A centrifugal pump driven tidal flow extracorporeal membrane oxygenation system tested with neonatal mock circulation

In 1993, Chevalier published his experiences with tidal flow venovenous ext racorporeal membrane oxygenation (ECMO) featuring a single lumen cannula, n on-occlusive roller pump, and alternating clamps. Using a neonatal mock cir culation (NMC), which enables different hemodynamic states for neonatal ECM O research, the tested hypothesis was that it is possible to create a centr ifugal pump driven tidal flow neonatal venovenous ECMO system. Additionally , the resulting hemodynamic effects in a condition of circulatory impairmen t were investigated. The ECMO circuit tested was assembled using a pediatri c centrifugal pump head, a distensible reservoir, and a rotary clamp separa ting drainage from the injection phase. Using the NMC, end tidal volumes, m ock circulation flow, and arterial and venous pressures were measured at di fferent pump speeds after the drainage and injection phases. Effective veno venous ECMO flow (evvEF) was calculated. Mock circulation baseline values ( ECMO clamped) were compared to values during tidal flow ECMO. At 3,000 rpm, a centrifugal pump speed of 75 ml/kg/min evvEF was reached, and it increas ed with higher pump speeds. At this point, the end tidal mock circulation f low (representing cardiac output) after drainage differed significantly fro m that during the injection phase (p < 0.01) but not from the baseline valu e. The end tidal arterial and venous pressures after the drainage phase wer e found to be significantly decreased compared to the baselines (p < 0.01). In conclusion, a centrifugal pump driven tidal flow venovenous ECMO system can be created enabling sufficient tidal volumes. Tested in the described NMC simulating posthypoxic circulatory impairment, significant hemodynamic effects could be demonstrated. Animal experiments for confirmation are nece ssary.