Giving blood donors something to drink before donation can prevent fainting symptoms: is there a physiological or psychological reason?

Donation related fears predict vasovagal reactions and donor attrition among high school donors

BACKGROUND

This longitudinal study of high school whole blood donors examined relationships among donation-related fears assessed prior to donation, vasovagal reactions to donation, and the proportion of donors who attempted another donation over the subsequent 60 weeks.

STUDY DESIGN AND METHODS

Data regarding vasovagal reactions and attempted donation were obtained from donor records of 530 female and 342 male high school donors who answered questions about five types of fear (ie, of blood draw, needles, seeing blood, feeling pain, or fainting) prior to their index donation.

RESULTS

Each type of fear was associated with an increased risk of vasovagal reactions (all P < .001) and a smaller percentage of attempted donations was seen among those who reported at least one type of fear (53%) as compared to those who did not report any fear (62.1%); P = .022; β = -0.374, OR = 0.69; 95% CI, 0.50-0.94. Path analyses of the relationships among fear, vasovagal reaction, and attempted donation revealed significant indirect effects for each type of fear. Specifically, donors who reported fear were at increased odds of experiencing a vasovagal reaction, which, in turn, was associated with decreased odds of attempting a repeat donation.

CONCLUSION

Donation-related fears are associated with reduced donor return rates, and this effect is mediated through an increased risk for vasovagal reactions. For both practical and ethical reasons, blood collectors are encouraged to identify and intervene with fearful donors to reduce the likelihood of negative donation-related symptoms and enhance donor retention.

Effect of pre-donation fluid intake on fluid shift from interstitial to intravascular compartment in blood donors

BACKGROUND

Fluid shifts from interstitial to intravascular space during blood donation helps in compensating the lost blood volume. We aimed to determine the volume of fluid shift following donation in donors with and without pre-donation fluid intake.

METHODS

We studied the fluid shift in 325 blood donors prospectively. Donors were divided in groups- with no fluid intake (GI) and either water (GII) or oral rehydrating fluids (GIII) before donation. Fluid shift following donation was calculated based on the difference between the pre and post donation blood volume. The influence of oral fluid intake, age, gender and body mass index (BMI) on volume of fluid shift was analyzed.

RESULTS

The fluid shift was significant between donors without fluids (GI: 127 ± 81 ml) and donors with fluid intake (GII & III: 96 ± 45 ml) (p < 0.05). The difference was not significant between donors with water intake (GII: 106 ± 52 ml) and oral rehydrating fluid intake (GIII: 87 ± 41 ml). The shifted fluid volume increased with increasing BMI and decreased with increasing age in females. The fluid shift increased in females than in males.

CONCLUSION

The age, gender, BMI and VVR did not significantly contribute to the volume of fluid shift following donation. As per our observation, the oral fluids before donation might not contribute to increase in fluid shift in blood donors after donation.