Microemboli generation, detection and characterization during CPB procedures in neonates, infants, and small children.

In our laboratory, we study different factors that influence the microemboli counts in the extracorporeal circuit using a simulated pediatric cardiopulmonary bypass (CPB) model identical to the one used in our operating rooms. For monitoring and classification of microemboli, we use the novel Emboli Detection and Classification (EDAC) Quantifier system which allows for real-time monitoring, localization, and size characterization of microemboli as small as 10 microm. Our results show that high flow rates, low perfusate temperature, use of vacuum assisted venous drainage (VAVD), use of roller pump, and pulsatile flow results in higher microemboli counts at postpump site. Microemboli counts at postoxygenator, and postfilter sites are significantly less. This indicates that hollow fiber membrane oxygenator was able to remove most of the microemboli, and an opened arterial filter purge line augments the removal of microemboli that were not captured by the oxygenator. Majority of the microemboli detected at all sites were <40 microm in size. Based on the results of our studies, we started using the EDAC Quantifier system in our operating rooms at Penn State Hershey Children's Hospital. More basic science studies and clinical outcome data are needed for further study in minimizing the adverse effects of pediatric CPB procedure.