Guía de manejo obstétrico y del recién nacido en madre aloinmunizada / Guidelines for the obstetric management of an alloimmune mother and her newborn / Guia de manejo obstétrico e neonatal em mães aloimunizadas

Resumen: La aloinmunización es una respuesta biológica frente a la exposición de antígenos no propios. La gestación, las transfusiones de hemocomponentes, los trasplantes de órganos sólidos y células hematopoyéticas, así como el consumo de drogas intravenosas exponen a las pacientes al desarrollo de aloanticuerpos antieritrocitarios. El hallazgo de los mismos debe cumplir con las instancias diagnósticas para identificar la probabilidad de estar asociados a enfermedad hemolítica feto neonatal (EHFN) y su oportuna derivación a policlínica de alto riesgo obstétrico (ARO) para su correcto seguimiento. Es fundamental que sean los laboratorios de inmunohematología de los servicios de hemoterapia y medicina transfusional los encargados de los estudios diagnósticos de aloinmunización eritrocitaria(1). En este sentido hemos elaborado esta guía con el objetivo de protocolizar de manera multidisciplinaria el manejo de las embarazadas aloinmunizadas y sus recién nacidos.

Abstract: Alloimmunization is the biological response to exposure to non-HLA antigens. Pregnancy, transfusion of blood components, solid organ and hematopoietic cell transplantation, as well as intravenous drug use expose patients to the development of anti-erythrocyte antibodies. When the latter are found, they must match diagnostic criteria to identify the potential association to hemolytic disease of the fetus and newborn (HDFN) and its timely referral to the high-risk obstetric risk polyclinic for due follow-up. It is of the essence for erythrocyte alloimmunization diagnostic tests to be carried out by the immunohematology laboratories of the Hemotherapy and Transfusional Medicine services. To that end, we have prepared these guidelines with the purpose of providing a multidisciplinary protocol for the handling of maternal alloimmunization and alloimmunization of the newborn.

Resumo: A aloimunização é uma resposta biológica à exposição a antígenos não próprios. A gravidez, as transfusões de hemocomponentes, os transplantes de órgãos sólidos e células hematopoiéticas, bem como o uso de drogas intravenosas expõem os pacientes ao desenvolvimento de anticorpos antieritrocitários. O achado destes deve obedecer a critérios diagnósticos para identificar a doença e a probabilidade de estarem associados a doença hemolítica feto neonatal (DHPN) e seu encaminhamento oportuno para uma unidade de alto risco obstétrico para acompanhamento adequado. É fundamental que os laboratórios de imuno-hematologia dos serviços de Hemoterapia e Medicina Transfusional se encarreguem dos estudos diagnósticos da aloimunização eritrocitária. Elaboramos este guia com o objetivo de estabelecer um protocolo multidisciplinar para o manejo de gestantes aloimunizadas e seus recém-nascidos.

Administración de surfactante profiláctico por vía orofaríngea previo al pinzamiento de cordón umbilical en el recién nacido de muy bajo peso en la maternidad del Hospital Universitario / Prophylactic oropharyngeal surfactant administration before cord clamping in very low birth weight newborns at the University Children Hospital Maternity Department / Administração de surfactante profilático por via orofaríngea antes do clampeamento do cordão umbilical em recém-nascidos de baixo peso extremo na Maternidade do Hospital Pediátrico Universitário

Resumen: En la era de la búsqueda de estrategias ventilatorias mínimamente invasivas, la administración profiláctica de surfactante con técnicas sencillas, que no requieren elevada destreza y que pueden ser realizadas en ámbitos de baja complejidad, deben ser investigadas para potencialmente disminuir la morbilidad y mortalidad del pretérmino. Se reporta el uso de surfactante en la orofaringe de cuatro recién nacidos de muy bajo peso (promedio de peso de 1.236 g y 28 semanas de edad gestacional), y concomitante colocación de presión positiva continua por pieza nasal antes de la primera inspiración extrauterina manteniendo el cordón intacto. No se registraron efectos adversos y la aspiración gástrica posterior demostró que el surfactante fue inspirado a los pulmones del recién nacido. La administración de surfactante orofaríngeo es una técnica innovadora, segura, factible y reproducible. A la vez que minimizamos los riesgos de posible iatrogenia por la técnica utilizada, facilitamos una transición cardiovascular más estable, manteniendo la circulación fetoplacentaria.

Summary: In the era of minimally invasive ventilatory procedures, the prophylactic administration of surfactant using simple techniques that can be performed in low complexity settings, should be researched as a tool to potentially reduce preterm morbidity and mortality. We report the use of oropharyngeal surfactant in 4 very low birth weight newborns (average birth weight 1236g and 28 weeks of gestational age) and of continuous positive airway pressure before the first intrauterine inspiration and keeping an intact umbilical cord. No adverse effects happened, and the aspiration of gastric residual confirmed that surfactant had reached the lungs. The administration of oropharyngeal surfactant is an innovative, safe, feasible and reproducible technique. It minimizes the risks of possible iatrogenesis due to the technique used, and it also facilitates a more stable cardiovascular transition, maintaining the fetus' placental circulation.

Resumo: Na era da procura de técnicas ventilatórias minimamente invasivas, a administração profilática de surfactante utilizando técnicas simples, que não requerem muita destreza e que pode ser realizada em contextos de baixa complexidade, deve ser pesquisada para reduzir potencialmente a morbidade e mortalidade dos pré-termos. Reportamos o uso de surfactante na orofaringe em 4 recém-nascidos com baixo peso ao nascimento (peso médio de 1,236 g e 28 semanas de idade gestacional), e colocação concomitante de pressão positiva contínua por adaptador nasal, antes da primeira inspiração extrauterina e mantendo o cordão umbilical intacto. Não houve efeitos adversos e o aspirado gástrico subsequente mostrou que o surfactante foi inspirado e observado nos pulmões dos recém-nascidos. O surfactante de administração orofaríngea é uma técnica inovadora, segura, viável e reprodutível. Minimiza os riscos iatrogênicos eventuais devido à técnica utilizada, à vez que proporciona uma transição cardiovascular mais estável porque mantém a circulação da placenta fetal.

Inhibition of excitatory synaptic transmission in the trigeminal motor nucleus by the nitric oxide-cyclic GMP signaling pathway.

Nitric oxide (NO) and cyclic GMP (cGMP) suppressed glutamatergic synaptic transmission to trigeminal motoneurons in brain stem slices of neonatal rats. Histological studies showed guanylate cyclase (GC) containing fibers in the trigeminal motor pool. Glutamatergic excitatory postsynaptic currents (EPSCs) were recorded from neonatal trigeminal motoneurons in response to stimulation of the supratrigeminal nucleus (SuV). The NO donors DETA/NONOate (DETA/NO), at a concentration which released 275.1 nM of NO, and Spermine/NONOate (Sper/NO) reduced the amplitude of the EPSC to 52.7±0.6% and 60.1±10.8% of control values, respectively. These actions were not blocked by the GC inhibitors, ODQ or NS-2028. However, in the presence of YC-1 or BAY41-2272, modulators of GC that act as NO sensitizers, lower and otherwise ineffective concentrations of DETA/NO induced a reduction of the EPSC to 60.6±5.2%. Moreover, NO effects were mimicked by 8BrcGMP and by Zaprinast, an inhibitor of Phosphodiesterase 5. Glutamatergic currents evoked by exogenous glutamate were not reduced by DETA/NO nor 8BrcGMP. Paired-pulse facilitation was increased by NO donors. Under "minimal stimulation" conditions NO donors and cGMP increased the failure rate of evoked EPSCs. Protein kinase inhibitors antagonized cGMP effects. The results suggest that NO, through the synthesis of cGMP, presynaptically inhibits glutamatergic synaptic transmission on trigeminal motoneurons. We propose that NO has complex actions on motor pools; specific studies are needed to elucidate their physiological significance in the behaving animal.

Serotoninergic control of glycinergic inhibitory postsynaptic currents in rat hypoglossal motoneurons.

This report presents the results of a study of the frequency potentiation of inhibitory postsynaptic currents (IPSCs) in hypoglossal motoneurons and its modulation by serotonin. A release-site model of synaptic plasticity was used to characterize the frequency-related potentiation of evoked IPSCs. Data were obtained to determine if the frequency potentiation of IPSCs occurs as a consequence of a low baseline quantal content of evoked IPSCs using whole cell patch-clamp recordings from hypoglossal motoneurons in the neonatal rat brainstem slice preparation. In these motoneurons, EPSCs and GABAergic IPSCs were blocked by the application of CNQX, AP-5 and bicuculline. Glycinergic IPSCs were evoked by threshold stimulation of inhibitory neurons in the nucleus of Roller, which is located ventro-lateral to the hypoglossal nucleus. IPSC responses to trains of stimuli were recorded in control solutions and in solutions containing serotonin, which is known to reduce IPSPs in this preparation. The amplitude of non-potentiated IPSCs was reduced and their frequency potentiation was enhanced when serotonin was added to the bath. These data were examined using a release-site model of synaptic plasticity in which facilitation is attributed to a time-dependent increase in the probability of transmitter release; depression is attributed to a time-dependent decrease in the number of sites available for release. Using this model, the effect of serotonin on frequency potentiation was explained by a combination of a reduction in the baseline probability of transmitter release and an increase in the time constant of decay of the increase in probability of release that follows a stimulus.