Donor complications and donor care
Authors: Nakajima K. 
Published: October 2009

Vasovagal reaction (VVR) is the most common adverse reaction associated with blood donation, and we have analysed risk factors and suggested preventive measures for VVR.

Donor complications  In Japan, there were 5 137 612 donations in 2008, and the incidence of all donor complications was 1·16% (male 0·87%, female 1·76%). The distribution of complications was: VVR 76·8%, hematoma 16·5%, local pain 2·3%, citrate reaction 0·9%, nerve injury 0·8% and others 2·8%.

Risk factors of VVR  The incidence of VVR with respect to donation types, sex and ages was evaluated. The incidence was significantly higher for donors aged 16–29 than for donors who are older for both sexes and all donation types, except for the female apheresis group in which the incidence was higher also for the donors aged 45 and older. The multivariate statistical analysis was performed to assess risk factors for donors at the JRC Tokyo Metropolitan Blood Center. The VVR risk was significantly higher for younger donors, female donors, those with a low BMI, predonation tachycardia, and those who had less sleep. The risk was lower with 200 ml donations than with other donations.

Delayed VVR  We also studied the incidence of VVR after leaving donation sites for 400 ml whole blood (WB) donors using a questionnaire. We found that 5·22% of donors (3·6% for males, 9·6% for females) felt symptoms such as discomfort, dullness or dizziness. Syncope occurred in 0·13%. At higher risk for delayed VVR were younger, female, and first‐time donors, similar to immediate‐type VVR. Donors with delayed VVR were significantly more likely to have had a previous incidence of VVR than donors without delayed VVR.

VVR and autonomic nerve function  We studied changes in autonomic nerve activities by inducing VVR in volunteers using the Schellong test, and analysed heart rate variability with electrocardiographs. The Schellong test after blood donation induced VVR in 45% (9/20) of the volunteers. There was a tendency for the parasympathetic nerve activity to be more dominant in the VVR group than in the non‐VVR group, but not significantly. It is difficult to recognize donors with a higher risk of VVR before blood donation by autonomic nerve activities.

Preventative measures for VVR  A decrease in circulating blood volume by phlebotomy and an imbalance in autonomic nerve function inducing hypotension and peripheral ischemia are considered to be causes of VVR. Thus, drinking water before and after donation is a universal practice. As stress and psychological tension make the autonomic nerve function unstable, the vagal nerve activity may become dominant and induce VVR. Consideration was shown to the donor with explanations in a relaxed atmosphere before the donation, and enough rest afterwards are necessary, particularly for first time and younger donors. It is also necessary to inform the donors about the possibility of fainting, the causes of it and measures which should be taken to avoid it, including what should be done when symptoms occur, to avoid serious incidents. Donors who have experienced VVR repeatedly should refrain from making blood donations.