034 Increased Risk of Acute Kidney Injury Following Weight-Based Gentamicin Administration in the Setting of Urologic Prosthetic Surgery

Abstract

Despite the known nephrotoxicity of gentamicin, multiple societies (including the American Urological Association in 2008 and American Society of Health-System Pharmacists in 2013) have published guidelines recommending a single preoperative gentamicin dose of 5 mg/kg ideal body weight for antimicrobial prophylaxis during urologic prosthetic surgery. This recommendation is based on the theoretical renal safety and increased antimicrobial activity of a single large dose. In 2014, our own institution revised its prophylaxis protocol from gentamicin 80 mg to weight-based dosing. The goal of our investigation was to identify and characterize rates of acute kidney injury (AKI) in urologic prosthetic surgery both before and after the implementation of weight-based gentamicin dosing. We performed a single-institution retrospective study of all patients receiving perioperative gentamicin during implant, revision, or explant of inflatable penile prostheses, malleable penile prostheses, or artificial urinary sphincters between the years 2000 - 2017. Patients were stratified into two groups, based on administration of either weight-based gentamicin (5 mg/kg ideal body weight, 3 mg/kg ideal body weight in cases of chronic kidney disease) or standard-dose gentamicin (80 mg). Patient characteristics and perioperative outcomes were identified. Patients with available preoperative and postoperative (≤ 7 days) serum creatinine values were included. AKI was defined by Kidney Disease: Improving Global Outcomes (KDIGO) criteria as a rise in serum creatinine of at least 0.3 mg/dL within 48 hours, or an increase of 50% within 7 days. Comparative analyses were performed between patients receiving weight-based gentamicin and standard-dose gentamicin.