Evaluation of Renal Oxygenation in Pediatric Retrograde Intrarenal Surgery (RIRS) and Ureteroscopy (URS) Procedures by Near Infrared Spectroscopy (NIRS)

The study will involve ASA class I-III pediatric patients aged 1-18 undergoing RIRS, URS, and hypospadias surgery under general anesthesia. Patients will be divided into three groups: Group R (RIRS), Group U (URS), and Group H (Hypospadias/Control). Data collection will include patient height and weight. In Groups R and U, pre- and postoperative measurements such as hemoglobin, hematocrit, leukocyte count, BUN, serum creatinine, procalcitonin, interleukin-6, and CRP values will be recorded.

All three groups will undergo NIRS monitoring alongside routine ASA monitoring. Renal NIRS probes will be positioned using ultrasonography, and the average of three measurements will determine the regional oxygen saturation index (rSO2) as the initial value. NIRS, pulse oximetry, and hemodynamic data will be recorded every 5 minutes until recovery from anesthesia just prior to induction. A decrease of 20% or more than 20% when comparing NIRS values during follow-up with the baseline will be considered significant. The study will also document anesthesia and surgery times, as well as postoperative fever and the amount of irrigation fluid used in Groups R and U.