Renal PerfusionRRI-NIRSNCT07635160
Assessment of Renal Perfusion Using Ultrasound and Near-Infrared Spectroscopy in Patients Undergoing Minimally Invasive Abdominal Surgery
An observational study of Renal Perfusion and Minimally Invasive Surgical Procedures, run by Istanbul University - Cerrahpasa at 1 site in Turkey (Türkiye).
Trial summary
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… Read more about this study
- Who is it for?
- Ages 18 to 80 years
- Conditions the study is for
- Renal Perfusion, Minimally Invasive Surgical Procedures, Acute Kidney Injury
- How many people
- 51 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 7 Jan 2026to 7 Jan 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: 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).
Who may be able to join
- Patients aged 18 to 80 years
- Patients with ASA physical status I, II, or III
- Patients undergoing elective minimally invasive abdominal surgery for any reason
- Patients whose expected surgical duration is longer than 1 hour
Who cannot join
- Body mass index greater than 35 kg/m²
- Severe respiratory system disease
- Severe heart failure, NYHA class III-IV
- Presence of a cardiac pacemaker or cardiac defibrillator implant
- Progressive neuromuscular disease
- High intra-abdominal pressure
Show all 10Show fewer
- Sudden deterioration of general condition
- Incomplete clinical or laboratory data
- Refusal to participate in the study
- Conversion to open surgery
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site, 1 recruiting
- Recruiting
Istanbul University Cerrahpaşa Faculty of Medicine
Istanbul, 34320
Lyudmila MARTYNENKO AYDOGDU, M.D., +90 5300613611, lyudmila.lylyly1@gmail.com
About this study
Official title: Prospective Observational Evaluation of Renal Perfusion Using Doppler Ultrasonography and Near-Infrared Spectroscopy in Patients Undergoing Elective Minimally Invasive Abdominal Surgery
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.
Read the detailed description
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
- Keywords
- Kidney Perfusion,Renal Resistive Index,Near-Infrared Spectroscopy,Acute Kidney Injury,Laparoscopic Surgery
- Medical subject headings
- Acute Kidney Injury
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Elective Minimally Invasive Abdominal Surgery Patients | 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. |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 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.
Measured: after endotracheal intubation, immediately before extubation, and 1 hour after extubation
Secondary outcomes (1)
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.
Measured: after endotracheal intubation, immediately before extubation, and 1 hour after extubation
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Jun 2026
- Study start7 Jan 2026
- Primary completion7 Jan 2027 (estimated)
- Study completion7 Jan 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Renal PerfusionStudies of the same condition, open and under way.
- More trials run by Istanbul University - CerrahpasaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 51 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Istanbul University - Cerrahpasa
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Lyudmila Martynenko Aydogdu, Istanbul University - Cerrahpasa
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07635160
- Sponsor's protocol ID
- CUC-RenalPerfusion-2026
- Acronym
- RRI-NIRS
- Status last verified
- Jun 2026
- First submitted
- 3 Jun 2026
- Last updated
- 9 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- 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.
Study at a glance
From the registry record, last updated by the sponsor on 9 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Prospective Observational Evaluation of Renal Perfusion Using Doppler Ultrasonography and Near-Infrared Spectroscopy in Patients Undergoing Elective Minimally Invasive Abdominal Surgery
- ClinicalTrials.gov ID
- NCT07635160
- Acronym / sponsor ID
- RRI-NIRS / CUC-RenalPerfusion-2026
- Keywords
- Kidney Perfusion,Renal Resistive Index,Near-Infrared Spectroscopy,Acute Kidney Injury,Laparoscopic Surgery
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 51 participants (estimated)
- Lead sponsor
- Istanbul University - CerrahpasaUniversity, hospital or other
- Study start
- 7 Jan 2026 (actual)
- Primary completion
- 7 Jan 2027 (estimated)
- Study completion
- 7 Jan 2027 (estimated)
- First posted
- 9 Jun 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Elective Minimally Invasive Abdominal Surgery Patients | – | –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. |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- 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).
Key inclusion criteria (4 listed)
- Patients aged 18 to 80 years
- Patients with ASA physical status I, II, or III
- Patients undergoing elective minimally invasive abdominal surgery for any reason
- Patients whose expected surgical duration is longer than 1 hour
Key exclusion criteria (10 listed)
- Body mass index greater than 35 kg/m²
- Severe respiratory system disease
- Severe heart failure, NYHA class III-IV
- Presence of a cardiac pacemaker or cardiac defibrillator implant
- Progressive neuromuscular disease
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Change in Renal Regional Oxygen Saturation Measured by NIRS
Time frame: after endotracheal intubation, immediately before extubation, and 1 hour after extubation
Renal regional oxygen saturation (rSO₂) will be measured bilaterally using Near-Infrared Spectroscopy (NIRS). NIRS values will be recorded at predefined perioperative time points.
Change in Renal Resistive Index
Time frame: after endotracheal intubation, immediately before extubation, and 1 hour after extubation
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.
1 secondary outcome
Relationship Between Renal Resistive Index and Renal Regional Oxygen Saturation
Time frame: after endotracheal intubation, immediately before extubation, and 1 hour after extubation
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Jun 2026.
- Individual participant dataSharing planned: 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.
Related trials for Renal Perfusion
Not yet recruiting
Hypothermic Kidney Machine Perfusion With Omnisol
End Stage Renal Disease (ESRD), Kidney Transplant
Recruiting
Early Deresuscitation Strategy Driven by Tissue Perfusion in Renal Replacement Therapy in Patients With Acute Renal Failure
Acute Kidney Injury, Fluid Overload
Not yet recruitingObservational study
Cumulative Intra-Abdominal Pressure Burden and Acute Kidney Injury After Emergency Abdominal Surgery
Acute Kidney Injury, Intra-Abdominal Hypertension
Not yet recruiting
Drone Transport of Deceased-Donor Kidney Grafts Between Two French Hospitals Before Transplantation: a Pilot Safety Study
Kidney Failure, Chronic, Kidney Transplantation
RecruitingObservational study
Intra-Abdominal Pressure Changes During Continuous Renal Replacement Therapy in Critically Ill Patients
Intra-Abdominal Hypertension, Critical Illness
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Renal Perfusion and Minimally Invasive Surgical Procedures, run by Istanbul University - Cerrahpasa at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 9 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Lyudmila MARTYNENKO AYDOGDU, M.D. (+90 5300613611, lyudmila.lylyly1@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Renal Regional Oxygen Saturation Measured by NIRS (time frame: after endotracheal intubation, immediately before extubation, and 1 hour after extubation). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Jun 2026; AzTrials last refreshed its copy on 8 Nov 2026.