Risk of vasovagal reactions in sleep-deprived and fasting blood donors

It remains unclear whether sleep deprivation and fasting increase the risk of vasovagal reactions (VVRs) in blood donors. This study explored this question.

A large observational study was conducted in a regional blood centre handling 309,971 blood donations from 83,709 donors between 2017 and 2022. From these non-duplicated donors, 83,234 donors who donated 400 mL whole blood or apheresis blood were selected as subjects for analysis, of whom 2132 (2.6%) had VVRs. The associations of sleep duration the night before donation and the timing of the last meal before donation with VVRs were analysed together with general risk factors for VVRs, such as age, sex, body weight, donation experience and blood collection type.

Younger age, female gender, lower body weight, first-time donation and apheresis donor were clear risk factors for VVRs in univariate analysis, although female gender and first-time donation were not identified as independent risk factors in multivariate analysis. There was no dose-dependent relationship between sleep duration or fasting time and VVR incidence, nor was any association identified in multivariate analysis.

Neither sleep duration nor donor-reported fasting time had any association with VVRs under the routine practice of providing snacks and drinks to donors just before blood donation. The present findings should help blood collection agencies to appropriately assess the risk of VVRs based on donor-reported sleep and fasting times.