RESUMO
In Bi-directional Glenn (BDG) physiology, the superior systemic circulation and pulmonary circulation are in series. Consequently, only blood from the superior vena cava is oxygenated in the lungs. Oxygenated blood then travels to the ventricle where it is mixed with blood returning from the lower body. Therefore, incremental changes in oxygen extraction ratio (OER) could compromise exercise tolerance. In this study, the effect of exercise on the hemodynamic and ventricular performance of BDG physiology was investigated using clinical patient data as inputs for a lumped parameter model coupled with oxygenation equations. Changes in cardiac index, Qp/Qs, systemic pressure, oxygen extraction ratio and ventricular/vascular coupling ratio were calculated for three different exercise levels. The patient cohort (n=29) was sub-grouped by age and pulmonary vascular resistance (PVR) at rest. It was observed that the changes in exercise tolerance are significant in both comparisons, but most significant when sub-grouped by PVR at rest. Results showed that patients over 2 years old with high PVR are above or close to the upper tolerable limit of OER (0.32) at baseline. Patients with high PVR at rest had very poor exercise tolerance while patients with low PVR at rest could tolerate low exercise conditions. In general, ventricular function of SV patients is too poor to increase CI and fulfill exercise requirements. The presented mathematical model provides a framework to estimate the hemodynamic performance of BDG patients at different exercise levels according to patient specific data.
Assuntos
Exercício Físico/fisiologia , Hemodinâmica , Oxigênio/metabolismo , Circulação Pulmonar/fisiologia , Função Ventricular/fisiologia , Criança , Pré-Escolar , Tolerância ao Exercício/fisiologia , Cardiopatias Congênitas/fisiopatologia , Ventrículos do Coração/fisiopatologia , Humanos , Lactente , Recém-Nascido , Descanso/fisiologia , Resistência Vascular/fisiologia , Veia Cava Superior/fisiopatologiaRESUMO
Fundamento: A persistência da veia cava superior esquerda (PVCSE), embora rara, é a anomalia venosa mais comumente encontrada no tórax. Quando identificada durante procedimentos de implante de dispositivos cardíacos eletrônicos implantáveis (DCEI), pode ser um desafio para a técnica. Objetivo: Avaliar os casos descritos na literatura de implantes de todos os tipos de DCEI em portadores dessa anomalia venosa. Método: Após dois implantes bem sucedidos de cardiodesfibriladores implantáveis de dupla-câmara em pacientes com PVCSE, buscou-se descrever os casos existentes na literatura de implante de DCEI em portadores de PVCSE nas bases de dados do PubMed e Lilacs. Os critérios de inclusão foram: artigos em inglês ou português publicados na íntegra sobre a PVCSE em pacientes submetidos a implantes de marcapassos (MP), cardiodesfibriladores (CDI) e ressincronizadores cardíacos associados ou não ao CDI (TRC-D e TRC). Foram descritos o tipo de dispositivo implantado, o número de casos, os dados clínicos dos pacientes, a presença ou ausência de veia cava superior direita...
Persistent left superior vena cava (PLSVC), although a rare case, is the most common thoracic venous anomaly. It may be observed during implantable electronic cardiac devices (IECD) implantation and is challenge for the technique. Objective: After two successful implants of implantable dual-chamber cardiac defibrillator in patients with PLSVC, the objective of this study is to evaluate the existing scientific literature on all types of IECDs in patients with this venous anomaly. Methods: Describe cases of IECD implantation in patients with PLSVC reported in the literature obtained from searches in the PubMed and Lilacs database. For the inclusion criteria we analyzed full articles on PLSVC in patients submitted to pacemaker (PM), cardiac defibrillator (ICD) and cardiac resynchronization implantation associated or not to the ICD (CRT-D and CRT) in humans, published both in English or Portuguese. We describe the type of implanted device, the number of cases, clinical data of patients, presence or absence of the right superior...
Assuntos
Marca-Passo Artificial , Veia Cava Superior/fisiopatologia , Técnicas e Procedimentos Diagnósticos , Desfibriladores Implantáveis , Dispositivos de Terapia de Ressincronização Cardíaca , Terapia de Ressincronização CardíacaRESUMO
The knowledge of the mechanisms underlying circulating volume control may be achieved by stretching a balloon placed at the junction of the superior vena cava-right atrial junction (SVC-RAJ). We investigated whether the inflation of a balloon at the SVC-RAJ inhibits the intake of 0.3M NaCl induced by GABAA receptor activation in the lateral parabrachial nucleus (LPBN) in euhydrated and satiated rats. Male Wistar rats (280-300 g) with bilateral stainless steel LPBN cannulae and balloons implanted at the SVC-RAJ were used. Bilateral injections of the GABAA receptor agonist muscimol (0.5 ηmol/0.2l) in the LPBN with deflated balloons increased intake of 0.3M NaCl (30.1 ± 3.9 vs. saline: 2.2 ± 0.7)ml/210 min, n=8) and water (17.7 ± 1.9 vs. saline: 2.9 ± 0.5 ml/210 min). Conversely, 0.3M NaCl (27.8 ± 2.1 ml/210 min) and water (22.8 ± 2.3 ml/210 min) intake were not affected in rats with inflated balloons at the SVC-RAJ. The results show that sodium and water intake induced by muscimol injected into the LPBN was not affected by balloon inflation at the SVC-RAJ. We suggest that the blockade of LPBN neuronal activity with muscimol injections impairs inhibitory mechanisms activated by signals from cardiopulmonary volume receptors determined by balloon inflation.
Assuntos
Agonistas de Receptores de GABA-A/farmacologia , Coração/fisiopatologia , Muscimol/farmacologia , Ponte/metabolismo , Receptores de GABA-A/metabolismo , Cloreto de Sódio/metabolismo , Animais , Cateterismo , Ingestão de Líquidos , Coração/efeitos dos fármacos , Átrios do Coração/fisiopatologia , Masculino , Ratos Wistar , Cloreto de Sódio/administração & dosagem , Veia Cava Superior/fisiopatologiaRESUMO
OBJECTIVE: To determine the hemodynamic impact of fluid restriction in preterm newborns with significant patent ductus arteriosus. STUDY DESIGN: Newborns ≥24 and <32 weeks' gestational age with significant patent ductus arteriosus were eligible for this prospective multicenter observational study. We recorded hemodynamic and Doppler echocardiographic variables before and 24 hours after fluid restriction. RESULTS: Eighteen newborns were included (gestational age 24.8 ± 1.1 weeks, birth weight 850 ± 180 g). Fluid intake was decreased from 145 ± 15 to 108 ± 10 mL/kg/d. Respiratory variables, fraction of inspired oxygen, blood gas values, ductus arteriosus diameter, blood flow-velocities in ductus arteriosus, in the left pulmonary artery and in the ascending aorta, and the left atrial/aortic root ratio were unchanged after fluid restriction. Although systemic blood pressure did not change, blood flow in the superior vena cava decreased from 105 ± 40 to 61 ± 25 mL/kg/min (P < .001). The mean blood flow-velocity in the superior mesenteric artery was lower 24 hours after starting fluid restriction. CONCLUSIONS: Our results do not support the hypothesis that fluid restriction has beneficial effects on pulmonary or systemic hemodynamics in preterm newborns.
Assuntos
Permeabilidade do Canal Arterial/fisiopatologia , Doenças do Prematuro/fisiopatologia , Água/administração & dosagem , Ecocardiografia Doppler , Hemodinâmica , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Pulmão/fisiopatologia , Estudos Prospectivos , Artéria Pulmonar/fisiopatologia , Fluxo Sanguíneo Regional/fisiologia , Veia Cava Superior/fisiopatologiaAssuntos
Técnica de Fontan , Síndrome do Coração Esquerdo Hipoplásico/diagnóstico , Síndrome do Coração Esquerdo Hipoplásico/cirurgia , Imageamento por Ressonância Magnética , Artéria Pulmonar/cirurgia , Circulação Pulmonar , Veia Cava Inferior/cirurgia , Veia Cava Superior/cirurgia , Técnica de Fontan/efeitos adversos , Humanos , Síndrome do Coração Esquerdo Hipoplásico/fisiopatologia , Masculino , Cuidados Paliativos , Artéria Pulmonar/fisiopatologia , Fluxo Sanguíneo Regional , Resultado do Tratamento , Veia Cava Inferior/fisiopatologia , Veia Cava Superior/fisiopatologia , Adulto JovemRESUMO
Objetivos: Establecer la relación entre la saturación de oxígeno en la vena cava superior, la presión intrabdominal y el gasto urinario en pacientes con traumatismo abdominal abierto versus cerrado ingresados en la unidad de Shock Trauma del Hospital Daniel Alcides Carrión desde Enero 2010-Diciembre 2011. Material y métodos: La muestra estuvo constituida por 54 pacientes con traumatismo abdominal que ingresaron a ]a Unidad de Shock trauma del Hospital Daniel Alcides Carrión entre Enero 2010 y Diciembre del 2011. Los datos obtenidos-durante la investigación, por medio de la ficha de recolección de datos, elaborada para los fines de la investigación se ordenaron y procesaron, valiéndonos del programa SPSS 18.0 para Windows 2007. Resultados: El 85.2 por ciento de los pacientes fueron del sexo masculino. La enfermedad preexistente más frecuente fue la gastritis (14.8 por ciento) seguido de hipertensión arterial (7.4 por ciento). Hubo una mayor frecuencia de traumatismo abdominal abierto en el 59.3 por ciento de los casos. El 25.9 por ciento de los pacientes presentaron shock. Hubo una mortalidad de 25.9 por ciento. Hubo una mayor frecuencia de presiones intrabdominales de grado 1 en el 51.9 por ciento de los casos. Hubo una mayor frecuencia de saturación venosa mayor o igual de 70 por ciento en el 81.5 por ciento de los casos. Hubo una mayor frecuencia de gasto urinario mayor o igual de 0.5ml/Kg/Hr en el 79.6 por ciento de los casos. Conclusiones: Existe una correlación estadísticamente significativa entre la saturación de oxígeno en la vena cava superior, la presión intrabdominal y el gasto urinario en pacientes con traumatismo abdominal. A mayor presión intrabdominal, menor saturación venosa y menor flujo urinario en los pacientes independientemente del tipo de trauma abdominal. La mortalidad estuvo asociada a la presencia de Shock, presión intrabdominal grado III; saturación de oxigeno menor de 70 por ciento; y gasto urinario menor de 0.5mI/Kg/Hr...
Assuntos
Masculino , Feminino , Humanos , Adulto , Pessoa de Meia-Idade , Idoso , Hipertensão Intra-Abdominal , Nível de Oxigênio/análise , Transtornos Urinários , Traumatismos Abdominais , Veia Cava Superior/fisiopatologia , Estudos ProspectivosRESUMO
Purpose. To demonstrate the utility of 4D flow MR imaging for analyzing blood flow patterns and flow distribution in patients with congenital heart diseases. Methods: Six patients with congenital heart diseases were scanned using a standard cardiac MRI protocol, according to their condition. Additionally, 2D flow sequences of the great vessels, and a 4D flow sequence covering the entire heart were acquired. Flow patterns were visualized by using vector fields, streamlines and particle traces. Results: 4D flow technique depicted vortices and helical flow in the pulmonary artery of most patients, as well as in the aorta and superior vena cava of one patient with corrected aortic coarctation and a levoatrial cardinal vein. Conclusion: 4D flow MR imaging enables the identification of flow patterns difficult to detect with other diagnostic modalities. Comprehensive evaluation of flow patterns might help to understand the hemodynamic consequences of congenital heart diseases and their surgical procedures.
Objetivo. Demostrar la utilidad de 4D flow para el análisis de patrones y distribución de flujos en pacientes con cardiopatías congénitas. Métodos: Seis pacientes con cardiopatías congénitas fueron escaneados con un protocolo de resonancia magnética cardíaca estándar. Además se incluyeron secuencias de flujo 2D en los principales vasos del tórax y una secuencia 4D flow que cubría todo el corazón. Para la visualización de los patrones de flujo se emplearon vectores de velocidad, líneas de flujo y trazadores de partículas. Resultados: 4D flow reveló vórtices y hélices en la arteria pulmonar de la mayoría de los pacientes, y en la aorta y vena cava superior de un paciente con coartación aórtica reparada y vena cardinal levoatrial. Conclusiones: 4D flow permite identificar patrones de flujo en pacientes con cardiopatías congénitas, difíciles de observar con otros métodos diagnósticos. La evaluación de patrones de flujo podría contribuir a comprender las consecuencias hemodinámicas de diferentes cardiopatías congénitas.