RESUMEN
BACKGROUND: The cloud is a promising resource for data sharing and computing. It can optimize several legacy processes involving different units of a company or more companies. Recently, cloud technology applications are spreading out in the healthcare setting as well, allowing to cut down costs for physical infrastructures and staff movements. In a public environment the main challenge is to guarantee the patients' data protection. We describe a cloud-based system, named ReportFlow, developed with the aim to improve the process of reporting and delivering electroencephalograms. METHODS: We illustrate the functioning of this application through a use-case scenario occurring in an Italian hospital, and describe the corresponding key encryption and key management used for data security guarantee. We used the X2 test or the unpaired Student t test to perform pre-post comparisons of some indexes, in order to evaluate significant changes after the application of ReportFlow. RESULTS: The results obtained through the use of ReportFlow show a reduction of the time for exam reporting (t = 19.94; p < 0.001) and for its delivering (t = 14.95; p < 0.001), as well as an increase of the number of neurophysiologic examinations performed (about 20%), guaranteeing data integrity and security. Moreover, 68% of exam reports were delivered completely digitally. CONCLUSIONS: The application resulted to be an optimal solution to optimize the legacy process adopted in this scenario. The comparative pre-post analysis showed promising preliminary results of performance. Future directions will be the creation and release of certificates automatically.
Asunto(s)
Nube Computacional , Registros Electrónicos de Salud , Seguridad Computacional , Electroencefalografía , Humanos , Difusión de la InformaciónRESUMEN
OBJECTIVES: This study was carried out to investigate growth indicators of fetal lean mass and fat mass in the second half of the gestational period in pregnancies complicated by gestational diabetes mellitus (GDM) in comparison to normal control pregnancies. METHODS: Forty-three control and 171 GDM pregnancies were followed longitudinally by ultrasound examinations, measuring both traditional biometric parameters and six non-traditional parameters for the evaluation of lean and fat mass. A mixed linear model derived from the log-Count function was used to model fetal growth and to make comparisons between groups. Factor analysis was used to evaluate the associations between gestational diabetes and fetal size and fetal fat/lean mass ratios. RESULTS: A total of 506 scans were obtained in the 214 pregnancies, a mean of 2.4 scans per pregnancy (range 2-5). Maternal age, prepregnancy weight and body mass index were significantly higher in GDM pregnancies. Fetuses of GDM pregnancies showed greater growth, at the same gestational age, for each lean and fat non-traditional parameter, having a significantly greater amount of total tissue mass and a higher fat mass/lean mass ratio, independent of gestational age, in comparison to control pregnancies. CONCLUSIONS: A non-invasive, repeatable evaluation of fetal body composition in utero could represent a useful method for the early detection of growth abnormalities and for direct estimation of the fetal metabolic status.
Asunto(s)
Tejido Adiposo/crecimiento & desarrollo , Peso al Nacer/fisiología , Diabetes Gestacional/fisiopatología , Desarrollo Fetal/fisiología , Tejido Adiposo/diagnóstico por imagen , Tejido Adiposo/fisiología , Adulto , Biometría , Índice de Masa Corporal , Diabetes Gestacional/diagnóstico por imagen , Femenino , Edad Gestacional , Humanos , Estudios Longitudinales , Edad Materna , Variaciones Dependientes del Observador , Embarazo , Factores de Riesgo , Ultrasonografía PrenatalRESUMEN
A number of genetic and environmental factors are taken into account as responsible for intrauterine growth restriction (IUGR); nevertheless, the relevance of genetic alteration in IUGR aetiology remains to be determined. The aim of this study was to investigate using a combined cytogenetic-molecular approach, improved by a new application of QF-PCR method, the presence of mosaic chromosomal changes in fetal/placental samples from 12 pregnancies with unexplained severe IUGR. This multiple approach allowed us to reveal and quantify subtle chromosomal mosaicisms with less than 5% of trisomic cells even in cases in which cytogenetic and FISH analyses failed to reveal them. These are three pregnancies with a mosaic trisomy for chromosomes 7, 2 and 14; the former case presented matUPD7 and was previously described in this journal (Placenta 22 (2001) 813) in association with pre- and postnatal growth restriction. It is intriguing that chromosomes 7, 2 and 14 are known or suspected to harbour imprinted genes, so that an unbalanced gene dosage in a subset of cells during embryonic development could lead to an early impairment of placental function. Our findings indicate that extensive molecular and cytogenetic studies of IUGR fetal and placental tissues are necessary to reveal at least part of the heterogeneous genetic lesions implicated in IUGR phenotypes.
Asunto(s)
Cromosomas Humanos , Desarrollo Fetal/genética , Retardo del Crecimiento Fetal/genética , Predisposición Genética a la Enfermedad , Mosaicismo/embriología , Placenta , Adulto , Células Cultivadas , Bandeo Cromosómico , Femenino , Retardo del Crecimiento Fetal/diagnóstico por imagen , Retardo del Crecimiento Fetal/etiología , Fluorescencia , Edad Gestacional , Humanos , Hibridación Fluorescente in Situ , Cariotipificación , Leucocitos Mononucleares , Masculino , Fenotipo , Placenta/patología , Reacción en Cadena de la Polimerasa/métodos , Embarazo , Secuencias Repetidas en Tándem/genética , UltrasonografíaRESUMEN
In 1997 we started a collaboration among three groups, combining our experience with Doppler examination of the human fetus, blood flow studies on fetal lamb, and mathematical modeling of human circulation. In preliminary investigations on fetal lambs, the same Doppler method designed for the human fetus was used to measure venous blood flow in the umbilical veins of seven fetal lambs. Doppler measurements and diffusion technique groups for umbilical venous flow were 210.8+/-18.8 and 205.7+/-38.5 ml/min/kg, respectively (p = 0.881). In human pregnancy the interobserver variabilities for the vein diameter, mean velocity, and absolute umbilical venous blood were 2.9%, 7.9%, and 12.7%, respectively. A cross-sectional study allowed us to establish normal reference values. Venous blood flow/kg of estimated fetal weight showed a nonsignificant linear reduction with gestational age, from 128.7 ml/min/kg at 20 weeks to 104.2 ml/min/kg at 38 weeks. In a series of 37 growth-restricted fetuses, the UV flow per kilogram was significantly lower in the more severe growth-restricted fetuses (abdominal circumference below the second percentile and abnormal umbilical arterial p.i.) than in normal comparable fetuses (p < 0.001). In a series of 140 normal fetuses, we calculated that the absolute blood flow rate in the ductus venosus (DV) increases significantly with advancing gestational age from 20 to 38 weeks of gestation (from 23.2+/-9.6 ml/min to 43.5+/-21.5 ml/min). This means that the percentage of umbilical blood flow shunted through the DV decreases significantly during gestation (from 50% at midgestation to 20% at 38 weeks). In a series of 45 growthrestricted fetuses, delivered because of nonreactive fetal heart rate (group 2) and for other reasons but still with a normal heart rate pattern (group 1), we measured the ductal inlet diameter. In these fetuses, the diameters at the ductal isthmus, normalized for the dimension of the abdominal circumference (inlet diameter/abdominal circumference), were significantly larger (group 1 = 6.8+/-2.3; group 29.4+/-2.8 ) than in the control group (6.1+/-0.3). This means that in this subset of fetuses the amount of blood shunted can be increased as a compensatory mechanism.
Asunto(s)
Retardo del Crecimiento Fetal/diagnóstico por imagen , Feto/irrigación sanguínea , Ultrasonografía Prenatal , Femenino , Retardo del Crecimiento Fetal/fisiopatología , Humanos , Embarazo , Flujo Sanguíneo Regional/fisiología , Ultrasonografía Doppler , Cordón Umbilical/diagnóstico por imagen , Cordón Umbilical/fisiologíaRESUMEN
The aim of this study was to assess and compare uterine artery (UtA) blood flow volume in pregnant patients with an abnormal uterine Doppler pulsatility index (PI) who delivered fetuses with an appropriate weight for gestational age (AGA) or with intrauterine growth restricted (IUGR). We prospectively recruited singleton pregnancies with abnormal uterine arteries P.I. between 18 and 38 weeks of gestation regardless of estimated fetal weight (EFW). Vessel diameter and blood flow velocity were measured along the UtA upstream to the vessel bifurcation in both the right and left UtAs. Uterine blood flow volumes measured in these pregnancies were compared to historical Control-pregnancies. Forty-three patients delivered at term a normal weight newborn (AGA-pregnancies). Thirty patients delivered growth restricted newborns at 32 weeks (i.r. 29-36w) with a median weight of 1160 gr (i.r. 1000-2065 gr) (IUGR-pregnancies). At mid-gestation (18 + 0 - 25 + 6 weeks + days of gestation) a significantly lower uterine blood flow volume per unit weight was observed between the two study groups and compared to controls: 142 ml/min/kg in IUGR-pregnancies, 217 ml/min/kg in AGA-pregnancies and 538 ml/min/kg in Control-pregnancies. These striking differences in blood flow volume were already present at mid-gestation, at a time when EFW was still normal. In late gestation (27 + 0 - 37 + 6 weeks + days of gestation), pregnancies with an abnormal uterine P.I. showed persistently low UtA flow (<50% of controls) even when corrected for fetal weight: 81 ml/min/kg in IUGR-pregnancies, 105 ml/min/kg in AGA-pregnancies, and 193 ml/min/kg in Control-pregnancies; p < 0.0001. Our findings are consistent with other recent studies regarding the association between reduced uterine blood flow volume and fetal growth restriction. However, the study brings new insight into the finding of abnormal uterine P.I. in normally grown fetuses typically dismissed as "falsely abnormal" or "false positive" findings. Our study suggests that blood flow volume measurement may serve as a new tool to assess this group of patients and possibly those with ischemic placental diseases that may provide some basis for therapeutic interventions.
Asunto(s)
Arteria Uterina/fisiología , Útero/irrigación sanguínea , Velocidad del Flujo Sanguíneo/fisiología , Volumen Sanguíneo/fisiología , Femenino , Retardo del Crecimiento Fetal/fisiopatología , Peso Fetal , Edad Gestacional , Humanos , Recién Nacido , Embarazo , Flujo Pulsátil , Flujo Sanguíneo Regional/fisiología , Ultrasonografía Doppler , Ultrasonografía PrenatalRESUMEN
The primary aim of this pilot study was to study uterine artery (UtA) blood flow volume in uneventful human pregnancies delivered at term, at mid and late gestation by means of 3D and bi-dimensional ultrasound imaging with angio-Doppler combined with fluid-dynamic modeling. Secondary aims were to correlate flow volume to placental site and to UtA Pulsatility Index (PI). Women with singleton, low-risk pregnancies were examined at mid and late gestation. The structure and course of the uterine artery (UtA) was studied in each patient by means of 3D-angio-Doppler and included vessel diameter D, blood flow velocity and PI (measured along the UtA). Fetal weight estimation and placental insertion site were assessed by ultrasound. A robust fluid-dynamic modeling was applied to calculate absolute flow and flow per unit fetal weight. Mean UtA diameter and blood flow velocity increased significantly (p < 0.0001) from mid-gestation to late gestation from 2.6 mm and 67.5 cm/s, to 3.0 mm and 85.3 cm/s, respectively, yielding an increasing absolute flow troughout gestation. h coefficient, derived by fluid-dynamic modeling to calculate mean velocity, increased significantly from 0.52 at mid-gestation to 0.57 at late gestation. UtA blood flow volume ml/min/kg-fetal weight was significantly higher at mid-gestation than at late gestation (535 ml/min/kg vs 193 ml/min/kg; p < 0.0001). In cases with strictly lateral placentas the ipsilateral UtA accommodates at mid and late gestation 63% and 67% of the total UtA flow. In central placentas UtA flow was evenly distributed between the two vessels. An inverse correlation was observed between PI and blood flow volume ml/min/kg (Pearson's coefficient r = -0.54). Our work confirms the technological and methodological limitations in the measurement of uterine artery blood flow. However, Doppler measurements supported by three-dimensional angio imaging of the uterine vessel, high resolution imaging and diameter measurement, and a robust mathematical model of local circulation adds a genuine new area of investigation into human uterine circulation during pregnancy.
Asunto(s)
Hemodinámica/fisiología , Flujo Sanguíneo Regional/fisiología , Ultrasonografía Doppler en Color/métodos , Ultrasonografía Prenatal/métodos , Arteria Uterina/diagnóstico por imagen , Arteria Uterina/fisiología , Angiografía/métodos , Peso al Nacer/fisiología , Técnicas de Diagnóstico Cardiovascular , Femenino , Edad Gestacional , Humanos , Imagenología Tridimensional/métodos , Recién Nacido , Modelos Teóricos , Proyectos Piloto , Placenta/irrigación sanguínea , Placenta/diagnóstico por imagen , Embarazo , Flujo Pulsátil/fisiología , Nacimiento a TérminoRESUMEN
OBJECTIVE: We have previously shown, in a cross-sectional study, that the reduction in umbilical vein blood flow in intrauterine growth-restricted fetuses is due to reduced umbilical vein velocity. The purpose of this longitudinal study in intrauterine growth-restricted fetuses was to determine whether the umbilical vein velocity reduction, which, in turn, reduces blood flow, persists throughout gestation or represents a late event that precedes indicated delivery. STUDY DESIGN: Twenty-one intrauterine growth-restricted fetuses with an abnormal umbilical artery velocimetry underwent serial sonographic and Doppler examinations from 23 to 36 weeks of gestation. Umbilical vein diameter and velocity were measured, and umbilical vein absolute (milliliters per minute) and weight-specific blood flow (milliliters per minute per kilogram) were calculated. Umbilical vein diameter, velocity, and blood flow were expressed per abdominal circumference. Intrauterine growth-restricted findings were compared to local reference data. RESULTS: Intrauterine growth-restricted fetuses showed persistent reductions in umbilical vein blood flow per abdominal circumference and weight-specific blood flow (milliliters per minute per kilogram) from the time of diagnosis of intrauterine growth-restriction. Umbilical vein velocity was reduced in the intrauterine growth-restricted fetuses, although umbilical vein diameter did not change. CONCLUSION: Reduction of umbilical vein blood flow is an early finding in intrauterine growth-restricted fetuses, and it can persist for several weeks until delivery. This reduction in blood flow is due to reduced umbilical vein velocity.
Asunto(s)
Retardo del Crecimiento Fetal/diagnóstico por imagen , Retardo del Crecimiento Fetal/fisiopatología , Resultado del Embarazo , Adulto , Velocidad del Flujo Sanguíneo , Estudios de Casos y Controles , Femenino , Sangre Fetal , Edad Gestacional , Humanos , Estudios Longitudinales , Embarazo , Probabilidad , Estudios Prospectivos , Valores de Referencia , Sensibilidad y Especificidad , Factores de Tiempo , Ultrasonografía Doppler , Ultrasonografía PrenatalRESUMEN
AIM: To compare sonographic measurements of fetal fat tissue in pregnancies complicated by gestational diabetes (GD), with patients undergoing either a diet only or a combined diet and insulin treatment, to those obtained in pregnancies with a normal glucose challenge test. METHODS: Forty-five singleton pregnancies complicated by GD but free of any other maternal disease known to affect fetal growth were recruited. GD was diagnosed by a 3-hour OGTT, and treatment was differentiated according to the glycemic profile. GD mothers were divided into two treatment groups: glycemic profile normalized by diet only treatment (n=16) and by combined diet and insulin treatment (n=29). Fetal biometry and subcutaneous fat tissue thickness of the anterior abdominal wall were sonographically evaluated at the time of diagnosis and every 4 weeks afterwards in both GD and normal glucose challenge test group (n=25). RESULTS: No differences were found in neonatal outcomes between combined diet and insulin treatment group and normal cases, whereas neonatal weight showed a statistically significant difference between diet only treatment group and healthy population. Abdominal circumference in fetuses from GD mothers and normal fetuses was similar, but there was a difference in the fetal fat tissue thickness at the time of diagnosis. CONCLUSION: Increased fetal fat tissue thickness in GD mothers at recruitment and its growth rate reduction during adequate treatment may be a new criterion for direct estimation of fetal metabolic status instead of the traditional indirect evaluation based on maternal glucose concentrations.
Asunto(s)
Tejido Adiposo/diagnóstico por imagen , Diabetes Gestacional/diagnóstico por imagen , Feto/anatomía & histología , Ultrasonografía Prenatal , Biometría , Diabetes Gestacional/fisiopatología , Femenino , Prueba de Tolerancia a la Glucosa , Humanos , Embarazo , Resultado del EmbarazoRESUMEN
We investigated the hemodynamics of the ductus venosus in the human fetus by means of a combined approach based on Doppler and computational techniques. The aim of our study was to assess the blood velocity changes across the ductus venosus. Color Doppler equipment was used to investigate 29 normal fetuses between 20 and 39 weeks of gestation. Velocities at the systolic peak (S), diastolic peak (D) and atrial contraction (A) were measured at the isthmus and at the outlet of the ductus venosus, and the corresponding angle-independent indices (S/A, (S-A)/S, (S-A)/D) were calculated. A parametric computational model was developed in order to investigate the influence of anatomical features of the ductus venosus on the hemodynamics of the vessel. In all the fetuses the S, D and A velocities at the outlet portion were significantly lower than those at the isthmic part of the ductus venosus (p < 0.0001). The mean percentages of velocity reduction were 23.1%, 26.5% and 33.6%, respectively. Computational simulations also showed a relevant decrease of the velocity along the ductus venosus during the whole cardiac cycle. Velocity reduction along the ductus was mainly due to its conicity and this reduction generally caused velocity values at the outlet to be below the normal range. Conversely, angle-independent indices measured both at the isthmus and at the outlet lay within the same range of the reported reference values and therefore were not influenced by sampling site.
Asunto(s)
Feto/irrigación sanguínea , Modelos Teóricos , Ultrasonografía Prenatal , Venas Umbilicales/diagnóstico por imagen , Velocidad del Flujo Sanguíneo , Estudios Transversales , Femenino , Edad Gestacional , Humanos , Embarazo , Ultrasonografía Doppler en Color , Venas Umbilicales/embriología , Venas Umbilicales/fisiología , Venas/diagnóstico por imagen , Venas/fisiología , Vena Cava Inferior/diagnóstico por imagen , Vena Cava Inferior/embriología , Vena Cava Inferior/fisiologíaRESUMEN
OBJECTIVE: To determine whether umbilical blood flow is reduced in a subset of growth-restricted (IUGR) fetuses when expressed as flow per kilogram or flow per unit of specific sonographic fetal measurements. DESIGN: Prospective. SUBJECTS: Thirty-seven IUGR fetuses were examined by Doppler ultrasound within 4 h of the last non-stress test prior to delivery. This population was divided into three groups of varying clinical severity according to the characteristics of umbilical arterial pulsatility index (PI) and heart rate. METHODS: Absolute and weight-specific umbilical vein (UV) flow were calculated from measurements of UV diameter and UV mean velocity. Umbilical vein diameter, velocity and UV flow were calculated also per unit head (HC) or abdominal circumference (AC) and correlated with gestational age. RESULTS: Umbilical vein flow (UVf) per kilogram fetal weight was significantly lower in the more severe IUGR fetuses (abnormal umbilical arterial PI) than in normally grown comparable fetuses (P < 0.001). Umbilical vein flow per unit HC was significantly lower in the three groups (P < 0.001) than in the control population. The UV diameter/HC ratio was normal whereas UV velocity/HC ratio was significantly lower in IUGR fetuses than in comparable controls. CONCLUSIONS: The present study clearly establishes that umbilical venous blood flow is reduced in IUGR fetuses on a weight-specific basis. The sonographic growth parameter which best distinguishes umbilical flow differences of IUGR fetuses from normal fetuses is the head circumference.
Asunto(s)
Retardo del Crecimiento Fetal/diagnóstico por imagen , Retardo del Crecimiento Fetal/fisiopatología , Ultrasonografía Prenatal/métodos , Venas Umbilicales/diagnóstico por imagen , Adulto , Análisis de Varianza , Velocidad del Flujo Sanguíneo , Estudios Transversales , Femenino , Humanos , Modelos Lineales , Embarazo , Tercer Trimestre del Embarazo , Estudios Prospectivos , Sensibilidad y Especificidad , Ultrasonografía Doppler/métodosRESUMEN
OBJECTIVE: To test the hypothesis that reduced birth weight in normal fetuses born at moderately high altitude (Denver), compared with the birth weight in normal fetuses born at sea level (Milan), is caused by a reduction in both lean mass and subcutaneous fat mass. STUDY DESIGN: Ninety-four normal singleton pregnancies (46 in Denver, 48 in Milan) had serial ultrasonographic axial images obtained to assess subcutaneous tissues of fetuses as a measure of body fat. The abdominal wall thickness and mid upper arm and mid thigh were examined. The equation was: Subcutaneous tissue equals total cross-sectional area minus bone and muscle area. Lean mass included the area of muscle and bone, head circumference, and femur length. RESULTS: Gestational age at delivery was similar between groups. Birth weight was less at Denver's altitude (2991 +/- 79 g versus 3247 +/- 96 g; P =.04). Abdominal wall thickness, mid upper arm, and mid thigh subcutaneous tissues measurements were significantly reduced at Denver's altitude and increased further in significance with advancing gestational age. Lean mass measurements were similar between groups. CONCLUSIONS: The reduced birth weight of the newborns in Denver was the result of a reduction in fetal subcutaneous fat tissue and not lean mass. Ultrasonography can be used to follow subcutaneous measurements longitudinally and to detect differences, and potentially disease processes, in study populations.
Asunto(s)
Altitud , Composición Corporal/fisiología , Retardo del Crecimiento Fetal/diagnóstico por imagen , Músculo Esquelético/diagnóstico por imagen , Ultrasonografía Prenatal/métodos , Tejido Adiposo/diagnóstico por imagen , Adulto , Índice de Masa Corporal , Colorado , Femenino , Humanos , Italia , Embarazo , Probabilidad , Valores de Referencia , Sensibilidad y EspecificidadRESUMEN
OBJECTIVE: Our aim was to test the hypothesis that Doppler velocimetry of the peripheral and central circulations in normal fetuses is not affected by moderately high altitude (Denver, Colo-1609 m) compared with sea level (Milan, Italy-40 m). STUDY DESIGN: One hundred nineteen patients with singleton pregnancies underwent Doppler waveform analysis of the following: umbilical artery, uterine artery, middle cerebral artery, ductus venosus, and the tricuspid and mitral valves. RESULTS: Birth weights were reduced at Denver's altitude (P<.001). The early/late diastolic inflow ratios of the atrioventricular valves increased with gestational age (P<.01), whereas systolic/diastolic ratios of the uterine and umbilical arteries decreased with gestational age (P<.01). There were no Doppler velocimetry differences in any vessel between Denver's and Milan's altitudes. CONCLUSIONS: Gestational age has the same effect on Doppler index at both high and low altitudes. Moderately high altitude does not affect uteroplacental or fetal vascular Doppler index and may reflect normal acclimatization in the smaller Denver fetuses.
Asunto(s)
Altitud , Velocidad del Flujo Sanguíneo/fisiología , Vasos Sanguíneos/embriología , Feto/fisiología , Ultrasonografía Doppler , Ultrasonografía Prenatal , Adulto , Arterias/diagnóstico por imagen , Arterias/embriología , Peso al Nacer , Vasos Sanguíneos/diagnóstico por imagen , Femenino , Edad Gestacional , Humanos , Embarazo , Cordón Umbilical/irrigación sanguíneaRESUMEN
OBJECTIVE: To identify the temporal sequence of abnormal Doppler changes in the fetal circulation in a subset of early and severely growth-restricted fetuses. METHODS: This was a prospective observational study in a tertiary care/teaching hospital. Twenty-six women who were diagnosed with growth-restricted fetuses by local standards before 32 weeks' gestation and who had abnormal uterine and umbilical artery Doppler velocimetry were enrolled onto the study. To compare Doppler changes as a function of time, pulsed-wave Doppler ultrasound was performed on five vessels in the fetal peripheral and central circulations. Doppler examinations were performed twice-weekly and on the day of delivery if the fetal heart rate tracing became abnormal. Doppler indices were scored as abnormal when their values were outside the local reference limits on two or more consecutive measurements. Biometry for assessment of fetal growth was performed every 2 weeks. Computerized fetal heart rates were obtained daily. Delivery was based on a non-reactive fetal heart rate tracing and not on Doppler information. Patients with a severely growth-restricted fetus who were delivered for maternal indications such as pre-eclampsia were excluded. Perinatal outcome endpoints included: intrauterine death, gestational age at delivery, newborn weight, central nervous system damage of grade 2 or greater, intraventricular hemorrhage and neonatal mortality. RESULTS: Mean gestational age and newborn weight at delivery were 29 (standard deviation (SD), 2) weeks and 818 (SD, 150) g, respectively. The sequence of Doppler velocimetric changes was described by onset time cumulative curves that showed two time-related events. First, for each vessel there was a progressive increase in the percent of fetuses developing a Doppler abnormality. Second, severely growth-restricted fetuses followed a progressive sequence of acquiring Doppler abnormalities which were categorized into 'early' and 'late' Doppler changes. Early changes occurred in peripheral vessels (umbilical and middle cerebral arteries; 50% of patients affected 15-16 days prior to delivery). Late changes included umbilical artery reverse flow, and abnormal changes in the ductus venosus, aortic and pulmonary outflow tracts (50% of patients affected 4-5 days prior to delivery). The time interval between the occurrence of early and late changes was significantly different (P < 0.0001) and late changes were significantly associated with perinatal death (P < 0.01). CONCLUSIONS: Doppler velocimetry abnormalities develop in different vessels of the severely growth-restricted fetus in a sequential fashion. Late changes in vascular adaptation by the severely growth-restricted fetus are the best predictor of perinatal death.
Asunto(s)
Circulación Sanguínea/fisiología , Retardo del Crecimiento Fetal/fisiopatología , Monitoreo Fetal , Feto/irrigación sanguínea , Ultrasonografía Doppler , Ultrasonografía Prenatal , Velocidad del Flujo Sanguíneo/fisiología , Femenino , Muerte Fetal , Edad Gestacional , Humanos , EmbarazoRESUMEN
OBJECTIVE: This study was undertaken to assess the accuracy of triplex ultrasonographic measurement of venous umbilical blood flow in comparison with the steady-state diffusion technique and to determine the impact of cotyledon weight and number on umbilical blood flow. STUDY DESIGN: Six late-gestation ewes with long-term catheter placement were studied for venous umbilical blood flow with the ethanol steady-state diffusion technique and with triplex-mode ultrasonography (color Doppler, pulsed-wave Doppler, and real-time ultrasonography). At necropsy the number and weight of the cotyledons serving each umbilical vein were recorded. RESULTS: Umbilical blood flow determined by triplex-mode ultrasonography (207. 5 +/- 8.6 mL. kg(-1) fetus. min(-1)) was virtually identical to that determined with the steady-state diffusion technique (208.1 +/- 7.3 mL. kg(-1) fetus. min(-1); P =.9). When values were normalized for the weight or number of cotyledons serving each vein, there was no difference in umbilical blood flow between small and large umbilical veins in all the sheep. CONCLUSIONS: Our study validates the accuracy of the triplex ultrasonographic method and provides justification for its use in future human investigations. In absolute terms umbilical blood flow frequently differs between the 2 veins. When expressed per number or mass of cotyledons, however, the umbilical blood flows are similar.
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Cabras/fisiología , Preñez/fisiología , Ultrasonografía Doppler , Venas Umbilicales/diagnóstico por imagen , Venas Umbilicales/fisiología , Animales , Difusión , Femenino , Tamaño de los Órganos , Embarazo , Flujo Sanguíneo Regional , Análisis de Regresión , Sensibilidad y Especificidad , Factores de TiempoRESUMEN
OBJECTIVE: Our purposes were to determine the relationship of the growth of umbilical blood flow to growth in body measurements of human fetuses in uncomplicated pregnancies. The study also aimed to assess the relative contributions of growth in umbilical vein diameter and of increased velocity to the increase in umbilical blood flow. STUDY DESIGN: An animal study was conducted to assess the accuracy of umbilical vein blood flow measurements obtained by triplex mode ultrasonography. Seven pregnant ewes underwent triplex mode umbilical vein flow determination. These results were compared with historical flow data obtained by a steady-state diffusion technique in 34 ewes matched for gestational age and weight. In a separate study performed on human beings, reproducibility and precision of triplex mode flow determination were assessed, as were the relationships between umbilical vein flow and gestational age and head and abdominal circumferences. This cross-sectional study was performed with 70 healthy fetuses ranging from 20 weeks' gestation to term. Best-fit interpolating equations and confidence limits were calculated for blood flow measurements versus gestational age and head and abdominal circumferences. RESULTS: In the validation study performed on sheep there were no significant differences between triplex mode and steady-state measurement groups with respect to gestational age or weight. The umbilical vein flows were similar between triplex mode and steady-state measurement groups (P =.881). In the human study the intraobserver and interobserver coefficients of variation for the vein diameter, mean velocity, and absolute umbilical vein blood flow varied from 2.9% to 12.7%. The mean duration of examination was 3 +/- 1 minutes. The umbilical vein diameter and mean velocity increased throughout pregnancy. The absolute umbilical vein flow increased exponentially from 97.3 mL/min at midgestation to 529.1 mL/min at 38 weeks' gestation, whereas umbilical vein flow per kilogram of fetal weight did not change significantly with gestational age. There was a strong correlation between absolute umbilical vein flow and the fetal head and abdominal circumferences. CONCLUSIONS: The triplex mode ultrasonographic technique can play an innovative role in obtaining quick and reproducible measurements of umbilical vein blood flow. The approach was validated with a sheep model. Umbilical vein blood normalized for fetal weight (milliliters per minute per kilogram of fetal weight) and absolute flow (in milliliters per minute) are consistent with previous human studies. We have established new reference values of umbilical vein blood flow relative to head and abdominal circumferences. The growth of umbilical venous diameter accounted for most of the growth in umbilical vein flow.