Cystatin-C C-guided Vancomycin Dosing in Critically Ill Patients: A Quality Improvement Project

This is a prospective, quality improvement study that evaluated critically ill patients initiated on intravenous vancomycin. Between January 2012 through October 2013, vancomycin was dosed at 15-20mg/kg at an interval guided by creatinine clearance using the Cockcroft Gault equation (control arm). Steady state trough concentrations were assessed prior to the 4th dose of a consistent regimen and compared to the individualized target trough range (10-15mg/L or 15-20mg/L) appropriate for the suspected or documented source of infection. Given low overall trough achievement observed with standard care, a quality improvement project was undertaken. After approval by local clinical practice committees with representation from the Division of Infectious Diseases, Pharmacy and Critical Care, a quality improvement project was undertaken to implement a new vancomycin dosing nomogram with dosing intervals based on the Chronic Kidney Disease Epidemiology Collaborative (CKD-EPI) creatinine-cystatin GFR equation, expressed in mL/min. After structured education was provided, the dosing algorithm was rolled out from December 2013 through May 2015 (intervention arm). Steady state target vancomycin trough achievement was compared between study arms with and without adjustment for potential confounders.

Inclusion criteria

• Hospitalized in one of three intensive care units at Mayo Clinic in Rochester, Minnesota
• Suspected or documented gram-positive infection
• Prescribed IV vancomycin at a consistent dose and scheduled with 8, 12, or 24 hour Vancomycin dosing interval

Exclusion criteria

• Vulnerable population
• Received greater than 1 dose of Vancomycin in the 96 hours before ICU admission
• Baseline glomerular filtration rate (GFR) of less than 20 milliliters/minute
• Undergoing renal replacement therapy
• Body mass index > 40kg/m2
• Weight < 40kg