Effective peripheral blood stem cell collection in a 4.6-kg child

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.