Effective peripheral blood stem cell collection in a 4.6-kg child
Jennifer M Jones1,2, Joseph E Kiss2,3, Irina Chibisov1,2
1Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA.
Insights
Peripheral blood stem cell (PBSC) collection is challenging in children under 5kg. This study adapted protocols, successfully collecting stem cells in a 4.6kg child, demonstrating feasibility and safety in this low-weight population.
Area of Science:
- Hematology
- Pediatric Oncology
- Apheresis Medicine
Background:
- Effective peripheral blood stem cell (PBSC) collection presents unique challenges in pediatric patients weighing less than 5kg.
- Previous reports on successful PBSC collection in this low-weight demographic are inconsistent.
- This case study details PBSC procedures in a 4.6kg child undergoing myeloablative chemotherapy for high-grade glioma.
Observation:
- A multidisciplinary team adapted existing PBSC protocols to meet the specific needs of a small pediatric patient.
- Key adaptations included optimizing the timing of collection relative to chemotherapy, securing appropriate vascular access, and implementing strategies for monitoring and managing adverse events.
- Initial attempts at collection were suboptimal due to clotting, necessitating adjustments to the anticoagulant (AC) ratio and infusion rate.
Findings:
- Modified protocols, including a reduced AC ratio (8:1) and adjusted AC infusion rates (1.5-1.7 mL/min/L total blood volume), improved collection efficiency over three procedures.
- Increased acid-citrate-dextrose exposure was managed with continuous calcium chloride infusion, preventing hypocalcemia, hypotension, or patient distress.
- The procedures successfully collected 15 × 10^6 CD34+ cells/kg, meeting collection targets for the pediatric patient.
Implications:
- This retrospective review demonstrates that peripheral blood stem cell collection can be safely and effectively performed in pediatric patients weighing less than 5kg.
- The findings support the adaptation of apheresis protocols for successful stem cell collection in extremely low-weight pediatric oncology patients.
- This work provides valuable insights for clinicians managing pediatric patients requiring hematopoietic stem cell transplantation.
Background:
Due to unique technical challenges, effective peripheral blood stem cell collections (PBSCs) have not been consistently reported in patients weighing less than 5 kg. We describe three PBSCs performed in a 4.6-kg child undergoing myeloablative chemotherapy for high-grade glioma.
Study Design And Methods:
A multidisciplinary group representing the clinical and apheresis teams adapted a PBSC protocol to accommodate the patient's size and collection targets. Special considerations included timing of the collection relative to chemotherapy, vascular access, strategies for monitoring adverse events during collection, and contingencies.
Results And Discussion:
The patient underwent three PBSC procedures over 2 days due to suboptimal collection after the first two procedures. For procedure 1, a conservative inlet: anticoagulant (AC) ratio and AC infusion rate of 15 and 0.6 mL/min/L total blood volume (TBV) resulted in premature discontinuation due to clotting. A ratio of 8 and AC infusion rate of 1.5-1.7 mL/min/L TBV with subsequent titration to higher levels were adopted for the second and third procedures. These changes resulted in greater acid-citrate-dextrose exposure, that was managed by continuous calcium chloride infusion. There was no hypocalcemia, hypotension, or distress during any procedure. A total of 15 × 106 CD34+ cells/kg were collected. This retrospective review illustrates that PBSC can be safely undertaken in children weighing less than 5 kg.
