The efficacy and effectiveness of drinking interventions to reduce vasovagal reactions in blood donors: A systematic review and meta-analysis.

ABSTRACT

BACKGROUND AND OBJECTIVES: Blood establishments strive to ensure the safety and comfort of blood donors while minimizing adverse events. This review aims to assess the efficacy and effectiveness of eating and/or drinking interventions before, during and/or after blood donation in reducing vasovagal reactions (VVRs). MATERIALS AND METHODS: We analysed randomized and non-randomized controlled trials comparing eating and/or drinking interventions to no intervention, placebo or usual practice on (pre-)syncopal VVRs and related symptoms. The GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach was used to assess the risk of bias and overall certainty of the evidence. RESULTS: Pre-donation water ingestion likely results in reduced on-site VVRs, compared to no water (2 fewer per 100 donors, moderate-certainty evidence). A pre-donation isotonic drink likely results in reduced VVRs, compared to usual practice (2 fewer per 100 donors, moderate-certainty evidence). Pre-donation salt-loaded sweetened lemon water may result in fewer off-site VVRs, compared to sweetened lemon water only (1 fewer per 100 donors, low-certainty evidence). Pre-donation water and a gel cap containing sucrose with 250 mg caffeine may result in fewer blood donor reaction ratings, compared to pre-donation water only (low-certainty evidence). CONCLUSIONS: Pre-donation plain water ingestion or isotonic drink probably results in a large reduction in on-site and off-site VVRs. Pre-donation water ingestion with caffeine consumption or salt supplementation may result in a VVR reduction, compared to water ingestion only. Future large trials are required to increase the certainty of the effect of these and other interventions in the prevention of VVRs.