This prospective observational study evaluates the real-time urine output response to fluid therapy and diuretics in cardiothoracic intensive care unit (CTICU) patients monitored with the FIZE kUO® device. The study aims to assess how continuous urine output monitoring can inform fluid management and improve patient outcomes post-cardiac surgery.

The study involves adult patients undergoing coronary artery bypass graft (CABG) or valve replacement/repair surgeries. Utilizing the FIZE kUO® device, continuous urine output data will be collected to analyze responses to hemodynamic interventions, including fluid boluses and diuretics. Secondary objectives include assessing urine output differences in patients with and without postoperative acute kidney injury (AKI), responses to vasopressors, and capturing real-time urine output data from FIZE kUO® for observational analysis.

Inclusion Criteria:

1. Adults aged 18 years and older scheduled for CABG or valve surgery and expected postoperative admission to CTICU
2. Ability to provide informed consent

Exclusion Criteria:

1. Pregnancy
2. Preoperative dialysis (chronic or acute)
3. Enrollment in other interventional trials assessing urine output or AKI

Adult cardiac surgery patients in the cardiothoracic ICU who require continuous urine output monitoring and are connected to the FIZE kUO® device as part of routine clinical care.