Extracellular Fluid Accumulation Predicts Fluid Responsiveness after Hydroxyethyl Starch 70/0.5 Bolus Infusion during Major Abdominal Surgery

Objective: The purpose of this study was to test the hypothesis that extracellular fluid accumulation predicts fluid responsiveness after hydroxyethyl starch (HES) solution bolus infusion during major abdominal surgery. Methods: Twenty patients who underwent elective pancreaticoduodenectomy under general anesthesia were studied. Patients received 4 mL/kg boluses of Ringer’s acetate or 6% HES 70/0.5 solution over 15 min in random order when urine output decreased below 1.0 mL/kg/h. Stroke volume variation (SVV) and stroke volume index (SVI) were measured using the FloTracTM/VigileoTM system at pre-bolus, 15, 30, and 60 min after initiating bolus infusion. The percent change in pre-bolus extracellular fluid volume relative to that at the skin incision for arm (ΔVECF) was measured by bioelectrical impedance. Prediction of fluid responsiveness (an increase in SVI of ≥5%) by pre-bolus SVV or pre-bolus ΔVECF was tested by calculating the area under the receiver operating characteristic curve (AUC). Results: Fluid bolus infusions in this study consisted of 61 Ringer’s acetate infusions and 62 HES infusions. The best AUCs for identifying fluid responsiveness were seen with pre-bolus ΔVECF for HES at 30 min and 60 min (AUC = 0.74, P = 0.022; AUC = 0.74, P = 0.0054, respectively). Optimal threshold values of pre-bolus ΔVECF for predicting fluid responsiveness were 6.5% for 30 min (sensitivity: 78%, specificity: 58%) and 7.7% for 60 min (sensitivity: 56%, specificity: 76%). Conclusion: Extracellular fluid volume predicts fluid responsiveness after HES solution bolus infusion during major abdominal surgery. Substantial fluid responsiveness is observed upon increased accumulation of extracellular fluids.