Decision support guided fluid challenges and stroke volume response during high-risk surgery: a post hoc analysis of a randomized controlled trial.

Intravenous fluid is administered during high-risk surgery to optimize stroke volume (SV). To assess ongoing need for fluids, the hemodynamic response to a fluid bolus is evaluated using a fluid challenge technique. The Acumen Assisted Fluid Management (AFM) system is a decision support tool designed to ease the application of fluid challenges and thus improve fluid administration during high-risk surgery. In this post hoc analysis of data from a randomized controlled trial, we compared the rates of fluid responsiveness (defined as an increase in SV of ≥ 10%) after AFM-guided or clinician-initiated (control) fluid challenges. Patients undergoing high-risk abdominal surgery were randomly allocated to AFM-guided or clinician-initiated groups for fluid challenges titration, which consisted of 250-mL boluses of crystalloid or albumin given over 5 min. The fluid responsiveness rates and the mean SV increase in the two groups were compared. The original study included 86 patients (44 in the AFM group and 42 in the clinician-initiated group) and this sub-study analysed 85 patients with a total of 448 fluid challenges. The median rate of fluid responsiveness was greater in the AFM than in the control group (50 [44-71] % vs 33 [20-40] %, p<0.001). The mean increase in SV after fluid challenge was also higher in the AFM than in the control group (12 [9-16] % vs 6 [3-10] %, p<0.001). AFM-initiated fluid challenges were more often associated with the desired increase in SV than were clinician-initiated fluid challenges, and absolute SV increases were greater.