Abstract
In order to obtain some informations to treat the cardiogenic shock resulted from acute pulmonary embolism more in detail, changes in hemodynamics, blood gases and coronary blood flow were observed, and influence of controlled respiration and oxygen administration was studied at the maximum loading of the right ventricle induced by repeated miliary pulmonary embolization with Lycopodium spores. Material and Methods Fourty-one adult mongrel dogs were employed. Animals were anesthetized by intravenous injection of pentobarbital soda. Pulmonary arterial pressure (PAP), systemic arterial pressure (SAP), and right atrial pressure were monitored continuously. Lycopodium spore suspension in saline (50 mg/ml) was prepared and very small dose of the suspension (0.2 ml/kg) was administered intravenously for a single embolization in order to minimize reflex hemodynamic effects. Embolization was repeated with an interval of about 5 minutes until the final lethal stage. A) Influence of controlled respiration and oxygen administration upon the changes in hemodynamics and blood gases resulting from pulmonary embolization (Experiment l). Animals were divided into 4 study groups: l) spontaneous, room air breathing group (6 dogs), 2) spontaneous, oxygen breathing group (4 dogs), 3) controlled respiration with room air group (7 dogs) and 4) controlled respiration with oxygen group (5 dogs). Blood gases were analyzed. B) Changes in systemic circulation and cardiac function at the maximum loading of the right ventricle resulting from pulmonary embolization (Experiment 2). Aortic blood flow (ABF) was measured employing an electromagnetic flow meter in 10 dogs. Stroke power, external stroke work, small change (dp/dt) of the left ventricular pressure and total systemic vascular resistance were calculated continuously. Tension-Time-Index (TTI) of the both ventricles and pulmonary vascular resistance were also calculated. C) Change in coronary blood flow resulting from pulmonary embolization (Experiment 3). ABF and left circumflex or right coronary arterial blood flow were measured by means of an electromagnetic flow meter in 9 dogs.
