Vasovagal reaction among whole blood donors in Hospital Pulau Pinang. A statistical-epidemiological study.

CONTEXT: Whole blood donation is generally considered a safe procedure; however, a small percentage of donors could develop vasovagal reactions (VVRs) during or after completion of blood donation.

AIMS: This study was undertaken to establish the prevalence of VVR among whole blood donors in Hospital Pulau Pinang and to investigate factors that lead to its occurrence.

SETTINGS AND DESIGN: A cross-sectional study was conducted involving 27,890 whole blood donations in 2016.

SUBJECTS AND METHODS: For each donation, donor's demographic and blood donation-related information was extracted from the blood bank database.

STATISTICAL ANALYSIS USED: Qualitative data including age group, sex, race, frequency, and location of donation were analyzed using Chi-square tests, while blood pressure was analyzed using t -test.

RESULTS: Overall, 425 cases of VVRs were reported, resulting in a VVR rate of 1.5% (one event in every 65 donations). We found a statistically significant association ( P < 0.05) between the occurrence of VVRs with the young age group, female gender, Indian race, first-time donor, lower predonation blood pressure, and donation performed in a mobile donation campaign. The most common vasovagal symptoms are lightheadedness (88%), followed by nausea (5.4%), muscle twitching (3.5%), vomiting (1.4%), loss of consciousness <30 s (1.4%), and paresthesia (0.2%).

CONCLUSIONS: The prevalence of VVRs among whole blood donors in Hospital Pulau Pinang appeared to be low. Our study reaffirms that blood donation is a relatively safe process, and the incidence of VVR can be further reduced by ensuring strict screening procedure before blood donation.