Optimization of single-needle red cell exchange in patients with sickle cell disease.

The hypercoagulable state associated with sickle cell disease (SCD) can be challenging for apheresis procedures. Among 62 single-needle red cell exchanges (SN-RCEs) performed over a 15-month period, 4 patients experienced 6 hemolytic events with a discolored plasma layer, elevated plasma/RBC interface in the centrifuge, and accompanying alarms of "Cells were detected in plasma line from centrifuge" or "AIM system detected RBC at top of connector." The hemolysis originated from the apheresis instrument because samples from the apheresis belt but not the patients' peripheral blood were positive for hemolysis. Further analysis showed the alarms occurred more often in SN-RCEs (20.4%) than double-needle RCEs (2.7%), and the hemolysis was probably secondary to clumping. To optimize SN-RCE, we increased the anticoagulant dosage by changing Inlet/AC ratio from 13 to 8 and lowered the inlet rate to the level comparable to double-needle RCE. The adjustments were well-tolerated with no more hemolysis.

Contribution of donor- and recipient-associated factors to allergic transfusion reactions to platelets.

BACKGROUND: Pediatric hematology-oncology patients require frequent platelet transfusions to manage chemotherapy-induced thrombocytopenia, and allergic transfusion reactions (ATRs) are common. Risk for platelet-associated ATRs can result from recipient- or donor-specific factors. STUDY DESIGN AND METHODS: We report a rare case in which an individual platelet donor caused repeated ATRs in multiple recipients. This observation led us to conduct a retrospective study at a pediatric hematology-oncology center to identify donor- and recipient-associated risk factors for ATRs. RESULTS: Single-donor platelets from an individual donor precipitated ATRs in 78.6% (n = 11/14) of recipients and 66.7% (n = 12/18) of platelet transfusions. We found in a cohort of pediatric hematology-oncology patients that 12.6% of recipients and 1.0% of platelet transfusions were associated with ATRs. Recipients who were aged 4 to 18 years, male, and those with central nervous system or solid tumors and with a history of ATRs to platelets were more likely to experience ATRs. Donor-associated risk factors were not identified, and we did not implicate additional donors in our single-center cohort with a frequency of ATRs comparable to the index donor. Based on our findings, we developed a novel statistical model to identify recipients and donors prone to experiencing or mediating ATRs. CONCLUSIONS: Both donors and recipients contribute to ATRs. Identification of high-risk donors and recipients for further scrutiny and potential interventions can improve the safety of platelet transfusions.