Maternal hyperoxygenation: therapy or test in growth-retarded fetuses?
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Comment↗
Biomedical subjects
G Rizzo
Publications and source records attributed to G Rizzo.
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↗
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↗
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↗
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↗
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↗
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↗
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↗
Omeprazole vs. ranitidine in short-term treatment of Helicobacter pylori positive duodenal ulcer patients.
Forty-three patients with active duodenal ulcer and Helicobacter pylori positivity in gastric antrum were randomly assigned to either omeprazole treatment (20 mg once a day) or ranitidine treatment (300 mg once a day) for 28 days. Re-evaluation of the patients (clinical and endoscopic examination and assessments for H pylori detection) was repeated after 2 weeks and at the end of the treatment. Healing rates in the omeprazole group were 40% after 2 weeks and 90% after 4 weeks, in the ranitidine group ulcer healing was recorded in 20% of patients after 2 weeks and in 80% after 4 weeks. Differences between treatments at 2 and 4 weeks were not statistically significant. Clinical response (disappearance of ulcer-related symptoms) was better in the omeprazole group at 2 weeks (p less than 0.05) but not at 4 weeks. At the end of the trial H pylori positivity in gastric antrum disappeared in 95% of the patients treated with omeprazole and in 5% of the patients who received ranitidine (p less than 0.001). The results confirm the effectiveness of omeprazole in short-term treatment of duodenal ulcer and re-emphasize the powerful activity of the drug on H pylori infection.
Adult↗
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↗
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↗
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↗
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↗
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↗
Doppler echocardiographic assessment of time to peak velocity in the aorta and pulmonary artery of small for gestational age fetuses.
The time to peak velocity was measured at the level of the ascending aorta and pulmonary artery by Doppler echocardiography in 38 small-for-gestational age (SGA) fetuses before and during maternal hyperoxygenation. The values were compared to a reference range derived from the study of 142 appropriate-for-gestational age (AGA) fetuses. In the SGA fetuses the time to peak velocity at the level of pulmonary artery was significantly lower and at the level of the aorta significantly higher than in AGA fetuses. During maternal hyperoxygenation the aortic time to peak velocity decreased towards normal range but there was no significant change at the level of the pulmonary artery. These results may indicate variations of aortic and pulmonary pressures in SGA fetuses that can be partially modified by maternal hyperoxygenation and which may be associated with changes in the peripheral resistance of the cerebral circulation.
Aorta, Thoracic↗
Effects of maternal hyperoxygenation on atrioventricular velocity waveforms in healthy and growth-retarded fetuses.
In order to assess whether maternal hyperoxygenation induces modifications of Doppler-measured velocity waveforms across atrioventricular valves, 15 healthy and 15 growth-retarded fetuses were studied in basal conditions and during the maternal administration of 60% humidified oxygen. Recordings were performed at 5-min intervals before, during and after maternal oxygen administration. In basal conditions, growth-retarded fetuses exhibited significantly lower ratios between the velocities during early passive ventricular filling and active ventricular filling (E/A ratio) at the level of both mitral and tricuspid valves when compared to healthy fetuses. Furthermore in healthy fetuses the velocity time integral across the tricuspid valve always slightly exceeded that across the mitral valve, whilst growth-retarded fetuses showed an inversed ratio between these velocities. During oxygen administration no changes were found between the two groups of fetuses with regard to the E/A ratios. Similarly the velocity time integrals were unaffected by oxygen administration in the healthy fetuses. Besides growth-retarded fetuses exhibited significant temporary modifications during oxygen administration as expressed by an increase in the velocity time integral across the mitral valve associated with a decrease of that across the tricuspid. These changes result in an inversion of the ratio between transtricuspid and transmitral velocity time integrals reaching values similar to those of healthy fetuses. Short-term oxygen administration affects the intracardiac flow redistribution present in growth-retarded fetuses bringing it to a pattern similar to that of healthy fetuses whereas the E/A ratios were not affected by the treatment.
Blood Circulation↗
Acute ciclosporin nephrotoxicity in renal transplant patients.
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Acute Disease↗
Normal values of Pulsatility Index from fetal vessels: a cross-sectional study on 1556 healthy fetuses.
In a cross-sectional study of 1556 uncomplicated pregnancies velocity waveforms were recorded at the level of fetal umbilical artery, descending aorta, renal artery, internal carotid artery and middle cerebral artery. Reference limits for the Pulsatility Index of each vessel were constructed by regression analysis and a progressive fall during gestation was evidenced in all the vascular districts investigated with the exception of descending aorta. Furthermore we calculated the ratios between Pulsatility Index values of cerebral and peripheral vessels which may be relevant for the early diagnosis of the haemodynamic abnormalities occurring during the brain sparing effect.
Arteries↗