MP297ELECTIVE MAJOR NON CARDIAC SURGERY AND ACUTE KIDNEY INJURY. IMPACT OF THE EXCESS CHLORIDE LOAD. A SINGLE-CENTRE, PROSPECTIVE COHORT STUDY

Abstract

INTRODUCTION AND AIMS: Acute kidney injury (AKI) occurs in 1% to 5% of all hospital admissions, and in the perioperative period has serious implications, being consistently associated with high mortality, morbidity and a more complicated hospital course with associated cost implications. Whereas peri-operative risk factors associated with AKI after cardiac surgery have been well described, this is not the case for major non-cardiac surgery. Hyperchloremia is often associated with over-zealous fluid resuscitation with 0.9% saline and has been associated with a decrease in renal blood flow. Recently, the impact of a high chloride load in the pathogenesis of AKI has been suggested. This study was performed in order to identify possible intra-operative risk factors linked to peri-operative AKI development in a group of non-cardiac surgery patients. METHOD(S): This prospective cohort study included adults undergoing elective major abdominal (including vascular) surgery. Patients with chronic kidney disease (CKD) stage IV and V were excluded. AKI was defined according to Acute Kidney Injury Network criteria within 48 hours after surgery. Patients pre-operative demographics (sex, age, hypertension, coronary artery disease, congestive heart failure, chronic obstructive pulmonary disease, diabetes mellitus, CKD stage) and intra-operative anesthetic management (type of surgery, intravenous fluids, blood products, vasopressors, mean arterial blood pressure, urine output and blood loss) were evaluated as predictors of AKI. Furthermore, chloride ion content of intra-operatively administered crystalloids and colloids was estimated. RESULT(S): Of 61 patients (47 males, 77 %) included in the study, 10 (16.4%) developed postoperative AKI (AKI group) and 51 (73.6%) did not (non-AKI group). Four intraoperative variables, as shown in table 1, were identified as predictors of AKI: Intraoperative blood loss (p=0.002), transfusion of fresh frozen plasma (p=0.004) and red blood cells, (p=0.038), as well as high chloride load (AUC=0.715 +/-0.095, p=0.033, cut off value >500). The remaining pre- and intra-operative variables did not differ significantly between the two groups. CONCLUSION(S): The use of chloride-rich intravenous fluid administration has recently been associated with post-operative AKI as a result of the excess chloride load during cardiac surgery. Our study's results indicate that a high intra-operatively administered chloride load is strongly associated with increased risk of post-operative AKI in patients undergoing elective major non-cardiac surgery.