Vasovagal reactions in blood donors: risks, prevention and management.

This narrative review examines current research on risk factors, prevention methods and management strategies for vasovagal reactions (VVRs) that occur during or as a result of blood donation. VVRs are important to blood collection agencies (BCAs) as they negatively impact the number of completed collections, perceptions of the safety of blood donation and rates of donor return. There has been significant progress in understanding and preventing VVRs in blood donation in recent years, with a multitude of risk factors identified. This has resulted in many BCAs implementing evidence-based strategies, such as donor age and weight restrictions. However, the profile of our most vulnerable donors and features of the donation setting that may protect these donors from experiencing a VVR have not been identified. Furthermore, an increased number of trials of physiological and psychological prevention interventions to reduce both immediate and delayed VVRs have been reported. However, a lack of methodological consistency in operationalising interventions to reduce or prevent VVRs means that the identification of effective VVR prevention strategies remains a challenge for practitioners. Furthermore, research is still required to determine how to successfully implement prevention and management strategies into standard operating procedures within collection centres. Finally, research in the management and mitigation of the effect of VVRs is currently only suggestive of what should be done to care for the donor who reacts and how to empower those donors to return. Collectively, research into these aspects of VVRs will provide support to donors and BCAs and improve the safety of blood donation.