Utility of Inferior Vena Cava Distensibility and Respiratory Variation in Peak Aortic Blood Flow Velocity to Predict Fluid Responsiveness in Children with Shock.

Objectives: To evaluate the sensitivity and specificity of inferior vena cava (IVC) distensibility index (∆IVC) and respiratory variation in peak aortic blood flow velocity (∆Vpeak) to predict fluid responsiveness in ventilated children with shock and to find out the best cut-off values for predicting fluid responsiveness.

Methods: In this prospective observational study, conducted in a pediatric ICU from January 2019 through May 2020, consecutive children aged 2 mo to 17 y with shock requiring fluid bolus were included. ∆IVC and ∆Vpeak were measured before and immediately after 10 ml/kg fluid bolus administration. ∆IVC and ∆Vpeak were compared between responders and non-responders, defined by a change in stroke volume index (SVI) of ≥10%.

Results: Thirty-seven ventilated children [26 (70.4%) boys] with median age of 60 (36, 108) mo were included. The median (IQR) ∆IVC was 21.7% (14.3, 30.9) and the median (IQR) ΔVpeak was 11.3% (7.2, 15.2). Twenty-three (62%) children were fluid responsive. The median (IQR) ∆IVC was higher in responders compared to non-responders [26% (16.9, 36.5) vs. 17.2% (8.4, 21.9); p = 0.018] and mean (SD) ΔVpeak was higher in responders [13.9% (6.1) vs. 8.4% (3.9), p = 0.004]. The prediction of fluid responsiveness with ΔIVC [ROC curve area 0.73 (0.56-0.9), p = 0.01] and ΔVpeak [ROC curve area 0.78 (0.63-0.94), p = 0.002] was similar. The best cut-off of ∆IVC to predict fluid responsiveness was 23% (sensitivity, 60.8%; specificity, 85.7%) and ΔVpeak was 11.3% (sensitivity, 74%; specificity, 86%).

Conclusions: In this study, authors found that ∆IVC and ΔVpeak were good predictors of fluid responsiveness in ventilated children with shock.