Pulsus paradoxus

Palpable diminution of the radial pulse on inspiration in patients with cardiac tamponade.

An exaggeration of the normal inspiratory decrease in blood pressure which occurs because of negative intrapleural pressures during inspiration that cause increased venous return and right heart filling which results in bowing of the septum to the left and decreases filling of the left heart.

In a normal heart, inspiration results in ventricular interdependence, a mildly decreased stroke volume and blood pressure.

During cardiac tamponade ventricular interdependence is exaggerated because the high pericardial pressure compresses the entire heart.

During inspiration the left heart filling is greatly restricted by right heart filling.

Detected by palpating the radial pulse and noting inspiratory diminution of the pulse during normal respirations.

Most commonly measured with a manual sphygmomanometer with slow deflation during normal respirations, while listening for the first Korotkoff sounds.

The sounds become audible with expiration and inaudible with inspiration.

Can be detected by observation of inspiratory diminution of the peripheral pulse on an arterial catheter tracing or during pulse oximetry.

Defined as a greater than 10 mm Hg difference between the initial detection of sounds on expiration and the constant presence of sounds with each heartbeat throughout the respiratory cycle.

Total paradox is known as pulse obliteration defined as inspiratory disappearance of the brachial and radial pulses, with total disappearance of the Korotkoff sounds.

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