KINE 639 - Dr. Green Section 1 Clinical Physiology I, II, III, IV

21. Development of the Driving Pressure in the Human Cardiovascular System

27. With an increase in intrapulmonary pressure (valsavla maneuver) the vena cava collapse, causing a reduction in central venous pressure (right atrial pressure). The pressure also compresses the aorta causing increased aortic pressure (afterload). Combined with the decrease in right atrial pressure, this causes a decrease in Q. With a pneumothorax, the normal negative intrapleural pressure (-4mmHg) is equalized with atmospheric pressure, which puts 4 mmHg of additional pressure on the heart. This means that to maintain normal function, central venous pressure must increase to compensate With sympathetic stimulation, the HR inccreases and the contractility of the myocardium increases which serve to pump blood out of the venous storage system and reduce the pressure in that system, so for a given level of CVP, cardiac output will be higher (for a given level of cardiac output in the enhanced sympathetic state, CVP will be lower because more blood is being pumped out of venous system) With an increase in intrapulmonary pressure (valsavla maneuver) the vena cava collapse, causing a reduction in central venous pressure (right atrial pressure). The pressure also compresses the aorta causing increased aortic pressure (afterload). Combined with the decrease in right atrial pressure, this causes a decrease in Q. With a pneumothorax, the normal negative intrapleural pressure (-4mmHg) is equalized with atmospheric pressure, which puts 4 mmHg of additional pressure on the heart. This means that to maintain normal function, central venous pressure must increase to compensate With sympathetic stimulation, the HR inccreases and the contractility of the myocardium increases which serve to pump blood out of the venous storage system and reduce the pressure in that system, so for a given level of CVP, cardiac output will be higher (for a given level of cardiac output in the enhanced sympathetic state, CVP will be lower because more blood is being pumped out of venous system)

29. Increasing peripheral resistance means that more blood has to be pumped out of the venous reservoir to overcome the increased pressure. At the same time, peripheral vasoconstriction at the arteriolar level results in less blood being dumped back into the veins, so, for a given level of cardiac output, CVP will be less. Decreasing peripheral resistance ( increased peripheral vasodilation ) will result in more blood being dumped into the veins causing and increased in CVP Sympathetic stimulation will constrict the majority of the vessels, especially the veins, so CVP and MCP will both be increased Increasing peripheral resistance means that more blood has to be pumped out of the venous reservoir to overcome the increased pressure. At the same time, peripheral vasoconstriction at the arteriolar level results in less blood being dumped back into the veins, so, for a given level of cardiac output, CVP will be less. Decreasing peripheral resistance ( increased peripheral vasodilation ) will result in more blood being dumped into the veins causing and increased in CVP Sympathetic stimulation will constrict the majority of the vessels, especially the veins, so CVP and MCP will both be increased