Respirophasic Carotid Peak Systolic Velocity Variation as a Predictor of Volume Responsiveness in Mechanically Ventilated Patients with Septic Shock

Introduction: The evaluation of fluid responsiveness in patients with hemodynamic instability remains to be challenging. This investigation aimed to determine whether respiratory variation in carotid systolic velocity (CSV) predicts fluid responsiveness in mechanically ventilated patients with septic shock. Methods: Our study was a prospective interventional study that was carried out on 40 adult mechanically ventilated patients with septic shock. Two sets of measurements were performed before and immediately after volume expansion. Cardiac output (CO), stroke volume (SV), stroke volume index (SVI), IVC distensibility index (IVC -DI) were measured by transthoracic echocardiography and carotid systolic velocity index (CSV index) was measured by carotid Doppler. Respiratory variation of pulse pressure (PPV%) and central venous pressure (CVP) were recorded. Fluid challenge responders were defined as patients whose cardiac output was increased >= 15%. The area under the receiver operating characteristic curve (AUC) was compared for each predictive parameter. Results: Our study found that the most important baseline patient parameters that could predict the fluid responsiveness of patient with septic shock are the CSV index followed by PPV% then IVC-DI. For CSV index AUC was 1.000 the cut-off point was 10.5% with sensitivity 95% and specificity was 95%. For PPV%, (AUC) was 0.974, the cut-off point was 14% with sensitivity 95% and specificity was 90%. For IVC-DI, (AUC) was 0.913 the cut-off point 14.5% carried a sensitivity 85% and specificity 90%. Conclusions: The CSV index is a sensitive and promising parameter in predicting fluid responsiveness of mechanically ventilated patient with septic shock is promising parameter followed by PPV% then IVC-DI.