Background Information and justification
Platelet apheresis is a method of collecting platelets performed by a device which separate platelets and return the rest of blood to the donor in a safely manner. Donor should be connected to the apheresis machine through the sterile tubing system with the help of a large bore needle. After removing blood from the donor using a large bore needle, a measured amount of anticoagulant (Citrate) is mixed to prevent the coagulation. Then it is transferred to the place where the separation is taken place, either the centrifugation bowl, chamber or belt. The same principle is applied in apheresis as for the blood component preparation by the whole blood. Based on specific gravity and the weight of the constituents’ separation of blood components is done. While the platelets are diverted to the temporary storage remaining elements are returned to the donor by intermittent or continuous flow. (Modern332)
Although platelet aphaeresis procedures are well tolerated than whole blood donations significant level of adverse events (AEs) occur during and after the procedure. Those AEs can be severe in apheresis procedures but are less often with comparison to the whole blood donations. AEs to apheresis procedures can be categorized as systemic or local.
Citrate toxicity is known to be the most frequent systemic reaction in apheresis occurs as a result of the anticoagulant acid- citrate-dextrose. Chelation of calcium ions by citrate causes hypocalcaemia which can be presented as per oral tingling and parasthesia, chills, nausea, twitching, tremors or severe symptoms like carpopedal spasms, seizures, tetany and cardiac arrhythmias. Vaso vagal reaction can be triggered by the anxiety and tension for the undergoing procedure or due to the pain causes by the venepuncture. It is characterized by the pallor, sweating, dizziness, nausea, hypotension and syncope.
Local reactions include hematomas, brusing and phlebitis as a result of defective venepuncture and irritation or allergy to needles.
Adverse effects due to platelet apheresis are mostly under reported. This is mainly due to the high tolerance of the regular platelet apheresis donors. Being most frequent adverse effect of platelet apheresis citrate toxicity is highly under reported as the mild symptoms such as peri oral tingling and parasthesia are well tolerated and not complained by the donors. Therefore addressing and reporting of each and every adverse event lies a greater importance in ensuring the donor safety and stabilizing the donor pool.
No study has yet been carried out in Sri Lanka in relevant to adverse effects in platelet apheresis. The scarcity of studies done elsewhere in the world, demands for more research as to improve the donor safety and to promote apheresis procedures.
· To assess the frequency of adverse events due to platelet apheresis donations
· To evaluate donor variables as potential risk factors for different types adverse events (AEs) during apheresis collections
· To assess the knowledge and attitude on adverse effects of apheresis procedures in platelet apheresis donors
· To identify the frequency of underreported adverse events as a result of the tolerance by the donors