Department of Medicine, Academic Medical Centre, University of Amsterdam, The Netherlands.
Transfusion. 2011 Dec;51(12):2727-38. doi: 10.1111/j.1537-2995.2011.03202.x. Epub 2011 Jun 3.
Vasovagal syncope (VVS) is a consistent, but infrequent (0.1%-0.3%) complication of volunteer, whole blood donation. Given the large number of blood donations, a significant number of donors is involved. Syncope occasionally leads to injury. Recent rigorous data collection and analysis have led to the association of a small number of donor and donation factors with the risk of syncope. An analysis of the time course of syncope reactions among approximately 500,000 whole blood donors suggests that there are three distinct periods of risk for vasovagal reactions before, during, and after phlebotomy. This review examines the physiologic mechanisms that contribute to these periods of increased risk including the direct effects of removal of approximately 500 mL of whole blood, the psychological stress of instrumentation and giving blood (i.e., fear of needles, pain, and the sight of blood), and the orthostatic effects superimposed on a hypovolemic state after the donation. Specifically, we describe interventions that have been useful in controlling VVS in patients with fainting syndromes and we examine the potential of these interventions in the blood donation context, based on the physiologic principles involved. Finally, we propose an intervention (dietary replacement of salt lost with blood donation) that has not been applied in transfusion medicine previously but which has the potential to reduce risk.
血管迷走神经性晕厥（VVS）是自愿性全血捐献的一种常见但不频繁（0.1%-0.3%）的并发症。鉴于献血人数众多，涉及到大量献血者。晕厥偶尔会导致受伤。最近对严格的数据进行了收集和分析，这些数据将少数献血者和献血因素与晕厥的风险联系起来。对大约 50 万名全血献血者的晕厥反应时间过程的分析表明，在采血前、采血中和采血后有三个明显的血管迷走反应风险期。这篇综述检查了导致这些风险增加期的生理机制，包括大约 500 毫升全血的直接去除效应、仪器操作和献血的心理压力（即害怕针头、疼痛和看到血液），以及在捐献后血容量减少状态下叠加的直立位效应。具体来说，我们描述了在晕厥综合征患者中控制 VVS 的有用干预措施，并根据涉及的生理原理检查了这些干预措施在献血背景下的潜力。最后，我们提出了一种干预措施（用献血丢失的盐替代饮食），以前在输血医学中没有应用过，但有降低风险的潜力。
