Pulsus Paradoxus: Cardiac Function and Assessment

PULSUS PARADOXUS PATHOPHYSIOLOGY In normal hemodynamic conditions, during inspiration, adequate cardiac, vascular function and adequate blood volume, certain changes in blood pressure occur. Keep in mind, when we measure blood pressure, we are assessing arterial pressures, not venous. • Normally during inspiration, Cardiac Output (CO) decreases slightly, since the Left Ventricle (LV) does not have the adequate amount of space to expand for full capacity preload •This drop in blood pressure is normally < 10mmHg •The heart rate also increases, as a compensatory mechanism, in an attempt to maintain normal Oxygen Delivery (DO2) In a short summary, this occurs due to: •  Intrathoracic pressures increase venous return to the Right Ventricle (RV) •This increase in Central Venous Pressure (1-6mmHg) which reflects the pressure of the RV, increases the RV volume and capacity, forcing the Interventricular Septum (the wall dividing the ventricles) towards the left •This Septum shift towards the left slightly reduces the LV capacity. This is even more marked during a Pericardial Effusion (fluid in the pericardial sac), where the LV can’t expand properly due to the pressure from the Septum and the pericardial sac, decreasing it’s internal diameter, leading to decreased Stroke Volume (SV) since it can’t produce a strong contraction •A decrease in pulmonary vein blood volume to the LV due to blood pooling from increased lung expansion also reduces the amo...
Source: EMS 12-Lead - Category: Cardiology Authors: Tags: patient-management Pulsus Paradoxus Training Assessment Cardiac Function Source Type: research