Association between total fluid volume and postoperative morbidity after cytoreductive surgery with hyperthermic intraperitoneal chemotherapy

BACKGROUND: While intraoperative fluid management has been explored in various clinical settings, the impact of perioperative fluid administration on outcomes in patients undergoing cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (CRS with HIPEC) remains under investigated. We aimed to assess the association between perioperative fluid balance in patients undergoing CRS with HIPEC and 28-day outcomes, and to describe postoperative complications. METHODS: This retrospective, single-center, observational case-control study included patients undergoing CRS with HIPEC between January 2019 and June 2024. The primary outcome was the Comprehensive Complication Index (CCI) at day 28. Secondary outcomes included a detailed description of postoperative complications. Multivariable analysis was performed to identify independent prognostic factors. RESULTS: A total of 132 patients were included. The median CCI at day 28 was 21 (IQR 0-31). Crystalloids were the most frequent administered fluids during surgery (132 patients, 100%), whereas colloids were used in 16 patients (12%). The median intraoperative fluid rate was 13.6 (IQR 11.0-17.7) mL/kg/h. Median intraoperative fluid administration was 18.4 mL/kg/h (IQR 14.7-32.1) in the first CCI tertile and 33.3 mL/kg/h (23.5-51.7) in the third CCI tertile (p < 0.001). Median total day-0 fluid administration was 110.9 mL/kg (84.1-157.1) in the first CCI tertile and 175.7 mL/kg (133.3-251.9) in the CCI third tertile (p < 0.001). Seventy-five patients (57%) experienced at least one complication. Higher total fluid volume administered on the day (intra and postoperative) of surgery was significantly associated with increased morbidity (OR 1.12 [95% CI 1.06-1.19], p < 0.001). CONCLUSION: In patients undergoing CRS with HIPEC, total fluid balance on the day of surgery-including intraoperative and immediate postoperative fluids-was associated with postoperative morbidity at day 28. These findings highlight the importance of careful fluid management beyond the intraoperative period and support the need for prospective studies focusing on fluid balance in these patients to refine perioperative strategies and improve patient outcomes.