Hipertensão pulmonar persistente do recém-nascido / Persistent pulmonary hypertension of the newborn

A hipertensão pulmonar persistente do recem-nascido resulta de uma transição anormal da circulação fetal para a neonatal, sendo caracterizada pela manutenção de elevada resistência vascular pulmonar após o nascimento e consequente shunt direita-esquerda através do forame oval ou do canal arterial. As principais causas são as doenças parenquimatosas pulmonares do recém-nascido, aspiração de líquido meconial e hipoplasia pulmonar, podendo também ser idiopática. O quadro clínico é caracterizado por hipoxemia acentuada e o diagnóstico diferencial com algumas cardiopatias congênitas por vezes é muito difícil, sendo a ecocardiografia com mapeamento de fluxo em cores imprescindível para esse diagnóstico. Os avanços obtidos nos últimos anos, com melhor utilização de técnicas ventilatórias, uso de óxido nítrico inalatório e, em algumas situações, oxigenação extracorpórea com membrana, têm melhorado a sobrevida desses recém nascidos, embora a morbidade continue elevada.

Experience with inhaled nitric oxide therapy in hypoxic respiratory failure of the newborn.

BACKGROUND: Respiratory diseases are the commonest cause of morbidity and mortality in newborns. Inhaled nitric oxide (iNO) has been shown to be effective in the management of persistent pulmonory hypertension of newborn (PPHN). OBJECTIVES: To retrospectively analyse data to determine the effectiveness of inhaled nitric oxide (iNO) in the management of newborns with PPHN in terms of survival and changes in oxygenation status. METHODS: Neo-natal data since inception of iNO therapy at the unit (past six years) was reviewed. Pertinent demographic and clinical information was collected from medical records of newborns that received inhaled nitric oxide therapy during their stay. Details of underlying illnesses, other therapeutic modalities, arterial blood gas, ventilatory and nitric oxide parameters were assessed and analysed to ascertain efficacy of iNO. RESULTS: A total of 36 babies (gestational age ranging from 24-41 weeks) received iNO during this period; two were excluded from final analysis. Overall survival rate was 80 percent. There was a statistically significant increase in systemic oxygenation (PaO2) from 41.1 +/- 2.1 mmHg to 128.5 +/- 13.2 mmHg and a decline in oxygenation index (OI) from 49.4 +/- 5.9 to 17.3 +/- 2.5, when assessed after four hours (P < 0.001). Mean duration of iNO therapy was 63 +/- 7.3 hours and the maximum methaemoglobin levels were noted to be 2.1 percent. CONCLUSIONS: Inhaled nitric oxide appears to be an effective rescue therapy for the management of PPHN associated with hypoxic respiratory failure. It is safe and well tolerated with no evidence of clinical or biochemical side effects.

Cardiac abnormalities in birth asphyxia.

Cardiac abnormalities in birth asphyxia were first recognised in the 1970s. These include (i) transient tricuspid regurgitation which is the commonest cause of a systolic murmur in a newborn and tends to disappear without any treatment unless it is associated with transient myocardial ischemia or primary pulmonary hypertension of the newborn (ii) transient mitral regurgitation which is much less common and is often a part of transient myocardial ischemia, at times with reduced left ventricular function and, therefore, requires treatment in the form of inotropic and ventilatory support (iii) transient myocardial ischemia (TMI) of the newborn. This should be suspected in any baby with asphyxia, respiratory distress and poor pulses, especially if a murmur is audible. It is of five types (A to E) according to Rowe's classification. Type B is the most severe with respiratory distress, congestive heart failure and shock. Echocardiography helps to rule out critical left ventricular obstructive lesions like hypoplastic left heart syndrome or critical aortic stenosis. ECG is very important for diagnosis of TMI, and may show changes ranging from T wave inversion in one lead to a classical segmental infarction pattern with abnormal q waves. CPK-MB may rise and echocardiogram shows impaired left ventricular function, mitral and/or tricuspid regurgitation, and at times, wall motion abnormalities of left ventricle. Ejection fraction is often depressed and is a useful marker of severity and prognosis. Treatment includes fluid restriction, inotropic support, diuretics and ventilatory resistance if required (v) persistent pulmonary hypertension of the newborn (PPHN). Persistent hypoxia sometimes results in persistence of constricted fetal pulmonary vascular bed causing pulmonary arterial hypertension with consequent right to left shunt across patent ductus arteriosus and foramen ovale. This causes respiratory tension and right ventricular failure with systolic murmur of tricuspid, and at times, mitral regurgitation. Treatment consists of oxygen and general care for mild cases, ventilatory support, ECMO and nitric oxide for severe cases. Cardiac abnormalities in asphyxiated neonates are often underdiagnosed and require a high index of suspicion. ECG and Echo help in early recognition and hence better management of these cases.

Cardiac abnormalities in birth asphyxia.

Cardiac abnormalities in birth asphyxia were first recognised in 1970s. These include (i) transient tricuspid regurgitation which is the commonest cause of a systolic murmur in a newborn and tends to disappear without any treatment unless it is associated with transient myocardial ischemia or primary pulmonary hypertension of the new born (ii) transient mitral regurgitation which is much less common and is often a part of transient myocardial ischemia, at times with reduced left ventricular function and therefore, requires treatment in the form of inotropic and ventilatory support, (iii) transient myocardial ischemia (TMI) of the newborn. This should be suspected in any baby with asphyxia, respiratory distress and poor pulses especially if a murmur is audible. It is of five types (A to E) according to Rowe's classification. Type B is the most severe with respiratory distress, congestive heart failure and shock. Echocardiography helps to rule out critical left ventricular obstructive lesions like hypoplastic left heart syndrome or critical aortic stenosis. ECG is very important for diagnosis of TMI, and may show changes ranging from T wave inversion in one lead to a classical segmental infarction pattern with abnormal q waves. CPK-MB may rise and echocardiogram shows impaired left ventricular function, mitral and/or tricuspid regurgitation, and at times, wall motion abnormalities of left ventricle. Ejection fraction is often depressed and is a useful marker of severity and prognosis. Treatment includes fluid restriction, inotropic support, diuretics and ventilatory resistance if required, (v) persistent pulmonary hypertension of the new born (PPHN). Persistent hypoxia sometimes results in persistence of constricted fetal pulmonary vascular bed causing pulmonary arterial hypertension with consequent right to left shunt across patent ductus arteriosus and foramen ovale. This causes respiratory distress and cyanosis (sometimes differential). Clinical examination also reveals evidence of pulmonary arterial hypertension and right ventricular failure with systolic murmur of tricuspid and, at times, mitral regurgitation. Treatment consists of oxygen and general care for mild cases, ventilatory support, ECMO and nitric oxide for severe cases. Cardiac abnormalities in asphyxiated neonates are often underdiagnosed and require a high index of suspicion. ECG and Echo help in early recognition and hence better management of these cases.

Complicaciones agudas en neonatos de término con asfixia perinatal severa / Acute complications in newborns with severe perinatal asphyxia

En un grupo de 50 recién nacidos de término, con asfixia grave al nacer, definida por un pH de arteria umbilical igual o menor de 7.10, se evaluaron las complicaciones sistémicas agudas, los antecedentes perinatales y se correlacionó el pH de cordón con la calificación de Apgar. En 56 por ciento de los casos, no se detectó la asfixia antes del nacimiento; la causa más frecuente de ella fue el trabajo de parto o periodo expulsivo prolongado, seguida del desprendimiento prematuro de placenta. El riñón y el sistema nervioso central se afectaron en casi la mitad de los casos; un 24 por ciento de los neonatos tuvieron enfermedad pulmonar grave, un porcentaje similar tuvo afectación cardiovascular y 44 por ciento tuvo hipocalcemia. No hubo correlación entre calificación de Apgar y pH de cordón. La mortalidad fue de 22 por ciento y su causa principal fue la Hipertensión Pulmonar persistente

Malposición de los vasos pulmonares y displasia capilar alveolar / Misalignment of pulmonary vessels and alveolar capillary dysplasia

Se presenta un caso de la combinación malposición de los vasos pulmonares y displasia capilar alveolar. Esta alteración del desarrollo pulmonar es causa de hipertensión pulmonar persistente en recién nacidos. Su patología es característica e incluye en recién nacidos. Su patología es característica e incluye sacullos pulmonares con intersticio aumentado conteniendo pocos capilares, y venas pulmonares acompañando a las arterias y bronquios intrapulmonares. En este caso se hallaron además células hematopoyéticas en el intersticio.

Neonatal pulmonary hypertension: unusual presentation

Se presenta el caso de un infante que desarrolló cianosis y cansancio durante la alimentación en la segunda semana de edad. El diagnóstico tentativo inicial fue sepsis y cardiopatía congénita. Fue trasladada a nuestro centro por presentar bradicardia. Las pruebas de diagnóstico, incluyendo ecocardiogramas y cateterismo cardíaco fueron compatibles con hipertensión pulmonar la cual respondía a la administración de tolazolina pero empeoraba al interrumpir la misma. La paciente falleció a los dos meses de edad y el examen histopatológico del pulmón demostró las alteraciones en la vasculatura pulmonar compatibles con el síndrome de hipertensión pulmonar del neonato. El síndrome de hipertensión pulmonar neonatal puede tener diversas etiologías y el manejo satisfactorio del mismo depende de un mejor conocimiento de la etiopatogenia de la enfermedad. Se hace incapie en la diferenciación entre el síndrome de hipertensión pulmonar y las cardiopatías congénitas cianosantes y se describen las formas para establecer dicha diferenciación mediante las pruebas de hiperoxia, hiperventilación y ecocardiografía