Thursday, January 5, 2012
A pulse of small volume is characteristic of shock and of low output heart failure and may occur with severe stenos is of any valve or severe pulmonary hypertension. A pulse of large volume is found in fevers, aortic incompetence, thermo of the aorta, extreme bradycardia as with heart block and in diseases in which there is an increased cardiac output e.g. severe anemia, thyrotoxicosis and some patients with cor pulmonale. If the brachial pulses are unequal, it can be inferred that there is a vascular block of which the most common causes are embolism thrombosis and atherosclerosis of the aorta. In pericarditis with effusion or in constrictive pericarditis the normal increase in venous return to the right side of the heart during inspiration cannot be accommodated. The normal increase in capacity of the pulmonary vascular bed which occurs during inspiration results in a diminished return of blood to the left side of the heart. Hence the volume of the pulse is decreased by inspiration. Pulsus paradoxes are also found in asthma or strider, where there is a change in increased intrathoracic pressure with respiration. Thanks.