Time course of vasovagal syncope with whole blood donation

A discrete-event simulation model for analysing and improving operations in a blood donation centre

Background and objectives

Healthcare systems require effective and efficient blood donation supply chains to provide an adequate amount of whole blood and blood components to hospitals and transfusion centres. However, some crucial steps of the chain, for example blood collection, are not adequately studied in the literature. This work analyses the operations in a blood collection centre with the twofold aim of analysing different configurations and evaluating the effectiveness and feasibility of schedules defined at higher planning levels.

Materials and methods

The analyses are performed through a discrete event simulation (DES) model that describes a customizable collection centre. Moreover, a feedback loop from the DES to the higher planning level allows to adjust scheduling decisions if they determine criticalities or infeasibilities at the operational level.

Results

Numerical tests have been conducted considering a real Italian provider. An experimental plan has been designed to compare different configurations for the blood collection centre and evaluate the best ones in terms of cost and service quality for the three main actors involved (donors, workers and managers). The best configurations have been also used to test the feedback loop.

Conclusions

Results confirm the appropriateness of the proposed DES model, which can be considered a useful decision support tool for dimensioning and managing a blood collection centre, either as a standalone tool or in conjunction with a scheduler.

Management of young blood donors

The emphasis on high-school blood drives and acceptance of 16-year-old blood donors led to more research on physiologic and psychological ways to decrease vasovagal reaction rates in young blood donors and to increase donor retention. Research on how to accomplish this has been advantageous for the blood collection industry and blood donors. This review discussed the current situation and what can be done psychologically, physiologically, and via process improvements to decrease vasovagal reaction rates and increase donor retention. The donation process can be significantly improved. Future interventions may include more dietary salt, a shorter muscle tension program to make it more feasible, recommendations for post-donation muscle tension / squatting / laying down for lightheadedness, more donor education by the staff at the collection site, more staff attention to donors with fear or higher risk for a vasovagal reaction (e.g. estimated blood volume near 3.5 l, first-time donor), and a more focused donation process to ensure a pleasant and safer procedure.

Factors associated with fainting: before, during and after whole blood donation

BACKGROUND  Whole blood (WB) donation encompasses several periods during which some donors faint. Identification of factors associated with fainting during each period should guide intervention strategies. Reducing faint reactions may reduce donor injuries and disability. METHODS  Blood donation was divided into three periods: Period 1 - registration; Period 2 - phlebotomy; and Period 3 - post-phlebotomy. Period 3 consists of two sub-periods (3A - on-site and 3B - off-site). For each Period, stratified rates of fainting in relation to various donor and donation characteristics were calculated and multivariable logistic regression analyses to identify factors associated with fainting were conducted. Donor injuries in each period were also analysed. RESULTS  Of the 956 766 donors registered in 2007, 554 534 (58%) donated WB. There were 43 fainting episodes and two injuries in Period 1 and 1520 faints and 73 injuries in Periods 2 and 3. Regression analyses showed that youth and donor first-time status are associated with fainting in all periods; but most significantly in Period 1. Small estimated blood volume is notably not a factor in Period 1 but is significant in Periods 2 and 3. The highest injury rate is seen in Period 3A (0·07 and 0·09/1000 donations) for male and female donors, respectively. CONCLUSIONS  Variability in factors associated with fainting across defined periods of the donation process suggest differing underlying mechanisms and the possibility that interventions for the reactions most associated with injury during each time period can be designed. The highest rate of injury per donation occurred in ambulating donors.

Interventions to reduce the vasovagal reaction rate in young whole blood donors

BACKGROUND

There have been multiple reports concerning the predictors of fainting reactions in blood donors, but few attempts to reduce the rates of fainting reactions with concomitant rigorous attempts to monitor the success of the interventions.

STUDY DESIGN AND METHODS

We used a retrospective observational cohort study design, comparing the likelihood of reaction from 213,031 allogeneic whole blood donations made by 17- to 22-year-old donors in two separate 12-month periods before and after the implementation of interventions to reduce reactions. The interventions were 1) a limit on the maximum percentage of estimated blood volume young donors could donate, 2) encouraging applied muscle tension during donation, and 3) providing approximately 500 mL of water before donation. Reactions were defined by severity and time in relation to the end of phlebotomy and documented according to standard procedures. Data analysis included comparison of stratified reaction rates and multivariable logistic regression analysis.

RESULTS

The interventions decreased the aggregate reaction rates in male and female donors by 24% (p < 0.0001). There was a 25% decrease in delayed reactions (p = 0.0006) and a 38% decrease in off-site reactions (p = 0.001) in female donors. The impact of the three interventions together on reaction rate was greater than the combined impact of exercises and water provision. Multivariable modeling showed that the interventions reduced reactions but did not prevent their occurrence in identified higher risk groups.

CONCLUSION

The interventions to reduce vasovagal reactions in whole blood donors were effective. Future efforts to reduce reactions in blood donors can build on the strengths and avoid the weaknesses identified while conducting and analyzing the data from this study.