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Completed

NCT Number: NCT07304297

Effect of Tidal Volume on fURS Parameters

The goal of this prospective clinical trial is to evaluate how intraoperative tidal volume settings affect surgical parameters and outcomes in adult patients undergoing flexible ureteroscopy (fURS) for kidney stones. The participant population includes patients over 18 years of age with unilateral, single renal stones located in the upper/middle calyx or renal pelvis.

This study aims to answer are:

Does intraoperative tidal volume influence operative time and surgical efficiency during fURS?

Does tidal volume affect laser energy use, lasing efficiency, stone-free rates, and complication rates (infection or bleeding)?

The investigators will compare two groups based on tidal volume recorded during anaesthesia:

Group 1: Low tidal volume (< 500 mL)

Group 2: Standard tidal volume (≥ 500 mL)

to determine whether tidal volume differences impact surgical performance and postoperative outcomes.

Participants will:

Undergo fURS performed under general anaesthesia with standard ASA monitoring, including ETCO₂ and TOF monitoring.

Have their respiratory parameters (tidal volume, peak airway pressure, PEEP, respiratory rate, ETCO₂) and surgical data (operative time, laser settings, fluoroscopy use, stone-free status) recorded during and after surgery.

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Key information

Conditions

Urolithiasis Female Urogenital Diseases Female Urogenital Diseases and Pregnancy Complications Flexible Ureteroscopy Male Urogenital Diseases Tidal Volume Urogenital Diseases Urologic Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Marmara University School of Medicine Urology Department

Istanbul, Pendik, 34854, Turkey (Türkiye)

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Age ≥18 years

Unilateral, single kidney stones located in the upper or middle calyx or in the renal pelvis

Exclusion criteria

Chronic obstructive pulmonary disease (COPD)

Pregnancy

History of abdominal, retroperitoneal, or thoracic surgery

Kidney anomalies

Stones located in the lower calyx

Treatment and study plan

flexible ureteroscopy

Procedure

Between October 2025 and December 2025, Patients who underwent fURS surgery in our clinic, with the surgical indication determined according to the EAU guidelines, were included in the study. Patients over 18 years of age with unilateral, single stones located in the upper or middle calyx or in the renal pelvis were included in the study. Patients with chronic obstructive pulmonary disease, pregnancy, a history of abdominal, retroperitoneal, or thoracic surgery, kidney anomalies, or stones located in the lower calyx were excluded.

Primary outcomes

  1. Correlation Between Intraoperative Respiratory Parameters and Surgical Outcomes

    Time frame: 2 months

    Respiratory parameter measured:

    Tidal Volume (mL/kg)

    Measurement tool: Anaesthesia ventilator/monitoring system

    Unit: milliliters per kilogram (mL/kg)

    Surgical outcomes assessed:

    Stone-free rate (%), assessed by postoperative non-contrast CT scan

    Operative time (minutes), recorded from surgical logs

    Complications, graded using the Clavien-Dindo classification

    The objective is to determine the statistical correlation between tidal volume and each of these surgical outcomes.

Secondary outcomes

  1. Correlation Between Intraoperative Respiratory Parameters and Seconder Outcomes

    Time frame: 2 months

    Operative time (minutes), recorded from surgical logs

    Surgical efficiency (stone volume / operative time, mm³/min)

    Laser time (seconds), recorded from laser console

    Laser energy used (Joules), recorded from laser console

    Lasing efficiency (stone volume / lasing time, mm³/sec)

    Complications, graded using the Clavien-Dindo classification

    Bleeding rate (%), incidence of significant intra- or postoperative bleeding

    Infection rate (%), incidence of postoperative urinary tract infection

    Length of hospital stay (days), total postoperative hospitalization

Sponsors and collaborators

Lead sponsor

Tarik Emre Sener

Other

Registry information

Official study title

Impact of Intraoperative Tidal Volume on Surgical Parameters During Flexible Ureteroscopy

Acronym: TIDAL-fURS

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Dec 26, 2025
Registry last updated
Dec 26, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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