Impact of intraoperative zero-balance fluid therapy on the occurrence of acute kidney injury in patients who had undergone colorectal cancer resection within an enhanced recovery after surgery protocol: a propensity score matching analysis.

Purpose: An enhanced recovery after surgery (ERAS) protocol for colorectal cancer resection encourages perioperative euvolemic status, and zero-balance fluid therapy is recommended for low-risk patients. Recently, several studies have reported concerns of increased acute kidney injury (AKI) in patients within an ERAS protocol. In the present study, we investigated the impact of intraoperative zero-balance fluid therapy within an ERAS protocol on postoperative AKI.

Methods: Patients who underwent elective surgery for primary colorectal cancer were divided into zero-balance and non-zero-balance fluid therapy groups according to intraoperative fluid amount and balance. After propensity score (PS) matching, 210 patients from each group were selected. Incidences of AKI were compared between the two groups according to the Kidney Disease Improving Global Outcomes criteria. Postoperative kidney functions and surgical outcomes were also compared.

Results: AKI was significantly higher in the zero-balance fluid therapy group compared to the non-zero-balance fluid therapy group (21.4% vs. 13.8%, p = 0.040) in PS-matched patients. The decrease in the estimated glomerular filtration rate on the day of surgery was significantly higher in the zero-balance fluid therapy group (- 5.9 mL/min/1.73 m vs. - 1.4 mL/min/1.73 m, p = 0.005). There were no differences in general morbidity or mortality rate, although surgery-related complications were more common in the zero-balance group.

Conclusions: Despite the proven benefits of zero-balance fluid therapy in colorectal ERAS protocols, care should be taken to monitor for postoperative AKI. Further studies regarding the clinical significance of postoperative AKI occurrence and optimised intraoperative fluid therapy are needed in a colorectal ERAS setting.