Key result
Low-flow CPB increases PVR in isolated lamb placentas, an effect worsened by hypothermia.
Why the study?
How do varying perfusion flow rates and hypothermia affect placental vascular resistance during experimental fetal cardiopulmonary bypass?
Population
7 isolated in situ lamb placentas
Comparison
Cardiopulmonary bypass with varying perfusion… vs Normothermia vs hypothermia; varying perfusion…
Design
Preclinical
Authors
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May warrant threshold perfusion targets in fetal CPB models to limit resistance; leaves open human translation.
How do varying perfusion flow rates and hypothermia affect placental vascular resistance during experimental fetal cardiopulmonary bypass?
Decreased placental flow and pressure during fetal cardiopulmonary bypass, particularly under hypothermia, increases placental vascular resistance, which may further impair placental perfusion and gas exchange.
Assad et al. (1992) studied Placental hemodynamics during fetal cardiopulmonary bypass (n=7). Cardiopulmonary bypass with varying perfusion flow rates and temperatures was evaluated on Placental vascular resistance (PVR). In isolated lamb placentas on CPB, placental vascular resistance increased when perfusion pressure and flow fell below 40 mmHg and 150 ml.min-1.kg-1, an effect exacerbated by hypothermia.
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