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Biomedical subjects

D Arduini

Publications and source records attributed to D Arduini.

At least 91 records · Page 5Linked to original sources
PubMed1992

Inferior vena cava flow velocity waveforms in appropriate- and small-for-gestational-age fetuses.

Reference ranges of inferior vena cava flow velocities were constructed from a cross-sectional study of 118 appropriate-for-gestational-age fetuses of 18 to 40 weeks of gestation. Blood flow velocity waveforms were recorded with color and pulsed Doppler equipment. Peak velocities and time velocity integrals were measured from inferior vena cava during systole, early diastole, and atrial contraction. The systolic-to-diastolic ratios between the peak velocities and time velocity integrals were calculated, and the reverse flow with atrial contraction was quantified as the percentage of forward flow (percentage of reverse flow). Recordings were also obtained from 79 small-for-gestational-age fetuses free of structural and chromosomal abnormalities, divided into three groups according to umbilical artery velocity waveforms: normal pulsatility index values (group 1, n = 26), pulsatility index greater than 95th percentile of our reference limits but presence of end-diastolic velocities (group 2, n = 33), and absence of end-diastolic velocities (group 3, n = 20). Fourteen fetuses of groups 2 and 3 were also studied at weekly intervals until the onset of antepartum late heart rate decelerations. In appropriate-for-gestational-age fetuses no changes were evident in peak velocities and time velocity integrals ratios, whereas the percentage of reverse flow significantly decreased with gestation. No significant differences were found between these values and those obtained in small-for-gestational-age fetuses of group 1. A significant increase of peak velocities and time velocity integrals ratios and of percentage of reverse flow was evidenced in fetuses of both group 2 and 3. The fetuses of groups 2 and 3 with a percentage of reverse flow above the 95% confidence interval showed a poorer perinatal outcome when compared with the fetuses of the same groups but with values inside the normal range. In the 14 fetuses longitudinally followed up until the onset of late heart rate decelerations a significant and progressive increase of peak velocities and time velocity integrals ratios and percentage of reverse flow was evidenced in spite of minimal changes in the pulsatility index from both umbilical artery and different peripheral fetal vessels. This study presents evidence that in small-for-gestational-age fetuses with abnormal Doppler-measured placental resistance the modified flow velocity patterns in the inferior vena cava seem to deteriorate progressively with advancing gestation.

Blood Flow Velocity↗
PubMed1992

Umbilical vein pulsations: a physiologic finding in early gestation.

OBJECTIVES: The purpose of this study was to establish the incidence of umbilical vein pulsations in normal early pregnancies and to evaluate whether these pulsations are related to Doppler-measured vascular resistances in umbilical artery or central venous flow patterns. STUDY DESIGN: We performed a cross-sectional study on 257 uneventful pregnancies at 7 to 16 weeks of gestation by means of transvaginal color and pulsed Doppler ultrasonography. Blood flow velocity waveforms were recorded from the umbilical artery, umbilical vein and, in 48 cases, also from fetal inferior vena cava. RESULTS: Pulsations in the umbilical vein were evidenced in all cases until 8 weeks. From this gestational age on pulsations progressively disappeared, becoming completely absent at greater than or equal to 13 weeks. The incidence of pulsations in the umbilical vein was unrelated to umbilical artery pulsatility index values, the incidence of absent end-diastolic flow in umbilical artery, and fetal heart rate. In the inferior vena cava, reverse flow during atrial contraction was significantly higher (p less than or equal to 0.002) in cases with umbilical vein pulsations than in those cases without pulsations at a similar gestational age. CONCLUSIONS: Pulsations in the umbilical vein are physiologically present during the first trimester of pregnancy and seem to be related to inferior vena cava flow patterns.

Adult↗
PubMed1992

Prediction of fetal outcome in small for gestational age fetuses: comparison of Doppler measurements obtained from different fetal vessels.

Blood flow velocity waveforms were recorded from different vascular districts including umbilical artery, descending aorta, renal artery, internal carotid artery and middle cerebral artery in a population of 120 small for gestational age fetuses free from structural and chromosomal abnormalities. The pulsatility index from each vessel as well as the ratios between the pulsatility indices from peripheral and cerebral vessels were calculated and related to perinatal outcome. The pulsatility index of middle cerebral artery resulted the most efficient measurement to predict the development of perinatal adverse outcome when each vessel was considered singularly, however, better results were achieved when the ratios between pulsatility indices were related to perinatal outcome; this is mot evident for the ratio between the pulsatility indices of umbilical artery and middle cerebral artery. Our results suggest the usefulness of this ratio in differentiating small for gestational age fetuses at risk of unfavorable outcome.

Adult↗
PubMed1992

Accelerated cardiac growth and abnormal cardiac flow in fetuses of type I diabetic mothers.

OBJECTIVES: To determine the growth patterns of the fetal heart and the development of cardiac function during gestation in fetuses of diabetic mothers, and to compare these findings with those of normal fetuses. METHODS: Serial M-mode and Doppler echocardiographic recordings were made at 4-week intervals in 14 fetuses of well-controlled type I insulin-dependent diabetic mothers and in ten control fetuses at 20-36 weeks' gestation. The following variables were measured: interventricular septal thickness, left ventricular wall thickness, right ventricular wall thickness, ratio between the peak velocities during early passive ventricular filling and active atrial filling at the level of the atrioventricular valves, peak velocities, and time to peak velocity at the level of the ascending aorta and pulmonary artery. RESULTS: In both groups of fetuses, all of the indices increased linearly with gestation. However, fetuses of diabetic mothers showed significant differences in the slope and intercept values for the function describing the growth of the interventricular septum (P less than or equal to .001) and the right and left ventricular wall thicknesses (P less than or equal to .01), resulting in accelerated cardiac growth. The function describing the development of the ratios between early and active ventricular filling showed differences in slope and intercept values at the level of both the mitral (P less than or equal to .001) and tricuspid valves (P less than or equal to .001), resulting in a lower rate of increase during diabetic pregnancy when compared with control fetuses. Significantly higher intercept values were found in the functions describing the increase of peak velocities in the aorta and pulmonary artery in fetuses of diabetic mothers (P less than or equal to .01), whereas the slopes were similar to those of control fetuses. No differences were found in the time to peak values between the groups of fetuses. No relationships were found between the echocardiographic results and the metabolic control of pregnancy or fetal characteristics. CONCLUSIONS: This study suggests that strict maternal diabetes control does not exclude accelerated fetal cardiac growth and abnormal development of cardiac function.

Adult↗
PubMed1992

Changes of pulsatility index from fetal vessels preceding the onset of late decelerations in growth-retarded fetuses.

Thirty-six growth-retarded fetuses selected from a population of 214 cases were studied by Doppler ultrasonography at weekly intervals for at least 4 weeks between the diagnosis of Doppler abnormalities suggestive of the existence of the brain-sparing effect (ie, ratio between umbilical artery and middle cerebral artery pulsatility indexes [PIs] above the 95th percentile of our reference limits) to the onset of antepartum late fetal heart rate (FHR) decelerations. Recordings were made from the umbilical artery, descending aorta, renal artery, internal carotid artery, and middle cerebral artery and the PIs were calculated. Statistically significant changes in PI occurred in all the vessels studied. However, different trends were found when the modifications in cerebral vessels were compared with those in fetal peripheral vascular beds and in the umbilical artery. In cerebral arteries, a nadir of vasodilatation was reached 2 weeks before the onset of antepartum late FHR decelerations, whereas significant changes in the peripheral and umbilical vessels occurred close to the onset of abnormal FHR patterns. This study demonstrates that despite a brain-sparing effect, there are further Doppler-detectable modifications in fetal circulation that differ between the cerebral and peripheral vascular beds.

Cerebrovascular Circulation↗
PubMed1991

Ultrasound measurements of fetal limb bones.

In order to establish the growth patterns of fetal limbs, measurements of femur, humerus, tibia, fibula, radius and ulna were made by ultrasound and related to gestational age. To this end, 2317 normal singleton pregnant women were studied cross-sectionally at 13-40 weeks of gestation. Patients were selected on the basis of a certain last menstrual period, history of regular cycles and at least one ultrasound scan before 16 weeks confirming gestational age. Linear growth of all limb measurements was observed between 13 and 28 weeks of gestation. From this gestational age onwards, a flattening of the growth curve was seen. A second-degree polynomial equation turned out to be the best model to describe this phenomenon. The measurements of all six fetal long bones showed a high correlation with menstrual age (r >or= 0.99). The femur displayed the largest mean weekly increments (2.8 mm per week from 13 to 28 weeks and 1.7 mm per week from 29 to 40 weeks of gestation) and the radius had the smallest (2.08 mm per week from 13 to 28 weeks and 1.25 mm per week from 29 to 40 weeks' gestation). Considering inter and intraoperator variations and the weekly increment of fetal long bone length, a correct evaluation of limb growth is possible for the femur every week before 28 weeks and every 2 weeks after 28 weeks. For the remaining limb bones, a correct evaluation is possible every 2 weeks at all gestational ages.

Journal Article↗
PubMed1991

Doppler ultrasonography in early pregnancy does not predict adverse pregnancy outcome.

A transvaginal color and pulsed Doppler study was performed on 330 pregnancies at 7-16 weeks of gestation. Blood flow velocity waveforms were recorded from the main uterine arteries and their branches (arcuate and trophoblastic vessels) and from the umbilical arteries. The systolic/diastolic velocity ratio and the pulsatility index were calculated as indices of vascular resistance, respectively, at uterine and umbilical levels. A total of 282 patients had an uneventful pregnancy outcome, 19 developed an early pregnancy failure (missed abortion, n = 8; anembryonic pregnancy, n = 11) and 29 developed later complications such us hypertension (n = 10), fetal growth retardation (n = 13) or both n = 6). In normal pregnancies, Doppler-measured vascular resistances significantly decreased with advancing gestation at the level of both uterine and umbilical circulations. When the Doppler indices of the patients with early pregnancy failure or with later complications were compared to those of normal pregnancies, no evident differences were found in either of the vascular districts considered. However, in the patients who developed hypertension and/or fetal growth retardation, abnormal velocity waveforms were frequently present in uterine and umbilical arteries during second- or third-trimester examinations. Our results suggest a limited clinical value of Doppler velocimetry in early pregnancy.

Journal Article↗
PubMed1991

Fetal cardiac function in intrauterine growth retardation.

Blood-flow velocity waveforms are altered in several peripheral vascular beds of fetuses whose intrauterine growth is retarded because of placental insufficiency. We investigated these concomitant changes in cardiac function. Color and pulsed Doppler echocardiographic recordings were performed in 124 fetuses with intrauterine growth retardation. These fetuses were free of structural and chromosomal abnormalities and were characterized by increased umbilical artery resistance and reduced middle cerebral artery resistance. Twenty-four of these fetuses were also studied at weekly intervals until the onset of antepartum late heart rate decelerations. Blood-flow velocity waveforms were obtained from the aortic and pulmonary valves, and the following variables were measured: peak systolic velocity, time to peak velocity, the product of time velocity integral multiplied by heart rate, left and right cardiac output, and the right/left ratios of the product of time velocity integrals multiplied by heart rate and cardiac output. When compared with previously established norms, both aortic and pulmonary peak systolic velocities and pulmonary time to peak velocity were reduced; aortic time to peak velocity increased. Left cardiac output and the product of the aortic time velocity integral multiplied by the heart rate increased and right cardiac output and the product of the pulmonary time velocity integral multiplied by the heart rate decreased, resulting in reduced right/left ratios. In the 24 fetuses studied longitudinally, time to peak velocities and the right/left flow ratios remained stable. However, aortic and pulmonary peak velocities and cardiac output declined significantly in contrast to an expected rise with advancing gestation. The fall in cardiac output and aortic and pulmonary peak velocities was directly related to umbilical artery pH at birth. This study provides evidence of a modified cardiac function that seems to deteriorate progressively with the advancing gestation of fetuses with intrauterine growth retardation.

Cardiac Output↗
PubMed1991

Cardiac function in fetuses of type I diabetic mothers.

Cardiac function was cross-sectionally studied by means of M-mode and Doppler echocardiography in 40 fetuses of mothers with well-controlled insulin-dependent diabetes at 20 to 38 weeks of gestation. These variables were measured: interventricular septal thickness, ratio between the peak velocities during early passive ventricular filling and active atrial filling at the level of the atrioventricular valves, peak velocities, and the time to peak velocity at the level of the ascending aorta and the pulmonary artery. The values obtained were compared with our reference limits for gestation. A significant increase of interventricular septal thickness that was unrelated to maternal glycosylated hemoglobin levels was evidenced. Early passive ventricular filling/active atrial filling ratios were significantly lower in fetuses of diabetic mothers than in control fetuses. These differences were significantly related to interventricular septal thickness. No significant modifications were found in either aortic or pulmonary peak velocities or in time to peak velocity values. These findings suggest that in spite of an adequate metabolic control an interventricular septal hypertrophy that affects cardiac diastolic function develops in fetuses of diabetic mothers.

Adult↗
PubMed1991

Cardiac output in anencephalic fetuses.

The cardiac output was measured by means of Doppler echocardiography in four anencephalic fetuses during the late second or third trimester of pregnancy. Anencephalic fetuses showed a higher dominance of right ventricular output when compared to healthy fetuses, suggesting that the relationship between brain mass and body weight affects the distribution of cardiac output.

Anencephaly↗
PubMed1991

Longitudinal assessment of behavioural transitions in healthy human fetuses during the third trimester of pregnancy.

A longitudinal study was performed on 35 healthy fetuses in order to evaluate the developmental course of behavioural transitions during the last trimester of pregnancy. A progressive decrease in the duration of transitions as a function of gestational age was evidenced for both transitions from 1F to 2F and transitions from 2F to 1F. Concerning the sequence in change of behavioural variables (fetal heart rate, fetal eye movements and fetal gross body movements) a random distribution was found until 30 weeks for 1F to 2F transitions and until 34 weeks for 2F-1F transitions. After these gestational ages fetal heart rate and fetal gross body movements respectively become the first variable to change during 1F-2F and 2F-1F transitions. Reference values for these parameters are calculated in order to provide a basis for the diagnosis of behavioural abnormalities in high risk fetuses.

Analysis of Variance↗
PubMed1991

Doppler velocimetry versus nonstress test in the antepartum monitoring of low-risk pregnancies.

One thousand singleton low-risk pregnancies were cross-sectionally studied at 36-40 weeks gestation with continuous-wave Doppler ultrasonography in order to assess its usefulness as an antepartum monitoring technique for the identification of fetuses at risk of developing an adverse outcome. Uterine artery and umbilical artery S/D values were measured and related to fetal outcome. Results were compared with those of the nonstress test. No significant differences in fetal outcome, with the exception of birth weight, were found between patients with normal and abnormal uterine S/D values. In pregnancies with abnormal umbilical S/D values, a higher incidence of cesarean section for fetal distress and lower birth weight were observed. Moreover, those newborns more frequently had complications such as low 5-minute Apgar score, requiring resuscitation and admission to the intensive care unit. When compared to nonstress test, umbilical velocimetry showed a higher efficiency in identifying fetuses at risk for adverse outcome.

Arteries↗
PubMed1991

Fetal renal artery velocity waveforms and amniotic fluid volume in growth-retarded and post-term fetuses.

Renal blood flow velocity waveforms were recorded by Doppler ultrasonography in 114 growth-retarded fetuses and in 97 post-term fetuses. The pulsatility index (PI) values were compared with our reference limits for gestational age and related to the amount of amniotic fluid. Growth-retarded fetuses showed significantly increased PI values compared with normally grown fetuses, and this difference was particularly evident in cases of oligohydramnios. Furthermore, there was a significant negative correlation between the increase in PI and the amniotic fluid volume. Post-term fetuses showed no significant differences in PI values compared with term fetuses and no significant correlation between the amount of amniotic fluid and PI values.

Amniotic Fluid↗
PubMed1990

Effects of intravascular fetal blood transfusion on fetal intracardiac Doppler velocity waveforms.

In 12 fetuses from pregnancies with red blood cell isoimmunization Doppler velocity waveforms were recorded at the level of atrioventricular valves immediately before and at 15-minute intervals for 2 hours after the intravascular transfusion. The left and right cardiac outputs, the ratio between the peak velocities during early passive ventricular filling and active atrial filling at the level of both ventricles as well as the heart rate were calculated. Before transfusion, the left and right cardiac outputs were significantly higher than reference ranges for gestation that were constructed from the cross-sectional study of 187 normal pregnancies. After transfusion there was a significant temporary fall in right and left outputs associated with increased ratios between the peak velocities during early passive ventricular filling and active atrial filling. Within 2 hours after transfusion both parameters returned toward the normal range. In addition, no significant changes were found for fetal heart rate values before and after transfusion. The fall of cardiac output was significantly related to the amount of expansion of the feto-placental volume.

Blood Transfusion, Intrauterine↗
PubMed1990

Quantitative analysis of fetal rate: its application in antepartum clinical monitoring and behavioural pattern recognition.

A system based on an IBM compatible personal computer is described for the computerized analysis of the cardiotocograms. The system performs a quantification of both fetal heart rate and uterine contractions providing automatically several variables including heart rate baseline; number, duration and area of accelerations and decelerations; latency time between decelerations and uterine contractions; uterine resting tone; number, duration and area of contractions. The computerized description was compared to the visual analysis of the cardiotocogram and a good agreement was evidenced. This system was applied to the analysis of heart rate variability in order to recognize the different patterns characterizing fetal behavioral states. Up to now, however, the results obtained in this latter application are not sufficiently accurate and do not allow a reliable automatic recognition of heart rate patterns.

Cardiotocography↗
PubMed1990

Effects of behavioural states on cardiac output in the healthy human fetus at 36-38 weeks of gestation.

Doppler velocity waveforms from atrioventricular valves were recorded in 20 healthy fetuses at 36--38 weeks of gestation during both behavioural states 1F (quiet sleep) and 2F (active sleep). No significant changes were found in the ratios between the velocities during early passive ventricular filling and active ventricular filling (E/A ratios) at the level of both mitral and tricuspid valves when the measurements obtained during states 1F and 2F were compared. Moreover, during state 2F the left ventricular output increased and the right ventricular output decreased, resulting in a marked modification of the right to left cardiac output ratio. Our data suggest a redistribution of cardiac output in favour of the left side of the heart during state 2F.

Blood Circulation↗
PubMed1990

Doppler assessment of fetal blood flow velocity waveforms during acute maternal oxygen administration as predictor of fetal outcome in post-term pregnancy.

The changes in fetal blood flow velocity waveforms during maternal administration of 60% humidified oxygen were assessed by Doppler ultrasonography in 45 post-term fetuses. During oxygen treatment, nine fetuses exhibited temporary increases (24.3 +/- 2.0% [1 standard deviation] above pretreatment values) in the pulsatility index at the level of internal carotid artery. Although no significant changes (2.9 +/- 5.1%) were found in the remaining 36 fetuses. In this former group a higher incidence of emergency cesarean delivery due to fetal distress and more neonatal complications were observed. Also, meconium staining of the amniotic fluid and low 1- and 5-minute Apgar scores occurred more frequently in the group of fetuses who responded to maternal oxygen administration. An increase of at least 20% in the pulsatility index of internal carotid artery during maternal hyperoxygenation may be a useful marker of adverse outcome in post-term fetuses.

Adolescent↗