The prevention of vasovagal reactions (VVR) occurring during or after donation is a major issue for the French Blood Establishment (EFS), firstly to guarantee the safety of donors but also to retain them, as this reaction is one of the negative experiences affecting the return to donation.

The EVASION study conducted in the Auvergne Rhône-Alpes region (AURA) on 4828 donors representative of the French donor population, reported a beneficial effect of muscle contraction exercises to prevent the occurrence of VVR during donation, while hydric solutions, and even more so isotonic solutions, were likely to decrease the frequency of delayed VVR.

These preventive measures have been integrated into the internal guidelines and currently include muscular and breathing exercises and hydration. Nevertheless, the isotonic solution could not be routinely deployed for feasibility and cost reasons. A salty snack could replace the isotonic solution to produce the same effects with better feasibility and acceptability. Furthermore, a significant proportion of discomfort is psychological in origin, related to stress and anxiety which persist despite these measures, particularly in the first-time donor population.

These measures, which are mainly focused on the prevention of VVR of physiological origin, are still insufficient and can be optimized and complemented to reduce the occurrence of VVR, especially in first-time donors for whom anxiety and stress play an important role in the etiology of VVR.

Two measures could further reduce the occurrence of VVR:

• Reinforcement of the physiological strategy: ingestion of a salty snack before donation, the effect of which could be similar to the effect of the isotonic solution, which could not be delivered in practice because of its cost following the data of the EVASION study.
• Addition of a psychological strategy: flyer given at the interview presenting the four most frequent fears as well as a description of the recommended muscular and respiratory exercises, followed by the execution of the recommended exercises before the sampling.

Hypothesis is that the combination of a psychological and physiological strategies would allow a reduction of the occurrence of immediate and/or 48 h delayed VVR during the whole blood donation in first time donors compared to the current practices.

Inclusion Criteria:

• M/F between 18 and 70 years old,
• A first-time donor who wishes to donate blood in Lyon, either at a fixed site or at a mobile unit,
• Declared fit to donate whole blood after the EFS pre-donation interview,
• Weight ≥ 50kg and height ≥ 135 cm,
• Available for telephone contact between to 5d +/- 2 days after donation,
• Having signed a written consent to participate in the study.

Non-inclusion criteria:

• Known allergy to shellfish, and/or gluten, and/or milk, and/or soy,
• Incomprehension of the French language,
• First-time donor under protective measures (guardian, curator) or any other administrative measure,
• Not affiliated to the French social security system or any other equivalent system,
• Pregnant or breastfeeding woman,
• Subject participating in any other interventional or non-interventional research

Exclusion Criteria:

• Withdrawal of consent
• First-time donor with anemia following routine hemoglobin testing
• First-time donor not reachable for telephone interview