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Biomedical subjects

G R DeVore

Publications and source records attributed to G R DeVore.

At least 55 records · Page 3Linked to original sources
PubMed1988

Fetal umbilical velocimetry using continuous-wave and pulsed-wave Doppler ultrasound in high-risk pregnancies: a comparison of systolic to diastolic ratios.

Systolic to diastolic (S/D) ratios of umbilical velocimetry using either continuous-wave or pulsed-wave Doppler ultrasound have been used to assess downstream placental resistance. The purpose of this study was to compare the S/D ratios obtained by both types of instrumentation to determine whether there are significant differences between measurement values. Umbilical velocimetry was performed on 200 high-risk pregnancies in the third trimester using the Angioscan III to obtain continuous-wave velocimetry and the General Electric RT3600 to obtain pulsed-wave velocimetry. Systolic to diastolic ratios were considered abnormally high if they were greater than 3. One hundred sixty-five patients had normal S/D ratios and 35 patients had elevated ratios on both continuous-wave and pulsed-wave ultrasound. There was no significant difference in the mean S/D ratios obtained by either method for the entire population (continuous-wave S/D 2.81 +/- 1.79, pulsed-wave S/D 2.71 +/- 1.83, R = 0.98), the normal group (continuous-wave S/D 1.96 +/- 0.41, pulsed-wave S/D 1.95 +/- 0.40, R = 0.91), and the abnormal group (continuous-wave S/D 6.23 +/- 1.58, pulsed-wave S/D 6.35 +/- 1.52, R = 0.94). Least-square regression was performed to model the relationships between pulsed wave and continuous wave, with both used as dependent variables. The slopes and intercept for the normal and abnormal groups were evaluated and were significantly different (P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1988

Fetal umbilical velocimetry for the surveillance of pregnancies complicated by placenta previa.

Continuous-wave Doppler studies of the umbilical arteries were performed on 100 women with placenta previa prior to delivery in the third trimester and 100 control subjects matched for gestational age and with normally implanted placentas. The ratio of the maximum (systole [S]) and minimum (diastole [D]) velocities appeared to reflect downstream vascular resistance. An S:D ratio of greater than or equal to 3.0 indicated elevation. There was a statistically higher S:D ratio in the placenta previa group as compared to the control group, and that difference persisted even when growth-retarded fetuses were excluded from both groups. Placenta previa patients with S:D ratios greater than or equal to 3.0 were associated with a statistically higher incidence of adverse pregnancy outcomes. The sensitivity, specificity, and positive and negative predictive value of an elevated S:D ratio in predicting adverse pregnancy outcomes were 90.0%, 93.8%, 62.0% and 98.5%, respectively. Our data suggest that (1) placenta previa patients are at increased risk of intrauterine growth retardation and adverse pregnancy outcomes, (2) placenta previa patients with normal S:D ratios are at no greater risk of adverse outcomes than are controls, (3) when the S:D ratio is elevated in placenta previa patients, it is more likely to be associated with adverse pregnancy outcomes, and (4) placenta previa patients without growth failure have a higher S:D ratio than do those with normally implanted placentas. Umbilical artery velocimetry appears to be a useful adjunct to ultrasound in the surveillance of pregnancies complicated by placenta previa.

Adult↗
PubMed1988

Maternal and fetal blood flow velocity waveforms in patients with preterm labor: effect of tocolytics.

The effect of tocolytics on systolic to diastolic (S/D) ratios used to assess downstream vascular resistance and obtained from umbilical and uterine velocity waveforms has not been studied to date. Continuous-wave Doppler studies were performed on the umbilical and uterine arteries of 60 consecutive patients with the diagnosis of preterm labor. Forty patients receiving intravenous magnesium sulfate and 20 patients receiving intravenous ritodrine tocolysis underwent Doppler studies before therapy, during incremental therapy, and four hours post-therapy. There was a statistically significant (P less than .001) progressive decrease in the uterine and umbilical S/D ratios along with a concomitant increase in maternal and fetal heart rate associated with increasing infusion doses of ritodrine. Both the S/D ratios and heart rates returned to pretherapy range four hours after discontinuing therapy. Magnesium sulfate tocolysis was not associated with any significant change in S/D ratios or maternal and fetal heart rate. We conclude that intravenous ritodrine affects umbilical and uterine vascular resistance as measured by S/D ratios. This response may be secondary to changes in maternal and fetal heart rate.

Adult↗
PubMed1988

Fetal foot length: relationship to menstrual age and fetal measurements in the second trimester.

The purpose of this study was to describe the ultrasonic measurement of fetal foot length and to develop mathematical models to quantify the relationships between menstrual age and commonly measured fetal structures. We evaluated 120 patients with known last menstrual periods and normal pregnancies to develop a cross-sectional study population. All patients had ultrasonic measurement of the fetal foot length, biparietal diameter, head circumference, abdominal circumference, and femur length. Least-squares estimation of linear models was used to select the best mathematical models to describe the relationship between menstrual age and fetal foot length. A similar evaluation of the relationship between fetal foot length and the other measured parameters was performed. All models were best described by a linear equation. An R2 value of 0.94, with a standard error of the estimate of 0.204, was obtained for menstrual age versus fetal foot length. When the model for fetal foot length and menstrual age was compared with published anatomical data, close agreement was seen over the time interval studied. Our results suggest that the measurement of fetal foot length with ultrasound gives a reliable assessment of anatomical fetal or neonatal foot length and is highly correlated to the menstrual age of the fetus.

Female↗
PubMed1987

Fetal echocardiography. VII. Doppler color flow mapping: a new technique for the diagnosis of congenital heart disease.

One of the difficulties for the fetal sonographer is the complete elucidation of structural defects of the cardiovascular system that are associated with intracardiac or great vessel flow disturbances. With the recent introduction of Doppler color flow mapping, in which blood flow is displayed in color superimposed on a real-time image, it has been impossible to identify flow disturbances in the pediatric and adult patient. This study was undertaken to determine whether Doppler color flow mapping could be used in the fetus to identify normal and abnormal cardiovascular anatomy. Thirty-five normal and high-risk fetuses were examined between 16 and 40 weeks of gestation. Doppler color flow mapping identified normal and abnormal anatomy (ventricular septal defect, atrial septal defect, endocardial fibroelastosis, dysplastic pulmonary valve, and tricuspid regurgitation). It appears that Doppler color flow mapping will add a new dimension to fetal cardiovascular imaging.

Adult↗
PubMed1987

Diagnosis of intrauterine growth retardation: the use of sequential measurements of fetal growth parameters.

Given the current widespread use of diagnostic ultrasound, it is important to identify exactly what information is desirable during the examination. Although dating the pregnancy might be the reason for the initial evaluation, it is important to examine the fetus for structural malformations as well. Both can be accomplished with a second-trimester scan. Once the pregnancy is accurately dated, subsequent measurements of the head, abdomen, and femur should be plotted on growth curves in relation to the age of the fetus, based on the earlier ultrasound examination. The patient should not be related with subsequent examinations. If asymmetric growth failure occurs, then intervention or maternal bed rest should be considered. Intervention should be considered in the presence of abnormal antepartum testing and when fetal growth has arrested following the institution of maternal bed rest. If symmetric IUGR is present, careful evaluation of the fetus for structural malformations and an abnormal karyotype should be considered.

Adult↗
PubMed1987

Fetal echocardiography: the prenatal diagnosis of a ventricular septal defect in a 14-week fetus with pulmonary artery hypoplasia.

As the result of auscultation of fetal bradycardia in a class C diabetic, real-time and M-mode echocardiography were performed at 14 weeks of gestation. M-mode evaluation revealed fetal bradycardia (70 beats per minute) with atrial and ventricular systole occurring simultaneously, suggesting a nodal rhythm. Real-time examination demonstrated a ventricular septal defect, pericardial effusion, ventricular wall hypertrophy, and a dilated aortic root. Also present were fetal ascites and situs inversus of the stomach. A repeat ultrasound examination revealed fetal death at 16 weeks of gestation. Autopsy confirmed the above structural abnormalities, and also demonstrated bilobed lungs, pulmonary artery and valve hypoplasia, midline small intestine, and asplenia.

Adult↗
PubMed1986

Fetal echocardiography. VI. Assessment of cardiothoracic disproportion--a new technique for the diagnosis of thoracic hypoplasia.

Fifty-eight fetuses were studied with use of diagnostic real-time and M-mode ultrasound between 15 and 40 weeks of gestation in which the chest circumference, biventricular outer dimension of the heart, biparietal diameter, head circumference, abdominal circumference, and femur length were measured. The chest circumference correlated with the biparietal diameter (r = 0.978), head circumference (r = 0.977), abdominal circumference (r = 0.989), femur length (r = 0.983), and biventricular outer dimension (r = 0.972). Regression analysis with predicted mean and 95% and 5% confidence limits demonstrated a linear relationship between the chest circumference and the following: biparietal diameter, head circumference, abdominal circumference, femur length, and biventricular outer dimension. Four representative cases (triploidy [69,XXX], osteogenesis imperfecta, intrauterine growth retardation, and renal agenesis) illustrate the usefulness of the data when thoracic hypoplasia is suspected.

Abdomen↗
PubMed1986

Altered fetal growth and development in a patient with Turner's syndrome.

Fertility in cases of Turner's syndrome is rare. In cases where conception does occur, spontaneous abortion and structural and chromosomal defects commonly are discovered. A review of the literature and a case report are presented in which pregnancy was complicated by severe intrauterine growth retardation and musculoskeletal deformities of the fetus.

Abnormalities, Multiple↗
PubMed1986

Role of amniocentesis in ultrasound-detected fetal malformations.

Sixty-three patients with antenatally diagnosed fetal malformations over the period of 14 months were prospectively offered genetic amniocentesis, irrespective of gestational age. An additional 15 patients were excluded from the study because of a known lethal malformation (13 anencephaly, two amniotic bands). Twenty patients accepted amniocentesis, and seven chromosomal disorders were found. Obstetric management was altered in some of these patients as a result of the anomalies.

Adult↗
PubMed1985

Modification of fetal intraventricular amniotic shunt.

The benefits of fetal intraventricular amniotic shunt remain unknown. Nevertheless, the use of this technique has been described by several authors. One of the potential complications arising from its placement is the inability to retract the catheter once it is placed through the large needle. This communication describes a modification of the shunt procedure. A suture placed through the distal end of the catheter allows retrieval of the catheter shunt for as long as the needle remains in place.

Amniotic Fluid↗
PubMed1985

Fetal echocardiography. V. M-mode measurements of the aortic root and aortic valve in second- and third-trimester normal human fetuses.

The aortic root dimension and aortic valve excursion of 43 normal fetuses were recorded with M-mode echocardiography and the measured dimensions correlated with noncardiac measurements (biparietal diameter, head circumference, abdominal circumference, and femur length) and cardiac measurements (diastolic biventricular inner dimension, diastolic left ventricular internal dimension, and mitral valve excursion). The correlation coefficients for the aortic root dimension ranged between 0.87 and 0.95, while those for the aortic valve excursion ranged between 0.78 and 0.87. Regression analysis demonstrated that the best fit of the data was a linear model from which the 5% and 95% confidence limits were computed for individual predictions of aortic root dimension and aortic valve excursion from noncardiac and cardiac measurements.

Aorta↗
PubMed1985

Ultrasonic estimation of weight in the very low-birth weight fetus: a resident versus staff physician comparison.

The estimation of weight in the very low-birth weight fetus (less than 1500 gm) is becoming more important in obstetric management as neonatal nurseries are reporting better outcome in this weight category. It has become clear that assessment of weight can best be accomplished through the use of ultrasound. In many institutions, however, ultrasonography is under the control of other departments and is not readily available. This arrangement prevents rapid access and compromises the benefit of the technique. To evaluate the accuracy of scans performed in very low-birth weight infants by personnel with limited training in ultrasonography, we undertook a systematic study of weight estimates in this select group of patients. To date, 31 ultrasound examinations have been performed by staff physicians and 50 by resident physicians. Comparisons made between ultrasound examinations by staff and resident physicians showed that the absolute error between the ultrasound-predicted weight and the actual weight, though less in the case of staff physician examinations, was not statistically significant.

Birth Weight↗
PubMed1985

The prenatal diagnosis of congenital heart disease--a practical approach for the fetal sonographer.

With the widespread use of diagnostic ultrasound to evaluate the human fetus, it is now possible to diagnose a number of anomalies of varying organ systems. Although most anomalies of the central nervous, gastrointestinal, genitourinary, and skeletal systems are recognizable at birth, serious ones involving the cardiovascular system are often silent until the neonate demonstrates signs of cardiovascular compromise. Because an ever increasing number of fetuses are routinely scanned during pregnancy, it becomes imperative to incorporate a simple, logical approach to screen for cardiovascular disease during each fetal examination. The approach outlined in this paper would suggest that one method is the routine examination of the four-chamber view. Although there are a number of fetal and maternal risk factors which predispose to congenital heart disease, we have diagnosed a number of anomalies simply on the basis of the "screening" four-chamber examination in the "low-risk" fetus. For this reason, an attempt to examine the four-chamber view of the fetal heart should be done during each routine fetal examination. If an abnormality is noted, then a Level II, or consultative echocardiographic examination should be carried out. If a fetus at risk for congenital heart disease is being examined, a complete examination of the cardiovascular system (Levels I and II) should be performed. If the above approaches are integrated into obstetrical scanning, in the not too distant future it will be commonplace to diagnose cardiovascular anomalies prior to birth and thus provide the best care during the transition from the intrauterine to the extrauterine environment for the potentially cardiovascularly compromised neonate. The experience gained in our laboratory during the past 5 years strongly suggests that what is "today's research will become tomorrow's clinical tool."

Echocardiography↗
PubMed1985

Evaluation of ultrasonic obstetrical parameters by hand-held calculator.

One consequence of the development of the use of ultrasound in obstetrics is the multiplication of parameters studied by the ultrasonographer. This has prompted the development of expensive computerized systems to assist the person doing the examination in evaluating his results. A program designed to be used with a relatively inexpensive, hand-held calculator is described. It gives the gestational age corresponding to the most commonly measured dimensions, the estimation of fetal weight of the examined fetus, and numerous other parameters used in clinical interpretation of ultrasound examinations.

Body Weight↗
PubMed1985

The use of the abdominal circumference as a means of assessing M-mode ventricular dimensions during the second and third trimesters of pregnancy in the normal human fetus.

Eighty-two normal fetuses were scanned from 18 to 41 weeks of gestation. The following M-mode measurements were correlated with the abdominal circumference: diastolic biventricular outer (r = 0.951) and inner (r = 0.948) dimensions; diastolic right (r = 0.942) and left (r = 0.925) internal dimensions; tricuspid (r = 0.916) and mitral (r = 0.900) valve opening excursions; and right (r = 0.774), left (r = 0.731), and interventricular septal (r = 0.753) wall thickness. Polynomial regression demonstrated that linear regression best described the data from which the mean and 5 per cent and 95 per cent confidence limits for predicted M-mode measurements were computed for the abdominal circumference between 12 and 35 cm.

Embryonic and Fetal Development↗