The effect of water drinking before blood donation in practice to reduce vasovagal syncope

Abstract

Background : The incidence of vasovagal syncope at mobile blood donation in Chanthaburi Province was 6.56 percent. Several reports showed that 400-500 ml of water drinking could prevent vasovagal reaction. But in real life most of the donors cannot tolerate drinking water 400-500 ml in half an hour.
Objectives : To evaluate the effectiveness of 250 mL water ingestion before blood donation in preventing the vasovagal syncope.
Study design and Methods: The intervention was implemented in October 2008. All donors have to drink a glass of water (250 ml) half an hour before donation. The incidences of vasovagal syncope during April 2007 to September 2008 were calculated in attribute Proportion (P) control chart as set-up data. Then the subsequent data were plotted in this control chart to detect for the special cause variation. To demonstrate the efficacy of the intervention, three patterns of special cause variations were used as indication of statistical significance.
Results : There were 1,518 episodes of vasovagal syncope in 30,195 donations from April 2007 to September 2008 (before the intervention) and 985 episodes in 41,963 donations from October 2008 to September 2010 (after the intervention). The control