HFNO Flow Rates and Cerebral Oxygenation During Deep Sedation for Cystoscopy

Official 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

Overview

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.

Interventions

• 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.
• 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.
• 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.

Primary outcome measures

• 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.]

Secondary outcome measures (10)

• 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.]
• 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.]
• 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.]
• 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.]
• 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.]
• 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.]
• 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.]
• Patient State Index (PSI) [Time frame: 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.]
• 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).]

Eligibility criteria

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

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Triple blind

Primary purpose

Screening

Study locations

Turkey (Türkiye) · 1 center

• Fırat University Faculty of Medicine Hospital — Elâzığ

Identifiers

NCT: NCT07630038 · 47669

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗