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Biomedical subjects

R Lewinsky

Publications and source records attributed to R Lewinsky.

8 recordsLinked to original sources
PubMed1991

Fetal and uteroplacental flow velocity waveforms and placental grading.

Doppler studies were performed on umbilical, fetal internal carotid, and arcuate arteries within 36 to 40 weeks of gestation in 85 women (66 with healthy pregnancies and 18 complicated by growth retardation, and results were analyzed by calculating the pulsatility index. In each case the placenta was examined and graded sonographically. No significant correlation was found between pulsatility index in fetal and uteroplacental vessels and placental grading in normal pregnancies. This suggests that tissue changes responsible for the echogenicity of maturing placenta are not directly related to vascular impedance of the placental vascular bed.

Adult↗
PubMed1990

Fetal blood flow velocity waveforms in pregnancies complicated by intrauterine growth retardation.

Fifty-three pregnancies suspected for a small-for-gestational age fetus (SGA) by ultrasonographic weight estimation (below the 10th percentile of Brenner nomograms) were studied using pulsed Doppler (Duplex) for recording fetal blood flow velocity waveforms from the umbilical artery and fetal internal carotid artery. The pulsatility index (PI) for each artery was calculated as an index of vascular resistance. The gestational age ranged from 29 to 40 weeks. In 42 cases an SGA newborn was delivered (according to Brenner tables corrected for maternal parity and fetal sex), 34 newborns were SGA according to Usher and McLean (2 SD below the mean). Fetal structural and/or chromosomal defects were found in four cases, all of which showed symmetric intrauterine growth retardation and normal PI values in the fetal internal carotid artery. After excluding the infants with congenital abnormalities and using nomograms constructed for our own population, the ratio between the PI of the umbilical artery and the internal carotid artery was found to be the best predictor of SGA (sensitivity 84.2%, specificity 90.9%, positive predictive value 97.0%, negative predictive value 62.5%). Using the more demanding criteria for SGA according to Usher and McLean, sensitivity improved to 100%, specificity was 80.0%, positive predictive value 87.9%, and negative predictive value 100%.

Blood Flow Velocity↗
PubMed1989

Maternal echocardiography in hypertensive pregnancies.

Echocardiographic hemodynamic and left ventricular parameters were determined in 14 normotensive and 18 hypertensive women during the last trimester of pregnancy. The hypertensive patients had significantly higher mean values of total peripheral resistance (p less than 0.001), maximum velocity of posterior wall motion (p less than 0.05), mean velocity of circumferential fiber shortening (p less than 0.01) and percent fiber shortening of left ventricular diameter (p less than 0.05). The mean values for heart rate, stroke volume, cardiac output, cardiac index, left ventricular posterior wall thickness and septal thickness did not differ significantly in both groups. These results reflect increased cardiac contractility related to elevated peripheral vascular resistance in subjects with pregnancy-induced hypertension.

Adult↗
PubMed1988

Decrease in pulsatile flow in the internal carotid artery in fetal hydrocephalus.

The effect of ventriculomegaly on pulsatile flow in the internal carotid arteries has been studied by Doppler ultrasound in four hydrocephalic fetuses. The pulsatility index showed progressive elevation proportional to the developing ventriculomegaly and thus may be a valuable index for the study of the mechanism of brain injury and for the determination of optimal timing of intervention.

Carotid Artery, Internal↗
PubMed1988

Fetal internal carotid artery flow velocity time waveforms in twin pregnancies.

The fetal internal carotid artery and umbilical artery flow velocity time waveforms were studied in 17 consecutive twin pregnancies. The pulsatility index was calculated for each fetus in each artery as an index of vascular resistance. All studies were done within 14 days before delivery. In 8 pregnancies both fetuses were of birthweight appropriate for gestational age; whereas, in 9 patients one or both of the infants were small for gestational age (SGA). From ultrasound criteria and Doppler studies of the umbilical and fetal internal carotid arteries, decreased fetal internal carotid artery pulsatility index (cut off value less than or equal to 1.2) was found to be the best predictor of SGA (sensitivity 83%, specificity 95%, positive predictive value 91%, negative predictive value 91%).

Birth Weight↗
PubMed1988

Fetal arrhythmia associated with sinus node dysfunction--a case report.

Real time and M-mode echocardiography were used for evaluation of fetal bradycardia. Sinus bradycardia was revealed without structural abnormalities. An abdominal wall derived fetal electrocardiogram and the failure of the sinus rate to increase in response to maternal exercise or I.V. atropine suggested sinus node dysfunction. Postnatal evaluation revealed sinus bradycardia with blunted response to I.V. atropine and an abnormal sinus node recovery time. A gradual increase in heart rate was demonstrated in the neonatal period, possibly due to decrease in vagal tone.

Adult↗