An intervention study for the prevention of vasovagal reactions and evaluating donors' experience: Analysis of donors' return for subsequent donation

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

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.

Prevention of Blood Donation-related Vasovagal Response by Applied Muscle Tension: a Meta-analysis

Objective

Vasovagal reaction (VVR) is an adverse reaction to blood donation. Applied muscle tension (AMT) has been reported to reduce the probability of VVR during blood donation; however, the results have been controversial. We therefore conducted a meta-analysis to systematically evaluate the effect of AMT in reducing VVR.

Methods

We searched six major databases using “applied muscle tension” and “blood donation-related vasovagal response” as keywords. Relevant articles published in English or Chinese between 1 January 2000 and 30 June 2021 were included in the analysis. The quality of the included articles was evaluated and publication bias was assessed by forest and funnel plots and by Egger's test.

Results

Fifty-one articles were identified, of which six were included according to the pre-defined inclusion and exclusion criteria. A fixed-effects model was adopted for effect size combination and revealed a relative risk of 0.52 (95% confidence interval 0.40 to 0.67). The AMT group was superior to the control in terms of VVR prevention. A funnel plot and Egger's test suggested that the findings were accurate and reliable with low publication bias.

Conclusion

AMT could effectively reduce VVR during blood donation. Further multicenter studies with large sample sizes are needed to confirm these results.