RESUMEN
A new radiologic method for measuring the rotation of a scoliosis from CT pictures is described. Normal deviation from the 0 position at the level of the first lumbar vertebra in 50 patients without clinically demonstrable scoliosis when accurately positioned, was M = 0.06 degrees +/- 2.95 SD. Direct measurements of the rotation of the spine and of the displacement of the sternum permit serial observation of the progress of the scoliosis and of the consequent thoracic deformity, as well as the result of treatment.
Asunto(s)
Vértebras Lumbares/diagnóstico por imagen , Escoliosis/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Artrografía , Humanos , Articulaciones/patología , Vértebras Lumbares/patología , Escoliosis/patología , Escoliosis/terapia , Esternón/diagnóstico por imagen , Esternón/patologíaRESUMEN
The present experiments have been conducted to study the immediate effects of graded immersion on the central circulation. When taking heart volume as an indicator, it was found that immersion to the diaphragm of a standing subject produces the same changes as assumption of the supine posture. Heart volume increases by approximately 130 ml. When the water level is raised to the neck, an extra pressure corresponding to a water column extending from the diaphragm to the surface of the water of approximately 25 cm H2O forces blood into the thorax. The heart becomes distended by an additional 120 ml. Correspondingly the central venous pressure at the height of the right atrium increases from 2.5 to 12.8 mm HG when the water level rises from the diaphragm to the neck. The greater filling of the pulmonary circulation is accompanied by a decrease in vital capacity and visualized by scintigrams. The preferential increase in blood volume of the apical regions is striking. When raising the water level from the symphysis to the xiphoid heart rate falls by about 15%.
Asunto(s)
Circulación Sanguínea , Inmersión , Adulto , Cardiomegalia , Presión Venosa Central , Corazón/fisiología , Frecuencia Cardíaca , Humanos , Pulmón/fisiología , Masculino , Postura , Circulación Pulmonar , Flujo Sanguíneo Regional , Capacidad VitalRESUMEN
13 subjects standing in a narrow upright tank were exposed to rapid water immersion up to the neck. The tank was filled from an elevated reservoir in less than 4 s. In 8 subjects heart size was measured by Roentgen-cinematography combined with video tape recording. Planimetry of the diastolic postero-anterior area of the heart showed an average increase in heart size of 30% within 6 s. In 5 subjects central venous pressure and the height of hydrostatic pressure in the tank were recorded. The two pressures rose and fell simultaneously without delay when the hydrostatic pressure exceeded the level of the diaphragm. Rapid immersion caused a fall in heart rate of approximately 20%. The findings speak in favor of the concept that the right heart does not constitute a resistance and that the pulmonary circulation and the systemic capacitance vessels form a functional unit.
Asunto(s)
Cardiomegalia , Presión Venosa Central , Corazón/fisiología , Inmersión , Adulto , Frecuencia Cardíaca , Humanos , Masculino , Postura , Factores de TiempoRESUMEN
The effective compliance is defined as the relation of change in blood volume to change in central venous pressure. It was measured in 8 upright sitting male subjects and amounted to 3.3 ml/(mm Hg X kg BW). It is, therefore, by about 50% greater than the effective compliance in the supine subject which amounts to 2.3 ml/(mm Hg X kg BW). . This difference is probably due to the posture dependent blood volume distribution in the low pressure system whose "upper" and "lower" sections have nonlinear pressure-volume characteristics. Immersion to the neck reduces the effective complicance to about half the control value (1.9 ml/(mm Hg X kg BW) which probably constitutes the effective compliance of the intrathoracic circulatory compartment.