Asunto(s)
Enfermedades Pulmonares Obstructivas/fisiopatología , Neumonía/fisiopatología , Alveolos Pulmonares/fisiopatología , Circulación Pulmonar , Respiración , Adulto , Gasto Cardíaco , Cateterismo , Enfermedad Crónica , Humanos , Técnicas de Dilución del Indicador , Verde de Indocianina , Métodos , Persona de Mediana Edad , Oxígeno , Radioisótopos , Espirometría , Relación Ventilacion-Perfusión , Capacidad Vital , XenónAsunto(s)
Defectos del Tabique Interatrial/diagnóstico , Verde de Indocianina , Arteria Pulmonar , Venas Pulmonares , Xenón , Animales , Fístula Arteriovenosa/diagnóstico , Gasto Cardíaco , Ensayos Clínicos como Asunto , Perros , Humanos , Masculino , Métodos , Oxígeno/sangre , Alveolos Pulmonares/fisiopatología , Factores de TiempoRESUMEN
In order to evaluate separately changes in vascular tone occurring in arteries and veins, we measured pulmonary capillary red blood cell (RBC) concentration under zone II (waterfall) conditions in isolated dog lungs rapidly frozen with Freon 12. The lungs were frozen while being perfused from artery to vein and from vein to artery breathing normal and hypoxic gas mixtures and during infusions of serotonin and histamine. Changes in capillary RBC concentration which occurred during the experimental conditions indicated an alteration in vascular resistance upstream from the capillaries. Alveolar hypoxia caused a significant decrease in capillary RBC concentration during forward perfusion, but no change from the control values during reverse perfusion. Serotonin infusion caused a decrease in RBC concentration during forward perfusion comparable with that of hypoxia and a small but significant decrease during reverse perfusion. Histamine infusion caused no change in RBC concentration from control values during forward perfusion, but a large decrease during reverse perfusion. We conclude that vasoconstriction occurs (a) exclusively in arteries during alveolar hypoxia, (b) predominantly in arteries but to a lesser extent in veins during serotonin infusion, and (c) exclusively in veins during histamine infusion.
Asunto(s)
Histamina/administración & dosificación , Hipoxia/fisiopatología , Alveolos Pulmonares , Serotonina/administración & dosificación , Sistema Vasomotor/efectos de los fármacos , Animales , Arterias/efectos de los fármacos , Presión Sanguínea , Capilares/efectos de los fármacos , Constricción , Perros , Recuento de Eritrocitos , Congelación , Histamina/farmacología , Técnicas In Vitro , Inyecciones Intraarteriales , Inyecciones Intravenosas , Pulmón/efectos de los fármacos , Métodos , Perfusión , Alveolos Pulmonares/irrigación sanguínea , Serotonina/farmacología , Factores de Tiempo , Resistencia Vascular/efectos de los fármacos , Venas/efectos de los fármacosAsunto(s)
Respiración , Espacio Muerto Respiratorio , Adolescente , Adulto , Factores de Edad , Anciano , Arterias , Dióxido de Carbono/sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Presión Parcial , Descanso , Fumar/fisiopatología , EspirometríaAsunto(s)
Presión Sanguínea , Volumen Sanguíneo , Pulmón/irrigación sanguínea , Presión , Circulación Pulmonar , Presión Venosa , Animales , Anastomosis Arteriovenosa , Permeabilidad Capilar , Perros , Técnicas In Vitro , Tinta , Pulmón/fisiología , Rendimiento Pulmonar , Tamaño de los Órganos , Perfusión , Alveolos Pulmonares/fisiología , Edema Pulmonar/etiologíaAsunto(s)
Pulmón/irrigación sanguínea , Alveolos Pulmonares/fisiología , Flujo Sanguíneo Regional , Animales , Presión Sanguínea , Dióxido de Carbono/sangre , Dextranos/farmacología , Perros , Histamina/farmacología , Concentración de Iones de Hidrógeno , Isoproterenol/farmacología , Pulmón/anatomía & histología , Métodos , Oxígeno/sangre , Radioisótopos , Serotonina/farmacología , Resistencia Vascular/efectos de los fármacos , XenónAsunto(s)
Pulmón/fisiología , Circulación Pulmonar/fisiología , Automatización , Velocidad del Flujo Sanguíneo , Computadores , Humanos , Métodos , Radioisótopos , XenónRESUMEN
The effect of acetylcholine was studied on the region of increased vascular resistance at the lung bases in patients with mitral stenosis. The patients had moderate elevations of pulmonary artery pressure. The distribution of blood flow and ventilation were measured in both lungs of 10 patients using radioactive xenon-133 and a scanning technique. Acetylcholine was then infused into one main pulmonary artery, and the distribution of blood flow and ventilation were measured again. One lung served as a control during the drug infusion. There was a small but significant increase in perfusion to the dependent lung zone during the drug infusion without a change in pulmonary artery pressure indicating localized vasodilation. Relative underperfusion was still present during the acetylcholine administration which indicated that increased vasomotor tone was not the principal pathophysiological mechanism for the increased vascular resistance. There was a decrease in ventilation to the lower zone of the lung receiving acetylcholine.
