Source: Perel P, Roberts I. Colloids versus crystalloids for fluid resuscitation in critically ill patients. Cochrane Database Syst Rev. 2011 Mar 16;(3):CD000567. Review. PubMed PMID: 21412866.
Finfer S, Bellomo R, Boyce N, French J, Myburgh J, Norton R; SAFE Study Investigators. A comparison of albumin and saline for fluid resuscitation in the intensive care unit. N Engl J Med. 2004 May 27;350(22):2247-56. PubMed PMID: 15163774.
Delaney AP, Dan A, McCaffrey J, Finfer S. The role of albumin as a resuscitation fluid for patients with sepsis: a systematic review and meta-analysis. Crit Care Med. 2011 Feb;39(2):386-91. Review. PubMed PMID: 21248514.
Efficacy Endpoints: Mortality
Harm Endpoints: Not reported
Narrative: In the critically ill, fluid replacement is believed to be an essential part of resuscitation. While there is consensus regarding the importance of early delivery of fluids, the evidence regarding which type of fluid has been confusing and often contradictory. Colloid solutions increase intravascular osmotic pressure, with a proposed benefit of increased volume expansion per unit of solution infused when compared to standard crystalloid solutions.
This Cochrane Review includes 65 trials (n = 11,623) involving critically ill patients undergoing fluid resuscitation. The trials were divided into 3 subgroups: colloids vs. isotonic crystalloid, colloids and hypertonic saline vs. isotonic crystalloid and colloids vs. hypertonic crystalloids. Administration of colloids yielded no mortality benefit, regardless of the type of colloid used or the manner in which it was delivered.
Caveats: Over 60% of all patients in this review come from a single trial (Finfer et al. 2004, the 'SAFE' trial). However, of all the included trials it was the most methodologically rigorous. Because of concerns about potentially important differences among the various colloids, the authors of this review also performed analyses stratified by type of colloid. Once again, they failed to find any mortality benefit, regardless of which type of colloid was used. There was also significant heterogeneity among the included trials, including patient population, type of colloid and resuscitation algorithm.
A recent meta-analysis (Delaney et. al 2011) specifically examined the role of albumin in patients undergoing treatment for sepsis, a subgroup not examined in the Cochrane review. When the authors pooled the results, they did find a borderline mortality benefit, with an OR = 0.82 (95% CI 0.67-1.0, p=0.047). Less than half of the included studies specifically enrolled patients with sepsis and all of these were small (n < 90). Finally, using a random-effects analysis of the data (a statistical tool that calculates pooled results with greater allowances for variations among studies), the difference was no longer statistically significant. This leaves the question of albumin in sepsis open. Presuming expected mortality rates of 20-30% in patients with sepsis the odds ratio of 0.82 for mortality found in the albumin groups from the Delaney review would suggest, if true, an absolute reduction of 3-4% in mortality.
Despite the limitations of the Cochrane analysis, the results suggest that there is no compelling reason to use colloid solutions during resuscitation of critically ill patients. While there were no identifiable harms associated with colloid use the fact remains that the agents cost 10-20 times more than their crystalloid counterparts and in general it appears that colloids offer no benefit. However, there remains some question about their possible benefit in septic patients and a large, high quality trial is needed to clarify the issue. For this narrow question (albumin use for sepsis patients compared to crystalloids) we would grade the issue unresolved, i.e. color-code Yellow. Overall, we see no evidence of benefit, i.e. Red.
Author: Daniel Runde, MD
Published/Updated: September 28, 2011
The title bar is color-coded with our overall recommendation.
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