296 SPO Abstracts

177 EPIDURAL ANESTHESIA AND DO P P L E R YELOCIMETRY OF UMBILICAL AND UTERINE ARTERIES IN NORMAL AND HYPERTENSIVE TERM PARTURIENTS. E.Ramos~.L. Devoe, M. Wakefield~ D. Sherline, W. Metheny~ Depts. of OBGYN and Anesthesiology. Medical College of Georgia. Augusta, Georgia.

To study effects of epidural anesthesia on uterine and umbilical artery blood flow in preeclampsia, we observed 25 term parturients: 7 had preeclampsia; 8, chronic hypertension; 10, no complications. Doppler velocimetry of uterine and umbilical arteries was done before and after intravenous fluid loading, and at 30' and 60' after epidural block. After epidural, mean maternal blood pressure fell significantly and mean maternal and fetal heart rates were not changed in any. No anesthetic complications occurred. After epidural block, mean uterine artery systolic-diastolic (S:D) ratios did not change in chronic hypertensive or normal groups; mean S:D ratios fell significantly in preeclamptic patients to values similar to those of normal patients. Mean umbilical artery S:D ratios did not change in any group. CONCLUSIONS: Epidural anesthesia may help to reduce uterine artery vasospasm associated with preeclampsia and may benefit intrapartum fetal wellbeing.

78 THE EFFECT OF EPIDURAL ANESTHESIA WITH AND WITHOUT FENTANYL ON FETAL HEART RATE p, TInsmanx, S. Davidson. A. MerkowX. C.B. Martin; University of Wisconsin and Mertter-Park Hospital. Madison. WI.

A study was designed to determine the effects of epidural fentanyl on the fetal heart rate (FHR) pattern. A study group (N = 17) was identified that had a combination of bupivacaine and fentanyl in the epidural solution. These were matched to a bupivacaine only control group (N = 17). All patients had internal fetal monitoring. FHR tracings were blindly evaluated one hour pre- and one hour post­placement of the epidural. Each five-minute segment was scored for predominant FHR pattern (quiet vs. active), bandwidth variability and mean FHR. Epidural placement was associated with an increase in quiescent patterns (X = 18.95 vs. 28.91 min. p<.OI) across conditions. No difference was found between the drug conditions. Epidural had no effect on the bandwidth variability in either condition. Initiation of epidural anesthesia with fentanyl was l!§soclated with an increase in FHR during quiescence (X = 132.0 vs. 138.9 BPM. p<.OI). We conclude that epidural anesthesia is associated with an Increase In fetal quiescence in the first hour after initiation and that the addition of fentanyl to the epidural causes a small increase in the fetal heart rate during quiescence but no overall change in FHR variability.

January 1991 Am J Obstet Gynecol

179 MAGNESIUM SULFATE IS A POOR INHIBITOR OF OXY­TOCIN INDUCED CONTRACTIONS IN SHEEP. Margaret Watt-Morse, M.D., M.P.H.,x Steve N. Caritis, M.D. Pamela Kridgen,X University of Pittsburgh, Magee-Womens Hospital, Pittsburgh, PA

180

Although magnesium sulfate (MgS04)is a widely utilized toco· lytic agent, there are few data demonstrating its ability to inhibit uterine contractility (UC) in vivo. In the present study, we used oxytocin (OT) as a myometrial stimulant and determined the inhibitory effect of various concentrations of MgS04. We inserted catheters in the femoral artery and vein and amniotic cavity of five pregnant sheep between 113-125 days geMation (term = 147 days). We first established a linear dose response curve with OT (67·3000 mu boluses) and uterine activity which was quantified by integrating the area under the time-uterine pressure curve (AUC) using the Bioquant II computer program. We chose 1000 mu as our standard OT dose because this produced a half maximal response. Animals received loading doses of MgS04 and then maintenance infusion rates of 0.028,0.057, and 0.OS5 mg/kg/hr (equivalent to 2, 4, and 6 gm/hr in a 70 kg woman). After steady state was achieved, the animal received 1000 mu OT bolus. The table below indicates the percent inhibition (+SD) of oxytocin-induced UC at various infu-sion rates. The mean ( + SD )serum Mg concentration is also listed. -Infusion Rate (mg/kg/hour) 0.028 0.057 0.OS5

Average MJf04 concentra- 3.32:0.3~ 5.3+0.41 7.3+0.74 tion (mEq )

% Inhibition UC 4.0+6.4 16.0+27.2 20.3+28.4 Prolonged MgS04 mfuslOns (6-S hours) were earned out In 2 animals at above 3 infusion rates. No increased tocolytic effec· tiveness was seen. MgS04 is a poor inhibitor of OT induced UC in this animal model. ThiS compares with previous work in our laboratory in which 40-60% inhibition was obtained with clinically relevant concentrations of ritodrine.

SERIAL CORDOCENTESIS IN THE EVALUATION OF INTRAUTERINE CYTOMEGALOVIRUS INFECTION. tlarttwert,r&ttuMorse. M.DpM.P.lP.', Steven Laifer, M.Di'iLyndon

. I, . . ruvemtyot Ittsburgh, Magee-Womens ospital, Pittsburgh, PA

The natural history of intrauterine cytomegalovirus (IUCMV) infection is not well documented. We present a case of IUCMV infection followed from 24+ weeks gestation (GA) until delivery. An asymptomatic 20-year-old white -female was referred because offetal ascites. Maternal evaluation was notable for positive CMV IgM and IgG. Ultrasound (US), amniocentesis, and cordocentesis were performed at the time of presentation and serially throughout the pregnancy. Thy fetal karyotype was 46,XY. Otlier pertinent resu1ts are summanzed below'

GA Hct WEe Pit T. GtP

Alb CMY AF Bili IgM CMV

24.S 31.8 2.S 14k 3.5 659 1.S (D NA

27.7 33.4 3.6 23k 3.1 377 2.0 (D (D

32.S 32.4 5.2 67k 2.1 352 2.3 NA (D

38.6 (cord blood) 67. 20.0 120k 2.1 272 3.7 - NA US at 24+ weeks revealed placentomegaly, cardiomegaly, hep.a­tomegaly with calcifications and ascites. AT 27.7 weeks, mild polyliydramnios and ventriculomegaly were present. US findings remained stable until 38.3 weeks when the ascites resolved. 5 Hie pa!ient was delivered of a 2950 gm m,!-le infant (Apgars 61 S ) by pnmary low transverse cesarean sectIon for failure to progress. Placental immunocytochemical stains for CMV were negative. Neonatal evaluation revealed urine culture positive for CMV, mild hypotonia, mild ventriculomegalyon CT scan, and a few calcifica· tlOns in tlie liver on abdominal US. This case demonstrates the course of IUCMV infection. Of note is the profound thrombocytopenia which resolved slowly. This has important clinical implications with respect to mode of delivery. Additional reports !ll'e necesSarY. to fl!rther clarify the natura1 history and prognOSIS of IUCMV mfectlOn.