The circulatory effects produced in a patient with pneumopericardium by artificially varying the intrapericardial pressure

Abstract

1. 1. Observations on changes in pulse rate, respiratory rate, arterial pressure, venous pressure, and circulation time were made with artificially produced changes in intrapericardial pressure in a patient with pneumopericardium. These relationships have been illustrated graphically.2. 2. The intrapericardial pressure fluctuated with respiration, and, as higher pressures were reached, these fluctuations decreased.3. 3. The intrapericardial pressure fluctuated with systole and diastole. Kymographic tracings were made of the fluctuations in intrapericardial pressure caused by respiration and the heartbeat. With the higher intrapericardial pressures, the changes in pressure produced by systole and diastole were less marked.4. 4. Significant changes in pulse rate, arterial pressure, venous pressure, and circulation time did not occur until the intrapericardial pressure was elevated to, or above, 145 mm. of water.5. 5. In order to maintain the circulation, it was necessary that venous pressure exceed intrapericardial pressure by at least 35 to 40 mm. of water.