An observational study in Renal Perfusion, Minimally Invasive Surgical Procedures and Acute Kidney Injury, sponsored by Istanbul University - Cerrahpasa. Recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2026-06-09.
Sponsored by Istanbul University - Cerrahpasa · Observational
This prospective observational study aims to evaluate renal perfusion in adult patients undergoing elective minimally invasive abdominal surgery. Renal perfusion will be assessed using two non-invasive monitoring techniques: Doppler ultrasonography-derived Renal Resistive Index (RRI) and Near-Infrared Spectroscopy (NIRS)-derived renal regional oxygen saturation (rSO₂).
Measurements will be obtained at predefined perioperative time points, including after induction of anesthesia, during pneumoperitoneum, before extubation, and during the early postoperative period. Perioperative changes in renal perfusion parameters will be analyzed and correlated with clinical variables such as intra-abdominal pressure, pneumoperitoneum duration, hemodynamic parameters, fluid administration, urine output, and postoperative renal function.
The study also aims to investigate the relationship between intraoperative renal perfusion changes and the development of postoperative acute kidney injury. The findings may contribute to improved perioperative monitoring and optimization of renal perfusion during minimally invasive abdominal surgery.
Minimally invasive abdominal surgery has become increasingly common because of reduced surgical trauma, faster recovery, and lower postoperative morbidity compared with conventional open surgery. However, laparoscopic procedures require the creation of pneumoperitoneum, which may increase intra-abdominal pressure and adversely affect renal blood flow, renal oxygen delivery, and kidney function.
Renal hypoperfusion during surgery may contribute to postoperative renal dysfunction and acute kidney injury (AKI). Traditional indicators of renal injury, such as serum creatinine and urine output, often fail to detect early changes in renal perfusion. Therefore, reliable non-invasive methods for real-time assessment of renal perfusion are needed.
Doppler ultrasonography-derived Renal Resistive Index (RRI) and Near-Infrared Spectroscopy (NIRS)-derived regional renal oxygen saturation (rSO₂) are promising techniques for evaluating renal perfusion and oxygenation. Both methods provide non-invasive, bedside assessment and may allow early detection of perfusion abnormalities before conventional markers become abnormal.
This prospective single-center observational study will evaluate perioperative renal perfusion in adult patients undergoing elective minimally invasive abdominal surgery. Renal perfusion measurements will be obtained using Doppler ultrasonography and NIRS at predefined perioperative time points, including after induction of anesthesia, during pneumoperitoneum, before extubation, and during the early postoperative period.
Demographic characteristics, comorbidities, baseline renal function, intraoperative hemodynamic variables, pneumoperitoneum duration and pressure, fluid administration, urine output, blood loss, ventilatory parameters, and postoperative renal function will be recorded. Associations between perioperative renal perfusion parameters and postoperative renal outcomes, including acute kidney injury, will be investigated.
The findings of this study may improve understanding of perioperative renal perfusion changes during minimally invasive abdominal surgery and contribute to the development of strategies for optimizing renal protection and perioperative patient management
1,596 studies on the registry are indexed under Acute Kidney Injury; 371 are open to participants now.
This study's planned enrollment of 51 is below the median of 151 across 774 observational studies indexed under Acute Kidney Injury.
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Adult patients aged 18-80 years with ASA physical status I-III undergoing elective minimally invasive abdominal surgery at Istanbul University-Cerrahpaşa Faculty of Medicine. Patients will be prospectively evaluated for perioperative renal perfusion using Doppler ultrasonography and Near-Infrared Spectroscopy (NIRS).
Exclusion Criteria:
Adult patients aged 18 to 80 years undergoing elective minimally invasive abdominal surgery under general anesthesia. Renal perfusion will be assessed perioperatively and postoperatively(postoperative 1. hour) using Doppler ultrasonography-derived Renal Resistive Index (RRI) and Near-Infrared Spectroscopy (NIRS)-derived regional renal oxygen saturation (rSO₂). Measurements will be performed at predefined perioperative time points and correlated with intraoperative variables, postoperative renal function, and the occurrence of acute kidney injury.
Change in Renal Regional Oxygen Saturation Measured by NIRS
Renal regional oxygen saturation (rSO₂) will be measured bilaterally using Near-Infrared Spectroscopy (NIRS). NIRS values will be recorded at predefined perioperative time points.
Time frame: after endotracheal intubation, immediately before extubation, and 1 hour after extubation
Change in Renal Resistive Index
Renal Resistive Index (RRI) measured by Doppler ultrasonography at predefined perioperative time points. RRI will be calculated from peak systolic velocity and end-diastolic velocity obtained from renal interlobar or arcuate arteries.
Time frame: after endotracheal intubation, immediately before extubation, and 1 hour after extubation
Relationship Between Renal Resistive Index and Renal Regional Oxygen Saturation
The relationship between renal Doppler ultrasonography-derived Renal Resistive Index (RRI) and NIRS-derived renal regional oxygen saturation (rSO₂) will be evaluated for the right and left kidneys at predefined perioperative measurement time points.
Time frame: after endotracheal intubation, immediately before extubation, and 1 hour after extubation
Plan to share: No — Individual participant data (IPD) will not be shared because the study was not designed with a data-sharing plan and participant confidentiality will be protected in accordance with institutional and ethical requirements.
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Istanbul University - Cerrahpasa