expected based on the number of platelets collected [78] because platelets are mobilized during the apheresis procedure [79].
A platelet count is not necessary before the initial donation because the decrease in platelet count following donation is not so extensive as to create a risk for the donor. At least 48 hours must elapse between platelet donations. If donors are to donate more frequently than every 4 weeks, a platelet count must be done to ensure that it is at least 150,000/μL before a subsequent donation. The platelet count can be obtained before the donation, or a count obtained after a previous donation can be used. Platelet donors should not have taken aspirin or drugs that interfere with platelet function, or must wait the specified time interval for that drug before donating (e.g., 3‐day waiting period for aspirin).
Red cell loss
Collection of platelets, granulocytes, lymphocytes, or stem cells by cytapheresis results in very little red cell loss. Thus, red cell depletion is not considered a possible complication of any individual collection unless there is an instrument malfunction. However, because apheresis collections can occur with high frequency (e.g., 24 plateletpheresis collections in 12 months), cumulative red cell loss from test sampling can cause anemia and low ferritin stores [80].
Blood volume shifts
Because no more than 15% of the donor’s blood is extracorporeal at any time, there is no greater risk for blood volume shift than with whole blood donation. In addition, during apheresis, citrate and saline solutions are infused, replacing some of the lost blood volume. Thus, shifts in blood volume leading to hypotension are not a problem. Because of the administration of hydroxyethyl starch (HES) during leukapheresis as sedimenting agent, there was concern that a net increase in blood volume might occur because HES is also used as a blood volume expander. This could lead to hypertension or acute heart failure. The volume of HES administered ranges typically from 200 to 400 mL and, combined with the removal of approximately 50–200 mL of granulocyte concentrate, does not result in complications caused by excess blood volume.
Potential complications of serial donations
Because cytapheresis donors can donate more often than whole blood donors, there are some complications that could result from multiple frequent donations. These involve depletion of cells or plasma proteins.
Platelet depletion
Platelet depletion is a concern if donors undergo frequent plateletpheresis during a short period, although this was not observed in 352 donors who donated an average of six times [77].
Leukapheresis donors
Because the HES used in granulocyte collection is a blood volume expander, some blood banks use lower blood pressure levels than those used for whole blood donors when selecting granulocyte donors. This is not a requirement, however. Granulocyte donors usually receive corticosteroids, and many also receive granulocyte colony‐stimulating factor (G‐CSF) to increase their granulocyte count and the granulocyte yield (see Chapter 6). Thus, donors should be questioned about conditions that might be exacerbated by corticosteroids. These include hypertension, peptic ulcers, cataracts, and diabetes. Because corticosteroids are given to granulocyte donors, donation frequency is limited to prevent complications. If frequent donation is required, it needs to be under the close supervision of a physician with written plans for monitoring the donor for side effects of accumulation of HES or cumulative effects of corticosteroids and/or G‐CSF.
Plasmapheresis donors
If plasma is donated no more than every 4 weeks (infrequent donor), the donor assessment procedures are the same as for whole blood. The FDA limitations for plasma removal are no more than 800 mL of plasma at one donation depending on the donor’s weight. These volumes may be slightly different when semiautomated instruments are used. Donors may give again in 48 hours as for platelets, but not more than twice within a 7‐day period. For donors undergoing plasmapheresis more often than once every 4 weeks (frequent donor), the serum protein must be monitored and found to be within normal limits.
Allogeneic donors for hematopoietic cell transplantation
Hematopoietic cell transplantation now uses a variety of donors, such as unrelated marrow, peripheral blood stem cells (PBSCs), or cord blood. Transfusion medicine physicians are involved in this donor selection process. The criteria for whole blood and apheresis donation serve as the basis for donor selection, but these criteria may be modified because the advantage of a particular donor may outweigh a very small or theoretical increased risk of the cellular product. Criteria intended to protect the donor are less likely to be modified, but as new donation situations, such an unrelated marrow or cord blood, have arisen, donor selection criteria for each situation were developed.
Physical examination of apheresis donors
The physical examination of cytapheresis donors is the same as for whole blood donation.
4.7 Adverse reactions in apheresis donors
General
Adverse reactions in apheresis donors (Table 4.5) are similar in character to those encountered in whole blood donation. Although double red cell collections by cytapheresis are now common, most cytapheresis procedures carried out in normal donors are plateletpheresis. Because the required interval between double red cell donation is proportionally increased, the long‐term potential for anemia/ferritin deficiency is probably similar to whole blood donation, although acute changes with each donation are greater. Normal donors undergoing plateletpheresis may report an adverse reaction following up to 50% of procedures when asked; however, such reactions cause the procedure to be discontinued only 0.1–1.0% of the time [81]. These reactions are almost entirely due to citrate toxicity and can be alleviated by slowing the rate of blood return and thus the rate of citrate infusion.
Some potential complications of apheresis apply to all types of procedures because they have to do with the instrument or activities that are common to all types of procedures, while others are unique to certain apheresis procedures [81–83].
Vasovagal reactions
Vasovagal reactions are similar to those associated with whole blood donation, but may be reduced depending on the amount of volume replacement with the method. The symptoms include weakness, pallor, diaphoresis, bradycardia, cold clammy skin, lightheadedness or fainting, and, if severe, convulsions. The treatment is as described for whole blood donors. Because the donors are usually experienced whole blood donors, they rarely experience vasovagal reactions.
Table 4.5 Potential complications and adverse reactions to cytapheresis donation.
| Reactions similar to whole blood donation |
| Citrate toxicity |
| Hematoma caused by reinfusion of red blood cells via pump |
| Mechanical hemolysis |
| Air embolus |
| Platelet depletion |
| Lymphocyte depletion |
| Plasma protein depletion |
Anticoagulation
The anticoagulant used for plateletpheresis is citrate. Cardiac toxicity caused by calcium binding can occur