Exploring the best predictors of fluid responsiveness in patients with septic shock

Objective: To evaluate respiratory variations in carotid and brachial peak velocity and other hemodynamic parameters to predict responsiveness to fluid challenge. Methods: A prospective observational study was performed on mechanically ventilated patients with septic shock. Outcomes included the measurements of central venous pressure, intrathoracic blood volume index, stroke volume variation (SVV), pleth variability index(PVI), and ultrasound assessments of respiratory variations in inferior vena cava diameter (Delta IVC), carotid Doppler peak velocity (Delta CDPV), and brachial artery peak velocity (Delta Vpeak brach). Results: All patients received 200 mL normal saline challenge. There were 27 responders and 22 non-responders. Responders had higher SVV, PVI, Delta IVC, Delta CDPV, and Delta Vpeak brach measurements. In addition, all these measurements had statistically significant linear correlations with changes in cardiac index (CI). When responders were defined by Delta CI >= 10%, receiver operating characteristics (ROC) curve analysis showed that fluid responsiveness could be predicted: 11.5% optimal cut-off levels of SVV with sensitivity of 75% and specificity of 85%, 15.5% optimal cut-off levels of PVI with sensitivity of 65% and specificity of 80%, 20.5% optimal cut-off levels of Delta IVC with sensitivity of 67% and specificity of 77%, 13% optimal cut-off levels of Delta CDPV with sensitivity of 78%% and specificity of 90%, 11.7% optimal cut-off levels of Delta Vpeak brach with sensitivity of 70% and specificity of 80%. Conclusion: Ultrasound assessment of Delta IVC and Delta Vpeak brach, especially Delta CDPV, could predict fluid responsiveness and might be recommended as a continuous and noninvasive method to monitor functional hemodynamic parameter in mechanically ventilated patients with septic shock. (C) 2017 Elsevier Inc. All rights reserved.