CHEST 2024 Pulmonary and Critical Care Medicine (PCCM) Fellows Course-SV Determination by Echocardiography Article

SV Determination by Echocardiography Article

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The article "Stroke Volume Determination by Echocardiography" discusses the critical role of echocardiographic techniques in critical care, particularly focusing on the assessment of stroke volume (SV). Traditional two-dimensional (2D) echocardiographic methods, despite their efficiency and ease of learning, fall short in capturing the hemodynamic significance of detected abnormalities. The SV, representing the volume of blood ejected by the left ventricle during systole, is essential for a rapid assessment of whether cardiac dysfunction is contributing to shock.<br /><br />The preferred non-invasive way to measure SV is using pulsed-wave Doppler to obtain the left ventricular outflow tract (LVOT) velocity-time integral (VTI). This method, endorsed by the American Society of Echocardiography, aligns well with invasively derived measurements and can be widely applied in various acute care settings, including emergency departments and ICUs.<br /><br />The LVOT VTI measurement technique involves using phased-array probes to obtain views of the LVOT and applying color Doppler to rule out obstructions or regurgitation. Stroke volume is derived from the product of LVOT VTI and the cross-sectional area of the LVOT. The article recommends integrating SV and cardiac output assessments into critical care echocardiography (CCE) examinations to contextualize 2D findings better.<br /><br />It highlights a case study of a 71-year-old patient with pneumonia and septic shock to illustrate the practical application of these techniques to differentiate between chronic cardiac abnormalities and acute hemodynamic changes.<br /><br />Despite the powerful insights provided by LVOT VTI, the article acknowledges limitations, such as errors from dynamic LVOT obstruction, significant aortic insufficiency, and arrhythmias, which can complicate accurate measurement. It emphasizes the need for proper training and competence in these methods for optimal utilization.<br /><br />Conclusively, the article advocates for routine use of SV and cardiac output measurements in CCE to enhance diagnostic accuracy and tailor patient management, particularly in critical care scenarios.

Keywords

Stroke Volume

Echocardiography

Critical Care

Pulsed-wave Doppler

LVOT VTI

Cardiac Output

Hemodynamic Assessment

Phased-array Probes

Septic Shock

Cardiac Dysfunction