title: Vasovagal reactions in whole blood donors at three REDS-II blood centers in Brazil.
abstract: BACKGROUND
  In Brazil little is known about adverse reactions during donation and the donor characteristics that may be associated with such events. Donors are offered snacks and fluids before donating and are required to consume a light meal after donation. For these reasons the frequency of reactions may be different than those observed in other countries.
  
  
  METHODS
  A cross-sectional study was conducted of eligible whole blood donors at three large blood centers located in Brazil between July 2007 and December 2009. Vasovagal reactions (VVRs) along with donor demographic and biometric data were collected. Reactions were defined as any presyncopal or syncopal event during the donation process. Multivariable logistic regression was performed to identify predictors of VVRs.
  
  
  RESULTS
  Of 724,861 donor presentations, 16,129 (2.2%) VVRs were recorded. Rates varied substantially between the three centers: 53, 290, and 381 per 10,000 donations in Recife, São Paulo, and Belo Horizonte, respectively. Although the reaction rates varied, the donor characteristics associated with VVRs were similar (younger age [18-29 years], replacement donors, first-time donors, low estimated blood volume [EBV]). In multivariable analysis controlling for differences between the donor populations in each city younger age, first-time donor status, and lower EBV were the factors most associated with reactions.
  
  
  CONCLUSIONS
  Factors associated with VVRs in other locations are also evident in Brazil. The difference in VVR rates between the three centers might be due to different procedures for identifying and reporting the reactions. Potential interventions to reduce the risk of reactions in Brazil should be considered.
authors.affiliation: Blood Systems Research Institute, 270 Masonic Avenue, San Francisco, CA 94118, USA. tgoncalez@bloodsystems.org
authors.forename: Thelma T
authors.initials: TT
authors.lastname: Gonçalez
authors.forename: Ester C
authors.initials: EC
authors.lastname: Sabino
authors.forename: Karen S
authors.initials: KS
authors.lastname: Schlumpf
authors.forename: David J
authors.initials: DJ
authors.lastname: Wright
authors.forename: Silvana
authors.initials: S
authors.lastname: Leao
authors.forename: Divaldo
authors.initials: D
authors.lastname: Sampaio
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Takecian
authors.forename: Anna B
authors.initials: AB
authors.lastname: Proietti
authors.forename: Anna B
authors.initials: AB
authors.lastname: Proitetti
authors.forename: Edward
authors.initials: E
authors.lastname: Murphy
authors.forename: Michael
authors.initials: M
authors.lastname: Busch
authors.forename: Brian
authors.initials: B
authors.lastname: Custer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001782:Blood Donors; D001938:Brazil; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D019462:Syncope, Vasovagal / Q000453:epidemiology*
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