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Renalert: Real-time Monitor for Acute Kidney Injury

Team Members:
  • Aaron Chang
  • Allie Sibole
  • Madeleine Clegg
  • Patience Osei
  • Sriram Chadalavada
  • Nevin M. Katz, MD
  • Viachaslau Barodka, MD
  • Derek M. Fine, MD
  • Dan E. Berkowitz, MBBCH
  • J. Trent Magruder, MD
  • Sharon Allan, RN
  • Steve Brooks, MD
  • Rengaswamy Srinivasan, PhD
  • Soumyadipta Acharya, MD, PhD
  • Youseph Yazdi, PhD


Acute kidney injury, defined as a sudden loss of renal function, occurs in 15 percent of the 600,000 cardiac procedures in the U.S. each year, leading to costly and morbid ICU stays. One of the most common causes is a drop in renal perfusion, leaving the kidney deprived of oxygen and unable to filter properly. As a result, the kidney decreases its urine production and increases its sodium retention. Kidney damage is potentially reversible through simple interventions, but the current gold standard detects the injury 48 hours too late. This has significant clinical and economic impact. Up to 2 percent of patients undergoing cardiac surgery leave the hospital requiring dialysis, and hospital-acquired acute kidney injury costs the U.S. health care system $10 billion each year.

The Renalert team is working with cardiac surgery, anesthesiology, and nephrology specialists at Johns Hopkins Hospital to facilitate the early detection of acute kidney injury. Our device, Renalert, provides real-time feedback about kidney function during cardiac surgery and in the intensive care unit. It uses continuous urinalysis to provide a patient-specific indication of kidney perfusion, and incorporates a unique algorithm of perioperative risk factors and hemodynamic parameters to assess the patient’s risk of acute kidney injury. Renalert detects declines in kidney function at the onset, alerting clinicians to make timely interventions that can prevent the associated complications of acute kidney injury.

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