Value Proposition:
· Real-Time Continuous Urine Monitoring: Provides minute-to-minute automated urine output measurement with gravimetric precision, eliminating the subjectivity and inaccuracy of manual Foley bag readings
· Early Detection of Acute Kidney Injury (AKI): Integrates real-time urine output with fluid and medication inputs to support early identification of AKI risk before serum creatinine rises
· Integrated Clinical Decision Support: Multiparameter monitor incorporates adaptive, self-learning algorithms and established risk scores (ex: Society of Thoracic Surgeons risk score) for real-time AKI risk stratification
· Reduced Clinician Burden & Human Error: Fully automated monitoring reduces nursing workload and minimizes missed early physiologic deterioration
· Seamless Perioperative & ICU Integration: Portable system designed for use during surgery and continued monitoring in the ICU with direct connection to anesthesia monitors
· Scalable Across Surgical and Critical Care Settings: Initially designed for cardiac surgery, with expansion potential to all high-risk surgical and critical care populations
Unmet Need:
Acute kidney injury affects 5-30% of cardiac surgery patients and is a major contributor to morbidity, mortality, prolonged ICU stays, and escalating healthcare costs. Current AKI detection relies primarily on intermittent, subjective urine output measurements and delayed serum creatinine changes, which often fail to identify kidney injury early enough for intervention. Existing Foley bag measurement is imprecise, infrequently recorded, and does not account for concurrent fluid and medication administration. There is a critical lack of accurate, continuous, automated renal monitoring platforms capable of detecting early physiologic deterioration in real time. Renalert directly addresses this gap by enabling continuous automated urine output measurement integrated with perioperative clinical data and predictive AKI analytics.
Technology Description:
Researchers at Johns Hopkins have developed the Renalert System, a portable, real-time urine monitoring and kidney status assessment platform composed of two integrated components:
· RenAdapter Device:
A clip-on insert placed between the Foley catheter and urine collection bag. It utilizes a gravimetric weight-based sensor to measure urine volume every minute using mass-to-volume density conversion. The device automatically compensates for external disturbances such as bag movement or accidental bumping. It is externally powered by the monitor and mounts vertically from the bed.
· Renalert Multiparameter Monitor:
A portable tablet-based display that receives continuous urine output data from the RenAdapter while simultaneously capturing fluid and medication administration inputs from the anesthesia monitor. The system displays real-time graphical trends of urine flow versus time alongside medications and fluids. The monitor also supports adaptive, multi-input algorithms for real-time AKI risk assessment.
Principle of Operation:
The device is attached prior to Foley placement, calibrated using urine density, and activated at the start of surgery. Continuous minute-to-minute urine output is captured throughout surgery and continued into the ICU. Clinicians visualize trends in real time and correlate renal output with hemodynamics, drugs, and fluids
Clinical Validation:
The investigators are conducting studies in 200 cardiac surgery patients, examining minute-to-minute urine output patterns before, during, and after cardiopulmonary bypass. Prior studies using continuous digital urine monitors demonstrated up to 91% positive predictive value for AKI detection, validating the importance of real-time urine monitoring
Stage of Development:
Late Preclinical / Early Clinical Research Stage - System has completed engineering development with ongoing clinical research studies in cardiac surgery patients. Positioned for regulatory pathway planning and prospective validation trials
Data Availability:
· Data available upon request
Select Publications:
Chang, Aaron J., et al. "Validation of a real-time minute-to-minute urine output monitor and the feasibility of its clinical use for patients undergoing cardiac surgery." Anesthesia & Analgesia 125.6 (2017): 1883-1886
