The predictive ability of carotid artery corrected flow time and respirophasic variation in blood flow peak velocity measured by ultrasonography for fluid responsiveness in parturients for cesarean delivery

BACKGROUND: Ultrasonic measurements of carotid artery corrected flow time (FTc) and respirophasic variation in blood flow peak velocity (ΔVpeak) were recently introduced to predict fluid responsiveness in non-obstetric patients. We designed the present study to evaluate the performance of these two ultrasonic indices in predicting fluid responsiveness in healthy parturients. METHODS: Seventy-five parturients undergoing elective cesarean delivery were enrolled. Carotid doppler parameters including FTc, ΔVpeak, the inferior vena cava diameter at the end of expiration (IVCexp) and inspiration (IVCins), Inferior Vena Cava Collapsibility Index (IVCCI), and Stroke Volume Index (SVI) were measured before and after fluid challenge. Fluid responsiveness was defined as a 15% or more increase in SVI as assessed by transthoracic echocardiography after the fluid challenge. RESULTS: FTc and ΔVpeak but not IVCins, IVCexp and IVCCI were proved to be two independent predictors for fluid responsiveness by multivariate logistic regression, with the odds ratios of 1.191 (95% confidence interval (CI), 1.070 to 1.326) and 0.521 (95% CI, 0.351 to 0.773). The area under the ROC curve to predict fluid responsiveness for FTc was 0.846 (95% CI, 0.751-0.940) and for ΔVpeak was 0.810 (95% CI, 0.709-0.910), which were significantly higher than those for IVCins (0.436, 95% CI, 0.300-0.572), IVCexp (0.595, 95% CI, 0.460-0.730) and IVCCI (0.548, 95% CI, 0.408-0.688). CONCLUSIONS: Compared with IVCins, IVCexp and IVCCI, FTc and ΔVpeak measured by ultrasonography seem to be the highly feasible and reliable methods to predict fluid responsiveness in parturients with spontaneous breathing undergoing elective cesarean delivery.