Dynamic arterial elastance for predicting mean arterial pressure responsiveness after fluid challenge in spontaneously breathing septic patients: A protocol for prospective observational study

Background: Fluid resuscitation is essential for patients with sepsis and septic shock; however, the response of blood pressure to fluids is still challenging. Dynamic arterial elastance (Eadyn), defined as the ratio between pulse pressure variation (PPV) and stroke volume variation (SVV), is one of the parameters that has been proposed to predict mean arterial pressure (MAP) response to fluid administration. PPV and SVV are obtained from the heart-lung interaction concepts, in which spontaneous breathing is an important limitation. In this study, we evaluate the accuracy (sensitivity and specificity) of Eadyn in predicting the MAP response after fluid administration in predicted fluid responsive, spontaneously breathing septic patients. Methods: Spontaneously breathing patients with sepsis or septic shock and acute circulatory failure who were predicted to be fluid responders by the passive leg raising test or the mini-fluid challenge test were enrolled. PPV, SVV, Eadyn and the other hemodynamic parameters were measured by an arterial catheter connected to FloTracTM sensor integrated with the HemoSphereTM platform before and after a fluid challenge. Patients were classified according to the increase in MAP after fluid administration into 2 groups: MAP-responders (MAP increase ≥ 10%) and MAP-nonresponders (MAP increase < 10%). Hypothesis: In predicted fluid responders and spontaneously breathing septic patients, Eadyn should have predicted blood responsiveness. Ethics and dissemination: The Ramathibodi Human Research Ethics Committee has approved the trial. The findings plan to be presented in peer-reviewed publications and conferences in critical care medicine.