Transfusion Medicine, 2010, 20, 129 133 doi: 10.1111/j.1365-3148.2009.00984.x ORIGINAL ARTICLE Prevalence of immediate vasovagal reaction in blood donors visiting two blood banks of Karachi D. K. Rohra, 1,2 V. Juriasinghani, 3 K. Rai 4 &S.I.Azam 5 1 Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan, 2 Department of Pharmacology, University of Nizwa, Nizwa, Sultanate of Oman, 3 Chandka Medical College, Larkana, Pakistan, 4 Dr Ziauddin University, Karachi, Pakistan, and 5 Department of Community Health Sciences, Aga Khan University, Karachi, Pakistan Received 30 August 2009; accepted for publication 2 November 2009 summary. Vasovagal reaction (VVR) is a very common adverse event related to blood donation. No study has been conducted in Pakistan to estimate the prevalence of VVR in blood donors. This study was conducted to estimate the prevalence of immediate VVR in blood donors of Karachi, Pakistan. The study was conducted in two blood banks of Karachi. Data regarding the development of immediate VVR were documented. The effect of blood donation on vital parameters like pulse rate, blood pressure (BP), temperature and respiratory rate was also observed. Six hundred and seventy-four blood donors were recruited. All the donors who consented were males. Weakness and dizziness were two most common symptoms which were reported by 91 (13.5%) and 73 (10.8%) of the participants, respectively. Out of 91 donors in whom signs and symptoms of immediate VVR were observed, a significant drop in systolic BP (13.5 ± 2.5 mmhg) and decrease in pulse rate (13.3 ± 3.6) were concurrently noted in 55 donors (8.2% of all the participants). There was lack of association of age, body mass index (BMI), estimated blood volume, ethnicity, educational status, profession and first time donation status with the frequency of VVR. Only marital status was found to be significantly associated with higher frequency of immediate VVR, where married donors were having higher odds as compared to singles. The prevalence of VVR in the blood donors at two blood banks of Karachi is at least 8.2%. Furthermore, married men are at more risk of experiencing VVR in our population. Key words: blood donation, Pakistan, vasovagal reaction. Increasing demand of blood and blood products for patients has created a challenge for the blood banks in Pakistan. Although there are regular blood donors for many blood banks in Pakistan, it has been observed that donors are arranged by the family and friends of patient at the time of need. These donors are obliged to donate blood for their friends and family members even unwillingly or under stress. In order to maintain adequate blood supply in the wake of increasing demand, new blood donors need to be constantly recruited. This pressure has prompted US blood banks to ask for more relaxations for donors in terms of age and some exclusion criteria like hereditary haemochromatosis (Eder et al., 2008). Correspondence: Dileep K. Rohra, Department of Pharmacology, University of Nizwa, Birkat Al Mouz, Nizwa, Sultanate of Oman. Tel.: +968 921 56783; fax: +968 254 46246; e-mail: dileep@unizwa.edu.om Although blood donation is considered safe, there are some inherent risks to donors. Haematoma, thrombophlebities, risk of infection and vasovagal reactions (VVR) are among few complications related to blood donation. A VVR is a general feeling of discomfort and weakness with anxiety, dizziness and nausea, which may progress to loss of consciousness. Commonly, there are minor symptoms associated with blood donation. However, rarely, serious and severe symptoms like loss of consciousness and convulsions or incontinence may occur. The VVR is caused by the parasympathetic nervous system, which can be further augmented by psychological factors, and the volume of blood removed causing relative hypovolemia. According to the Standard for Surveillance of Complications related to Blood Donation prepared by the International Society of Blood Transfusion and European Journal compilation 2009 British Blood Transfusion Society 129
130 D. K. Rohra et al. Haemovigilance Network, VVR are classified as immediate and delayed. Symptoms appearing before the donor has left the donation site are termed as immediate VVR and the symptoms appearing after the donor has left the donation site but within 24 h are classified as delayed VVR (http://www.isbt-web.org/members only/files/society/standardsurveillancedoco.pdf, website accessed on 15 August 2009). The safety of blood donor is of prime importance. In Pakistan, we do not have any regulatory laws to govern the safety of blood donors. Furthermore, no study has been conducted in Pakistan to estimate the prevalence of VVR in blood donors. Thus, this study was conducted to estimate the prevalence of immediate VVR in people donating blood in two leading blood banks of Karachi, Pakistan. An additional objective was to determine the association of various demographic and clinical characteristics with the frequency of immediate VVR. METHODS Karachi is the biggest city of Pakistan. The study was conducted in two leading blood banks of the city, i.e. Patient Welfare Association (PWA) Blood Bank, Dow Medical College and Hussaini Blood Bank (HBB). Written permission was sought from the administration of these blood banks before collection of data. All persons who visited these blood banks for blood donation from 1 November 2008 to 31 December 2008 during daytime were asked to participate in the study. An informed consent was taken before the start of interview. The demographic, clinical and other information were documented on a structured questionnaire. The personnel collecting the data from both blood banks were trained before the start of the study to eliminate any difference in the perception of the symptoms and the collection of data. Sphygmomanometers used in the study were matched for their recordings. All study participants were subjected to whole blood phlebotomy for approximately 500 ml. According to standard practices at these blood banks, after phlebotomy, all donors were advised to rest on the bed for at least 5 min and when they felt well, a drink was offered to them. The interview and examination was conducted 10 min after the completion of phlebotomy. Data regarding the development of only immediate VVR was documented. The severity of the immediate VVR was determined using definitions of International Society of Blood Transfusion and European Haemovigilance Network. According to this grading, severe VVR was considered as the one which needed hospitalisation or intervention or caused death. Other VVR like weakness, dizziness, sweating, discomfort, nausea/vomiting, pallor, anxiety and fainting/syncope with spontaneous recovery were graded as non-severe (mild to moderate). The donors were not followed for monitoring the occurrence of delayed VVR reaction. In addition to symptoms, the effect of blood donation on vital parameters like pulse rate, blood pressure (BP), temperature and respiratory rate was also observed. Estimated blood volume (EBV) of the blood donors was calculated from the following formula (Smetannikov & Hopkins, 1996). EBV in litres = [0.0236 (body height in cm) 0.725 ] [(body weight in kg) 0.425 1.229] The filled questionnaires were edited and coded. The data was entered twice by two different data entry operators in epidata (version 3.1). The final data were converted into spss (version 16.0) for analysis. Demographic and clinical data and the development of VVR in the study participants are presented as descriptive with number and percentages, whereas the comparison in pulse rate, BP, temperature and respiratory rate before and after the blood donation was made using independent samples t-test. We used simple binary logistic regression to determine the association of age, marital status, ethnicity, education, body mass index (BMI), EBV and history of previous blood donation with development of immediate VVR. A P value of <0.05 was considered statistically significant. RESULTS A total of 674 blood donors consented to participate in the study from both sampling units. Out of these, 279 (41.4%) and 395 (58.6%) donors were recruited from HBB and PWA, respectively. Demographic data of the study participants are presented in Table 1. As evident from the table, various age groups of the participants were well represented in the study. However, majority of the participants (35.6%) were less than 25 years old. Interestingly, all the donors who consented were males. Except for gender, we were able to recruit a diverse group of people in terms of marital status, ethnicity, educational status and occupation (Table 1). Table 2 depicts the clinical information of the study participants. As shown in the table, more than half of the donors were of normal weight. However, more than 40% of the participants were overweight having a BMI 25. The mean BMI of the donors under study was 24.6 ± 4.6. The mean EBV came out to be 4.6 ± 0.5 L. Almost all the participants donated blood for exchange (replacement). Two-third of the donors had a history of previous blood donation. Table 3 shows the distribution of signs/symptoms of immediate VVR experienced by the blood donors. None
Vasovagal reaction in blood donors of Karachi 131 Table 1. Demographic characteristics of study subjects Characteristics n (%) Age group (in years) <25 years 239 (35.6) 25 29 196 (29.1) 30 34 129 (19.1) 35 and above 110 (16.2) Gender Male 674 (100.0) Marital status Married 360 (53.4) Single 314 (46.6) Mother tongue Urdu 217 (32.2) Sindhi 143 (21.2) Pashto 79 (11.7) Balochi 73 (10.8) Others 162 (24.1) Educational status 1 Illiterate 172 (25.8) Primary and middle 187 (28.0) Matric and intermediate 221 (33.1) Graduate and postgraduate 87 (13.0) Occupation Unskilled worker 118 (17.6) Skilled worker 181 (27.0) Business-related 110 (16.4) Government servants 66 (9.9) Professional (upper category) 33 (4.9) Students 32 (4.8) Agriculture-related 31 (4.6) Professional (lower category) 26 (3.9) Others including missing data 77 (10.9) 1 The total number of responses in this category does not match with the total number of study participants because some of the responses were missing. of the donors developed a serious VVR. All VVR were non-severe (mild to moderate). Weakness and dizziness were two most common symptoms which were reported by 91 (13.5%) and 73 (10.8%) of the participants, respectively. It should be mentioned that one or more signs/symptoms like dizziness, sweating, discomfort, nausea/vomiting, pallor or anxiety were reported by the same donors who felt weakness. Grading the non-severe VVR into mild (subjective symptoms) and moderate (objective symptoms) was not possible because in majority of the donors both mild and moderate VVR were observed simultaneously. Only one participant fainted after blood donation who recovered spontaneously within the premises of blood bank after taking some rest. Out of 91 donors in whom signs and symptoms of immediate VVR were observed, a significant drop in systolic BP (13.5 ± 2.5 mmhg) and decrease in pulse rate (13.3 ± 3.6) were concurrently noted in 55 donors. Table 2. Clinical information of the study participants Characteristic n (%) BMI 1 <18.5 21 (3.1) 18.5 24.99 378 (56.6) 25 and above 269 (40.3) Estimated blood volume 1 <4.5 L 321 (48.1) 4.5 5.49 L 319 (47.8) >5.5 L 28(4.2) Blood group A 161 (23.9) B 222 (32.9) AB 66 (9.8) O 225 (33.4) Rhesus factor Positive 641 (95.1) Negative 33 (4.9) Reason for donation of blood 1 Volunteer 5 (0.8) Exchange 656 (99.2) History of previous blood donation 1 Yes 441 (65.6) No 231 (34.4) 1 The total number of responses in this category does not match with the total number of study participants because some of the responses were missing. Table 3. Distribution of the number of study participants experiencing signs/symptoms of immediate VVRs after blood donation Signs/symptoms related to immediate VVR Number of participants n (%) Weakness 91 (13.5) Dizziness 73 (10.8) Sweating 54 (8.0) Discomfort 40 (5.9) Nausea/vomiting 27 (4.0) Pallor 24 (3.6) Anxiety 17 (2.5) Fainting/syncope 1 (0.2) Table 4 shows the comparison of the BP, pulse rate, respiratory rate and body temperature of all the study subjects before and after the blood donation. As mentioned previously, an overall significant drop in systolic blood pressure and pulse rate was noted after the donation. We then determined the association of age, BMI, EBV, ethnicity, educational status, profession, marital status and first time donation status with the frequency of VVR. Interestingly, only marital status was found
132 D. K. Rohra et al. Table 4. Changes in blood pressure, pulse rate, respiratory rate and body temperature after donating blood Before blood donation After blood donation Mean difference (mean ± SD) (mean ± SD) (95% C.I.) P value Systolic blood pressure (mmhg) 121.6 ± 8.7 115.1 ± 3.5 6.5 (4.08, 8.93) <0.001 Diastolic blood pressure (mmhg) 80.1 ± 7.9 77.7 ± 3.6 2.4 ( 0.68, 5.55) 0.125 Pulse rate (per minute) 86.3 ± 68.7 78.8 ± 13.3 7.5 (1.93, 13.06) 0.008 Respiratory rate (per minute) 20.7 ± 5.5 20.2 ± 5.6 0.5 ( 0.003, 0.83) 0.062 Body temperature ( F) 96.3 ± 5.5 96.2 ± 1.8 0.1 ( 0.23, 0.38) 0.611 to be significantly associated with higher frequency of immediate VVR, where married donors were having higher odds as compared to singles (Odds Ratio = 1.49; 95% C.I.: 1.04, 2.13; P value = 0.031). All other characteristics were not significantly associated with frequency of immediate VVR. DISCUSSION VVR is the most common type of adverse event related to blood donation (Popovsky et al., 1995; Yuan et al., 2008). These studies have reported VVR as 67 95% of all the donation related events. This is the first study conducted in Pakistan to estimate the prevalence of immediate VVR associated with blood donation. The findings of this study and similar bigger studies across the country will serve to identify the vulnerable groups of population who are at increased risk of developing VVR due to blood donation. In this study, 91 out of 674 (13.5%) blood donors experienced one or more symptoms of immediate VVR, which were mild to moderate in severity. One may question the objectivity of the data on symptoms and the translation of these symptoms into VVR. However, out of those 91, a concurrent significant drop in systolic BP and pulse rate was also noted in 55 (8.2% of the total study participants) blood donors, which are the hallmark features of VVR (Klein et al., 2005). From these data, it is reasonable to conclude that at least 8.2% of all the participants in our study experienced immediate VVR after blood donation. The prevalence of immediate VVR in our population is much higher than that reported in studies conducted in other countries. A prevalence of 0.9 and 2.6% has been reported by Zervou et al. (2005) and Newman (2003), respectively. There are few plausible explanations for this higher prevalence of VVR in Pakistani population. First, ours is a prospective surveillance study which has a potential to observe higher rates of VVR compared to retrospective surveillance data collected in other studies. Second, there are no data regarding the frequency and risk factors of VVR in Pakistani population. In the absence of criteria for donation, failure to identify the volunteers at risk of developing VVR might be one reason for this exaggerated prevalence of VVR. Third, Tondon et al. (2008) have reported a clear association of age with frequency of VVR showing decreasing frequency and severity of VVR with increasing age. In the present study, about 65% of the blood donors were less than 30 years of age. This could be another contributory factor in the high prevalence of VVR. Fourth, it was observed with surprise that the EBV in Pakistani population is low. In almost half of the blood donors, the EBV was calculated to be less than 4.5 L. In addition to that, 500 ml of blood was collected from the donors under study compared to 450 ml in UK (Klein et al., 2005). Although we could not find any association of EBV with frequency of VVR in our study, this needs to be further validated in larger studies in Pakistan. There is a continuous debate about the factors which place the blood donors at high risk of developing VVR. Previous studies conducted elsewhere have reported association of various factors like age, weight, first time blood donation status, race, EBV and gender with the higher incidence of VVR (Trouern-Trend et al., 1999; Newman, 2002, 2003; Zervou et al., 2005; Eder et al., 2008; Kamel et al., 2009) We could not find any association of age, ethnicity, education status, BMI or first time blood donation status of the donor with increased frequency of VVR. The association of gender with VVR could not be analysed because all blood donors in our study were males. Interestingly, a significant association was observed between the marital status of the donors and the development of immediate VVR. Married donors were more vulnerable to this reaction compared to singles. To the best of our knowledge, there is no any report that has mentioned marital status as a risk factor associated with VVR. Further studies are needed to validate this finding. The question of how marital status might be related to VVR is difficult to answer. One plausible explanation would be that married men are more anxious and afraid of the complications due to their increased liabilities compared to singles and anxiety itself has been reported to be an important contributory factor in VVR (Byrne & Ditto, 2005; Ditto & France, 2006). This explanation may be culture-specific and may not be relevant to other societies.
Vasovagal reaction in blood donors of Karachi 133 In our study, we focussed on the immediate VVR because these are easy to observe and do not need follow up of the donors. All donors developed nonsevere VVR. Only one participant fainted who recovered spontaneously without medical treatment or hospitalisation. Nevertheless, whatever the minor reaction is, it has significant implications on the behaviour of the donor. These implications may be the self-deferral or unwillingness for the return blood donation in the future (Popovsky, 2002). Any complication due to blood donation is bound to decrease the likelihood of return donations thus decreasing the pool of eligible blood donors. Considering the high prevalence of immediate VVR observed in our study, it is prudent to take measures to avoid this phenomenon. The first and foremost measure would be to collect national data about the EBV and correspondingly having the guidelines about the volume or percent of total blood that can be collected in a single donation. Until this is done, blood banks can start practicing methods like offering fluids before starting phlebotomy and/or training blood donors about applied muscle tension exercises. The former method has been shown to decrease markedly the development of VVR among blood donors (Ditto et al., 2003). One limitation of the study is the small sample size which hinders the generalisation of the results. It is also likely that small sample lacks the power to detect the association of various factors like age, body weight, EBV and first time donation status with the occurrence of VVR. Another limitation is that all the participants in this study were males and we could not study the association of gender with VVR. In conclusion, the prevalence of VVR in the blood donors at two blood banks of Karachi is at least 8.2%, which is considerably higher than that reported from studies in developed countries. Furthermore, married men are at more risk of experiencing VVR in our population. ACKNOWLEDGMENTS We are thankful to the administration of the Patient Welfare Association and the Hussaini Blood Bank for allowing us to collect data from their blood banks. REFERENCES Byrne, N. & Ditto, B. (2005) Alexithymia, cardiovascular reactivity, and symptom reporting during blood donation. Psychosomatic Medicine, 67, 471 475. Ditto, B. & France, C.R. (2006) Vasovagal symptoms mediate the relationship between predonation anxiety and subsequent blood donation in female volunteers. Transfusion, 46, 1006 1010. Ditto, B., Wilkins, J.A., France, C.R., Lavoie, P. & Adler, P.S.J. (2003) On-site training in applied muscle tension to reduce vasovagal reactions to blood donation. Journal of Behavioral Medicine, 26, 53 65. 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