The effect of a 473-mL (16-oz) water drink on vasovagal donor reaction rates in high-school students

BACKGROUND: Recent clinical studies found that a water drink prevented orthostatic hypotension in healthy subjects subjected to a tilt-table test. A water drink was tested as a method to decrease vasovagal donor reactions in high-school students. STUDY DESIGN AND METHODS: A total of 8894 high-school donations in Fall 2004 and 2005 were assigned to groups receiving or not receiving a 473-mL water drink after acceptance for whole-blood donation. In addition, 4340 donations in 2004 were reduced to 2895 donations ("balanced 2004 group") with an algorithm that equally balanced the donors between the water and no water arms. RESULTS: The donor reaction rate was 9.9 percent (349 reactions/3534 donations) in donors given a water drink versus 12.5 percent (668 reactions/5360 donations; p = 0.0002) in donors not given a water drink. Donors given a water drink had a 21 percent reduction in their donor reaction rate. The main benefit of water was in Caucasian, first-time donors. In the balanced 2004 group, the donor reaction rate was 10.6 percent (153 reactions/1438 donations) in donors given a water drink versus 14.8 percent (216 reactions/1457 donations; p = 0.0008) in donors not given a water drink. Donors given a water drink in the balanced 2004 group had a 28 percent reduction in their donor reaction rate. The use of water did not interfere with donor processing and was judged by collection staff as easy to implement. CONCLUSION: A 473-mL water drink decreased the vasovagal donor reaction rate in high-school donors by 21 percent, but to varying degrees in different subpopulations.