Perioperative Hyperchloremia and its Association With Postoperative Acute Kidney Injury After Craniotomy for Primary Brain Tumor Resection: A Retrospective, Observational Study

Background: Hyperchloremia is known to influence postoperative outcomes and may result in postoperative acute kidney injury (AKI). This study sought to investigate whether hyperchloremia was associated with postoperative AKI in patients who underwent surgery for primary brain tumor resection. Materials and Methods: This is a retrospective, observational study of patients who underwent craniotomy for primary brain tumor resection at a single tertiary care hospital between January 2005 and October 2017. Maximum levels of serum chloride (mmol/L) measured on postoperative days (PODs) 0 to 3 and increase in serum chloride (mmol/L), (maximum serum chloride-baseline serum chloride before surgery) were measured. We examined whether perioperative hyperchloremia was associated with postoperative AKI during PODs 0 to 3. Univariate and multivariate logistic regression analyses were used in this study. Results: A total of 726 patients were included in the analysis; of these, 39 (5.4%) were diagnosed with postoperative AKI during PODs 0 to 3. The risk of postoperative AKI was associated with maximum chloride levels (odds ratio, 1.10; 95% confidence interval, 1.02-1.19; P=0.015) and with an increase in serum chloride levels during PODs 0 to 3 (odds ratio, 1.11; 95% confidence interval, 1.04-1.19; P=0.004). Conclusions: Our study shows that perioperative hyperchloremia during PODs 0 to 3 was associated with an increased risk of postoperative AKI during this period after craniotomy for primary brain tumor resection.