Colloids versus crystalloids for fluid resuscitation in critically ill patients
Abstract
Background
Colloid solutions are widely used in fluid resuscitation of critically ill patients. There are several choices of colloid and there is ongoing debate about the relative effectiveness of colloids compared to crystalloid fluids.
Objectives
To assess the effects of colloids compared to crystalloids for fluid resuscitation in critically ill patients.
Search methods
We searched the Cochrane Injuries Group Specialised Register, CENTRAL (The Cochrane Library 2008, Issue 3), MEDLINE, EMBASE, ISI Web of Science: Science Citation Index Expanded (SCI‐EXPANDED), ISI Web of Science: Conference Proceedings Citation Index‐Science (CPCI‐S), and The Controlled Trials metaRegister (www.controlled‐trials.com). Reference lists of relevant studies and review articles were searched for further trials. The searches were last updated in September 2008.
Selection criteria
Randomised controlled trials (RCTs) of colloids compared to crystalloids, in patients requiring volume replacement. We excluded cross‐over trials and trials in pregnant women and neonates.
Data collection and analysis
Two authors independently extracted data and rated quality of allocation concealment. We analysed trials with a 'double‐intervention', such as those comparing colloid in hypertonic crystalloid to isotonic crystalloid, separately. We stratified the analysis according to colloid type and quality of allocation concealment.
Main results
We identified 65 eligible trials; 56 of these presented mortality data.
Colloids compared to crystalloids
Albumin or plasma protein fraction ‐ 23 trials reported data on mortality, including a total of 7754 patients. The pooled relative risk (RR) from these trials was 1.01 (95% confidence interval (95% CI) 0.92 to 1.10). When we excluded the trial with poor quality allocation concealment, pooled RR was 1.00 (95% CI 0.91 to 1.09).
Hydroxyethyl starch ‐ 17 trials compared hydroxyethyl starch with crystalloids, n = 1172 patients. The pooled RR was 1.18 (95% CI 0.96 to 1.44).
Modified gelatin ‐ 11 trials compared modified gelatin with crystalloid, n = 506 patients. The pooled RR was 0.91 (95% CI 0.49 to 1.72).
Dextran ‐ nine trials compared dextran with a crystalloid, n = 834 patients. The pooled RR was 1.24 (95% CI 0.94 to 1.65).
Colloids in hypertonic crystalloid compared to isotonic crystalloid
Eight trials compared dextran in hypertonic crystalloid with isotonic crystalloid, including 1283 randomised participants. Pooled RR was 0.88 (95% CI 0.74 to 1.05).
Authors' conclusions
There is no evidence from RCTs that resuscitation with colloids reduces the risk of death, compared to resuscitation with crystalloids, in patients with trauma, burns or following surgery. As colloids are not associated with an improvement in survival, and as they are more expensive than crystalloids, it is hard to see how their continued use in these patients can be justified outside the context of RCTs.
PICOs
Plain language summary
No evidence that colloids are more effective than crystalloids in reducing mortality in people who are critically ill or injured
Trauma, burns or surgery can cause people to lose large amounts of blood. Fluid replacement, giving fluids intravenously (into a vein) to replace lost blood, is used to try to maintain blood pressure and reduce the risk of dying. Blood products, non‐blood products or combinations are used, including colloid or crystalloid solutions. Colloids are increasingly used but they are more expensive than crystalloids. The review of trials found no evidence that colloids reduce the risk of dying compared with crystalloids.
