A comprehensive echocardiographic analysis during simulated hypovolaemia: An observational study

Area of Science:

• Cardiology
• Critical Care Medicine
• Physiology

Background:

• Peri-operative and critically ill patients may experience hypovolemic shock with preserved mean arterial pressure (MAP) and heart rate (HR), but decreased stroke volume index (SVI).
• Understanding echocardiographic changes during mild to moderate hypovolemia is crucial for timely intervention.

Purpose of the Study:

• To evaluate echocardiographic parameters in response to simulated mild to moderate central hypovolemia.
• To assess changes in myocardial performance and cardiac volumes during graded hypovolemia.

Main Methods:

• Prospective preclinical study involving 30 healthy male volunteers.
• Simulated hypovolemia using lower body negative pressure (LBNP) at -15, -30, and -45 mmHg.
• Transthoracic echocardiography (TTE) performed at each stage to measure systolic and diastolic function, and cardiac volumes.

Main Results:

• Stroke volume index (SVI) decreased progressively with increasing hypovolemia.
• Left ventricular (LV) ejection fraction decreased at -30 and -45 mmHg.
• LV global longitudinal strain (LV GLS), tricuspid annular plain systolic excursion (TAPSE), and right ventricular (RV) S' decreased, indicating impaired ventricular function. Left-atrial end-systolic volume (LA ESV) also decreased.

Conclusions:

• Simulated central hypovolemia via LBNP did not consistently alter MAP or HR.
• A decrease in SVI was observed, associated with echocardiographic evidence of deteriorated right and left ventricular function.
• Decreased LA ESV characterized the reduced filling status during simulated hypovolemia.