Interventions to reduce vasovagal reactions in blood donors: a systematic review and meta-analysis

Safety and protection of plasma donors: A scoping review and evidence gap map

BACKGROUND AND OBJECTIVES

As part of a large-scale project to safely increase plasma collection in Europe, the current scoping review identifies the existing evidence (gaps) on adverse events (AEs) and other health effects in plasmapheresis donors, as well as factors that may be associated with such events/effects.

MATERIALS AND METHODS

We searched six databases and three registries. Study characteristics (publication type, language, study design, population, outcomes, associated factors, time of assessment, duration of follow-up, number and frequency of donations, convalescent plasma [y/n], setting and location) were synthesized narratively and in an interactive evidence gap map (EGM).

RESULTS

Ninety-four research articles and five registrations were identified. Around 90% were observational studies (57 controlled and 33 uncontrolled), and most of them were performed in Europe (55%) or the United States (20%). Factors studied in association with donor health included donor characteristics (e.g., sex, age) (n = 27), cumulative number of donations (n = 21), donation frequency (n = 11), plasma collection device or programme (n = 11), donor status (first time vs. repeat) (n = 10), donation volume per session (n = 8), time in donation programme (n = 3), preventive measures (n = 2) or other (n = 9).

CONCLUSION

The current scoping review provides an accessible tool for researchers and policymakers to identify the available evidence (gaps) concerning plasmapheresis donation safety. Controlled prospective studies with long-term donor follow-up are scarce. Furthermore, additional experimental studies comparing the health effects of different donation frequencies are required to inform a safe upper limit for donation frequency.

Prevention strategies for vasovagal reaction in whole blood donors: A quadri-armed randomised control trial

INTRODUCTION

Vasovagal reaction (VVR) is a frequently encountered generalised donor adverse reaction, associated with donor deterrence towards future donation. Several mitigation strategies for prevention of VVR were tried but still not standardised. This quadri-armed randomised study evaluated the utility of water ingestion, applied muscle tension (AMT) and combination of both in preventing the VVR among blood donors.

METHODS

A quadri-armed randomised controlled trial was performed on 4320 whole blood donors. Blood donors of 18-65 years of age were randomised into four groups based on the interventions performed i.e., control with no intervention (Group 1, n = 1081), water ingestion (Group 2, n = 1082), AMT (Group 3, n = 1070) and combined intervention (Group 4, n = 1087). VVR during and immediately after blood donation were observed along with assessment of risk factors in blood donors and the effectiveness of interventions were analysed.

RESULTS

The incidence of VVR observed 1.6% in our study, with the highest occurrence in the control group (2.5%) and the lowest in the combined intervention group (0.9%). Multivariable logistic regression revealed that the control group donors faced a 1.38-fold greater risk of VVR compared to those receiving interventions (OR: 1.38, 95% CI: 1.10-1.75). Other risk factors included younger age (OR: 1.5, 95% CI: 1.05-2.17), first-time donation (OR: 5.7, 95% CI: 1.66-5.74), prior history of VVR (OR: 2.5, 95% CI: 10.4-101.52).

DISCUSSION/CONCLUSION

The combined approach of water ingestion and AMT proved significantly more effective in VVR prevention compared to individual interventions.

A new risk predictive scoring system of vasovagal reactions in patients with preoperative autologous blood donation

BACKGROUND AND OBJECTIVES

Vasovagal response (VVR) is the most common adverse reaction during blood donation and it is the main element for the safety of the patients with preoperative autologous blood donation (PABD). Accurate identification high-risk group is of great significance for PABD. Our study aimed to establish a scoring system based on the nomogram to screen the high-risk population and provide evidence for preventing the occurrence of VVRs.

MATERIALS AND METHODS

A number of 4829 patients underwent PABD between July 2017 and June 2020 in the first medical center of Chinese PLA Hospital were recruited, 3387 of whom were included in the training group (70 %; 108 VVRs patients vs 3279 Non-VVRs patients), 1442 were included in the validation group (30 %; 46 VVRs patients vs 1396 Non-VVRs patients). The data were analyzed by univariate and multivariate logistic regression. The nomogram of the scoring system was created by using the RMS tool in R software.

RESULTS

Seven variables including BMI, hematocrit, pre-phlebotomy heart rate and systolic blood pressure, history of blood donation, age group and primary disease were selected to build the nomogram, which was shown as prediction model. And the score was 0-1 for BMI, 0-2 for hematocrit, systolic blood pressure, heart rate and no blood donation history, 0-10 for age, 0-3 for primary disease. When the total cutoff score was 11, the predictive system for identifying VVRs displayed higher diagnostic accuracy. The area under the curve, specificity, and sensitivity of the training group were 0.942, 82.41 % and 97.17 %, respectively, whereas those of the validation group were 0.836, 78.26 % and 78.15 %, respectively.

CONCLUSION

A risk predictive scoring system was successfully developed to identify high-risk VVRs group form PABD patients that performed well.

Evaluation of interventions to prevent vasovagal reactions among whole blood donors: rationale and design of a large cluster randomised trial

BACKGROUND

Vasovagal reactions (VVRs) are the most common acute complications of blood donation. Responsible for substantial morbidity, they also reduce the likelihood of repeated donations and are disruptive and costly for blood services. Although blood establishments worldwide have adopted different strategies to prevent VVRs (including water loading and applied muscle tension [AMT]), robust evidence is limited. The Strategies to Improve Donor Experiences (STRIDES) trial aims to reliably assess the impact of four different interventions to prevent VVRs among blood donors.

METHODS

STRIDES is a cluster-randomised cross-over/stepped-wedge factorial trial of four interventions to reduce VVRs involving about 1.4 million whole blood donors enrolled from all 73 blood donation sites (mobile teams and donor centres) of National Health Service Blood and Transplant (NHSBT) in England. Each site ("cluster") has been randomly allocated to receive one or more interventions during a 36-month period, using principles of cross-over, stepped-wedge and factorial trial design to assign the sequence of interventions. Each of the four interventions is compared to NHSBT's current practices: (i) 500-ml isotonic drink before donation (vs current 500-ml plain water); (ii) 3-min rest on donation chair after donation (vs current 2 min); (iii) new modified AMT (vs current practice of AMT); and (iv) psychosocial intervention using preparatory materials (vs current practice of nothing). The primary outcome is the number of in-session VVRs with loss of consciousness (i.e. episodes involving loss of consciousness of any duration, with or without additional complications). Secondary outcomes include all in-session VVRs (i.e. with and without loss of consciousness), all delayed VVRs (i.e. those occurring after leaving the venue) and any in-session non-VVR adverse events or reactions.

DISCUSSION

The STRIDES trial should yield novel information about interventions, singly and in combination, for the prevention of VVRs, with the aim of generating policy-shaping evidence to help inform blood services to improve donor health, donor experience, and service efficiency.

TRIAL REGISTRATION

ISRCTN: 10412338. Registration date: October 24, 2019.

Novel risk patterns of vasovagal reactions in NZ blood donations complicated by COVID-19 restrictions

Introduction

Vasovagal reactions (VVRs) are common but complex donor adverse reactions (DAEs) in blood donations. VVRs have been extensively studied with a multitude of risk factors identified including young age, female gender and first-time donor status. How they may interplay remains obscure.

Methods

A total of 1,984,116 blood donations and 27,952 immediate VVRs (iVVRs) and 1,365 delayed VVRs (dVVRs) reported between 2011 and 2021 in NZ were used in multivariate logistic regression analyses each concerning donations with iVVRs as cases and those free of DAEs as controls. For each analysis stepwise selection was used to identify the best model and risk factors carrying significant main effects and/or interactions. Identified interactions informed further in-depth regression analyses to dissect iVVR risk patterns.

Results

Over 95% of VVRs were iVVRs that had lower female preponderance and deferrals than dVVRs. iVVRs had a school seasonal pattern in whole blood donations driven by first-time donors from schools/colleges, and interactions between gender and age group differentiating the first-time from repeat donations. Subsequent regression analyses identified the known and novel risk factors of year and mobile collection sites and their interactions. iVVR rates were roundly elevated in 2020 and 2021 probably because of COVID-19 restrictions like facemask wearing. Exclusion of the 2020 and 2021 data removed the interactions with year, but confirmed interactions of gender with mobile collection sites (p = 6.2e-07) in first-time donations only and with age group in repeat donations only (p < 2.2e-16), together indicating young female donors at the highest risk of iVVRs. Our results also revealed that donation policy changes contributed to the year effects; donors had a lower iVVR risk at mobile sites than well-medicalized donation centers probably because of under-reporting.

Conclusion

Modeling statistical interactions is valuable in identifying odds and revealing novel iVVR risk patterns and insights into blood donations.

Prevalence and factors associated with vasovagal reaction among whole blood donors in hospital Universiti Sains Malaysia

Adverse donor reactions (ADR) are common to occur during the blood donation process. The most common is vasovagal reactions (VVR) and it cause negative impact in the donor return rate. The aim of this study is to determine the prevalence of VVR among blood donors and to study its associated factors, at Hospital University Sains Malaysia (USM). This retrospective case-control study was conducted from June 2018, until June 2021. Data was extracted from the blood bank database system and from donor adverse reaction form. Donors who developed adverse donor reactions were chosen and without VVR were chosen at random as controls. A total of 159 donors, out of 35 134 donors were reported to have VVR which resulted in an overall prevalence of 0.45 %. Dizziness or mild VVR were the most frequently observed adverse reactions, accounting for approximately 87/159 (54.7 %) of all adverse reactions. Multiple logistic regression (MLR) analysis showed VVR were significantly associated with age, female gender, first-time donor, and 450 ml volume of blood collected. The prevalence of vasovagal reactions among blood donors in this study was low which was similar to a few previous studies. Although it was low, still it is very important to reduce risks to a minimum so that the donor return rate could be maintained. The information regarding its associated factors can be used to identify high-risk donors to prevent the incidence in the future.

Pre-donation water and salty snacks to prevent vasovagal reactions among blood donors

BACKGROUND

Minimizing the risk of vasovagal reactions (VVRs) can prevent donor harms and improve donor return. We report the results of a program to reduce VVR rates.

STUDY DESIGN AND METHODS

The program was implemented on June 11, 2017 and consisted in drinking water and eating a salty snack before donating blood, plasma, or platelets. All donations made during the "pre-program period" (October 11, 2015-June 10, 2017) and "post-program period" (June 11, 2017-May 11, 2019) were included. Study outcomes comprised VVRs (any severity) and syncopal VVRs, whether employee- or donor-reported. An interrupted time series (ITS) analysis proxied causality based on the "pre-program trend," the "immediate trend" (i.e., immediately before versus after the program), and the "post-program trend". The relative risk (RR) of VVR (along with confidence intervals [CIs]) was reported, overall and stratified by subgroups based on age, sex, donor type (i.e., first-time versus repeat), and donation type (i.e., whole blood versus apheresis).

RESULTS

The monthly VVR rate (any severity) dropped from 4.6% in the pre-program period to 4.3% in the post-program period, and never reached its pre-program level. The ITS analysis revealed a statistically significant and increasing pre-program trend (RR [95% CI] = 1.011 [1.002-1.020]), a statistically significant and decreasing immediate trend (RR [95% CI] = 0.848 [0.743-0.969]), and a non-statistically-significant and stable post-program trend (RR [95% CI] = 0.999 [0.993-1.006]). Similar trends were observed for nearly all high- and low-risk subgroups. No statistically significant trend was observed for syncopal VVRs.

DISCUSSION

These results suggest that the herein-described program durably reduced the incidence of VVRs (any severity) by ~15%.

Prevention of Blood Donation-related Vasovagal Response by Applied Muscle Tension: a Meta-analysis

Objective

Vasovagal reaction (VVR) is an adverse reaction to blood donation. Applied muscle tension (AMT) has been reported to reduce the probability of VVR during blood donation; however, the results have been controversial. We therefore conducted a meta-analysis to systematically evaluate the effect of AMT in reducing VVR.

Methods

We searched six major databases using “applied muscle tension” and “blood donation-related vasovagal response” as keywords. Relevant articles published in English or Chinese between 1 January 2000 and 30 June 2021 were included in the analysis. The quality of the included articles was evaluated and publication bias was assessed by forest and funnel plots and by Egger's test.

Results

Fifty-one articles were identified, of which six were included according to the pre-defined inclusion and exclusion criteria. A fixed-effects model was adopted for effect size combination and revealed a relative risk of 0.52 (95% confidence interval 0.40 to 0.67). The AMT group was superior to the control in terms of VVR prevention. A funnel plot and Egger's test suggested that the findings were accurate and reliable with low publication bias.

Conclusion

AMT could effectively reduce VVR during blood donation. Further multicenter studies with large sample sizes are needed to confirm these results.

Vasovagal syncope after blood donation in active duty military personnel of the Spanish Army

BACKGROUND

All studies of vasovagal syncope (VVS) after blood donation have been performed with civilian donors. We hypothesized that military donors have a lower incidence of VVS and a particular set of predisposing factors.

STUDY DESIGN AND METHODS

Retrospective case-control study matching every case of VVS seen from 2011 to 2019 with two controls without VVS from the same blood drive. We used the odds ratio (OR) and its 95% confidence interval (CI), estimated by multivariate logistic regression, to identify independent predictors of VVS.

RESULTS

There were 105 episodes of VVS among 65.481 whole blood donations (0.15%). VVS was more frequent among donors from military academies than from other military units (0.37% vs. 0.10%, p < .001) and in collections conducted in mobile inside setups than in mobile buses (0.23% vs. 0.06%, p < .001). In the multivariate analysis, the only independent predictors of VVS were the status of first-time donor (OR 2.6, 95% CI 1.5-4.4; p < .001) and pre-donation systolic blood pressure (SBP) < 120 mm Hg (OR 1.9, 95% CI 1.1-3.3; p = .01). Donors with both risk factors had a 5.5-fold increased risk of VVS than donors without any risk factor. Age and female sex were not predictive of VVS.

DISCUSSION

Active duty military blood donors have a lower incidence of VVS than that reported in civilian donors. First-time donors and donors with SBP < 120 mm Hg should be temporarily deferred when immediate reincorporation to hazardous or strenuous duty tasks after donation is inescapable.

The vasovagal reaction experience among blood donors: A qualitative study of factors that affect donor return

RATIONALE

Blood collection agencies face ongoing challenges in retaining voluntary donors to meet the demand for blood and blood-related products by healthcare services. A known deterrent to continued blood donation is the experience of a vasovagal reaction (VVR). However, there has been little research into donors' experiences of these reactions and the factors that influence their decision to return, which is essential information to inform strategies to improve donor return.

OBJECTIVE

The aim of this paper was to explore blood donor views and experiences of a VVR, with a particular interest in how the reaction influenced their return behaviour, using the Transactional Model of Stress and Coping.

METHODS

We conducted 34 semi-structured in-depth interviews between February and April 2018 with a sample of Australian donors who had experienced a VVR in the last seven days. Transcripts were analysed using the Framework Method.

RESULTS

The VVR elicited various emotional responses, which appeared to be influenced by social support, being aware of the possibility of experiencing a VVR, or the donation outcome. In turn, the VVR experience affected intentions to return, with those who reported more positive experiences expressing stronger intentions. Further, donors felt more likely to return if they perceived their risk of a recurrent event as low and if they were able to identify appropriate problem and emotion-focused coping strategies.

CONCLUSION

This article provides novel insights into possible ways to encourage blood donor return following a VVR.

Implementation of measures to reduce vasovagal reactions: Donor participation and results

BACKGROUND

There are several strategies to reduce donor reactions. We report donor participation and reaction rates before and after implementing multiple measures at Canadian Blood Services.

STUDY DESIGN AND METHODS

We introduced a structured program of 500 mL of water and a salty snack pre-donation and applied muscle tension (AMT) during donation. Donors were not deferred for out of range blood pressure (BP); however, BP was measured in first time donors. Time on the donation chair post-donation was decreased from 5 to 2 min for repeat donors. We assessed participation rates using our quarterly survey of 10,000 recent donors. We extracted vasovagal reactions with loss of consciousness (LOC) from our operational database and compared pre-implementation (Oct 12,018-March 31,2019) and post-implementation (Oct 12,019-March 31,2020) periods.

RESULTS

Survey response rates varied from 11% to 16%. The percentage of donors who drank the water and ate the salty snack increased from 58% to 82% and 44% to 70% over 4 quarters; those performing AMT increased from 24% to 41%. Reactions decreased from 19.07 per 10,000 (744 reactions in 390,123 donations) to 14.04 per 10,000 (537 in 382,382 donations) (p < .0001). No first-time donors with high BP (n = 684) but 5 with low BP (n = 718) had reactions, CI were very large.

CONCLUSIONS

Achieving optimal participation was challenging. After implementation of a donor wellness initiative based on best practice, rates of vasovagal reactions with LOC decreased by 25%. A larger dataset is necessary to assess the safety contribution of BP deferrals when other mitigation measures are in place.

Vasovagal syncope related to pain procedures in a pain clinic at a tertiary Lebanese hospital between 2016 and 2019

Objectives

Our study focuses on evaluating the factors associated with vasovagal syncope (VVS) when having a pain procedure at the pain clinic as well as showing variation in vital signs associated with fainting across different periods of the procedure (before, during and after).A retrospective case control study was conducted in a university hospital in Lebanon (CHU-NDS) on adult Lebanese patients with data taken from the archives covering a 4 year period (2016–2019).

Results

The multivariable analysis showed that a higher systolic blood pressure per-procedure was significantly associated with lower odds of having vasovagal syncope. An adequate dose of a vasopressor like ephedrine can be used to prevent a vasovagal event from happening. In our study the blood pressure component was more significant than the heart rate component which stayed in the normal range limit in the three different periods of procedure. Cases having a pain procedure for the first time represent 59.6% of the occurrence of VVS. Vasovagal syncope is a complication that can be prevented in high risk patients. Our study suggests taking preventive measures for VVS for patients with first time infiltration status especially if appearing in an anxious state.

Examining knowledge translation in blood donor research: A review of vasovagal reaction literature

BACKGROUND

Knowledge translation focuses on the transfer of research findings into policy and practice. To provide insight into the state of knowledge translation in blood donor research, we undertook a rapid review of a key research area in the field with high potential for translation, vasovagal reactions (VVRs). We examined the number and nature of VVR-related studies to determine the availability of research evidence, and mapped the included articles along the research-to-practice trajectory using the Knowledge to Action framework.

STUDY DESIGN AND METHODS

PubMed, PsycINFO, CINAHL, and EMBASE were searched for peer-reviewed journal articles from inception to October 2019 using the terms blood don* AND vasovagal OR faint* OR syncope.

RESULTS

A total of 176 articles met our inclusion criteria. Studies relating to VVRs increased substantially from 1942 to 2019, with 84% published in the last 20 years. Articles were predominately observation (non-intervention) studies (117; 66%), followed by intervention (knowledge inquiry) studies (31; 18%) and review (knowledge synthesis) studies (20; 11%). The evidence from intervention research was limited, with 14 strategies tested in 31 studies and often by the same research groups. Only 5 (3%) implementation and evaluation studies were found; all focused on evaluating the effects of a newly introduced intervention on VVR rates through uncontrolled or cross-sectional study designs.

DISCUSSION

VVR research is in the early stages of knowledge translation. More intervention research is needed to provide a robust evidence base as well as more published implementation research to share knowledge of translating research into policy and practice.

Epidemiology of donors and recipients: lessons from the SCANDAT database

With the development of several 'vein-to-vein' databases, which capture data on the entire donor-recipient continuum and link this data to health outcomes, there has been an increasing number of studies investigating the health effects of all aspects of the practice of transfusion medicine. The Scandinavian Donations and Transfusions (SCANDAT) database is one of several such databases, which includes all electronically available data on blood donors, donations and transfusions since the late 1960s in Sweden and the early 1980s in Denmark. The SCANDAT database has been used to characterise disease occurrence among blood donors and transfused patients, as well as to investigate possible health effects of blood donations, aspects of transfusion care and possible transfusion transmission of disease. Recent publications include studies on recipient mortality associated with the storage lesion, studies on the effects of donor demographics on patient mortality and health effects of frequent blood donation. Although this research approach is clearly very powerful, the appropriate analysis of such real-world data is complex and requires close methodological attention. The purpose of this review is to present some of the research conducted within the SCANDAT collaboration. We hope more international collaboration may help improve our understanding of the important remaining questions about donor and recipient health.

Drinking Water to Prevent Postvaccination Presyncope in Adolescents: A Randomized Trial

BACKGROUND AND OBJECTIVES

Postvaccination syncope can cause injury. Drinking water prephlebotomy increases peripheral vascular tone, decreasing risk of blood-donation presyncope and syncope. This study evaluated whether drinking water prevaccination reduces postvaccination presyncope, a potential syncope precursor.

METHODS

We conducted a randomized trial of subjects aged 11 to 21 years receiving ≥1 intramuscular vaccine in primary care clinics. Intervention subjects were encouraged to drink 500 mL of water, with vaccination recommended 10 to 60 minutes later. Control subjects received usual care. Presyncope symptoms were assessed with a 12-item survey during the 20-minutes postvaccination. Symptoms were classified with a primary cutoff sensitive for presyncope, and a secondary, more restrictive cutoff requiring greater symptoms. Results were adjusted for clustering by recruitment center.

RESULTS

There were 906 subjects randomly assigned to the control group and 901 subjects randomly assigned to the intervention group. None had syncope. Presyncope occurred in 36.2% of subjects by using the primary definition, and in 8.0% of subjects by using the restrictive definition. There were no significant differences in presyncope by intervention group for the primary (1-sided test, P = .24) or restrictive outcome (1-sided test, P = .17). Among intervention subjects vaccinated within 10 to 60 minutes after drinking all 500 mL of water (n = 519), no reduction in presyncope was observed for the primary or restrictive outcome (1-sided tests, P = .13, P = .17). In multivariable regression analysis, presyncope was associated with younger age, history of passing out or nearly passing out after a shot or blood draw, prevaccination anxiety, receiving >1 injected vaccine, and greater postvaccination pain.

CONCLUSIONS

Drinking water before vaccination did not prevent postvaccination presyncope. Predictors of postvaccination presyncope suggest opportunities for presyncope and syncope prevention interventions.

Whole blood transfusion closest to the point-of-injury during French remote military operations

To improve the survival of combat casualties, interest in the earliest resort to whole blood (WB) transfusion on the battlefield has been emphasized. Providing volume, coagulation factors, plasma, and oxygenation capacity, WB appears actually as an ideal product severe trauma management. Whole blood can be collected in advance and stored for subsequent use, or can be drawn directly on the battlefield, once a soldier is wounded, from an uninjured companion and immediately transfused.Such concepts require a great control of risks at each step, especially regarding ABO mismatches, and transfusion-transmitted diseases. We present here the "warm and fresh" WB field transfusion program implemented among the French armed forces. We focus on the followed strategies to make it applicable on the battlefield, even during special operations and remote settings, and safe for recipients as well as for donors.