The Incidence of Vasovagal Reactions Among Whole Blood Donors During Or Immediately After Donation

Background: The incidence of vaso vagal reaction among the whole blood donors are common. Few percent of these reaction may progress to syncope. Objectives: To evaluate the incidence of vaso-vagal reaction (VVR) among whole blood donors. Methods: This prospective, observational study was done in the department of transfusion medicine in Bangabandhu Sheikh Mujib Medical University from 01-04-2008 to 31-03-2009. Total 19553 blood donors were observed for vaso-vagal reaction. Results: The incidence of vaso-vagal reaction was 0.37%, in male 0.33% and in female it was 0.67%. Female donors were significantly more prone to develop vasovagal reaction (p=0.001). 78.8% of donors were first time donor and 28.8% were repeat donor. The clinical character of the symptoms according to frequency wasSweating (86.3%), Nausea/ Vomiting (80.8%), Pallor (67.1%), Dizziness (39.7%), Loss of consciousness and fainting, increased rate of respiration (30.1%), anxiety presented (16.4%) and vertigo (1.4%). Conclusion: Although the incidence of vasovagal reactions in our study is lower than other studies, it is important to follow strict donor selection criteria and ensure careful monitoring during and immediate after the donation process to avoid the fatal consequences.

donor reaction before, during or 30 min after the blood donation was recorded on a Donor Reaction Report Form.This standardized form includes the biological characteristics of the donor, the symptoms of the adverse reaction and if the donor was sleepless tired or stressed before blood donation and any donor concealed this situation during the medical interview and examination.The responsible physician who examined the donor fills in the report form and asks the donor about sleeplessness, tiredness or stress.The scale is 'a little tired or stressed' and 'very tired or stressed' (the latter donors are excluded from blood donation).Concerning sleeplessness, the limit is less than 5 h of sleeping last night.All the necessary information and clinical data was systematically recorded in a pre-designed data collection sheet.
Statistical analyses of the results were obtained by using window based computer software devised with Statistical Packages for Social Sciences (SPSS-15) Version-15.0.Statistical significance was set at p<0.05 and confidence interval was set at 95% level.Data was analysed by Chisquare test.

Results:
The study was conducted over 19553 whole blood donors, among them 73 were found to be suffered with Vaso-vagal reaction with an incidence of 0.37%.The mean age was 27.63 ± 6.29 years, ranging from 18 to 40 years.Male: Female = 3.56 : 1, incidence of VVR in male donors was 0.33% and in female was 0.67% (p=0.011).0.19% were first time donor and 0.62% were regular donor (p=0.001).93.2% of donors had no previous history of such attack (

Discussion:
In Bangladesh the annual demand for blood transfusion is estimated to be 2,00,000 to 2,50,000 unit per year .But due to lack of voluntary donor and consciousness among people this demand is hardly met 3 .As donor safety is an essential prerequisite for an adequate and safe voluntary blood supply current study was carried out to evaluate the incidence of vaso-vagal reaction following whole blood transfusion.We analyzed clinical records of 19553 whole blood donors over a period of 12 months in the blood bank of BSMMU, Dhaka, Bangladesh.
In the current study the incidence of Vaso-vagal reaction was 0.37%, which is much smaller than the previous reports (2-3%) 6 , 5.3% 9 , 0.89% 12 .Our result is closer to Zervou et al 10 (0.53%).We believe that the most possible explanation for this difference is the fact that the physical examination and selection of blood donors is performed by experienced physicians and therefore we take a better evaluation of blood donors who have predisposition to complication.An additional reason for this difference is possibly the small number of donors in study.Although Crocco and D'Elia reported a much smaller incidence of VVR (0.2%) 5 .
The mean of the age was 27.63 ± 6.29 years, ranging from 18 to 40 years.Newman and Graves (2001) showed that donors with reactions were more likely to be young than those from the general donor population (median age, 28 vs. 42 years) 11 .The incidence of VVR with respect to donation types, sex and ages was evaluated by Nakajima 12 .The incidence was significantly higher for donors aged 16 to 29 than for donors who are older for both sexes and all donation types 12 .In our study Female donors had a statistically significant higher rate of VVR, which supports findings of previous studies [13][14][15] .On the other hand many other authors reported that there is no significant difference between men and women donors for VVR [16][17][18] .We found that 71.2% of donors suffered with VVR were new donor and 28.8% were repeat donor.Wiltbank et al, 19 Zervou et al, 10

Conclusion:
Although the incidence of vaso-vagal reaction is relatively smaller in our study, considering the latent risk of vasovagal reaction we should ensure the careful selection and evaluation of blood donors by experienced physicians and the presence of trained nurses in the donation room who closely attend the blood donors during and immediately after blood donation.

Table - III
Table-I & II).Distribution of clinical character of VVR among the whole blood donors.

Table - IV
Distribution of blood pressure before and after donation among the whole blood donors.

Table - V
Distribution of grade of reaction with basal characteristics of blood donors.
*Chi-square test was done to measure the level of significance.# Figure within parentheses indicates in percentage.
11wman et al,9and Ogata et al,20documented the higher rate of VVR in first time donors than repeat donors.25%)were the five most common clinical findings before syncope.Approximately one quarter of the donors with nausea, or 6 percent of all donors with syncope, experienced emesis11.Characteristics of reaction (grade 1 or grade 2) was not significantly different according to age, sex, body weight, first time donor or repeat donor and history of taking light meal before donation.