(P 377) INCIDENCE, RISK FACTORS, AND EFFECT ON 60-DAYS SURVIVAL OF ACUTE KIDNEY INJURY OCCURRED WITHIN 7 DAYS AFTER SURGERY IN ELDERLY PATIENTS WITH RETROPERITONEALL TUMORS: A RETROSPECTIVE COHORT STUDY

Objective: To investigate the incidence and risk factors of acute kidney injury (AKI) in elderly patients after retroperitoneal tumor resection and its effect on postoperative survival at 60 days.

Methods: Elderly patients who underwent retroperitoneal tumor resection at the Peking University International Hospital between October 2014 and December 2022 were included and retrospectively analyzed. The patients were divided into AKI and non-AKI groups according to the KDIGO guidelines. Demographics, clinical characteristics of the patients, modalities of anesthesia management, blood loss, transfusion, nephrectomy, peri-anesthesia biochemical tests as well as morbidities and mortalities were collected. Risk factors of postoperative 7d AKI were determined through Logistic regression in uni-and multi-variety analysis using the statistics software R 4.0.3, and the Kaplan-Meier curve was used to evaluate the survival data of patients with different renal function at 60 days after surgery, and Log-rank test was used for comparison.

Results: In total, 248 elderly patients (112 women) were included in the analysis. The median age of the patients was 69 (66-72) years. AKI occurred postoperatively in 44 patients. There was no significant difference in baseline values between patients with AKI and those without AKI. Surgical duration (P＜0.001), blood loss(P＜0.001), nephrectomy(P＜0.001), intraoperative red blood cell infusion(P＜0.001), intraoperative plasma infusion(P＜0.001), intraoperative use of prothrombin complex(P=0.03), intraoperative fluid balance(P＜0.001), post-operative hemoglobin level(P=0.043), post-operative lactic acid level(P＜0.001), and post-operative blood glucose level(P＜0.001) were included in the multivariate analysis. Operation duration (per hour) [OR=1.26, 95%CI 1.04-1.53,P=0.021], intraoperative nephrectomy [OR=7.29, 95%CI 2.84-18.72,P < 0.001], Lactic acid level (OR=1.38,95% CI 1.01-1.9,P=0.045) were found significantly associated with postoperative AKI. Log-rank test showed that AKI within 7 days after surgery was negatively correlated with the 60-day survival rate(P=0.0022).

Conclusion: Of the elderly patients with retroperitoneal tumors, 17.7% developed
AKI within seven days after surgery. For patients with a long operation time, intraoperative nephrectomy and postoperative elevated lactate levels, renal function should be closely monitored to prevent possible AKI.