Effect of Treatment With Balanced Crystalloids Versus Normal Saline on the Mortality of Critically Ill Patients With and Without Traumatic Brain Injury: A Systematic Review and Meta-Analysis.

BACKGROUND Some studies suggest that balanced solutions may improve outcomes in critical care patients. However, in patients with traumatic brain injury (TBI) existing data indicate that normal saline may be preferred. We hypothesized that mortality in critically ill patients with and without TBI would differ with the use of balanced salt solutions versus normal saline. METHODS We conducted a systematic review and meta-analysis to investigate the impact of balanced crystalloids versus normal saline on 90-day mortality in adult critical care patients with and without TBI. Secondary outcomes included length of hospital stay, renal complications, need for vasopressors or mechanical ventilation, and mortality in critically ill patients with sepsis. We followed the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analysis) statement and estimated the odds ratio (OR) and 95% confidence interval (CI) with a random-effects model. RESULTS We included 15 clinical trials involving 35,207 patients. The OR of mortality with balanced solutions versus saline in patients without TBI was 0.93 (95% CI, 0.87-0.98; P = .01; I2 = 0%), while the OR for mortality in patients with TBI was 1.31 (95% CI, 1.03-1.65; P = .03; I2 = 0%). We found no differences in secondary outcomes due to fluid choice although data were unavailable to calculate pooled estimates for some of the secondary outcomes for TBI patients. In patients with sepsis, the OR of mortality with balanced solutions was 0.92 (95% CI, 0.83-1.02; I2 = 0%). CONCLUSIONS In comparison to normal saline, balanced solutions were associated with a reduction in mortality in critical care patients without TBI. However, balanced solutions were associated with an increase in mortality in patients with TBI. These findings suggest that the effect of fluid choice on intensive care unit (ICU) outcomes may depend partially on the type of critical illness and in particular in patients with TBI.