Vasovagal reactions in apheresis donors.

BACKGROUND: The incidence rate of vasovagal reactions (VVRs) in apheresis is known to be higher in women than in men donors. VVRs in women apheresis donors were therefore analyzed to find out possible factors for their high incidence. STUDY DESIGN AND METHODS: VVR incidence was compared between whole blood (WB) and apheresis donation in relation mainly to age and circulatory blood volume (CBV). In addition, blood pressure and pulse rate were measured during apheresis. RESULTS: In WB donors, the VVR incidence was 0.83 and 1.25 percent, while in apheresis donors it was 0.99 and 4.17 percent in men and women, respectively. The VVR incidence decreased with age in WB donors, but age dependence was very weak in apheresis donors. In elderly women, the incidence increased with repeating cycle of apheresis. There were three different patterns of pulse fluctuation during apheresis, that is, stable (type A), increased rate during blood withdrawal (type B), and irregular pattern (type C). Elderly women donors and donors who suffered from VVRs mostly showed type B fluctuation. There was no particular fluctuation in blood pressure in relation to apheresis cycles. CONCLUSION: The VVR incidence rate was particularly high in women apheresis donors over 45 years old and increased with repeating cycles of apheresis. Smaller CBV, high sensitivity of low-pressure baroreceptors, and citrate effects on cardiovascular reflex might be major factors involved in the high incidence of VVRs.