Normal vs Low Tidal Volume Ventilation in Retrograde Intrarenal Surgery - A Randomized Controlled Trial

NCT07643324 | Recruiting

• 1 other identifier: 2026-17
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

Retrograde intrarenal surgery is commonly performed under general anesthesia for the treatment of renal stones. During the procedure, respiratory-related renal movement caused by positive-pressure ventilation may impair endoscopic image stability and reduce the efficiency of laser lithotripsy. This randomized controlled trial aims to compare the effects of normal ventilation and low tidal volume ventilation on intraoperative endoscopic image stability during RIRS using a video-based Motion Index. Eligible adult patients scheduled for elective RIRS under general anesthesia will be randomized in a 1:1 ratio to either normal tidal volume ventilation or low tidal volume ventilation. A standardized 60-second intraoperative video segment in which the stone and/or active laser lithotripsy is visible will be analyzed by blinded assessors. The primary outcome is the mean Motion Index value calculated from sequential video frames. Secondary outcomes include additional Motion Index parameters, laser activation time, anesthesia and surgical duration, intraoperative respiratory and hemodynamic safety parameters, vasopressor requirement, complications, and stone-free status at routine follow-up.

Conditions

Renal Calculi

Keywords

Retrograde intrarenal surgery , Low tidal volume ventilation, General anesthesia, Stone free, Video-based image analysis

Outcome Measures

Primary Outcomes (1)

• Mean Motion Index During Retrograde Intrarenal Surgery

  Mean Motion Index will be calculated from a standardized 60-second intraoperative endoscopic video segment in which the stone is clearly visible and/or laser lithotripsy is active. Consecutive video frames will be analyzed using a phase-correlation-based image registration method. Horizontal and vertical displacement components between consecutive frames will be used to generate the Motion Index time series, and the mean value will be used as the primary measure of endoscopic image motion.

  Intraoperative period, during a standardized 60-second video segment

Study Arms (2)

Normal Tidal Volume Ventilation

ACTIVE COMPARATOR

Participants in this group will receive standard mechanical ventilation after induction of general anesthesia and endotracheal intubation during retrograde intrarenal surgery. Tidal volume will be set at 6-8 mL/kg predicted body weight with 5 cmH₂O PEEP. Respiratory rate will be titrated to maintain EtCO₂ between 35 and 45 mmHg, and FiO₂ will be adjusted to maintain SpO₂ above 94%.

Procedure: low tidal volume ventilation

Low Tidal Volume Ventilation

EXPERIMENTAL

Participants in this group will receive low tidal volume mechanical ventilation after induction of general anesthesia and endotracheal intubation during retrograde intrarenal surgery. Tidal volume will be set at 4-6 mL/kg predicted body weight with 5 cmH₂O PEEP. Respiratory rate will be titrated to maintain EtCO₂ between 35 and 45 mmHg, and FiO₂ will be adjusted to maintain SpO₂ above 94%.

Procedure: low tidal volume ventilation

Interventions

low tidal volume ventilation PROCEDURE

Participants allocated to the normal tidal volume ventilation group will receive volume-controlled mechanical ventilation during retrograde intrarenal surgery under general anesthesia. Tidal volume will be set at 6-8 mL/kg predicted body weight with 5 cmH₂O PEEP. Respiratory rate will be titrated to maintain EtCO₂ between 35 and 45 mmHg, and FiO₂ will be adjusted to maintain SpO₂ above 94%.

Also known as: Normal Tidal Volume Ventilation

Low Tidal Volume Ventilation; Normal Tidal Volume Ventilation

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adult patients aged 18 years or older
• Patients scheduled for elective retrograde intrarenal surgery under general anesthesia
• ASA physical status I-III
• Patients who are able to read and understand the informed consent form
• Patients who provide written informed consent

You may not qualify if:

• Patients younger than 18 years
• Pregnancy
• Emergency surgery
• Severe chronic obstructive pulmonary disease, severe restrictive pulmonary disease, or preoperative hypercapnia
• Severe uncontrolled cardiovascular disease
• Active urinary tract infection, sepsis, or untreated infectious focus
• Cases in whom the standardized ventilation protocol is difficult to apply because of morbid obesity
• Patients scheduled for an additional major urological procedure in the same session
• Cases in which an intraoperative video recording of sufficient quality cannot be obtained
• Patients in whom the study protocol cannot be safely continued according to the investigator's clinical judgment

Sponsors & Collaborators

• Hitit University: lead

Study Sites (1)

Hitit university

Çorum, Turkey (Türkiye)

RECRUITING

MeSH Terms

Conditions

Kidney Calculi

Condition Hierarchy (Ancestors)

Nephrolithiasis; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Urolithiasis; Urinary Calculi; Male Urogenital Diseases; Calculi; Pathological Conditions, Anatomical; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Sibel Onen Ozdemir, MD

CONTACT

+905442892194; sibelonen89@gmail.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: Video-based Motion Index analyses will be performed by assessors who are blinded to the ventilation group allocation. Video files will be anonymized and coded so that the assigned ventilation strategy cannot be identified during outcome assessment.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Medical Doctor

Study Record Dates

• First Submitted: June 8, 2026
• First Posted: June 11, 2026
• Study Start: April 29, 2026
• Primary Completion (Estimated): August 15, 2026
• Study Completion (Estimated): September 1, 2026
• Last Updated: June 11, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)