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Biomedical subjects

K E Mehalek

Publications and source records attributed to K E Mehalek.

13 recordsLinked to original sources

Sonographic diagnosis of traumatic and later recurrent uterine rupture.

We report a case of traumatic transverse fundal uterine rupture with fetal death, followed by recurrent rupture during the subsequent (twin) pregnancy. Rupture was sonographically diagnosed within minutes of arrival at hospital following a motor vehicle accident in the first pregnancy and defined operative intervention, which was lifesaving for the mother. Rupture was again diagnosed sonographically in the second pregnancy based on extrusion of the bag of waters through the uterine incision without fetal distress. Emergency cesarean section was performed with good outcomes for both babies. Causes and clinical/sonographic diagnosis of uterine rupture are reviewed and obstetric management discussed. A high level of suspicion, early diagnosis, and expeditious management are keys to favorable outcome.

Cesarean Section↗

Umbilical and uterine artery flow velocity waveforms. Effect of the sampling site on Doppler ratios.

Pulsed Doppler duplex sonography was performed on 58 patients in order to determine whether Doppler ratios of umbilical and uterine artery flow velocity waveforms vary with the site at which measurements are taken along their respective arterial beds. Umbilical artery ratios were significantly higher at the fetal end of the cord when compared to ratios at the placental cord insertion. In the maternal circulation, ratios from arcuate artery waveforms were lower than those obtained from the uterine artery. This site-dependent difference in ratios could be clinically important when studying ratios from the umbilical artery. Accuracy of Doppler measurements in the individual patient and in scientific investigations may be improved if uniform measurement techniques are used.

Arteries↗

Ultrasound detection of Down syndrome: is it really possible?

Several ultrasonographic signs have been described in second-trimester fetuses at high risk for Down syndrome. We examined these parameters in twin pregnancies in which one fetus was affected with Down syndrome and the other was normal. Biparietal diameter to femur length ratio was concordant (either normal or abnormal) in eight of nine sets of twins. Actual femur length to expected femur length ratio was concordant in seven of nine sets of twins. Nuchal fold thickening (6 mm or more) correctly identified five out of nine affected fetuses and was not present in any of the normal fetuses. In conclusion, neither ratio was helpful in differentiating the fetus with Down syndrome from its normal cotwin. A thickened nuchal fold was the most informative parameter examined.

Diseases in Twins↗

Selective second-trimester termination of the anomalous fetus in twin pregnancies.

Selective termination of the affected fetus was performed during the second trimester in 17 pregnancies in which one twin was diagnosed to be anomalous. The affected twin had a chromosomal aneuploidy in 14 cases, neural tube defect in two cases, and an inborn error of metabolism in one case. With increasing operator skill and improvement in technique, a striking improvement occurred in pregnancy outcome in the last 11 patients as compared with the first six. In four of the first six cases, the entire pregnancy was lost. Among the last 11 patients, on the other hand, no pregnancy was lost. All 11 women delivered healthy, viable infants; eight delivered at term and three delivered between 31-35 weeks. Of the various techniques used, we found intracardiac injection of potassium chloride to be the most effective, but it should not be used in monochorionic twin gestations.

Abortion, Induced↗

Sonographic estimation of fetal weight and Doppler analysis of umbilical artery velocimetry in the prediction of intrauterine growth retardation: a prospective study.

A prospective study was undertaken to examine whether Doppler velocimetry studies of the umbilical artery give a better or an earlier prediction of intrauterine growth retardation (IUGR) than do sonographic estimation of fetal weight. A total of 385 examinations were performed between 30 and 42 weeks of gestation on 168 patients who were at risk for IUGR. Forty-two (25%) of the patients delivered an infant with a birth weight below the tenth percentile. Although sensitivity was lower for the systolic to diastolic ratio (55%) of the umbilical artery than for the sonographic estimation of fetal weight (76%), the umbilical artery studies had a higher specificity (92% versus 80%) and predictive value of a positive test (73% versus 58%) when the last study to delivery interval was within 2 weeks. Furthermore, among 21 IUGR pregnancies with serial studies, the umbilical systolic to diastolic ratio was abnormal at a significantly earlier gestational age than when the sonographic estimate of fetal weight identified growth retardation. These findings indicate that sonographic biometry is a more sensitive technique for identifying IUGR but that the umbilical artery waveforms are a valuable adjunct for improving the diagnostic accuracy for the prenatal detection of IUGR. These data also provide suggestive evidence that umbilical artery velocimetry may be predictive of IUGR at an earlier gestational age than sonographic estimation of fetal weight.

Adult↗

Efficacy and side effects of magnesium sulfate and ritodrine as tocolytic agents.

Ritodrine as the first-line drug in the treatment of established preterm labor has been supplanted in some centers by magnesium sulfate. To assess the relative efficacy and rates of side effects of these two agents, 120 patients were randomly assigned to receive one of these two drugs. Patients were included if they had intact membranes and met strict criteria for the definition of labor. In both groups excellent outcome was achieved, with 96.3% and 92.3% of patients receiving ritodrine and magnesium sulfate, respectively, obtaining a delay in delivery of greater than 48 hours. Side effects were comparable in both groups, although they tended to be more serious in the patients receiving ritodrine. In patients receiving both drugs together, the rate of side effects was 77% without a demonstrable benefit over a single agent. We conclude that ritodrine and magnesium sulfate are tocolytics of comparable efficacy and when used aggressively are highly successful in delaying delivery.

Adult↗

Comparison of continuous-wave and pulsed Doppler S/D ratios of umbilical and uterine arteries.

Continuous-wave and pulsed Doppler ultrasound measurements of blood flow velocity waveforms of both uterine and umbilical arteries were performed on 85 patients to assess the correlation between these two measurements techniques. Peak systolic to end-diastolic (S/D) ratios measured by continuous-wave devices were not statistically different (P greater than .05) from those measured by a pulsed Doppler device. The S/D ratios of the umbilical artery measured by each device showed a strong correlation, whether measured by one observer (r = 0.93) or two observers (r = 0.89). Uterine artery ratios showed a weaker, although still significant, correlation (r = 0.57). Pulsed Doppler is not routinely necessary for the identification and measurement of umbilical and uterine artery S/D ratios.

Blood Flow Velocity↗

Doppler umbilical velocimetry in the prediction of adverse outcome in pregnancies at risk for intrauterine growth retardation.

Perinatal indicators of fetal compromise were assessed according to the results of continuous-wave Doppler umbilical velocimetry for 172 patients at risk for intrauterine growth retardation (IUGR). Forty-three (25%) of the patients delivered an infant with a birth weight below the tenth percentile for gestational age. The last Doppler study before delivery was abnormal in 48.8% of the growth-retarded infants but in only 13.2% of the infants without evidence of IUGR. Furthermore, in the growth-retarded group, early delivery, reduced birth weight, decreased amniotic fluid at birth, admission to the neonatal intensive care unit, neonatal complications associated with IUGR, and a prolonged hospital stay were observed more frequently in those who had an abnormal ratio than in those with a normal ratio. The sensitivity of the systolic/diastolic ratio for an adverse perinatal outcome (operative delivery for fetal distress, neonatal morbidity associated with IUGR, and/or perinatal death) was significantly better for the infants with IUGR (66.7%) than for the infants without IUGR (27.8%; P less than .05). The predictive value of an abnormal ratio was also higher for the pregnancies complicated with IUGR (57.1%) than for those without IUGR (29.4%), but not to a statistically significant degree. These data suggest that Doppler umbilical velocimetry studies are valuable in identifying those growth-retarded fetuses at increased risk for an adverse perinatal outcome.

Blood Flow Velocity↗

The nonpredictive value of fetal urinary electrolytes: preliminary report of outcomes and correlations with pathologic diagnosis.

Fetal urine was sampled 12 times in nine fetuses with sonographically diagnosed urinary tract obstruction to assess renal function. By previously proposed criteria, four fetuses were predicted to have poor renal function. Two of these fetuses were found to have renal dysplasia on autopsy after elective termination. The other two died in the neonatal period but only one of these had histologic evidence of renal dysplasia. Five fetuses were predicted to have good renal function. Three of these developed renal failure after birth, one was found to have renal dysplasia on autopsy after elective termination, and one is alive and well. We conclude that fetal urine electrolytes are not necessarily an accurate predictor of neonatal renal function.

Chlorides↗

Technical aspects of intravascular intrauterine transfusions: lessons learned from thirty-three procedures.

Our technique for performing intravascular transfusions is described and four failed attempts are presented. The appropriate choice of needle, insertion site, and premedication are discussed. A rationale for intravenous fetal muscle blockade in selected cases is presented and a transfusion setup designed to minimize movement of the needle hub is described. Finally, the judicious use of intraperitoneal transfusions in some cases is suggested.

Blood Transfusion, Intrauterine↗

Prenatal diagnosis of fetal brain tumors.

Two cases of congenital brain tumors were detected during routine antepartum sonography at the Mount Sinai Medical Center Perinatal Ultrasound Unit. In both cases, diagnosis was made during the third trimester at 31 and 33 weeks, respectively. In one of these patients, no intracranial abnormalities were noted on a sonogram performed in conjunction with genetic amniocentesis at 18 weeks gestation. The histologic diagnosis of both tumors was glioblastoma multiforme grade III. Previous reports describing the prenatal sonographic diagnosis of intracranial tumors have been in cases with fetal intracranial teratomas.

Adult↗