Assessment of Cardiac Preload and Volume Responsiveness using Echocardiography

Abstract

Assessment of cardiac preload and of preload reserve is an important issue in intensive care unit (ICU) patients with cardiovascular compromise. For many decades, central venous and pulmonary artery occlusion pressures (PAOP), which are assumed to reflect right and left filling pressures respectively, have been used to assess right and left cardiac preload. Although obtained from invasive catheterization, they are still used by a lot of physicians in fluid infusion decision making process. However, filling pressures, by nature, cannot fully reflect cardiac preload and moreover, the existing literature does not support the use of such pressures to assess fluid responsiveness [1]. Many approaches have been proposed to assess preload using non-invasive techniques. Echocardiography and cardiac Doppler are extensively used in the cardiologic field. However, echocardiography is now considered by most European ICU physicians as the first line method to evaluate cardiac function in patients with hemodynamic instability, not only in terms of diagnosis but also in terms of therapeutic decision making process [2, 3]. Regarding cardiac preload and cardiac preload reserve, cardiac echo-Doppler can provide important information through either measurements of static parameters, such as dimensions of cardiac chambers, or of dynamic parameters such as respiratory variation of Doppler velocities.