Effect of Different-Flow High-Flow Nasal Cannula Versus Traditional Face Mask Oxygenation on Safe Apnea Time in Obese Patients

NCT07843810 | Not Yet Recruiting

• 1 other identifier: KY-20260701002-01
• Study Type: interventional
• Target: 147
• Locations: 1 country
• Sites: 1

Brief Summary

Obesity is a growing global health problem, and patients with obesity are at higher risk of hypoxemia during induction of general anesthesia. This is because excess body weight reduces the lungs' oxygen storage capacity, causing blood oxygen saturation to decline faster than in normal-weight individuals once breathing stops. Currently, the most common preventive method is preoxygenation with a face mask delivering 100% oxygen for several minutes before anesthesia induction. However, face masks often fail to seal properly in obese patients, potentially compromising preoxygenation effectiveness. High-flow nasal oxygen therapy is a newer technique that delivers heated and humidified oxygen at high flow rates through nasal cannulae. It not only provides effective preoxygenation but may also continue to supply oxygen during apnea (apneic oxygenation), thereby prolonging the safe apnea time. Nevertheless, it remains unclear which flow rate is most effective and whether high-flow nasal oxygen is truly superior to conventional face masks. This prospective randomized controlled trial will enroll 147 obese patients (BMI ≥ 28kg/m²) scheduled for elective surgery at Lianyungang First People's Hospital. Participants will be randomly assigned to one of three groups: (1) traditional face mask preoxygenation at 15 L/min, (2) high-flow nasal oxygen at 45 L/min, or (3) high-flow nasal oxygen at 70 L/min. All patients will receive 100% oxygen for 3 minutes. The primary outcome is safe apnea time - the duration from cessation of breathing until SpO₂ drops to 93%. Secondary outcomes include arterial blood gas values, patient comfort during preoxygenation, tolerance rate, and hemodynamic stability. The study hypothesis is that high-flow nasal oxygen at 70 L/min will provide a longer safe apnea time than both traditional face mask preoxygenation and high-flow nasal oxygen at 45 L/min in obese patients. The results will provide high-quality evidence for optimizing perioperative preoxygenation strategies in this population.

Conditions

Obesity

Keywords

Obesity; Preoxygenation; High-Flow Nasal Oxygen; Airway Management

Outcome Measures

Primary Outcomes (1)

• Safe Apnea Time

  Safe apnea time is defined as the duration from the onset of apnea (cessation of ventilation after complete neuromuscular blockade following rocuronium administration) to the first decline of peripheral oxygen saturation (SpO₂) to 93%, measured in seconds. Apnea is confirmed by visual assessment by a study team member. Oxygen delivery is discontinued upon confirmation of apnea. The patient remains apneic with the endotracheal tube open to atmosphere until the SpO₂ threshold is reached, at which point mechanical ventilation is initiated and the apnea period is terminated.

  From apnea onset to first SpO2 decrease to 93%, assessed up to 10 minutes (600 seconds) after apnea onset; censored if ventilation resumes before SpO2 reaches 93%.

Secondary Outcomes (7)

• Arterial Blood Gas Measurements During Preoxygenation and Apnea

  From baseline (before preoxygenation) to apnea termination (first SpO2 decrease to 93% or ventilation resumption), assessed up to approximately 13 min (780 sec; preoxygenation up to 3 min + apnea up to 10 min).

• Preoxygenation Comfort Visual Analog Scale Score

  Single assessment at 2.5 minutes after start of preoxygenation, during the 3-minute preoxygenation period.

• Preoxygenation Tolerance Rate

  From start of preoxygenation to end of preoxygenation, assessed up to 3 minutes.

• Systolic blood pressure (SBP)

  Baseline (before induction), immediately after induction, and immediately after intubation; assessed up to immediately after intubation.

• Diastolic blood pressure (DBP)

  Baseline (before induction), immediately after induction, and immediately after intubation; assessed up to immediately after intubation.

Study Arms (3)

Face Mask 15 L/min

ACTIVE COMPARATOR

Participants receive preoxygenation via a tight-fitting face mask (appropriate size selected based on facial dimensions) with oxygen flow at 15 L/min, FiO₂ = 1.0 (100% oxygen), for 3 minutes during tidal breathing. Preoxygenation is followed by standardized anesthesia induction and endotracheal intubation.

Device: Face Mask

High-Flow Nasal Oxygen 45 L/min

EXPERIMENTAL

Participants receive preoxygenation via a high-flow nasal cannula device (nasal cannula size selected based on nostril size) with oxygen flow at 45 L/min, FiO₂ = 1.0 (100% oxygen), gas heated and humidified (37°C, 100% relative humidity), for 3 minutes with mouth closed and nasal breathing. Preoxygenation is followed by standardized anesthesia induction and endotracheal intubation.

Device: High-Flow Nasal Cannula

High-Flow Nasal Oxygen 70 L/min

EXPERIMENTAL

Participants receive preoxygenation via a high-flow nasal cannula device (nasal cannula size selected based on nostril size) with oxygen flow at 70 L/min, FiO₂ = 1.0 (100% oxygen), gas heated and humidified (37°C, 100% relative humidity), for 3 minutes with mouth closed and nasal breathing. Preoxygenation is followed by standardized anesthesia induction and endotracheal intubation.

Device: High-Flow Nasal Cannula

Interventions

Face Mask DEVICE

Face mask preoxygenation delivered via a tight-fitting mask (appropriate size selected based on facial dimensions) with oxygen flow at 15 L/min, FiO₂ = 1.0 (100% oxygen), for 3 minutes during tidal breathing.

Face Mask 15 L/min

High-Flow Nasal Cannula DEVICE

High-flow nasal oxygen delivered via a dedicated nasal cannula (size selected based on nostril size), with FiO₂ = 1.0 (100% oxygen), gas heated and humidified (37°C, 100% relative humidity), for 3 minutes with mouth closed and nasal breathing. Flow rates are 45 L/min for the HF45 group and 70 L/min for the HF70 group.

High-Flow Nasal Oxygen 45 L/min; High-Flow Nasal Oxygen 70 L/min

Eligibility Criteria

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

You may qualify if:

• Age 18 to 65 years
• American Society of Anesthesiologists (ASA) physical status I \~ III
• Scheduled for elective surgery under general anesthesia with endotracheal intubation
• Body mass index (BMI) ≥ 28 kg/m²
• Willing and able to provide written informed consent

You may not qualify if:

• Cardiac disease including ischemic heart disease, heart failure (New York Heart Association class ≥ 2), current arrhythmia, or pulmonary hypertension
• Severe asthma or moderate to severe chronic obstructive pulmonary disease
• Pregnancy
• Current smoker or former smoker who quit less than 1 year prior to enrollment
• Baseline peripheral oxygen saturation (SpO₂) \< 95%
• Severe nasal obstructive disease that affects nasal ventilation or intubation
• Known or anticipated difficult airway
• Participation in another interventional clinical trial within 30 days prior to enrollment

Sponsors & Collaborators

• The First People's Hospital of Lianyungang: lead

Study Sites (1)

The First People's Hospital of Lianyungang

Lianyungang, Jiangsu, 222061, China

Location

MeSH Terms

Conditions

Obesity

Interventions

Masks

Condition Hierarchy (Ancestors)

Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Surgical Attire; Equipment and Supplies, Hospital; Equipment and Supplies; Protective Devices; Personal Protective Equipment; Surgical Equipment; Manufactured Materials; Technology, Industry, and Agriculture

Central Study Contacts

Xiaobao Zhang

CONTACT

18961322507; hotdog100@163.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 6, 2026
• First Posted: September 28, 2026
• Study Start: October 1, 2026
• Primary Completion (Estimated): May 31, 2027
• Study Completion (Estimated): July 1, 2027
• Last Updated: September 28, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)