Glycerol Infusion Versus Mannitol for Cerebral Edema: A Systematic Review and Meta-analysis

For the treatment of cerebral edema, the use of glycerol, an osmotic agent, as well as mannitol, is popular in Asia. However, the relative therapeutic benefit of glycerol remains unknown. The goal of this study was to investigate the comparative efficacy and safety of glycerol infusion versus mannitol infusion for cerebral edema. A systematic search was performed in PubMed, Cochrane Central Register of Controlled Trials, Web of Science, EMBASE, and Scopus for all eligible articles published before July 2020, with no restrictions on language. Two reviewers independently screened the articles, extracted data, and carefully assessed the quality of the evidence. Eight studies (6 clinical, 2 animal) were ultimately included in the qualitative analysis, and five were included in the quantitative analysis. Pooled analyses revealed nonsignificant differences in the successful control of cerebral edema (relative risk [RR], 0.97; 95% CI, 0.81–1.15). The combination therapy with glycerol led to a favorable trend in neurologic improvements. Regarding safety, glycerol was associated with a significantly lower risk of acute kidney injury (RR, 0.27; 95% CI, 0.11–0.69) and electrolyte disturbances (RR, 0.20; 95% CI, 0.06–0.64), as well as a lower possibility of rebound effects. No hemolysis was observed at the final follow-up. Although the data are limited, compared with mannitol, glycerol shows a similar level of effectiveness, a more favorable safety profile, and promising neurologic improvement in individuals with cerebral edema. Additional research is needed to confirm these findings. PROSPERO: CRD42020187702.