Fisiología respiratoria: el pulmón al momento de nacer / Respiratory Physiology - the lung at the moment of birth

La adaptación fisiológica de los recién nacidos de la vida intrauterina a la extrauterina incluye cambios fisiológicos complejos. Para que se complete con éxito la transición fetal a neonatal, los recién nacidos deben lograr el aclaramiento de líquido pulmonar, la generación de CRF e inicio de la respiración, para permitir el intercambio de gases y la oxigenación de los tejidos. En este artículo se describen estos mecanismos, algunas bases del desarrollo pulmonar y de la circulación fetal; y las medidas que se requieren para asistir al recién nacido cuando no logran completar esta transición espontáneamente, lo que ocurre en el 5 al 10 % de los casos.

The physiological adaptation of newborns from intrauterine to extrauterine life includes complex physiological changes. For the fetal to neonatal transition to be successfully completed, neonates must achieve lung fluid clearance, FRC generation, and initiation of respiration to allow gas exchange and tissue oxygenation. This article describes these mechanisms, some bases of lung development and fetal circulation; and the measures required to assist the newborn, when they fail to complete this transition spontaneously, which occurs in the 5 to 10% of cases.

Aortic isthmus doppler velocimetry in fetuses with intrauterine growth restriction: A literature review / Dopplervelocimetria do istmo aórtico em fetos com crescimento intrauterino restrito: Uma revisão da literatura

Abstract Intrauterine growth restriction (IUGR) is associated with poor perinatal prognosis and a higher risk of stillbirth, neonatal death, and cerebral palsy. Its detection and the evaluation of its severity by new Doppler velocimetric parameters, such as aortic isthmus (AoI), are of great relevance for obstetrical practice. The AoI is a vascular segment that represents a point of communication between the right and left fetal circulations. It is considered to be a functional arterial shunt that reflects the relationship between the systemic and cerebral impedances, and has recently been proposed as a tool to detect the status of hemodynamic balance and prognosis of IUGR in fetuses. In the present review, we noticed that in healthy fetuses, the AoI net flow is always antegrade, but in fetuses with IUGR the deterioration of placental function leads to progressive reduction in its flow until it becomes mostly retrograde; this point is associated with a drastic reduction in oxygen delivery to the brain. The more impaired the AoI flow is, the greater is the risk of impairment in the Doppler velocimetry of other vessels; and the alterations of the AoI Doppler seem to precede other indicators of severe hypoxemia. Although there seems to be an association between the presence of retrograde flow in the AoI and the risk of long-term neurologic disability, its role in the prediction of perinatal morbi-mortality remains unclear. The AoI Doppler seems to be a promising tool in the management of fetuses with IUGR, but more studies are needed to investigate its employment in clinical practice.

Resumo O crescimento intrauterino restrito (CIUR) está associado a um prognóstico perinatal adverso, com maior risco de óbito intrauterino e neonatal, bem como de paralisia cerebral. Assim, sua detecção e a determinação de sua gravidade por novos parâmetros Dopplervelocimétricos, como o istmo aórtico (IAo), são de fundamental importância na prática obstétrica. O IAo é um segmento vascular que representa um ponto de comunicação entre os sistemas circulatórios fetais esquerdo e direito. É considerado um shunt arterial funcional, capaz de refletir a relação entre as impedâncias dos circuitos cerebral e sistêmico, e foi proposto como uma ferramenta para detecção do status do equilíbrio hemodinâmico e do prognóstico de fetos com CIUR. Na presente revisão, observou-se que, em fetos saudáveis, o fluxo predominante no IAo é sempre anterógrado; mas em fetos com CIUR a deterioração do estágio de insuficiência placentária acarreta reduções progressivas no fluxo ístmico até este apresentar sentido predominantemente retrógrado e levar a uma drástica redução no aporte de oxigênio ao sistema nervoso central. Quanto mais alterado estiver o fluxo no IAo, maior a chance de haver alteração na Dopplervelocimetria de outros vasos; e as alterações no Doppler do IAo parecem preceder outros indicadores de hipoxemia severa. Embora o fluxo retrógrado no IAo pareça se correlacionar com maior risco de alteração no desenvolvimento neurológico a longo prazo, ainda não está claro o seu papel na predição de morbimortalidade perinatal. O Doppler do IAo parece ser um parâmetro promissor no manejo do CIUR; entretanto, mais estudos são necessários para avaliar seu emprego na prática clínica.

The types of connections between the portal sinus and main portal vein in foetuses / Tipos de conexiones entre el seno portal y la vena porta principal en fetos

In the prenatal period, the three types of connections between the portal sinus and main portal vein have been published in the literature: T, X and H-shaped. The T type is the most frequent in the literature, and the aim of our study is to define the percentage of the connection types during the prenatal period in our population. In this prospective study, 237 women between 20 and 38 weeks of pregnancy without a foetal anomaly or pregnancy-related complications were included, and the precordial veins of the foetuses were examined using a wide-band color Doppler technique. The types of connections were determined by two specialists according to the shape of the colour coded vessels in Doppler examinations. The criteria of Czubalski & Aleksandrowicz (2000) were used. All of the connection types in patients were confirmed using video clips and were stored in the picture archiving and communication system. In 237 patients, the types of connection were determined by the first specialist as 189 foetuses (79.7 %) with the X-shaped or side-to-side connection, 16 foetuses (6.8 %) with the T-shaped or end-to-side type and 32 foetuses (13.5 %) with the H-shaped or parallel-coursed vessels connected with a short segment. The most common types of connections between the portal sinus and main portal vein in foetuses are X shaped or side-to-side, which is contrary to previous studies.

En el período prenatal, se han publicado en la literatura los tres tipos de conexiones entre el seno portal y la vena porta principal: en forma de T, X y H. El tipo T es el más frecuente, y el objetivo de nuestro estudio fue definir el porcentaje de tipos de conexión durante el período prenatal en nuestra población. En este estudio prospectivo, se incluyeron 237 mujeres entre 20 y 38 semanas de embarazo, sin anomalías fetales o complicaciones relacionadas con el embarazo, y se examinaron las venas precordiales de los fetos utilizando una técnica Doppler de banda ancha. Los tipos de conexiones fueron determinados por dos especialistas según la forma de los vasos codificados por color en los exámenes Doppler. Se utilizaron los criterios del estudio de Czubalski & Aleksandrowicz. Todos los tipos de conexión en los pacientes se confirmaron mediante videoclips y se almacenaron en el sistema de comunicación y en archivo de imágenes. En 237 pacientes, el primer especialista determinó en 189 fetos (79,7 %) la conexión en forma de X o de lado a lado; en 16 fetos (6,8 %) la forma de T o Tipo de extremo a lado; y en 32 fetos (13,5 %) los vasos en forma de H o paralelos, conectados con un segmento corto. Los tipos más comunes de conexiones entre el seno portal y la vena porta principal en los fetos son en forma de X o de lado a lado, lo que es contrario a estudios anteriores.

Doppler velocimetry in fetal rats exposed to enoxaparin and unfractionated heparin (UFH) during pregnancy

Abstract Purpose: To evaluate the effects of enoxaparin and unfractionated heparin (UFH) administered in prophylactic and therapeutic doses on fetal vessels in healthy pregnant Wistar rats, according to Doppler velocimetry measurements. Methods: Fifty animals were assigned to one of five groups: controls (saline), prophylactic and therapeutic enoxaparin (1 and 2 mg/kg/day, respectively), and prophylactic and therapeutic UFH (72 and 400 UI/kg/day, respectively). Uterine horns were examined by ultrasound for identification of live fetuses. A sample of these fetuses underwent Doppler velocimetry. Spectral curves, peak systolic velocity (PSV), pulsatility index (PI), and resistance index (RI) of the middle cerebral artery, ductus venosus, and umbilical artery were investigated. Differences were considered statistically significant when p<0.05. Results: No significant differences in PSV, PI, or RI values were observed among the groups. Conclusion: Doppler velocimetry measurements revealed no significant effects of enoxaparin or unfractionated heparin on fetal vessels in pregnant Wistar rats.

Restricción del crecimiento intrauterino: una aproximación al diagnóstico, seguimiento y manejo / Intrauterine growth restriction: an approach to diagnosis, monitoring and management

ANTECEDENTES: La restricción del crecimiento intrauterino (RCIU) es una entidad de origen multifactorial que puede ser causada por una gran variedad de patologías a nivel materno, fetal o placentario, y que representa altas tasas de morbimortalidad materna y perinatal. Es importante realizar un diagnóstico certero de esta patología con el fin de llevar a cabo un enfoque de seguimiento y de manejo que pueda disminuir todas las complicaciones asociadas a la enfermedad. OBJETIVO: Realizar una revisión detallada y actualizada de la etiopatogenia, criterios diagnósticos, seguimiento con ecografía Doppler y manejo de la restricción del crecimiento intrauterino. MÉTODO: Se realizó una búsqueda de literatura publicada en inglés y español en bases de datos como PubMed/MEDLINE, Ovid, MDconsult utilizando las palabras clave: restricción del crecimiento intrauterino, feto pequeño para la edad gestacional, circulación fetal, ecografía Doppler, además de la búsqueda de estadísticas relacionadas con RCIU, de los resultados obtenidos se seleccionaron 61 artículos. La información obtenida fue clasificada y utilizada como soporte para la realización de esta revisión. RESULTADOS: Se presentan los estudios disponibles, las revisiones y artículos recomendados para la evaluación de pacientes con RCIU, adicionalmente aquellos que brindan nueva información con respecto al diagnóstico, evaluación de circulación fetal, seguimiento y manejo de esta entidad clínica. CONCLUSIÓN: La restricción del crecimiento intrauterino es una patología que presenta altas tasas de morbimortalidad perinatal. La identificación temprana de estos fetos y el seguimiento adecuado mediante la evalución Doppler permiten disminuir los resultados adversos y las secuelas a corto y largo plazo.

BACKGROUND: Intrauterine growth restriction has a multifactorial origin and can be caused by a variety of pathologies in the mother, fetus or placenta, representing high rates of maternal and perinatal morbidity and mortality. Therefore, it is important to accurately diagnose this condition in order to focus in the follow and management, which can reduce the complications associated with the disease. OBJECTIVE: To perform a detailed and up to date review of the etiology, diagnostic criteria, follow up with Doppler ultrasonography and management of intrauterine growth restriction. METHODS: A literature search was done in English and Spanish in databases such us PubMed/MEDLINE, Ovid, MDconsult using the following key words: intrauterine growth restriction, small for gestational age fetus, fetal circulation, Doppler ultrasonography. Also national statistics for intrauterine growth restriction were used, obtaining 61 documents. The information obtained was classified and used in the development of this review. RESULTS: The available studies are presented, and recommended revisions to the evaluation of patients with IUGR, additionally those that provide new information regarding the diagnosis, evaluation of fetal circulation, monitoring and management of this clinical entity. CONCLUSION: Intrauterine growth restriction is a pathology with a frequent diagnosis an represents high rates of perinatal morbidity and mortality. Early identification of these fetuses and adequate monitoring by Doppler evaluation allow reducing adverse outcomes and consequences in the short and long term.

Resultados perinatales en fetos con flujo umbilical diastólico ausente / Perinatal outcome in fetuses with absent end diastolic umbilical flow

Objetivo: Estudiar los resultados perinatales de fetos diagnosticados con flujo umbilical ausente en diástole en el Hospital Universitario de Canarias, España. Métodos: Estudio retrospectivo de gestantes con Doppler fetal umbilical con flujo diastólico ausente entre 2004 y 2011, excluyendo embarazos gemelares. Las variables estudiadas fueron: edad y enfermedades maternas, edad gestacional al diagnóstico y parto, vía de parto, Apgar y estado del recién nacido. Resultados: Se recogieron 57 casos. Hubo un 43 por ciento de gestantes hipertensas y 19 por ciento de diabéticas. La edad gestacional media al diagnóstico fue de 30+4 semanas. En el 89% de los casos se observó redistribución del flujo y en el 21 por ciento el Doppler umbilical fue reverso. El 28 por ciento se acompañó de oligoamnios y en el 26 por ciento el peso fetal estimado inferior al percentil 3. Hubo 3 muertes fetales. En el 80 por ciento de los casos la vía de parto fue por cesárea. La supervivencia fue del 83 por ciento con una tasa de mortalidad perinatal del 17 por ciento. En el seguimiento entre 1 y 6 años encontramos un 35 por ciento de niños sin secuelas. Conclusiones: En nuestra serie, el Doppler con flujo umbilical ausente en diástole se relaciona con alto riesgo de morbimortalidad perinatal. El 65 por ciento de los niños tendrán secuelas de algún tipo en el seguimiento entre 1 a 6 años. El momento óptimo para la extracción fetal debe ser individualizado y resuelto junto con el consejo pediátrico y participación de los padres.

Objective: To determine the perinatal outcome in fetal growth restriction were umbilical artery Doppler end diastolic flow was absent. Methods: A retrospective study performed at the Canary Islands University Hospital. All consecutive cases between 2004 and 2011 were included. We excluded twin pregnancies. Data was abstracted for maternal age, gestational age at diagnosis and delivery, mode of delivery, Apgar and perinatal adverse outcomes. Results: Fifty seven patients were included. Forty three percent had a pregnancy complicated by hypertension and 19 percent diabetes. Mean gestational age at diagnosis was 30+4 weeks. We found 89 percent and 21 percent absent umbilical artery end diastolic flow and reverse flow respectively. Oligohydramnios was seen in 28 percent of the cases. Fetal weight was below the third percentile in 26 percent of the cases. Fetal demise occurred in 3 cases. Mode of delivery was cesarean section in 80 percent of the cases. We found a rate of 17 percent perinatal mortality. At 1 to 6 years follow up 35 percent of the children had no sequelae. Conclusion: Absent end diastolic umbilical flow is associated with a high risk of perinatal mortality. Up to 65 percent of the children will show some type of sequelae. The optimal gestational date for fetal extraction should be individualized after multidisciplinary counseling.

Diagnóstico prenatal y evolución en fetos con agenesia de ductus venoso / Prenatal diagnosis and evolution in fetuses with ductus venosus agenesis

Antecedentes: El ductus venoso es una derivación vascular (shunt) presente en el feto que permite el paso de sangre oxigenada de la vena umbilical (VU) hacia la circulación coronaria y cerebral. Su agenesia se asocia con defectos cromosómicos, síndromes genéticos, defectos estructurales y complicaciones prenatales como crecimiento intrauterino retardado y muerte fetal. Resultados: Se analizaron 15 agenesias de ductus venoso (ADV) en gestaciones únicas entre enero de 2010 y diciembre de 2013. El 80 por ciento de ellas fueron diagnosticadas en la exploración rutinaria de la semana 12. Se realizó estudio de cariotipo en el 53 por ciento de los casos (8/15), bien por riesgo alto de cromosomopatía en el cribado combinado y/o translucencia nucal aumentada (75 por ciento) o malformaciones asociadas (25 por ciento). Sólo hubo un diagnóstico de trisomía 21 y postnatalmente de una microdelección del cromosoma 7. Realizaron interrupción legal del embarazo un total de 4 pacientes (por trisomía 21 o por alteraciones estructurales). Entre las 11 gestaciones restantes un 27 por ciento se diagnosticó RCIU, hubo una muerte neonatal a las 12 horas de vida por síndrome de aspiración meconial e hipertensión pulmonar. En un 60 por ciento se objetivó la presencia de un drenaje umbilicohepático y entre los 6 restantes con shunt portosistémico, 4 tenían conexión entre la VU y la VCI. Conclusión: La ADV es una anomalía infrecuente del sistema venoso fetal, de difícil diagnóstico y con mal pronóstico en aquellos casos en que se asocia con otros marcadores y/o anomalías estructurales que pueden aparecer tardíamente, por lo que debe realizarse un seguimiento adecuado.

Background: The ductus venosus (DV) is a unique shunt that allows direct passage of oxygenated blood from the umbilical vein (UV) to the coronary and cerebral circulation by a preferential passage through the foramen ovale. DV agenesis (DVA) is associated with chromosomal abnormalities, genetic syndromes, structural defects and prenatal complications such as intrauterine growth retardation (IUGR) or even stillbirth. Results: We report 15 cases of DVA in singleton pregnancies between January 2010 and December 2013. 80 percent of them were diagnosed on routine examination during the 11-14 weeks scan. Karyotyping was performed in 53 percent of cases (8/15) by high risk of chromosomal abnormalities in the first trimester combined screening and/or an increased nuchal translucency thickness in 6/8 (75 percent), or associated malformations 2/8 (25 percent). There was only one fetus diagnosed of trisomy 21 by amniocentesis and another fetus was postnatally diagnosed of a microdeletion of chromosome 7. 4 patients performed legal abortions (the trisomy 21 and in 3 cases for severe structural malformations). Among the remaining 11 pregnancies, 3 (27 percent) were diagnosed with IUGR and there was a neonatal death at 12 hours of life for meconium aspiration syndrome and pulmonary hypertension. 60 percent of the fetus presented an intrahepatic drainage and among the remaining 6 with portosystemic shunt, in 4 a connection between the UV and the inferior vena cava was observed. Conclusion: DVA is a rare anomaly of the fetal venous system, difficult diagnosis and poor prognosis in cases associated with other markers and/or structural abnormalities that may even appear late. A detailed survey of fetal anatomy and follow up of these fetuses is necessary.

Anatomical study on the psoas minor muscle in human fetuses / Estudio anatómico del músculo psoas menor en fetos humanos

The anatomy of the psoas minor muscle in human beings has frequently been correlated with ethnic and racial characteristics. The present study had the aim of investigating the anatomy of the psoas minor, by observing its occurrence, distal insertion points, relationship with the psoas major muscle and the relationship between its tendon and muscle portions. Twenty-two human fetuses were used (eleven of each gender), fixed in 10 percent formol solution that had been perfused through the umbilical artery. The psoas minor muscle was found in eight male fetuses: seven bilaterally and one unilaterally, in the right hemicorpus. Five female fetuses presented the psoas minor muscle: three bilaterally and two unilaterally, one in the right and one in the left hemicorpus. The muscle was independent, inconstant, with unilateral or bilateral presence, with distal insertions at different anatomical points, and its tendon portion was always longer than the belly of the muscle.

La anatomía del músculo psoas menor, en los seres humanos ha sido a menudo vinculada con cuestiones de orden étnico-raciales. Este estudio tuvo como objetivo evaluar la anatomía del músculo psoas menor en relación a su presencia, puntos de origen e inserción, relación con el músculo psoas mayor y sus porciones tendinosa y muscular. Se utilizaron 22 fetos humanos (11 de cada sexo) que fueron fijados en solución de formalina al 10 por ciento por perfusión a través de la arteria umbilical. El músculo psoas menor se encontró en 8 fetos de sexo masculino, siete bilateralmente y apenas uno unilateralmente en el hemicuerpo derecho. En los fetos de sexo femenino, cinco tenían el músculo psoas menor, tres bilateralmente y dos unilateralmente, siendo uno encontrado en el hemicuerpo derecho y otro en el izquierdo. El músculo es independiente, inconstante, de presencia unilateral o bilateral, con la inserción en diferentes sitios anatómicos y su porción tendinosa siempre mayor que el vientre muscular.

Conduta obstétrica na centralização da circulação fetal / Obstetric management in fetal brain sparing effect

A centralização do fluxo sanguíneo fetal é um fenômeno de compensação vascular bastante estudado na atualidade. Trata-se de alterações na resistência da circulação fetal, caracterizada pela redistribuição hemodinâmica do fluxo sanguíneo, com perfusão preferencial para órgãos nobres (cérebro, coração e glândulas adrenais) em detrimento dos pulmões, rins, baço e esqueleto, o que pode ser diagnosticado pelo estudo dopplervelocimétrico. O momento ideal para intervenção obstétrica ainda não é consenso. Uma das grandes preocupações, em relação à avaliação da vitalidade fetal, diz respeito ao momento ideal para interrupção da gravidez, uma vez que alguns dos métodos utilizados apresentam uma alta frequência de resultado falso-positivos, podendo ocasionar um nascimento prematuro, por vezes, desnecessário. Em fetos muito prematuros a opção pela interrupção da gravidez pode trazer consequências irreversíveis. Na tentativa de minimizar os danos, optou-se pela realização de uma revisão, baseada nas melhores evidências sobre a conduta nos fetos centralizados.

Fetal brain-sparing effect is a vascular compensation phenomenon widely studied today. Diagnosed by Doppler study it consists of changes on resistance in the fetal circulation characterized by hemodynamic redistribution of blood flow, with preferential perfusion to brain, heart and adrenal glands compared to the lungs, kidneys, spleen and skeleton. There is no consensus over ideal time for obstetric intervention. Ideal time for pregnancy termination is of major concern when assessing fetal vitality since methods used today have high false positives rate, leading to unnecessary prematurity. In extreme prematurity the decision to terminate pregnancy can lead to irreversible consequences. In an attempt to minimize damage, it was decided to carry out a review, based on the best evidence regarding conduct in fetal brain sparing effect.

Repercussões agudas do exercício físico materno sobre os parâmetros hemodinâmicos útero-placentários e fetais / Impact of acute maternal exercise on uteroplacental and fetal hemodynamics patterns

A atividade física está associada a diversos benefícios para a saúde física e mental. Entre as gestantes, a prática de exercícios físicos ganhou maior ênfase nas últimas décadas, porém, ainda persistem controvérsias quanto à possibilidade da ocorrência de potenciais efeitos lesivos ao feto. Esta revisão avaliou os estudos existentes que investigaram os efeitos agudos dos exercícios físicos maternos sobre os parâmetros hemodinâmicos útero-placentários e fetais. Verifica-se que ocorrem graus de desvio do fluxo sanguíneo para a musculatura esquelética solicitada durante o exercício. Esse efeito é acompanhado de vasoconstrição visceral e provável redução do fluxo uterino. Entretanto, em gestações normais, mecanismos compensatórios atuam no leito vascular útero-placentário e no feto, garantindo a homeostase das trocas gasosas e impedindo efeitos deletérios da hipoxia fetal. A análise dos estudos desta revisão permite conlcuir que os exercícios considerados de moderada intensidade em gestações não complicadas parecem ser seguros e podem ser recomendados.

Physical activity is associated with several benefits to physical and mental health. Among pregnant women, the practice of physical exercises has gained more emphasis over the last few decades, but controversy still persists regarding the possible occurrence of potential damaging effects on the fetus. The present systematic review evaluated existing studies that investigated the acute effects of maternal physical exercise on the hemodynamic uteroplacental and fetal parameters. The occurrence of varied degrees of blood flow deviation to the skeletal muscle involved in exercise was detected. This occurrence of varied degrees of blood flow deviation to the skeletal muscle involved in exercise was detected. This effect is accompanied by visceral vasoconstriction and by a probable reduction of uterine flow. However, in normal pregnancies, compensatory mechanisms may act on the uteroplacental vascular bed and on the fetus, in order to guarantee the homeostasis of gas exchanges and prevent deleterious effects of fetal hypoxia. Analysis of the studies reviewed in this survery permits us to conclude that exercises of moderate intensity in uncomplicated pregnancies seem to be safe and can be recommended.

Fetal Topographical Anatomy of the Pancreatic Head and Duodenum with Special Reference to Courses of the Pancreaticoduodenal Arteries

PURPOSE: The purpose of this study is to provide better understanding as to how the "double" vascular arcades, in contrast to other intestinal marginal vessels, develop along the right margin of the pancreatic head. MATERIALS AND METHODS: In human fetuses between 8-30 weeks, we described the topographical anatomy of the vessels, bile duct, duodenum as well as the ventral and dorsal primordia of the pancreatic head with an aid of pancreatic polypeptide immunohisto-chemistry. RESULTS: The contents of the hepatoduodenal ligament crossed the superior side of the pylorus. Moreover, the right hepatic artery originating from the superior mesenteric artery ran along the superior aspect of the pancreatic head. An arterial arcade, corresponding to the posterior pancreaticoduodenal arteries, encircled the superior part of the pancreatic head, whereas another arcade, corresponding to the anterior pancreaticoduodenal arteries, surrounded the inferior part. The dorsal promordium of the pancreas surrounded and/or mixed the ventral primordium at 13-16 weeks. Thus, both arterial arcades were likely to attach to the dorsal primordium. CONCLUSION: The fetal anatomy of the pancreaticoduodenal vascular arcades as well as that of the hepatoduodenal ligament were quite different from adults in topographical relations. Thus, in the stage later than 30 weeks, further rotation of the duodenum along a horizontal axis seemed to be required to move the pylorus posterosuperiorly and to reflect the superior surface of the pancreatic head posteriorly. However, to change the topographical anatomy of the superior and inferior arterial arcades into the final position, re-arrangement of the pancreatic parenchyma might be necessary in the head.

Prediction of perinatal outcomes in patient with pre-eclampsia: maternal hyperoxygenation test on fetal Doppler flow.

OBJECTIVE: Investigate if the maternal hyperoxygenation test in pregnancy with pre-eclampsia could be used for prediction of perinatal outcomes. MATERIAL AND METHOD: Fifty-four singleton pre-eclampsia pregnant women were enrolled in the present study. Positive hyperoxygenation test was defined as an increase of the middle cerebral artery (MCA) or the ductus venosus (DV) pulsatility index (PI), or a decrease of the uterine artery or the umbilical artery (UA) PI by at least 20%. Results of hyperoxygenation test were analyzed for the correlation with perinatal outcomes. RESULTS: Fetuses with positive hyperoxygenation test of the MCA had a birth weight less than the negative group significantly. Furthermore, there was a significantly higher rate ofsmall for gestational age (SGA) neonates and admission to the neonatal intensive care unit (NICU) in cases with positive test of the MCA. CONCLUSION: The present study shows the correlation of positive hyperoxygenation test of the MCA and low birth weight, SGA, and NICU admission.

Doppler en obstetricia / Doppler ultrasound in obstetrics

La aplicación del ultrasonido Doppler en Obstetricia ha determinado un avance importante en el cuidado de la salud fetal. Para el correcto uso de esta metodología es necesario poseer un acabado conocimiento de los principios físicos y de instrumentación. Así mismo es necesaria la adecuada interpretación de los resultados en cada uno de los diferentes territorios vasculares que se exploren. De tal manera la evaluación de las arterías uterinas constituye una herramienta de utilidad en el tamizaje de patologías del embarazo tales como preeclampsia, restricción de crecimiento intrauterino, desprendimiento de placenta y muerte fetal. El estudió de la forma de onda de velocidad de flujo de la artería umbilical se utiliza rutinariamente en el manejo de embarazos de alto riesgo con sospecha de hipoxia y los cambios en la velocimetría de la arteria cerebral medía son de utilidad en la evaluación de fetos con insuficiencia placentaria y anemia fetal. Finalmente mediante el estudio Doppler del sistema venoso fetal se dectectan estados más avanzados de hipoxia fetal generalmente acompañados de acidemia e insuficiencia cardiaca. En este artículo se revisan estas diferentes aplicaciones del Doppler en Obstetricia con el propósito de brindar al lector los principios elementales para su correcta aplicación.

The introduction of Doppler ultrasound in Obstetrics has determined an important advance in the care of fetal health. The adequate use of this methodology requires the knowledge of the physical principles and instrumentation of Doppler ultrasound. It is also of capital importance the correct interpretation of the findings in each one of the different vascular territories explored. Uterine artery Doppler ultrasound examination is considered a potential screening tool for the development of pre-eclampsia, fetal growth restriction, placental abruption and still birth. Umbilical artery Doppler waveform analysis is routinely used in the management of high-risk pregnancies with suspected hypoxia and middle cerebral artery recordings are incorporated regularly into the management of fetuses at risk of developing placental compromise and fetal anemia. Additionally Doppler evaluation of the fetal venous system is useful in the assessment of severe fetal hypoxia usually in association with acidemia and heart failure. In this article the different applications of Doppler ultrasound in Obstetrics are reviewed.

Fetal ductus venosus pulsatility index and diameter during 20-30 weeks gestation.

OBJECTIVE: To present normal range of the pulsatility index and the smallest diameter in the ductus venosus in normal fetuses throughout gestation. MATERIAL AND METHOD: This was a prospectively cross-sectional study. Three measurements were made for the ductus venosus diameter and the pulsatility index in each fetus during fetal quiescence. Statistical Package for the Social Sciences 14.0 software was used to create nomograms for the ductus venosus pulsatility index and diameter against gestational age. Four hundred and sixty normal fetuses aged seventeenth to thirty-seventh weeks were evaluated. RESULTS: The median diameter of the ductus venosus was linear across gestation. CONCLUSION: The nomograms for the ductus venosus pulsatility index and diameter are presented. The size of the narrowest portion of the DV grows in a linear relationship through gestation.

Doppler das artérias umbilicais e cerebral média fetal após sulfato de magnésio na pré-eclâmpsia / Doppler of the umbilical and fetal middle cerebral arteries after magnesium sulfate in preeclampsia

OBJETIVO: Comparar a relação da artéria umbilical e artéria cerebral média fetal através dos índices dopplervelocimétricos (índice de resistência, índice de pulsatilidade e relação S/D) antes e após a utilização do sulfato de magnésio nas gestantes com pré-eclâmpsia grave (pura ou superposta). MÉTODOS: Foi desenvolvido um estudo do tipo coorte prospectivo, no qual cada sujeito serviu como seu próprio controle. Foram selecionadas 40 gestantes com pré-eclâmpsia grave, submetidas ao exame dopplervelocimétrico antes e após 20 minutos da administração intravenosa de 6 g do sulfato de magnésio. As variáveis estudadas foram os índices dopplervelocimétricos da relação artéria umbilical e cerebral média fetal. A comparação das médias entre as duas medidas (antes e depois) de cada indivíduo foi realizada através do teste t student pareado. A comparação entre a distribuição de freqüência de diagnóstico fetal (normal, redução isolada na resistência da artéria cerebral média e centralizado) foi realizada através do teste Qui quadrado (c²) de Stuart-Maxwell. RESULTADOS: Não foi observada diferença estatisticamente significativa das médias da relação artéria umbilical/cerebral média nos índices dopplervelocimétricos antes e após o sulfato de magnésio. Verificou-se aumento da freqüência de redução isolada na resistência da artéria cerebral média após o sulfato de magnésio (25,0 por cento x 47,5 por cento; p = 0,01). CONCLUSÃO: A administração intravenosa do sulfato de magnésio nas gestantes com pré-eclâmpsia grave resultou em um aumento significativo na freqüência de fetos com diagnóstico de redução da resistência da artéria cerebral média na dopplervelocimetria.

BACKGROUND: To compare the ratio between the fetal middle cerebral artery and the umbilical artery using Doppler flow velocimetry indices (resistance index, pulsatility index and A/B relation) before and after administration of magnesium sulfate to pregnant women with severe preeclampsia (pure or superimposed). METHODS: A prospective cohort study was conducted with each pregnant woman representing her own control. Forty severe preeclamptic women were included and underwent Doppler sonography before and 20 minutes after administration of 6g of magnesium sulfate. Analysis variables were the Doppler flow velocimetry indices evaluating the ratio of the fetal middle cerebral artery to the umbilical artery. To compare the mean indices before and after magnesium sulfate for the same patient, the "t-paired" Student test was used. The Stuart-Maxwell c² was applied to determine the difference of fetal diagnosis (normal, brain-sparing or reduced middle cerebral artery resistance) before and after magnesium sulfate. RESULTS: No significant difference of the mean ratio between the middle cerebral artery and the umbilical artery, before and after administration of magnesium sulfate was observed. After magnesium sulfate (25.0 percent x 47.5 percent; p= 0.01), there was an increased frequency of isolated lower Doppler flow velocimetry indices in the middle cerebral artery. CONCLUSION: Intravenous administration of magnesium sulfate in patients with severe preeclampsia is associated with increased frequency of fetal Doppler diagnosis of reduced resistance in the middle cerebral artery.

Perfil biofísico fetal e dopplervelocimetria da circulação fetal e fetoplacentária em gestantes hipertensas: estudo comparativo das variáveis perinatais / Fetal biophysical profile and Doppler velocimetry of fetal and feto-placental circulation in pregnants with hypertensive disease: a comparative study of perinatal outcomes

Introdução: A síndrome hipertensiva, incluindo a doença hipertensiva espefícifica da gestação (DHEG), a hipertensão arterial sistêmica crônica e a HAC com DHEG superajuntada, pode resultar em insuficiência placentária que, por sua vez está fortemente relacionada à restrição de crescimento intra-uterino...

Introduction: Hypertension disease, including a specific hypertension disease of pregnancy (SHDP), systemical arterial hypertension (SAH), chronic systemic arterial hypertension (CSAH) and CSAH with SHDP, could result in placentall insufficiency which is...

Valor preditivo do resultado fetal da dopplervelocimetria de ducto venoso entre a 11ª e a 14ª semanas de gestação / Predictive value for fetal outcome of Doppler velocimetry of the ductus venosus between the 11th and the 14th gestation week

OBJETIVO: estudar o valor da dopplervelocimetria do ducto venoso (DV) entre a 11º e a 14º semanas de gestação, associado à medida da translucência nucal (TN), na detecção de resultado fetal adverso. MÉTODOS: foram estudados 1.268 fetos consecutivamente. Em 56 casos, realizou-se estudo citogenético no material obtido, por meio de biópsia de vilosidade coriônica e, em 1.181 casos, o resultado teve como base o fenótipo do recém-nascido. Todos os fetos foram submetidos, além da ultra-sonografia de rotina, à medida da TN e à dopplervelocimetria do DV. Trata-se de um estudo transversal e prospectivo. Foram calculados e analisados, para fins de prevalência e índices de acurácia: sensibilidade, especificidade, valor preditivo positivo (VPP), valor preditivo negativo (VPN), probabilidade de falso-positivo (PFP), probabilidade de falso-negativo (PFN), razão de probabilidade positiva e razão de probabilidade negativa. RESULTADOS: do total de 1.268 fetos, foram selecionados para análise 1.183 casos. Deste total, 1.170 fetos eram normais (98,9 por cento) e 13 fetos tiveram resultado fetal adverso ao nascimento (1,1 por cento) - incluindo morte fetal (trissomia 21 e 22) em dois casos, síndrome genética (Nooman) em um caso, fetos polimalformados em dois casos, cardiopatia em três casos e outros defeitos estruturais em cinco casos. A prevalência do DV alterado (onda A zero/reversa) na população estudada foi de 14 casos (1,2 por cento), com taxa de falso-positivo de 0,7 por cento. CONCLUSÕES: há correlação significativa entre alteração da dopplervelocimetria do DV e a medida da TN, como marcadores ultra-sonográficos de primeiro trimestre, na detecção de resultado fetal adverso, especialmente para malformações graves. O Doppler do DV foi capaz de diminuir o resultado falso-positivo, comparativamente ao uso isolado da TN, melhorando consideravelmente o VPP do teste.

PURPOSE: to study the value of Doppler velocimetry of the ductus venosus, between the 11th and 14th weeks of pregnancy, associated to the nuchal translucency thickness measurement, in the detection of adverse fetal outcome. METHODS: a transversal and prospective study in which a total of 1,268 fetuses were studied consecutively. In 56 cases, a cytogenetic study was performed on material obtained from a biopsy of the chorionic villus and, in 1,181 cases, the postnatal phenotype was used as a basis for the result. In addition to the routine ultrasonographic examination, all the fetuses were submitted to measurement of the nuchal translucency thickness and to Doppler velocimetry of the ductus venosus. Aiming at prevalence and accuracy indices, sensitivity, specificity, positive predictive value, negative predictive value, probability of false-positive, probability of false-negative, reason of positive probability and reason of negative probability were calculated and analyzed. RESULTS: from the total of 1,268 fetuses, 1,183 cases were selected for analysis. From this number, 1,170 fetuses were normal (98.9 percent) and 13 fetuses presented adverse outcome at birth (1.1 percent), including fetal death (trisomy 21 and 22) in two cases; genetic syndrome (Nooman) in one case; two cases of polymalformed fetuses; cardiopathy in three cases; and other structural defects in five cases. The prevalence of the modified ductus venosus (wave A zero/reverse) in the studied population was of 14 cases (1.2 percent), with a false-positive rate of 0.7 percent. CONCLUSIONS: there is a significant correlation between the alteration of the ductus venosus Doppler velocimetry and the thickness of the nuchal translucency as an ultrasonographic marker for the first trimester of gestation, in the detection of adverse fetal outcome, especially serious malformations. The ductus venosus was able to diminish the false-positive result in comparison to the isolated use of the nuchal translucency thickness, improving considerably the positive predictive value of the test.

Perinatal and neonatal outcomes of growth restricted fetuses with positive end diastolic and absent or reversed umbilical artery doppler waveforms

To evaluate the outcome of intrauterine growth restriction fetuses with absent or reversed end-diastolic flow in the umbilical artery. This was a retrospective study conducted at the Department of Maternal Fetal Medicine of the Bakirkoy Women and Children's Teaching Hospital, Istanbul, Turkey between 2002 and 2006. Three hundred and ten pregnant women with growth-restricted fetuses confirmed by ultrasound were followed up with Doppler studies of the umbilical artery. The population was subdivided into 2 groups. Group 1, intrauterine growth restriction with positive end diastolic flow velocity waveforms, n=137 and group 2, intrauterine growth restriction with absent or reversed end diastolic velocities, n=163. Perinatal and neonatal outcomes of the 2 groups were recorded. Group 1 was associated with a higher perinatal mortality and morbidity rate than group 2 p=0.02, odds ratio [OR]: 1.09, 95% confidence interval [CI] 1-3.5, p=0.03, OR: 2, 95% CI 1.2-3.2. In group 1, significantly more neonates were admitted to the neonatal intensive care unit, but no difference was seen in neonatal intensive care unit stay. The frequency of respiratory distress syndrome, septicemia, and necrotizing enterocolitis increased in group 1. There was no significant difference in need for ventilation of respiratory distress syndrome. Our data suggest that pregnancies with absent or reversed end-diastolic flow in the umbilical arteries have high perinatal mortality and morbidity