Zorio V, Lebreton T, Desgranges FP, et al. - Whether a 3 mL kg⁻¹ mini-fluid challenge over 2 minutes can predict fluid responsiveness in children under controlled ventilation, was investigated in this study. Participants were children scheduled for surgery under general anesthesia. These children were asked to receive a fluid challenge of 15 mL kg⁻¹ of crystalloid before incision administered over 10 minutes in two steps: 3 mL kg⁻¹ over 2 minutes then 12 mL kg⁻¹ over 8 minutes. There were 55 participants in total, with 43 being fluid responders. The definition of fluid responsiveness was: an alteration of ≥ 10% in cardiac output estimated by left ventricular outflow tract velocity time integral (VTI) as recorded by transthoracic ultrasound prior to and following the fluid challenge of 15 mL kg⁻¹. The rise in the VTI following the mini-fluid challenge (ΔVTI_miniFC) predicted fluid responsiveness with an area under the receiver operating characteristic curve of 0.77. Taking the least significant change into account, which was 7.9%, the threshold was 8% with a sensitivity and a specificity of 53% and 77%, respectively. In this patient sample of anesthetized children under controlled mechanical ventilation, the effects of a fluid challenge of 15 mL kg⁻¹ of crystalloid were weakly predicted by ΔVTI_miniFC.