Markers of physical integrity and metabolic viability of the perfused human placental lobule.

1. Peripheral lobules of term placentae obtained from healthy females at Caesarian section were perfused using separate maternal and fetal circulations for 6 h periods under either oxygenated or anoxic conditions. 2. Markers of physical integrity during setting-up and initial perfusion were establishment of dual perfusion within 25 min of placental delivery, pressure in the fetal capillary network less than 40 mmHg, leakage of perfusate from fetal to maternal compartments less than or equal to 2 ml/h, and overlap of maternal with fetal perfusion as indicated visually by appropriate blanching and verified by a fetal artery to vein oxygen gradient of greater than or equal to 90 mmHg. 3. Post-perfusion markers of metabolic viability were most reliably indicated by glucose consumption (oxygenated 7.8 +/- 1.5, anoxic 17.7 +/- 1.2 mmol/kg per h), lactate production (oxygenated 8.5 +/- 1.4, anoxic 33.9 +/- 2.5 mmol/kg per h) and human placental lactogen production (oxygenated 41.2 +/- 9.8, anoxic 12.2 +/- 3.4 mg/kg per h).