What is pulsus paradoxus?

• it is an abnormally large decrease in systolic blood pressure (> 10 mmHg) on inspiration

• it is caused by a limitation on the outward expansion of right ventricle as blood flows in during inspiration (the limitation is, of course, the cardiac tamponande) that results in bulging of the intraventricular septum into the left ventricle, leading to a large reduction of LV volume that contributes to a large decrease in stroke volume

• so you palpate the pulse. when the patient breathes in, the pulse weakens

Measuring pulsus paradoxus

• use a sphygomomanometer. raise cuff pressure above systolic and very slowly let the air out until you hear intermittent pulsations

• at this point, you are hearing only heart sounds during expiration

• then, lower it just until you start hearing every heart sound

• subtract these two pressures, and this is size of the pulsus

Pulsus paradoxus is not specific to cardiac tamponade

• cardiac tamponade without pulsus paradoxus is found in LV dysfunction, ASD, aortic insufficiency

• pulsus paradoxus occurs in conditions other than cardiac tamponade—for example, in severe lung disease, so it’s not completely exclusive

Category: Pathology Notes