SAN DIEGO (FRONTLINE MEDICAL NEWS)The rate of citrate reactions was nearly 7% in over 80,000 apheresis procedures involving nearly 15,000 donors, and risk increased with the level of citrate exposure, based on data presented from Héma-Québec, Montreal, presented at the annual meeting of the American Association of Blood Banks.

Vasovagal reactions were seen in 2.5% of procedures, and reactions with loss of consciousness occurred in 0.1%, reported Pierre Robillard, MD, of McGill University and Héma-Québec.

The fairly high rates of adverse reactions speak to the importance of taking preventive measures in donors undergoing apheresis, he said. Hypocalcemia and other citrate-induced abnormalities can affect neuromuscular and cardiac function. Most reactions are mild dysesthesias, but tetany, seizures, and cardiac arrhythmias can occur. Prophylactic oral or intravenous calcium supplements can correct decreased ionized calcium levels and manage the symptoms of hypocalcemia, which are especially likely in procedures involving platelet collection.

Donor exposure to citrate can vary depending on the type and length of the specific apheresis procedure as well as the type of system used, he said. The risk for vasovagal reactions also varies with the type of procedure performed and the use of volume replacement.

Dr. Robillard and his colleagues examined the severity of all cases of donor complications reported to Héma-Québec, beginning in October 2015. A Trima Accel system by Terumo BCT was used for single and double red blood cell collection, single and double platelets, platelets plus plasma, platelets plus red blood cells, platelets plus red blood cells plus plasma, double platelets plus red blood cells, and double platelets plus plasma. Plasma for fractionation was collected with a PCS®2 Plasma Collection System by Haemonetics.

During the study period, 80,409 apheresis procedures were conducted, involving 14,742 donors. Within this cohort, 5,447 (6.8%) had citrate reactions; 2,006 (2.5%) had vasovagal reactions without loss of consciousness, and 77 (0.1%) had vasovagal reactions with loss of consciousness.

Three quarters of the donors (74%) were male, and rates of citrate reactions were higher in men than in women (7% vs. 6%, P less than .001). There was a linear association between level of citrate exposure and citrate reactions rates (P less than .001).

“Vasovagal reactions were four times higher for female donors than for males, with or without loss of consciousness, and this difference was statistically significant,” said Dr. Robillard. Vasovagal reactions were higher in first-time donors.

The rate of vasovagal reactions without loss of consciousness was 6.2% in women and 1.6% in men, (P less than .001). Vasovagal reactions with loss of consciousness affected 0.22% of women and 0.06% of men (P less than .001).

The rates of citrate reactions were similar at all ages, but the rates of vasovagal reactions declined with age; the rates were 6.1% in patients aged 18-22 years and 1% among those over age 70.