Volunteer donor apheresis

Assessing the performance of a plateletpheresis unit at a tertiary-care academic medical center in Mexico: A 6-year experience

BACKGROUND

Optimization of platelet (PLT) apheresis collection is a priority to satisfy the increasing demand of hemato-oncology patients. We assessed the performance of a plateletpheresis unit supporting hematology patients.

STUDY DESIGN AND METHODS

This descriptive retrospective study included 561 plateletpheresis collections from 2013 to 2018. For data analysis, descriptive statistics and receiver operating characteristic (ROC) curve were used. A 5-item satisfaction questionnaire was analyzed.

RESULTS

Ninety percent of the donors were males. The median plateletpheresis time was 89 minutes; its success rate was 92.5%; median donor PLT count was 232 × 10⁹ /L, women median PLT count was 247 × 10⁹ /L vs 231x10⁹ /L in men (P = .017). Seventy-seven percent donors were candidates for a double product and 24.5% were processed; 20.8% of these donors had a weight ≤75 and 79.2% >75 kg, P = .003, and 6.6% were women and 93.4% men, P = .161. Thirty-six of donors had ≥250 × 10⁹ /L and 16.8% was processed as a triple product. ROC analysis showed that with donor PLT counts ≥200 × 10⁹ /L the sensitivity for obtaining double products was 0.981 and specificity 0.714, with an area under the curve (AUC) = 0.877. The adverse effect rate was 4.3%. Of the potential donors, 6.3% were rejected. The cost of processing single or double products was 430 USD. Comfort and time spent during plateletpheresis were areas for improvement.

CONCLUSION

Platelet count and donor weight predicted PLT yield and obtaining double products. Women had higher PLT counts, but no significant difference was found between donor gender and processed products. Assessment of the apheresis unit can help to improve its performance.

Preparation of highly concentrated and white cell-poor platelet-rich plasma by plateletpheresis

BACKGROUND AND OBJECTIVES

Contaminating white blood cells (WBC) contribute remarkably to the overall growth factor content of locally applicable platelet-rich plasma (PRP) or platelet (PLT) gel and change the relative proportions of the contained growth factors.

MATERIALS AND METHODS

To study the independent effects of locally applicated highly concentrated PLTs, the development of preparations is needed that contain large amounts of PLTs and no or at least very few leucocytes. Therefore, 20 plateletpheresis procedures were performed in voluntary blood donors to get highly concentrated and extremely WBC-poor plateletpheresis concentrates. The degree of spontaneous PLT activation, the PLT aggregation response to agonists and the level of the growth factor TGF-beta1 (transforming growth factor beta1) were measured immediately after the donation and 1 day later.

RESULTS

The concentrates contained 1.96 +/- 0.36 x 10e11 PLTs per unit in 55.2 +/- 7.9 ml, respectively. In comparison to the donors' blood, the PLT-enrichment factor was 15.3 +/- 5.4. At the same time, the concentrates contained extremely low residual numbers of WBCs (0.8 +/- 3.3 x 10e3/ml). The concentration of the growth factor TGF-beta1 was 743.2 +/- 243.9 ng/ml. On day 1, the PLT concentration and the TGF-beta1 content of the PLT concentrates had not decreased.

CONCLUSIONS

In summary, plateletpheresis is suited to provide PRP products with higher concentrations of human platelets and platelet-derived growth factors than previously reported PRP preparation methods but with extremely low numbers of contaminating leucocytes.

Blood volume regulation in donors undergoing intermittent-flow plasmapheresis involving a high extracorporeal blood volume

BACKGROUND

Intermittent-flow plasmapheresis (IFP) often involves a large extracorporeal blood volume (ECV) of donors during donation. Depending on equipment and donor characteristics, ECV can exceed 20 percent of a donor's blood volume (BV). It was the aim of this study to delineate mechanisms of BV regulation associated with these volume shifts.

STUDY DESIGN AND METHODS

Parameters of BV regulation were recorded in 60 donors (30 men, 30 women) undergoing IFP, who were randomly selected after stratification for sex and BV. Shock index (SI), stroke volume (SV), cardiac index (CI), and thoracic fluid content (TFC) were determined at the beginning of the procedure and when maximum ECV (ECV(max)) was reached with noninvasive techniques. In a control investigation, donors were kept in reclined position for the duration of an IFP session without actually donating.

RESULTS

SI increased significantly during IFP (+0.18; p < 0.0001). SV decreased significantly (-14.3 mL/stroke; p < 0.0001). CI did not decrease significantly (-0.07 L/min/m(2) body surface area; p = 0.33). Preservation of CI was due to a significant rise in heart rate (+13.4 beats/min; p < 0.0001). TFC decreased significantly during IFP (-0.77 kOmega(-1); p < 0.0001), indicating the development of an intravascular volume deficit. The changes of SI, heart rate, and TFC weakly correlated with ECV(max).

CONCLUSION

The hemodynamic response during IFP is consistent with a hypovolemic challenge of the donors and is sufficient to maintain cardiac function. ECV(max) during donation does not reliably predict the degree of hypovolemic stress, as long as it remains below 20 percent. This might warrant reevaluation of collection limits based on ECV(max).

Plateletpheresis does not cause long-standing platelet-derived growth factor release into the donor blood

BACKGROUND

Recently, long-standing elevations of soluble growth factors released from platelets (PLTs) after contact with artificial surfaces during dialysis were described. They could be jointly responsible for the high frequency of death from cardiovascular diseases in dialysis patients. There are no comparable data on the extent and the duration of a growth factor release by plateletpheresis procedures.

STUDY DESIGN AND METHODS

A total of 37 plateletpheresis procedures were performed with two different devices. PLT-derived growth factor (PDGF) isoform AB, transforming growth factor (TGF)-beta1, and beta-thromboglobulin (beta-TG) were measured in the donors' plasma samples, and PLT activation and function were measured by cytometry and aggregometry before and after plateletpheresis and 1 and 24 hours later.

RESULTS

Before apheresis, the following mean plasma levels were found: beta-TG, 98.6 +/- 37.3 IU per mL; PDGF-AB, 71.5 +/- 38.5 pg per mL; and TGF-beta1, 2.24 +/- 0.80 ng per mL. At the end of the apheresis procedures, the mean PDGF-AB level had increased by a factor of 1.8 (p < 0.05). One hour later, the mean PDGF-AB level had normalized again. No significant change in the levels of beta-TG and TGF-beta1 was found by the apheresis procedures. There was no influence of the blood cell separator type on the results.

CONCLUSION

Only a slight and rapidly reversible increase in soluble PDGF-AB was found during plateletpheresis and no increase in soluble TGF-beta1 and beta-TG was found. This change should not be harmful to the donor.

Multicomponent Donor Apheresis in the Americas

Multicomponent donor apheresis utilizes apheresis technology to collect combinations of red blood cells, platelets and plasma units. The United States has embraced this technology to the greatest extent of the countries in the Americas. As whole blood and apheresis collection have increased, so have the donor deferrals based on potential exposure to infectious agents. However, hemoglobin/hematocrit deferrals still remain the largest upfront deferral for volunteer donors. As the technology is refined in future years, multicomponent donor apheresis may become the predominant method of collecting blood products from donors.

Can better information increase hemapheresis?

We created a questionnaire in order to understand why donors generally did not want to give plasma and platelets the first time they were asked to donate. The hypothesis is that donors have a negative perception of hemapheresis due to insufficient information about procedures and emocomponent use. We collected 745 Questionnaires in the Marche and Abruzzo regions from February to April 2001. Results show that donors have an unfavourable perception of the hemapheresis compared to blood donation. We found differences in donors' perception between all kinds of donations regarding these aspects: (1) information about donation procedures, (2) awareness of emocomponent use, (3) importance of different kinds of donation, (4) availability of donors in relation to length of donations, (5) level of safety (regarding the possibility to contracting some viruses and also regarding possible immediate side-effects), (6) level of importance for saving lives. A key factor in determining an unfavourable perception of hemapheresis is the information level; in fact we found by linear regression that the information level affects the perception of safety and donation importance. These differences of perception show that there are prejudices about hemapheresis which are caused by a lack of Information. So we are convinced, also by statistical analysis, that better information is the most effective way to increase hemapheresis.