RESUMEN
During the last two decades there has been an enormous development in treatment possibilities for the extremely premature infants and the Neonatologists have to face in their daily practice many decisional problems and ethical, moral and legal dilemmas. These concern decisions to initiate or withhold treatment directly at birth, decision to withdrawn treatment with the possible consequence that the child will die. The debate between "sanctity" and "quality" of life, aggressive treatment in relation to discrimination toward the disabled, the principle of "beneficence" and the question of "proportionality" of treatment, the concept of the newborn's "best interest" are the ethical issues discussed. According to our opinion, ethical questions should not be regulated by law and the legal system should not interfere in the relationship patient - physician. Today more than ever, every neonatologist needs to become familiar with basic ethical concepts and the legal aspects in neonatal intensive care.
Asunto(s)
Cuidado Intensivo Neonatal/ética , Cuidado Intensivo Neonatal/legislación & jurisprudencia , Toma de Decisiones/fisiología , Humanos , Recien Nacido con Peso al Nacer Extremadamente Bajo/fisiología , Recién Nacido , Recien Nacido Prematuro/fisiología , Unidades de Cuidado Intensivo Neonatal/ética , Unidades de Cuidado Intensivo Neonatal/legislación & jurisprudencia , Obligaciones Morales , Neonatología/ética , Neonatología/legislación & jurisprudencia , Neonatología/métodos , Relaciones Médico-Paciente , Privación de TratamientoRESUMEN
BACKGROUND: In pediatric age echocardiographic evaluation of left ventricular systolic function is usually based on indexes obtained by measurements at the endocardial level. In the presence of ventricular hypertrophy this may lead to an overestimation of systolic function. The aim of this study was to assess the developmental changes of left ventricular systolic mechanics measured at the endocardial and midwall levels. METHODS: In 239 normal subjects divided into six age groups we measured left ventricular end-diastolic volume, mass and mass/volume ratio, fractional shortening, and rate-corrected mean velocity of circumferential shortening at the endocardial and midwall levels. Endocardial meridional end-systolic stress and midwall circumferential end-systolic stress were considered as indexes of afterload. Relations of extent and velocity of fiber shortening to afterload at the endocardial and midwall levels were used to assess left ventricular contractility. RESULTS: Blood pressure, left ventricular afterload, volume and mass increased, whereas the mass/volume ratio remained stable during growth. Fractional shortening and mean velocity of circumferential shortening at the endocardial level decreased and showed an inverse relation to afterload. Midwall fractional shortening and rate-corrected mean velocity of circumferential shortening were lower during the first months and did not change during the first year of life. CONCLUSIONS: Left ventricular volume and mass increase with age, mass/volume ratio remains almost constant while afterload increases. Endocardial systolic function indexes are higher in the first period of life, due to low afterload and increased mass/volume ratio. In the first months of life the left ventricular myocardium shows a greater sensitivity to changes in afterload and a reduced contractility measured at the midwall level.
Asunto(s)
Endocardio/fisiología , Hemodinámica/fisiología , Función Ventricular Izquierda/fisiología , Adolescente , Factores de Edad , Análisis de Varianza , Niño , Desarrollo Infantil/fisiología , Preescolar , Estudios de Cohortes , Ecocardiografía Doppler/métodos , Endocardio/diagnóstico por imagen , Femenino , Humanos , Lactante , Masculino , Contracción Miocárdica/fisiología , Probabilidad , Valores de Referencia , Sensibilidad y EspecificidadRESUMEN
AIMS: To identify factors predisposing to abnormal left ventricular geometry and mechanics in 52 patients after successful repair of aortic coarctation. METHODS AND RESULTS: We evaluated left ventricular remodelling, systolic midwall mechanics, and isthmic gradient by echo-Doppler, systemic blood pressure at rest/exercise and by ambulatory blood pressure monitoring, and the aortic arch by magnetic resonance imaging. Echocardiographic findings were compared with those of 142 controls. The patients with aortic coarctation showed an increased indexed left ventricular end-diastolic volume, increased mass index, increased ratio of mass to volume and systolic chamber function. The contractility, estimated at midwall level, was increased in 21 percent of the patients. In 26 (50 percent) of the patients, we found abnormal left ventricular geometry, with 9 percent showing concentric remodelling, 33 percent eccentric hypertrophy, and 8 percent concentric hypertrophy. These patients were found to be older, underwent a later surgical repair, and to have higher systolic blood pressures at rest and exercise as well as during ambulatory monitoring. The relative mural thickness and mass index of the left ventricle showed a significant correlation with different variables on uni- and multivariate analysis. Age and diastolic blood pressure at rest are the only factors associated with abnormal left ventricular remodelling. CONCLUSIONS: Patients who have undergone a seemingly successful surgical repair of aortic coarctation may have persistently abnormal geometry with a hyperdynamic state of the left ventricle. This is more frequent in older patients, and in those with higher diastolic blood pressures.