Preventive interventions for vasovagal reactions in whole blood donors: a cluster-randomised, stepped-wedge, crossover trial of 73 sites involving 1·4 million donors in England.

Blood services worldwide have implemented various strategies to prevent vasovagal reactions, often without robust evidence.

全球各地的血液服务机构已经实施了各种策略来预防血管迷走性反应，但往往缺乏有力的证据支持。

We compared standard practice in England with four vasovagal reaction prevention interventions used in other services or previously tested in small-scale studies.

我们比较了英格兰的标准做法与其他服务中使用的四种预防血管迷走反应的干预措施，或之前在小规模研究中测试过的干预措施。

Methods

This cluster-randomised, stepped-wedge, crossover trial involved 73 blood donation sites (clusters) across England, UK.

这项群组随机、阶梯式、交叉试验涉及英国英格兰的73个血液捐赠站点（群组）。

Each site was randomly allocated to one of 64 possible sequences for implementing one or more of four interventions over four 9-month periods, yielding a total of 292 site-periods for a 36-month overall trial duration.

每个地点被随机分配到64种可能的序列之一，用于在四个9个月的周期内实施一个或多个四种干预措施，从而得出36个月总试验期的292个地点周期。

Participants within each period were not unique, as repeat donations were included.

每个周期内的参与者并非唯一，因为包含了重复捐赠。

Cluster randomisation was chosen for operational feasibility.

由于操作上的可行性，选择了群组随机化。

Potential carry-over effects were minimised by use of stepped-wedge, crossover, and factorial design elements.

通过使用阶梯式、交叉和因素设计元素，最小化了潜在的持续效应。

The interventions assessed were: 500 mL pre-donation isotonic drink (vs standard 500 mL plain water), extended 3-minute post-donation rest on the donation chair (vs standard 2-minute rest), modified applied muscle tension (AMT) exercise (vs current AMT practice); and psychosocial intervention using preparatory materials (vs no materials).

评估的干预措施包括：500毫升献血前等渗饮料（与标准的500毫升纯水对比），延长献血后在献血椅上休息3分钟（与标准的2分钟休息对比），修改后的应用肌肉张力（AMT）练习（与当前的AMT实践对比）；以及使用准备材料的心理社会干预（与不使用材料对比）。

The primary outcome was in-session vasovagal reaction with loss of consciousness.

主要结果是在会话期间发生的血管迷走反应，伴有意识丧失。

Analysis was by intention-to-treat, including data from all donors attending the donation sites during the trial, unless the donor opted-out.

分析采用意向治疗分析法，包括了所有在试验期间到访捐赠点的捐赠者的数据，除非捐赠者选择退出。

This trial registered with isrctn.com (ISRCTN 10412338) and is complete.

该试验已在isrctn.com上注册（ISRCTN 10412338），并且已经完成。

Results

Between Nov 4, 2019, and Nov 3, 2022, we recruited 1 379 095 blood donors who made 4 134 712 blood donations.

2019年11月4日至2022年11月3日期间，我们招募了1,379,095名献血者，他们共进行了4,134,712次献血。

The median age of donors at time of baseline trial visit was 41 years (IQR 30-54), 785 271 (56·9%) of 1 379 095 donors were female and 593 824 (43·1%) were male. 461 954 (33·5%) were first-time donors.

在基线试验访问时，献血者的中位年龄为41岁（四分位数间距30-54），在1,379,095名献血者中，有785,271名（56.9%）为女性，593,824名（43.1%）为男性。有461,954名（33.5%）为首次献血者。

We recorded 4388 vasovagal reactions with loss of consciousness and 60 517 total in-session vasovagal reactions (ie, with and without loss of consciousness).

我们记录了4388例伴有意识丧失的迷走神经血管反应和60517例总的会话中迷走神经血管反应（即，包括有和没有意识丧失的情况）。

Compared with standard practices, none of the interventions clearly reduced the primary outcome (joint p=0·21) with an odds ratio of 0·98 (95% CI 0·92-1·04) for isotonic drink, 0·99 (0·92-1·06) for extended chair rest, 1·12 (1·00-1·26) for modified AMT, and 1·03 (0·93-1·14) for psychosocial intervention.

与标准实践相比，没有任何干预措施明显降低了主要结果（联合p=0.21），其中等渗饮料的比值比为0.98（95%置信区间0.92-1.04），延长椅子休息的比值比为0.99（0.92-1.06），改良的AMT比值比为1.12（1.00-1.26），心理社会干预的比值比为1.03（0.93-1.14）。

Absolute event rates per 10 000 donations were 10·7 without intervention and 10·5 with intervention.

在没有干预的情况下，每10000次捐献的绝对事件发生率为10.7，而有干预的情况下为10.5。

Findings were similar for total in-session vasovagal reactions with higher absolute event rates.

对于总在会话中的血管迷走反应，发现结果类似，但绝对事件发生率更高。

interpretation

Four interventions used to prevent donation-related vasovagal reactions showed no clear benefits compared with standard practices in England, suggesting potential policy implications for blood services worldwide to streamline donation practices and save resources.

用于预防捐赠相关血管迷走性反应的四种干预措施与英格兰的标准实践相比没有显示出明显的优势，这表明可能对全球血站服务政策产生影响，以简化捐赠程序并节省资源。

funding

NHS Blood and Transplant and the NIHR Blood and Transplant Research Unit in Donor Health and Behaviour (formerly Donor Health and Genomics).

NHS血液和移植以及NIHR血液和移植研究单位在捐赠者健康和行为研究（前身为捐赠者健康和基因组学）。