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Biomedical subjects

M L Wakefield

Publications and source records attributed to M L Wakefield.

5 recordsLinked to original sources
PubMed1991

The effects of epidural anesthesia on the Doppler velocimetry of umbilical and uterine arteries in normal and hypertensive patients during active term labor.

To study the effects of epidural anesthesia on uterine and umbilical artery blood flow in preeclampsia, we observed 25 patients in active labor at 36 or more weeks' gestation. Seven had preeclampsia, eight had chronic hypertension, and ten had no complications. Doppler velocimetry of the uterine and umbilical arteries was performed before and after intravenous fluid loading and at 30 and 60 minutes after epidural blockade. Maternal vital signs and fetal heart rate were monitored continuously. After epidural block, mean maternal blood pressure fell significantly in all groups, but no maternal hypotension was observed. Mean maternal and fetal heart rates were unchanged. After epidural block, mean uterine artery systolic-diastolic (S-D) ratios did not change in the chronic-hypertension and normal groups, but fell significantly in the preeclamptic group to values similar to those of the normal group. Umbilical artery S-D ratios did not change in any group. In preeclamptic pregnancy, epidural anesthesia may help to reduce uterine artery vasospasm and may benefit intrapartum fetal well-being.

Adult↗
PubMed1990

The effects of epidural anesthesia on the Doppler velocimetry of umbilical and uterine arteries in normal term labor.

To study the possible effects of epidural anesthesia on the Doppler velocimetry of the fetal umbilical and maternal uterine arteries, 15 normal term parturients were examined during active labor. Each Doppler study, conducted over 90 minutes after a 500-mL intravenous volume pre-load, was divided into three phases: 30 minutes of pre-anesthetic control, 30 minutes during epidural catheter placement and dosing, and 30 minutes after establishing effective regional blockade. During each phase, maternal blood pressure and pulse were monitored every 5 minutes, and continuous-wave Doppler recordings of the umbilical and uterine arteries were made at three separate intervals. Epidural placement and dosage techniques were similar for all patients; 0.25% bupivacaine solution was used and sensory levels of T6 obtained. The mean maternal systolic and diastolic blood pressures and pulse rate declined significantly, but no woman experienced hypotension. Mean systolic/diastolic ratios and pulsatility indices of the umbilical and uterine arteries did not change significantly during the study. We conclude that effective epidural anesthesia does not have a significant impact on Doppler flow characteristics of either the maternal or fetal umbilical vasculature, despite lowered maternal blood pressure and pulse rate.

Anesthesia, Epidural↗