Additional Interventions May Not Reduce Rate of VVRs in Whole Blood Donors

Several interventions intended to reduce vasovagal reactions (VVRs) in whole blood donors in England showed no clear benefit when compared with standard practices, according to new findings published in The Lancet Haematology.

While blood donation is generally considered a low-risk procedure, the research team noted that VVRs can result in donor injury, reduce donor return rates and disrupt collection operations, prompting blood services worldwide to adopt a range of preventive strategies.

In the STRategies to Improve Donor Experiences (STRIDES) trial, investigators from NIHR Blood and Transplant Research Unit in Donor Health and Behavior at the University of Cambridge evaluated whether four intervention options — pre-donation isotonic hydration, extended post-donation chair rest, modified applied muscle tension exercises and preparatory psychosocial materials — reduced the incidence of VVRs beyond standard donor care.

The study analyzed outcomes from more than 4 million whole blood donations collected at 73 NHS Blood and Transplant (NHSBT) donation sites in England, making it the largest and most comprehensive randomized controlled trial to evaluate strategies aimed at preventing VVRs in whole blood donors.

Across all donations, investigators recorded 4,388 in-session VVRs with loss of consciousness among 60,517 total in-session VVRs. None of the four interventions evaluated in STRIDES were associated with a statistically significant reduction in the primary outcome when compared with NHSBT’s standard practices, which include pre-donation water loading, applied muscle tension instruction and a two-minute post-donation chair rest. Results were consistent across donor subgroups defined by age, sex and previous donation experience.

The authors noted that these findings underline the challenges of achieving consistent compliance with in-session interventions, suggesting that maximizing adherence to established measures could be more effective than introducing additional enhancements.

“None of these interventions showed statistically significant benefit in reducing vasovagal reactions, either overall or in prespecified donor subgroups,” Emanuele Di Angelantonio, FMedSci, professor of clinical epidemiology and donor health at the University of Cambridge and director of the NIHR Blood and Transplant Research Unit in Donor Health and Behavior, said in an NHSBT statement. “These findings challenge assumptions underpinning existing policies and call into question the utility of additional interventions layered on top of standard practices."