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NCT Number: NCT07630038

HFNO Flow Rates and Cerebral Oxygenation During Deep Sedation for Cystoscopy

For Patients and Families

This study aims to investigate how high-flow oxygen therapy affects oxygen levels, especially brain oxygenation, during cystoscopy procedures performed under sedation. The goal is to improve patient safety and comfort by ensuring better oxygen delivery during the procedure. Different oxygen flow rates will be compared, while patients' breathing, oxygen levels, and vital signs are continuously monitored throughout the procedure. All methods used in the study are consistent with routine anesthesia practices, and patient safety remains the highest priority.

For Healthcare Professionals

This prospective randomized controlled study evaluates the effects of different high-flow nasal oxygen (HFNO) flow rates on cerebral oxygenation, peripheral oxygenation, and ventilation parameters in patients undergoing cystoscopy under procedural sedation. The primary aim is to determine the contribution of HFNO to sedation safety and to provide clinical evidence regarding the optimal flow rate. In addition, hypoxemia incidence, airway intervention requirements, hemodynamic variables, and sedation depth are being analyzed.

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Key information

Conditions

Deep Sedation Cerebral Oxygenation High Flow Nasal Canula PSI

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Fırat University Faculty of Medicine Hospital

Elâzığ, Elaziğ, 23100, Turkey (Türkiye)

Location contact

Ahmet Aksu, Assistant Professor

CONTACT

[email protected]

05303493896

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Age ≥18 years
  • Scheduled to undergo elective cystoscopy under procedural sedation in an operating room setting
  • American Society of Anesthesiologists (ASA) physical status classification I-III
  • Ability to provide written informed consent

Exclusion criteria

  • Known neurological disorders
  • History of ischemic or hemorrhagic stroke
  • Peripheral artery disease
  • Vasculitis
  • Severe heart failure
  • Uncontrolled hypertension
  • Uncontrolled diabetes mellitus
  • Advanced-stage chronic obstructive pulmonary disease
  • Severe anemia (hemoglobin <8 g/dL)
  • Skin lesions that could interfere with near-infrared spectroscopy (NIRS) measurements
  • History of head trauma
  • History of cranial surgery
  • Nasal deformity or nasal obstruction

Treatment and study plan

High-Flow Nasal Oxygen 40 L/min (HF40)

Device

Participants receive high-flow nasal oxygen (HFNO) therapy delivered through the OptiFlow™ system at a flow rate of 40 L/min with 100% heated and humidified oxygen during procedural sedation for cystoscopy. Sedation is achieved using midazolam, remifentanil, and propofol.

High-Flow Nasal Oxygen 55 L/min (HF55)

Device

Participants receive HFNO therapy via the OptiFlow™ system at a flow rate of 55 L/min with 100% heated and humidified oxygen during procedural sedation for cystoscopy, together with the same standardized sedation protocol.

High-Flow Nasal Oxygen 70 L/min (HF70)

Device

Participants receive HFNO therapy via the OptiFlow™ system at a flow rate of 70 L/min with 100% heated and humidified oxygen during procedural sedation for cystoscopy, together with the same standardized sedation protocol.

Primary outcomes

  1. Change in Regional Cerebral Oxygen Saturation (rSO₂)

    Time frame: From baseline measurement before sedation until the end of the cystoscopy procedure (intraoperative period). Cerebral oxygen saturation (rSO₂) values are recorded continuously during procedural sedation.

    Unit: %. Regional cerebral oxygen saturation values measured by near-infrared spectroscopy (NIRS) during procedural sedation will be compared among the three HFNO flow rate groups to evaluate the effect of different HFNO flow rates on cerebral oxygenation.

Secondary outcomes

  1. Peripheral Oxygen Saturation (SpO₂)

    Time frame: From baseline measurement before sedation until the end of the cystoscopy procedure (intraoperative period). Cerebral oxygen saturation (rSO₂) values are recorded continuously during procedural sedation.

    Unit: % . Evaluation of peripheral oxygenation levels during procedural sedation.

  2. Partial arterial carbon dioxide pressure (PaCO₂)

    Time frame: At baseline before the initiation of sedation and at the end of the cystoscopy procedure. Arterial blood gas analysis (PaCO₂) and end-tidal carbon dioxide (EtCO₂) measurements will be recorded at both time points.

    Unit: mmHg. Assessment of arterial carbon dioxide pressure levels during sedation.

  3. End-tidal carbon dioxide (EtCO₂)

    Time frame: At baseline before the initiation of sedation and at the end of the cystoscopy procedure. End-tidal carbon dioxide (EtCO₂) measurements will be recorded at both time points.

    Unit: mmHg. Assessment of end-tidal carbon dioxide levels during sedation.

  4. Incidence of Hypoxemia

    Time frame: From the initiation of procedural sedation until the end of the cystoscopy procedure. Hypoxemia episodes occurring during the intraoperative sedation period will be recorded continuously.

    Frequency of hypoxemia episodes defined as SpO₂ <90% or >20% decrease in rSO₂ from baseline.

  5. Airway Intervention Requirement

    Time frame: From the initiation of procedural sedation until the end of the cystoscopy procedure. Any airway intervention requirement occurring during the intraoperative period will be recorded.

    Need for airway maneuvers or ventilatory support during the procedure.

  6. Heart Rate

    Time frame: From baseline before sedation until the end of the cystoscopy procedure. Heart rate will be recorded continuously during the intraoperative sedation period.

    Unit: beats/min. Changes in heart rate during procedural sedation.

  7. Mean Arterial Pressure

    Time frame: From baseline before sedation until the end of the cystoscopy procedure. Blood pressure, will be recorded continuously during the intraoperative sedation period.

    Unit: mmHg. Changes in blood pressure during procedural sedation.

  8. Patient State Index (PSI)

    Time frame: From the initiation of sedation until the end of the cystoscopy procedure.

    Unit of Measure: score. Sedation depth will be continuously monitored intraoperatively using Patient State Index (PSI), a numerical electroencephalography-derived index ranging from 0 to 100, where lower values indicate deeper levels of sedation.

  9. Modified Observer's Assessment of Alertness/Sedation (MOAA/S) Score

    Time frame: From the initiation of sedation until the end of the cystoscopy procedure.

    Unit of Measure: score. Sedation depth will be assessed intraoperatively using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale, an ordinal sedation scale ranging from 0 to 5, where lower scores indicate deeper levels of sedation.

  10. Patient Satisfaction

    Time frame: Assessed once at the end of the recovery period immediately after completion of the cystoscopy procedure (postoperative period, approximately 30-60 minutes after the procedure).

    Postoperative patient satisfaction following cystoscopy under procedural sedation will be assessed using a 5-point Likert satisfaction scale, where higher scores indicate greater patient satisfaction.

Study contacts

Contact information is provided by the study sponsor or research team.

Ahmet Aksu, Assistant Professor

CONTACT

[email protected]

+905303493896

Sponsors and collaborators

Lead sponsor

Firat University

Other

Registry information

Official study title

Effect of Different Flow Rates of High-Flow Nasal Oxygen on Peripheral and Cerebral Oxygenation and Ventilation During Procedural Sedation for Cystoscopy: A Prospective Randomized Controlled Trial

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Jun 5, 2026
Registry last updated
Jun 5, 2026

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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