Effect of VTI(LVOT) variation rate on the assessment of fluid responsiveness in septic shock patients

This study aimed to assess the predictive value of velocity time integral (VTI) of the left ventricular outflow tract (LVOT) on volume expansion test (VET) as an indicator of volume responsiveness in septic shock patients. Septic shock patients undergoing mechanical ventilation were recruited. The hemodynamic parameters before and after VE were monitored by pulse indicated continuous cardiac output (PiCCO) and echocardiography. Heart rate, cardiac index (CI), mean arterial pressure (MAP), central venous pressure, stroke volume variation (SVV), CI and variation of pulse pressure (PPV), and the changes in cardiac parameters (Dheart rate, Dmean arterial pressure, Dcentral venous pressure, DSVV, DCI, and DPPV) were determined. The relationships of hemodynamic parameters and their changes with DVTI were further evaluated with Pearson relation analysis. The value of these parameters in fluid responsiveness prediction was evaluated by using the receiver operating characteristic (ROC) curve analysis. Results showed that 44 VETs were performed in 44 septic shock patients with responsiveness in 24 patients and non-responsiveness in 20. The CI increased by ≥ 15% in responsive patients, but by<15% in non-responsive patients after VET. There were significant differences in the SVV and PPV after VET between responsive and non-responsive groups. DSVV, DPPV, and DCI were positively related to DVTI. The area under ROC curve (AUC) for SVV in fluid responsiveness prediction was 0.80, and the sensitivity and specificity of SVV were 66.5% and 95%, respectively, when the cut-off value was 24.8%. The AUC for PPV in fluid responsiveness prediction was 0.843, and the sensitivity and specificity of PPV were 83.3% and 75%, respectively, when the cut-off value was 25.8%. The AUC for DVTILVOT in fluid responsiveness prediction was 0.956, and the sensitivity and specificity were 87.5% and 95%, respectively, when the cut-off value was 15.9%. In conclusion, DVTILVOT is effective to predict fluid responsiveness after VET in mechanical ventilation patients with septic shock. It may serve as a new, noninvasive and functional hemodynamic parameter with the same accuracy to SVV.