Factors associated with fainting – before, during and after whole blood donation M. Bravo, 1 H. Kamel, 1 B. Custer 1,2,3,4 & P. Tomasulo 1,2 1 Blood Systems, Inc., Scottsdale, AZ, USA 2 Blood Systems Research Institute, San Francisco, CA, USA 3 University of California, San Francisco, San Francisco, CA, USA 4 University of Washington, Seattle, WA, USA Received: 7 January 2011, revised 23 February 2011, accepted 23 February 2011, published online 3 May 2011 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 (0Æ07 and 0Æ09 ⁄ 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 possibil- ity 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 ambu- lating donors. Key words: adverse reactions, blood donors, donation time course, donor vigilance, vasovagal syncope. Introduction Previous studies identified risk factors for mild, moderate and severe reactions in whole blood donors as well as fac- tors associated with immediate and delayed reactions among whole blood and apheresis donors [1–4]. Tomasulo et al. [5] have shown that blood donor fainting reactions are not spread evenly over the entire time course of the donation process, but rather are concentrated in three peaks. It is our hypothesis that there are distinct periods during the donation process each with a different risk of injury and set of risk factors. Because some intervention measures have been shown to be effective in reducing the risk of fainting reactions [6,7], it becomes important to identify those donors most likely to react in each period and, if possible, why, so that appropriate interventions can be selected for reactions in each period and for reactions which are associated with injury. Our study focuses on all fainting reactions across the time course of donation; i.e. vasovagal syncope (VVS) or Correspondence: Peter Tomasulo, Blood Systems, Inc., Medical and Scientific Affairs, 6210 E Oak Street, Scottsdale, AZ 85257, USA E-mail: ptomasulo@bloodsystems.org Vox Sanguinis (2011) 101, 303–312 ORIGINAL PAPER ª 2011 The Author(s) Vox Sanguinis ª 2011 International Society of Blood Transfusion DOI: 10.1111/j.1423-0410.2011.01494.x 303