Left ventricular diastolic function compared to inferior vena cava diameter variation as predictor of fluid responsiveness in mechanical ventilated patients with shock: The research protocol

Background: Fluid responsiveness, defined as an increase in cardiac output by 15% after a fluid challenge, is recommended to be evaluated in-patients with shock. Left ventricular (LV) diastolic dysfunction is associated with a lower increment of cardiac output after fluid challenge. Despite being a non-invasive test, the echocardiographic evaluation of the left ventricular diastolic function was rarely studied for the prediction of fluid responsiveness. The objective of this study is to evaluate the efficacy of LV diastolic function in predicting fluid responsiveness, comparing with inferior vena cava (IVC) diameter variation method, among shock patients who required mechanical ventilation. Methods: We plan to enroll adult patients with shock admitted to the intensive care unit (ICU). The echocardiographic hemodynamic parameters include IVC diameter variation, peak velocity of early diastolic filling of mitral valve inflow (E wave), peak early diastolic velocity of the mitral valve annulus (Ea), mitral E/Ea ratio, left ventricular ejection fraction (LVEF) and transaortic cardiac output (CO), all at baseline and after fluid therapy are measured. A fluid challenge with an infusion of 300 ml of acetate Ringer’s solution within 15 minutes will be given. Patients who have an increase in systolic blood pressure of at least 10 mmHg, mean arterial pressure of at least 5 mmHg or cardiac output of at least 15% are defined as fluid responders. The primary outcome of this study is the efficacy of the mitral E/Ea ratio comparing with IVC diameter variation in predicting fluid responsiveness. The secondary outcomes include the rate of fluid responsiveness in mechanically ventilated patients and LVEF and CO in patients with shock in the intensive care units. Conclusion: This study will evaluate the efficacy of left ventricular diastolic function measured by the echocardiography (Mitral E/Ea ratio) in predicting fluid responsiveness among mechanical ventilated patients with shock. Trial registrations: Clinicaltrials.gov NCT05066256, registered on January 10th, 2021