Assessment of fluid responsiveness by analyzing stroke volume change with Transthoracic echocardiography on passive leg raising test in hemodynamically unstable patients

Hemodynamic instability in critically ill patients often prompts fluid resuscitation, yet overzealous fluid administration risks pulmonary edema, intracranial hypertension, and cardiac overload. Traditional static measures like CVP and PAOP poorly predict whether a patient’s cardiac output will actually improve after fluids, whereas dynamic assessments like stroke volume variation, pulse pressure variation, and especially passive leg raising offer greater sensitivity and specificity. PLR transiently increases preload by shifting venous blood centrally, acting as a reversible, noninvasive self-fluid challenge, and a 10 to 15 percent rise in stroke volume during PLR reliably identifies fluid responders. Transthoracic echocardiography, by measuring LVOT velocity time integral before and after PLR and combining SV changes with cardiac index and IVC collapsibility provides real time,risk free evaluation of fluid responsiveness. This study hypothesizes that PLR induced SV changes measured by TTE can accurately predict which hemodynamically unstable patients will benefit from fluid administration