Detection and classification of gaseous microemboli during pulsatile and nonpulsatile perfusion in a simulated neonatal CPB model

We compared the effects of perfusion modes (pulsatile vs. nonpulsatile) on gaseous microemboli delivery using the Emboli Detection and Classification (EDAC™) Quantifier at postpump, postoxygenator, and postarterial filter sites in a simulated pediatric cardiopulmonary bypass (CPB) model. The mock loop was subjected to five different pump flow rates of equal 100 ml/min intervals, ranging from 400 to 800 ml/min. When the target pump flow rate was achieved, 5 cc air was introduced into the venous line. The EDAC™ system recorded gaseous microemboli counts simultaneously at three locations in 5-minute intervals. Regardless of the type of perfusion mode, when the pump flow rate was increased, more gaseous microemboli were generated at postpump site. Compared with nonpulsatile flow, pulsatile flow did deliver significantly more gaseous microemboli at postpump site, but there was no difference between two groups at postoxygenator and postarterial filter sites. Capiox Baby-RX hollow-fiber membrane oxygenator significantly reduced the gaseous microemboli counts in both groups at all five pump flow rates with either pulsatile flow or nonpulsatile flow in this model. Our results suggest that using this novel EDAC™ system, we could detect the size of gaseous microemboli, as small as 10 μm, and the percentage of detected gaseous microemboli, <40 μm, was about 90% in total gaseous microemboli counts at any flow rate with pulsatile or nonpulsatile flow.