A case - controlled study of factors contributing to vasovagal reactions in blood donors

Background and ObjectivesVasovagal reaction occurs in a small but significant number of blood donors. Vasovagal reactions may decrease return donation and disrupt blood collection activities. The purpose of this study was to define the contributing role of sex, age, weight, and blood pressure in vasovagal reactions.Materials and MethodsThis case control study was performed on blood donors who referred to Shiraz Blood Transfusion Center in 2005. A questionnaire was filled out both for the blood donors who had developed vasovagal reactions (case group) and those who had not (control group) appearing prior and after the case group donors. Finally 1500 samples were randomly selected (500 cases & 1000 control). The questionnaire consisted of sociodemographic pattern of blood donors, and signs and symptoms of vasovagal reactions. Chi-square was used for data analysis.ResultsThe mean age and weight of the case group were 30.55 ± 9.33 and 71.23 ± 9.3 respectively. 72.6% of the case group were male and the average rate of blood donation attempts was 3.34 ± 2.19. The mean age and weight of the control group were 35.27 ± 4.72 and 78.61 ± 12.77 respectively. 90.3% of the control group were male and the average rate of blood donation attempts was 6.58 ± 7.08. The vasovagal reaction was higher in young, low weight, first time, female blood donors (p < 0.005). It was also higher in fatigued, hungry and stressful blood donors (p < 0.005). ConclusionsVasovagal reaction is a multi-factorial process. These reactions might be prevented in high risk donors. Considering these risk factors, it is possible to increase repeat donation and donor safety.