The effect of oral hydration in preventing vasovagal reactions in blood donors

Abstract

Despite improvements in modern medicine, many procedures and life-saving medical treatments are still dependent on the use or the administration of blood products and therefore demand remains high. As a result, injured people and chronically ill patients are still relying on voluntary persons who are willing to donate blood. Studies have constantly shown that the experiences of adverse events related to blood donation, have a negative impact on donor retention. Vasovagal reactions (VVRs), is the most common adverse event. A common physical intervention, which blood bank services customary provide to prevent VVRs, is drinking of water before blood donations. The aim of this study was to find out whether such ingestion of water before blood donation is effective in preventing symptoms of VVRs in blood donors. A PICO question was formulated: In blood donors, does water ingestion before donation reduce the risk of vasovagal reactions? This research question has a preventive element in reducing VVRs. The purpose of the study was to provide the Malta National Blood Transfusion Services (NBTS) with evidence based information, which could potentially be used, in developing the current work practice in this service area. A literature search was methodically conducted through HyDi, EBSCO host, Google Scholar and PubMed, using pre-determined search terms. In an effort to reduce selection bias inclusion and exclusion criteria were established before the literature search. Seven studies were selected; 5 RCTs, a systematic review and an observational (cohort) study. All were appraised by employing the Critical Appraisal Skills Programme (CASP) tool. The findings revealed that a strong body of evidence, which suggests that drinking at least two glasses of water before blood donation is beneficial to prevent VVRs in blood donors. Moreover, the intervention of water ingestion is more likely to determine a favourable effect on donors who are known to be at risk of experiencing VVRs. Therefore, identifying risk factors, which are associated with VVRs before the donation, is important to achieve a better result. The review of the evidence elicited a need for further larger research studies. Moreover, a local clinical trial is indicated to explore the incidence of VVRs and the outcome of such intervention in the specific of local content. The findings would allow for comparison between the local context and context abroad and for improved preparation of donors locally.