Prevention strategies for vasovagal reaction in whole blood donors: A quadri-armed randomised control trial.

Introduction: Vasovagal reaction (VVR) is a frequently encountered generalised donor adverse reaction, associated with donor deterrence towards future donation. Several mitigation strategies for prevention of VVR were tried but still not standardised. This quadri-armed randomised study evaluated the utility of water ingestion, applied muscle tension (AMT) and combination of both in preventing the VVR among blood donors.

Methods: A quadri-armed randomised controlled trial was performed on 4320 whole blood donors. Blood donors of 18-65 years of age were randomised into four groups based on the interventions performed i.e., control with no intervention (Group 1, n = 1081), water ingestion (Group 2, n = 1082), AMT (Group 3, n = 1070) and combined intervention (Group 4, n = 1087). VVR during and immediately after blood donation were observed along with assessment of risk factors in blood donors and the effectiveness of interventions were analysed.

Results: The incidence of VVR observed 1.6% in our study, with the highest occurrence in the control group (2.5%) and the lowest in the combined intervention group (0.9%). Multivariable logistic regression revealed that the control group donors faced a 1.38-fold greater risk of VVR compared to those receiving interventions (OR: 1.38, 95% CI: 1.10-1.75). Other risk factors included younger age (OR: 1.5, 95% CI: 1.05-2.17), first-time donation (OR: 5.7, 95% CI: 1.66-5.74), prior history of VVR (OR: 2.5, 95% CI: 10.4-101.52).

Discussion/conclusion: The combined approach of water ingestion and AMT proved significantly more effective in VVR prevention compared to individual interventions.