Authors: Craig Davidson, Dip Datta / Code: CMP5 / Published: 01/09/2014
Crystalloids vs colloids; the debate continues in this podcast on a recent paper.
CRISTAL Trial – Annane et al. Effects of Fluid Resuscitation With Colloids vs Crystalloids on Mortality in Critically Ill Patients Presenting With Hypovolemic Shock. JAMA. 2013;310(17):1809-1817. DOI:10.1001/jama.2013.280502
Study Question: In ICU patients with hypovolaemia (from any cause) does the use of colloids for resuscitation alter mortality compared to crystalloids.
Study Design: International, multicenter, prospective, randomised, open treatment, blinded endpoint trial. P- 2857 ICU patients recruited for 57 ICUs from Europe/N Africa/Canada. Acute hypovolaemia I- Use of colloids in treatment of hypovolaemia C- use of crystalloid O- 28 day mort. 2dary: 90 day mort, RRT/IPPV/pressors
Summary: There was no significant difference in primary endpoint of 28 day mortality. Secondary endpoints: At 90 days there was a statistically significant difference in mortality (RR 0.92 95% CI 0.86-0.99) although the authors consider this an exploratory finding. There was a reduced requirement for mechanical ventilation and vasopressors in the colloid group. There was no difference in the requirement for RRT.
- Thestudy was stopped early for futility and therefore didnt reach its power calculation.
- The lack of blinding to treating physicians could have influenced other aspects of management and therefore introduced confounders.
- Prior to getting to the ICU the colloid group patients often received crystalloid, and vice versa.
- There was significant heterogeneity in types of colloid/crystalloid given in each group. A harm from one type of fluid could have been masked by benefit from another.
- Recruitment period of 9 years starting in 2003 and ending in 2012, during which time other aspects of management/monitoring of patients has significantly changed.
- Heterogeneity in type of fluid used in each group makes it difficult to translate to local practice where one type of fluid is usually used.
- This study was into ICU patients and therefore does not attempt to guide initial management in the ED.
So what now? This paper does not provide any further evidence to support the use of colloid to treat hypovolaemia. This reinforces the findings of a recent Cochrane Review. Difficult to generalise the findings of this study to the ED. Given risks of allergy, increased costs and previous studies identifying harm in use of colloids (CHEST 2012 N Engl J Med. 2012; 367(20): 1901-1 the evidence currently rests in favour of the use of crystalloids in the resuscitation of patients with hypovolaemia (along with blood products and albumin in the context of hypoalbuminaemia). FOAMed Resources: http://pulmccm.org/main/2013/randomized-controlled-trials/colloids-vs-crystalloids-for-hypovolemic-shock-seem-equivalent-jama/ http://emcrit.org/blogpost/best-fluids-comment-ever/ http://thinkingcriticalcare.com/2013/12/10/the-glycocalyx-an-overview-for-the-clinician-foamed-foamcc/