A new non-invasive technique for perfusion of the human cotyledon

OBJECTIVE: To compare the maternal-fetal transfer of antipyrine using a non-invasive pressure perfusion technique to values observed with conventional place-mal perfusion models. STUDY DESIGN: A newly designed pressuri/ed jet apparatus was used to perfuse, the maternal surface of term placentae with standardiJ.ed M199 ((iIB(X>) perfusion medium, rather than perforating the imervillous space, which is current practice. The maternal flow rate (MFR) remained constant throughout the experiment, with a variable fetal flow rate (FFR). Antipvrine was introduced (o the maternal perl'usate and its malernal-fetal transfer evaluated. Data, including pH, pO2 and pressure from the perfusion was collected on a computeri/ed data acquisition s\siem (Straw-beny Tree. Inc.) Antipvrine concentrations and clearance values were compared lo established placental antipyrine transfer data. RESULTS: Fetal How rates were adjusted from 5 to 11 ml/min and antipyrine concentrations were determined with IV spertrophotometrv. Amipu'ine clearance was evaluated with the equation [fetal outflow]-[fetal inflow] FFR]/[nmternal inflow]. Our pressurized jet model allowed for FFR:MFR ratios from 0.147 to 0.323, which corresponds to antipvrine clearances from 0.53 ±0.09 ml/min to 1.43 ±0.11 ml/min, respectively. CONCLUSIONS: The non-invasi\e perfusion of the maternal cotyledon results in a similar antipyrine clearance at varying fetal perfusion rates, when compared lo classic perfusion models which bluntly perforate the maternal surface to perfuse the intervillous space. The perfusion jet model ma\ represent the maternal circulation, specifically the spiral arteriolar (iiculation. more accurately than established placental perfusion technology.