Manager Children's Hospital Los Angeles Glendale, California, United States
Background/Case Studies: Extracorporeal photopheresis (ECP) is an established immunomodulatory therapy, increasingly utilized in pediatric patients with graft-versus-host disease (GVHD). However, ECP presents unique challenges in low-weight patients due to the high extracorporeal volume (ECV) required during procedures. In patients weighing less than 20 kg, significant hemodynamic instability may occur without appropriate volume management. Reported adverse reaction rates for pediatric therapeutic apheresis procedures, including ECP, range from 4% to 55%, whereas adult rates range from 4% to 28%. At Children’s Hospital Los Angeles, we developed and implemented a modified blood prime protocol to enable safe and effective ECP treatment in this vulnerable patient population.
Study
Design/Methods: All patients included in this study were undergoing ECP for treatment of GVHD and weighed between 9 kg and 18 kg. A modified blood prime protocol was used in each procedure to mitigate the impact of ECV. Specifically, 100 mL of 0.9% normal saline was added to a 200–250 mL unit of whole blood to create a diluted prime. This modified prime was then used to initiate the ECP circuit prior to connection with the patient.
Results/Findings: A total of 98 ECP procedures were performed across four patients. Three mild to moderate adverse reactions (overall rate: 3.1%) were recorded:
Vasovagal reaction (n=1)
Hypotensive episode (n=1)
Hypertensive episode (n=1)
Importantly, none of the reactions led to early termination of therapy, and all procedures were successfully completed. No patients required escalation of care due to adverse events.
Conclusions: ECP can be performed safely in pediatric patients weighing less than 20 kg using a modified blood prime approach. The observed adverse reaction rate of 3.1% is on the lower end of published rates for pediatric therapeutic apheresis. These data suggest that a carefully designed prime protocol can reduce risks associated with large ECV while maintaining the therapeutic benefit of ECP in this population.
