HFNO Flow Rates and Cerebral Oxygenation During Deep Sedation for Cystoscopy

June 1, 2026 updated by: AHMET AKSU, Firat University

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

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.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

200

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Turkey (Türkiye)
    • Elaziğ
      • Elâzığ, Elaziğ, Turkey (Türkiye), 23100
        • Fırat University Faculty of Medicine Hospital
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Screening
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: HF40
Participants receive high-flow nasal oxygen (HFNO) therapy at a flow rate of 40 L/min during procedural sedation for cystoscopy.
Device: High-Flow Nasal Oxygen 40 L/min (HF40)
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.
Experimental: HF55
Participants receive HFNO therapy at a flow rate of 55 L/min during procedural sedation for cystoscopy.
Device: High-Flow Nasal Oxygen 55 L/min (HF55)
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.
Experimental: HF70
Participants receive HFNO therapy at a flow rate of 70 L/min during procedural sedation for cystoscopy.
Device: High-Flow Nasal Oxygen 70 L/min (HF70)
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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
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.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
From baseline before sedation until the end of the cystoscopy procedure. Heart rate will be recorded continuously during the intraoperative sedation period.
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.
From baseline before sedation until the end of the cystoscopy procedure. Blood pressure, will be recorded continuously during the intraoperative sedation period.
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.
From the initiation of sedation until the end of the cystoscopy procedure.
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.
From the initiation of sedation until the end of the cystoscopy procedure.
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.
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).

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Firat University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 1, 2026

Primary Completion (Estimated)

September 1, 2026

Study Completion (Estimated)

October 1, 2026

Study Registration Dates

First Submitted

May 22, 2026

First Submitted That Met QC Criteria

June 1, 2026

First Posted (Actual)

June 5, 2026

Study Record Updates

Last Update Posted (Actual)

June 5, 2026

Last Update Submitted That Met QC Criteria

June 1, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • 47669

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be publicly shared due to patient confidentiality, privacy concerns, and institutional ethical regulations. Data may be made available from the corresponding author upon reasonable request and with ethics committee approval

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Cerebral Oxygenation

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

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Norway

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe