AKI in Thoracic and Abdominal Surgery

This study will be designed as a prospective observational trial. After obtaining Institutional Review Board (IRB) approval, patients will be recruited and consented from the Anesthesia Pre-Operative Clinic. On the day of surgery, baseline urine samples will be obtained at the initial insertion of the Foley catheter, after induction of anesthesia. Urine samples will also be collected from the Foley catheter in the immediate post-operative period shortly after the patient is admitted to the Intensive Care Unit (ICU). Urine samples will continue to be collected for 72 hours post-operatively, at 0600 (6am) and 1800 (6pm) each day from the indwelling Foley catheter, which is standard of care in the ICU. Urine samples will be labeled and stored as per the instructions provided in a commercially available kit; six urine samples total will be collected and stored per patient. The electronic medical record (EMR) will be reviewed to determine whether the patient received ketorolac, ibuprofen, or no NSAIDs intra-operatively and postoperatively (within 72 hours of the beginning of surgery). Daily serum creatinine measurements and hourly urine output, which are standards of care in the ICU, will be obtained from the EMR as well.

AKI will be diagnosed and staged according to KDIGO criteria, which are based on changes in creatinine and urine output. In all patients with "KDIGO-diagnosed AKI" and in a matched non-AKI group, we will also compare the time course of new urinary biomarkers, including but not limited to uNGAL, to that of serum creatinine and urine output. We will match patients according to their demographics as well as clinical characteristics, including co-morbidities, type of surgery and anesthesia technique. Comparing the time course of current clinical markers (serum creatinine and urine output) with that of new urinary biomarkers will allow us to assess their role in guiding future preventive interventions.