Carotid Doppler ultrasound data as predictors of fluid responsiveness

Objective. To evaluate sensitivity and specificity of carotid Doppler parameters as predictors of fluid responsiveness after heart valve surgery. Material and methods. A prospective study enrolled 49 adults after elective heart valve surgery. On the first day after surgery, all patients underwent passive leg-raising test (PLR) during mechanical ventilation (MV) and spontaneous breathing (SB). We estimated hemodynamic parameters using prepulmonary thermodilution before and after the test. Carotid Doppler indices such as absolute (∆FTc, ms) and relative (∆FTc, %) change in corrected flow time were calculated. Responders had cardiac output (∆CO) increase >10%. Results. There was a moderate relationship between ∆CO and ∆FTc during PLR test under MV (r=0.551, p<0.0001) and SB (r=0.510, p<0.0001). Sensitivity and specificity of FTc-based PLR test in mechanically ventilated patients were 87% and 70%, respectively (∆FTc threshold value 16.4 ms), during spontaneous breathing — 88% and 79%, respectively (∆FTc threshold value 19.4 ms). Similar results were obtained for the relative increase of ∆FTc (%). Conclusion. The FTc-based PLR test has moderate sensitivity and specificity for analysis of fluid responsiveness after elective heart valve surgery. Further studies are required to demonstrate significant of carotid Doppler measurements as predictors of fluid responsiveness.