13

Abstract: 250 words | Main text: 5523 words Running title: Vasovagal reactions in blood donors This article is protected by copyright. All rights reserved. This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/tme.12488 1 ABSTRACT 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. Further, 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 operationalizing interventions to reduce or prevent VVRs means that it remains challenging for practitioners to identify effective VVR prevention strategies. Further, 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, BCAs, and improve the safety of blood donation. Keywords: Blood donor, Vasovagal, Retention, Donor Adverse Events, Reaction This article is protected by copyright. All rights reserved. 2 Introduction Blood Collection Agencies (BCAs) rely on healthy volunteers for the provision of blood. Although donating blood is safe and uncomplicated for most people, a small proportion of donors experience adverse reactions either during or after the procedure. The most common adverse event is a vasovagal reaction or vasovagal syncope (VVR). VVRs are thought to be triggered by various physical (such as standing up after losing 500mL of blood) and psychological stimuli (e.g., pain, stress, fear) (Gilchrist et al. 2015). During a VVR, the donor experiences a drop in arterial blood pressure and cerebral perfusion which reduces blood flow to the brain (Wieling et al. 2009). This results in pre-syncopal symptoms (e.g., feeling lightheaded or dizzy) or vasovagal syncope (i.e., loss of consciousness) which can be accompanied by mild seizures and/or incontinence (see Table 1) (Wiersum-Osselton et al. 2013; Gilchrist and Ditto 2015). Vasovagal symptoms can last several hours causing prolonged discomfort and, if the donor experiences syncope, can result in fall-related injuries such as fractures and head injuries (Eder et al. 2008). VVRs are more frequently recorded by BCAs in relation to whole blood (WB) donation than for other forms of blood product donation (Crocco et al. 2009). Across a range of BCAs, the incidence of pre-syncopal reactions for WB donations is 1.4 to 7.0%, and the incidence of vasovagal syncope is 0.1 to 0.5% (Amrein et al. 2012). In apheresis-type donations, VVRs are more common in platelet donations (0.68-0.81%) compared to plasma donations (0.16%) (Despotis et al. 1999; Crocco et al. 2009). Among WB donors, the largest number of VVRs occur at needle removal and when leaving the donation chair (Tomasulo et al. 2010). A small proportion of reported VVRs (9-12%) are known This article is protected by copyright. All rights reserved. 3 to occur after the donor has left the centre. However, the recorded number of off-site reactions may be an underestimate as donors may fail to report these to BCAs (Kamel et al. 2010; Bravo et al. 2011). Whilst VVR incidence rates provide good insight into the timing and number of reactions experienced, they do not provide information on the donors’ subjective experience of VVRs. BCA rating systems and records rely on phlebotomists’ reports as trained observers, and this does not always reflect what the donor feels they experience from donating blood (France et al. 2008a). To capture donors’ subjective perceptions of VVR-type

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19