Background: Ultrasonic measurements of carotid artery corrected flow time (FTc) and respirophasic variation in blood flow peak velocity (ΔV<inf>peak</inf>) 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, ΔV<inf>peak</inf>, the inferior vena cava diameter at the end of expiration (IVC<inf>exp</inf>) and inspiration (IVC<inf>ins</inf>), 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 ΔV<inf>peak</inf> but not IVC<inf>ins</inf>, IVC<inf>exp</inf> 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 ΔV<inf>peak</inf> was 0.810 (95% CI, 0.709-0.910), which were significantly higher than those for IVC<inf>ins</inf> (0.436, 95% CI, 0.300-0.572), IVC<inf>exp</inf> (0.595, 95% CI, 0.460-0.730) and IVCCI (0.548, 95% CI, 0.408-0.688).
Conclusions: Compared with IVC<inf>ins</inf>, IVC<inf>exp</inf> and IVCCI, FTc and ΔV<inf>peak</inf> 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.