Collection of peripheral blood progenitor cells from small pediatric patients provides many social and technical challenges not faced when collecting from adult patients. This paper provides a single institutions experience with 85 collections from 14 patients less than 25 kg of weight over a 2 year period. Specific challenges include obtaining venous access, anticoagulation, volume shifts, and obtaining patient cooperation. A systematic analysts of options for access, alternative modes of anticoagulation, and the effect of large ratios of extra‐corporeal volume to patient's blood volume are discussed. Access uniformly required central venous catheters (CVC) ranging from 7–10 Fr Anticoagulation included systemic heparmization titrating dose by activated clotting time in all cases and combined with nitrate at a ratio of 1:25 · 1:30 in most cases. Collections were performed on a COBE. Spectra, after priming with leukoreduced irradiated red cells and omitting both the initial 120cc diversion and rinse back of red cells at the end Social challenges include issues of assent and ability to distract patients for the duration of a prolonged collection. Progenitor yields from collections from 14 patients were quantitiated by CD34+ assay in all cases and C???GM in ten of 14 patients. A median of 4.5 + 106/kg CD34+ cells were obtained for each collection. Complications, including those related to catheter access are enumerated. In summary, large volume peripheral blood progenitor collection can be safely and efficaciously performed in small pediatric patients. © 1996 Wiley‐Liss, Inc.

In larger (older) patients, from whom fewer blood volumes were collected, there is a trend toward intra-apheresis recruitment, although less than reported previously. In the smaller (younger) patients, from whom more blood volumes were collected, no trend was observed. Lack of (or submaximal) prior mobilization in previously reported studies may have facilitated intracollection recruitment. Alternatively, the larger number of blood volumes collected from the smaller (younger) patients may have masked intra-apheresis recruitment. The study documents the feasibility of large-volume, 4-hour leukapheresis in pediatric patients.

Eight pediatric patients with fulminant meningococcemia, purpura, and disseminated intravascular cogulation who by multiple prognostic scoring systems were anticipated to have a poor outcome underwent intensive plasma exchange (IPE) or whole blood exchange (WBE) in addition to standard medical therapy. IPE/WBE was initiated shortly after admission with a mixture of both fresh frozen plasma and cryoprecipitate as the replacement solution. All IPE procedures were performed using a continuous flow system and a red cell prime. The mean fibrinogen level increased from 62 to 192 mg/dl, the prothrombin time (PT) decreased from a mean of 32.4 seconds to 15.1 seconds, and the mean activated partial thromboplastin time (APTT) decreased from 89.5 seconds to 40.1 seconds following completion of the initial IPE/WBE. There was a corresponding improvement in all coagulation factor levels but only slight improvement in antithrombin III (ATIII) and protein C levels. Seven of eight patients survived (87.5%) their initial presentation with the sole early death attributed to meningitis with cerebral edema. Mean fluid balance after the procedure was +10.8 +/- 5.87 cc/kg. There were no significant bleeding or cardiovascular complications during the procedure. There was no clinical or radiographic evidence of fluid overload after the procedure. This experience demonstrates that IPE/WBE may be conducted safely in critically ill, unstable pediatric patients and is effective in rapidly improving coagulopathy without fluid overload.

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