Background: Postoperative complications have been reported in elderly patients undergoing gastrointestinal surgical procedures, despite advancements in surgical and perioperative care. The clinical benefits of pleth variability index-directed fluid management for geriatric gastrointestinal surgical patients remain unclear. Therefore, this study aimed to evaluate the impact of intraoperative goal-directed fluid therapy based on the pleth variability index on geriatric gastrointestinal surgical outcomes.Methods: This randomised controlled trial was conducted in two university teaching hospitals from November 2017 to December 2020. A total of 220 older adults undergoing gastrointestinal surgery were randomised to the goal-directed fluid therapy group or conventional fluid therapy group (n=110 each). The final analyses included 201 patients (conventional fluid therapy group, n=99; goal-directed fluid therapy group, n=102). The patients received intraoperative goal-directed fluid therapy (pleth variability index Results: The total volumes of fluid administered and crystalloid infusion were less in the goal-directed fluid therapy group than in the conventional fluid therapy group (P=0.009 and P=0.007, respectively). Lactate concentrations at the beginning of surgery and at discharge were comparable between the conventional fluid therapy group and the goal-directed fluid therapy group (P=0.675 and P=0.733, respectively). The proportion of patients who died or experienced complications was similar between the conventional fluid therapy group and the goal-directed fluid therapy group (45.5% vs. 48.0%, P=0.713). The proportion of major postoperative complications was higher in the conventional fluid therapy group (25.3% vs. 13.7%, P=0.039). No significant between-group differences in the time to first flatus and postoperative length of stay were identified (P=0.415 and P=0.492, respectively).Conclusions: Among elderly patients undergoing gastrointestinal surgery, intraoperative goal-directed fluid therapy based on the pleth variability index did not reduce the occurrence of composite postoperative complications but was associated with a lower major postoperative complication rate than conventional fluid therapy.Trial Registration: http://www.chictr.org.cn/showproj.aspx?proj=20828, Identifier: ChiCTR-TRC-17012220
