Effects of volume loading during experimental acute pulmonary embolism

Area of Science:

• Cardiovascular Physiology
• Pulmonary Embolism Pathophysiology

Background:

• Volume loading is a common treatment for hemodynamically compromised patients with acute pulmonary embolism.
• However, evidence suggests volume loading may negatively impact left ventricular (LV) function post-embolism.
• Potential adverse effects include leftward septal shift, reduced LV end-diastolic volume, and decreased stroke work.

Purpose of the Study:

• To investigate the effects of volume loading on left ventricular (LV) function following acute pulmonary embolism.
• To assess the impact of repeated embolization episodes on the response to volume loading.

Main Methods:

• Utilized a closed-chest canine model with induced autologous clot pulmonary embolism.
• Measured hemodynamic parameters including LV, right ventricular, and right atrial pressures.
• Employed sonomicrometry to assess LV dimensions and septal wall motion before and after embolization and volume loading.

Main Results:

• Volume loading increased LV area index pre-embolism but showed no significant change after single embolization.
• Repeated embolizations led to a significant decrease in LV area index during volume loading.
• LV stroke work increased pre-embolism but decreased significantly after repeated embolizations, associated with leftward septal shift and increased pericardial pressure.

Conclusions:

• Volume loading after acute pulmonary embolism, particularly after repeated episodes, can impair LV diastolic volume and stroke work.
• A leftward shift of the ventricular septum contributes to the observed reduction in LV end-diastolic volume.
• Findings suggest caution when using volume loading in hemodynamically compromised patients with acute pulmonary embolism.