title: Predonation hydration and applied muscle tension combine to reduce presyncopal reactions to blood donation.
abstract: BACKGROUND
  A randomized controlled trial was conducted to test the effects of hydration and applied muscle tensing on presyncopal reactions to blood donation. Both interventions are designed to prevent the decreases in blood pressure that can contribute to such reactions, but due to the distinct physiologic mechanisms underlying their pressor responses it was hypothesized that a combined intervention would yield the greatest benefit.
  
  
  METHODS
  Before blood donation, first- and second-time blood donors (mean age, 20.2 years; SD, 4.9) were randomly assigned to 1) standard donation, 2) placebo (leg exercise before venipuncture), 3) predonation water, or 4) predonation water and leg exercise during donation.
  
  
  RESULTS
  Main effects of group were observed for phlebotomist classification of vasovagal reactions (chi(2)(3) = 8.38, p < 0.05) and donor reports of presyncopal reactions (chi(2)(3) = 13.16, p < 0.01). Follow-up analyses of phlebotomist classifications revealed fewer reactions in the predonation water and predonation water and leg exercise groups relative to placebo but not standard donation. Follow-up analyses of self-reported reactions revealed that women, but not men, had lower scores in both the predonation water and the predonation water and leg exercise groups relative to both placebo and standard donation.
  
  
  CONCLUSIONS
  Predonation hydration and a combination of hydration and leg exercise may help attenuate presyncopal reactions in relatively novice donors, although future studies with larger samples are required to confirm this effect.
authors.affiliation: Ohio University, Athens, Ohio 45701, USA. france@ohio.edu
authors.forename: Christopher R
authors.initials: CR
authors.lastname: France
authors.forename: Blaine
authors.initials: B
authors.lastname: Ditto
authors.forename: Mary Ellen
authors.initials: ME
authors.lastname: Wissel
authors.forename: Janis L
authors.initials: JL
authors.lastname: France
authors.forename: Tara
authors.initials: T
authors.lastname: Dickert
authors.forename: Aaron
authors.initials: A
authors.lastname: Rader
authors.forename: Kadian
authors.initials: K
authors.lastname: Sinclair
authors.forename: Sarah
authors.initials: S
authors.lastname: McGlone
authors.forename: Zina
authors.initials: Z
authors.lastname: Trost
authors.forename: Erin
authors.initials: E
authors.lastname: Matson
mesh_terms: D000328:Adult; D001782:Blood Donors; D001794:Blood Pressure; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D012737:Sex Factors; D013575:Syncope / Q000209:etiology / Q000517:prevention & control*; D014867:Water / Q000008:administration & dosage*
chemical_list: D014867:Water