Side effects of blood donation by apheresis

Apheresis is a method of obtaining one ore more blood components by machine processing of whole blood in which the residual components are returned to the donor or patient during or at the end of the process. To prevent clotting, immediately next to the needle, the donor’s/patient’s whole blood is mixed with an anticoagulant solution (usually trisodium citrate) in a specific whole blood to anticoagulant ratio. For apheresis techniques, specially developed machines which are classified as medical devices are used. Special disposables are available for each type of apheresis and each type of machine. The sterile disposable, incorporating collection bags, bacterial and/or separation filters and/or centrifuge chambers, etc., is placed in the machine. The disposable is classed as an open or closed system. To separate the requested blood component from the nonrequested components various techniques can be used, such as filtrationor centrifugation techniques, or a combination of both. Besides these two techniques, also elutriation and absorption techniques are applied. The apheresis procedure can be performed using a continuous flow technique or a discontinuous flow technique. In continuous flow techniques the blood is drawn, processed and returned at the same time. Two venipunctures are needed. In discontinuous flow techniques only one venipuncture is needed. Modern apheresis machines are computer-controlled devices with multiple safety features for both the donor/patient and collected product. Examples are monitoring the pressure in the draw/return line to the donor/patient during draw and return phase. If the pressure exceeds predetermined values set by the manufacturer the process stops and sounds an alarm. This prevents a too low or too high pressure in the vein of the donor. With many machines with the same sensors the pressure in the disposable, and therefore the possibility for wrong installation of the disposable on the machine or leakage of the disposable is monitored. Other sensors (with or without combination of cameras) take care of the collection of the intended blood components. Also one or more air detectors are included in the apheresis equipment. If a sensor detects air in the tubing the procedure stops and an alarm will sound. This prevents any risk of air entering the donor’s vein. The volume of donor blood processed and collected by the machine is accurately monitored. In procedures where the donor’s/patient’s height and weight are entered into the machine’s software, the donor is protected by the apheresis machine from removal of more than 15% of the donor’s total blood volume. The volume of anticoagulant during an apheresis procedure added to the donor blood is closely monitored. Fluid leakage in a centrifuge chamber is detected by sensors. If leakage occurs the process stops and an alarm sounds. S7 Side effects of blood donation by apheresis M. Neyrinck, H. Vrielink. AZ Delta hospital, Roeselare, Belgium; Sanquin Blood supply, Amsterdam, The Netherlands