UTEROPLACENTAL AND FETAL CIRCULATION DURING EXTRADURAL BUPIVACAINE ADRENALINE AND BUPIVACAINE FOR CESAREAN-SECTION IN HYPERTENSIVE PREGNANCIES WITH CHRONIC FETAL ASPHYXIA

We have studied the effects of an extradural block during Caesarean se ction using either bupivacaine plain or with adrenaline 85-100 mug on blood velocity waveforms of maternal uterine and placental arcuate art eries and fetal umbilical renal and middle cerebral arteries, in 20 hy pertensive parturients with chronic fetal asphyxia. Fetal myocardial f unction was investigated at the same time by M-mode echocardiography. Extradural anaesthesia resulted in a significant decrease in maternal mean systolic and diastolic arterial pressures in both groups, but thi s was more marked after plain bupivacaine. There were no significant d ifferences in any of the Doppler recordings relative to baseline value s after plain bupivacaine, but after bupivacaine with adrenaline there were significantly increased blood flow velocity indices for the mate rnal uterine and placental arcuate arteries and significantly decrease d indices in the fetal renal and middle cerebral arteries. Neonatal ou tcome as evaluated by Apgar scores and acid-base values in the umbilic al cord were similar in the two groups. The results suggest that adren aline added to the solution of bupivacaine increased vascular resistan ce in the uteroplacental circulation, indicating impaired blood flow.