Respiratory variation in aortic flow peak velocity and inferior vena cava distensibility as indices of fluid responsiveness in anaesthetised and mechanically ventilated children.

Background And Aims: Dynamic parameters such as the respiratory variation in aortic flow peak velocity (ΔVpeak) and inferior vena cava distensibility index (dIVC) are accurate indices of fluid responsiveness in adults. Little is known about their utility in children. We studied the ability of these indices to predict fluid responsiveness in anaesthetised and mechanically ventilated children.

Methods: This prospective study was conducted in 42 children aged between one to 14 years scheduled for elective surgery under general endotracheal anaesthesia. Mechanical ventilation was initiated with a tidal volume of 10 ml/kg. ΔVpeak, dIVC and stroke volume index (SVI) were measured before and after volume expansion (VE) with 10 ml/kg of crystalloid using transthoracic echocardiography. Patients were considered to be responders (R) and non-responders (NR) when SVI increased to either ≥15% or <15% after VE. ΔVpeak and dIVC were analysed between R and NR.

Results: The best cut-off value for ΔVpeak as defined by the receiver operator characteristics (ROC) curve analysis was 12.2%, for which sensitivity, specificity, positive predictive value and negative predictive value were 100%, 94%, 96% and 100%, respectively, the area under the curve was 0.975. The best cut-off value for dIVC as defined by the ROC curve analysis was 23.5%, for which sensitivity, specificity, positive predictive value and negative predictive value were 91%, 89%, 91% and 89%, respectively, the area under the curve was 0.95.

Conclusion: ΔVpeak and dIVC are reliable indices of fluid responsiveness in children.