ABSTRACT
BACKGROUND: Whole blood is optimal for resuscitation of traumatic hemorrhage. Walking Blood Banks provide fresh whole blood (FWB) where conventional blood components or stored, tested whole blood are not readily available. There is an increasing interest in this as an emergency resilience measure for isolated communities and during crises including the coronavirus disease 2019 pandemic. We conducted a systematic review and meta-analysis of the available evidence to inform practice. METHODS: Standard systematic review methodology was used to obtain studies that reported the delivery of FWB (PROSPERO registry CRD42019153849). Studies that only reported whole blood from conventional blood banking were excluded. For outcomes, odds ratios (ORs) and 95% confidence interval (CI) were calculated using random-effects modeling because of high risk of heterogeneity. Quality of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation system. RESULTS: Twenty-seven studies published from 2006 to 2020 reported >10,000 U of FWB for >3,000 patients (precise values not available for all studies). Evidence for studies was "low" or "very low" except for one study, which was "moderate" in quality. Fresh whole blood patients were more severely injured than non-FWB patients. Overall, survival was equivalent between FWB and non-FWB groups for eight studies that compared these (OR, 1.00 [95% CI, 0.65-1.55]; p = 0.61). However, the highest quality study (matched groups for physiological and injury characteristics) reported an adjusted OR of 0.27 (95% CI, 0.13-0.58) for mortality for the FWB group (p < 0.01). CONCLUSION: Thousands of units of FWB from Walking Blood Banks have been transfused in patients following life-threatening hemorrhage. Survival is equivalent for FWB resuscitation when compared with non-FWB, even when patients were more severely injured. Evidence is scarce and of relative low quality and may underestimate potential adverse events. Whereas Walking Blood Banks may be an attractive resilience measure, caution is still advised. Walking Blood Banks should be subject to prospective evaluation to optimize care and inform policy. LEVEL OF EVIDENCE: Systematic/therapeutic, level 3.