “chloride poor” is based on chloride content > or < 120 mmol/L.

bDiffers according to manufacturer because of differences in buffer type (e.g., sodium bicarbonate or sodium chloride) and amount used. Reported chloride content of

4% Albumex (CSL Bioplasma) is 128 mmol/L, and that of 20% Albumex (CSL Bioplasma) is 19 mmol/L (products used in Australia/New Zealand), which led to the

distinction of “chloride rich” and “chloride poor” for 4%–5% albumin and 20%–25% albumin, respectively. However, neither 5% Flexbumin (Baxter, Westlake Village,

CA) nor 25% Flexbumin (Baxter; products available in the United States) contains chloride.

controversies in colloid and crystalloid fluid utilization. Hosp Pharm 2015;50:446-53; and Yunos NM, Bellomo R, Hegarty C, et al. Association between a chloride-

ii.

An open-label sequential period study evaluated outcomes between a control period in which

chloride-rich fluids were routinely administered (n=760) and an intervention period in which

chloride-rich fluids were restricted to attending physician approval and chloride-poor fluids

were routinely used (n=773). In the intervention period, the incidence of acute kidney injury

(8.4% vs. 14%, p<0.001) and use of renal replacement therapy were significantly lower (6.3%

vs. 10%, p=0.005). Because the study was not blinded or randomized, the results should be

considered hypothesis generating.