Does a two-minute mini-fluid challenge predict fluid responsiveness in pediatric patients under general anesthesia?

Very little evidence for predictive markers of fluid responsiveness has been reported in children as compared to adults. The impact of hypovolemia or hypervolemia on morbidity has driven interest in the fluid challenge titration strategy.

The objective of this study was to explore the ability of a 3 mL kg^-1 mini-fluid challenge over 2 minutes to predict fluid responsiveness in children under controlled ventilation.

Children scheduled for surgery under general anesthesia were included and received a fluid challenge of 15 mL kg^-1 of crystalloid prior to incision administered over 10 minutes in two steps: 3 mL kg^-1 over 2 minutes then 12 mL kg^-1 over 8 minutes. Fluid responsiveness was defined as a change of ≥10% in cardiac output estimated by left ventricular outflow tract velocity time integral (VTI) as measured by transthoracic ultrasound before and after the fluid challenge of 15 mL kg^-1 .

Of the 55 patients included in the analysis, 43 were fluid responders. The increase in the VTI after the mini-fluid challenge (ΔVTI_miniFC ) predicted fluid responsiveness with an area under the receiver operating characteristic curve of 0.77; 95% CI (0.63-0.87), P = .004. Considering the least significant change which was 7.9%; 95% CI (6-10), the threshold was 8% with a sensitivity of 53%; 95% CI (38-68); and a specificity of 77%; 95% CI (54-100).

ΔVTI_miniFC weakly predicted the effects of a fluid challenge of 15 mL kg^-1 of crystalloid in anesthetized children under controlled mechanical ventilation.