Effect of High-Flow Nasal Oxygen on Laryngoscopic View

Effect of Different Flows Using High-Flow Nasal Oxygen (HFNO) on Laryngoscopic View Quality During Videolaryngoscopy

This prospective, multicenter observational study aims to evaluate the effect of different flow rates of high-flow nasal oxygen (HFNO) on the quality of the laryngoscopic view during videolaryngoscopy in adult patients undergoing general anesthesia. Each patient will serve as their own control, with repeated measurements obtained at three different HFNO flow settings (0, 40, and 60 L/min). The study will assess objective and subjective parameters of glottic visualization using standardized scoring systems.

Study Overview

• Status: Not yet recruiting
• Conditions: Difficult Airway; Laryngoscopy; Airway Complication of Anaesthesia; High Flow Nasal Canula; Airway Anesthesia; Difficult / Failed Intubation
• Intervention / Treatment: Device: HFNO flow 0; Device: HFNO flow 40; Device: HFNO 60

Detailed Description

Anaesthetic management Anaesthesia induction and airway management will be standardized as far as clinically feasible. Standard monitoring will be applied according to institutional practice. Preoxygenation will be performed using high-flow nasal oxygen (HFNO). General anaesthesia will be induced using standard intravenous agents, followed by administration of neuromuscular blockade to facilitate laryngoscopy. Mask ventilation will be performed as clinically indicated.

Videolaryngoscopy will be performed using a standardized device and blade type whenever possible. All procedures will be performed by anesthesiologists experienced in videolaryngoscopy.

Study procedure

After induction of anaesthesia and achievement of adequate conditions for laryngoscopy, videolaryngoscopy will be performed. During a single laryngoscopic sequence, images of the laryngeal view will be obtained under three predefined HFNO flow conditions:

• 0 L/min
• 40 L/min
• 60 L/min At each flow level, once a stable laryngeal view will be achieved, a still image will be captured using the videolaryngoscope recording system. The laryngoscope position will be maintained as stable as possible during acquisition of all three images. No attempt at tracheal intubation will be made during image acquisition.

After completion of the image capture protocol, tracheal intubation will be performed according to standard clinical practice.

All images will be anonymized and stored for subsequent offline analysis. Image assessment Captured images will be evaluated offline by an independent anesthesiologist blinded to HFNO flow rates and patient identity. Where applicable, evaluation will be performed by more than one assessor to allow assessment of inter-rater agreement.

Each image will be assessed using predefined objective and subjective measures (Percentage of Glottic Opening, Likert scale).

• Study Type: Observational
• Enrollment (Estimated): 150

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Adult patients undergoing elective surgical procedures requiring endotracheal intubation under general anesthesia.

Description

Inclusion Criteria:

• Age ≥18 years
• Scheduled for endotracheal intubation under general anesthesia
• Use of videolaryngoscopy

Exclusion Criteria:

• Anticipated difficult airway
• Emergency intubation
• Contraindications to HFNO
• Inability to obtain adequate video recording

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Group HFNO; Adult patients with HFNO support for airway management

Device: HFNO flow 0; Different flows will be applied to patients undergoing general anaesthesia during airway management. In this arm flow will be 0 l/min. During these flows images will be captured using videolaryngoscope.; Device: HFNO flow 40; Different flows will be applied to patients undergoing general anaesthesia during airway management. In this arm flow will 40 l/min. During these flows images will be captured using videolaryngoscope.; Device: HFNO 60; Different flows will be applied to patients undergoing general anaesthesia during airway management. In this arm flow will 60 l/min. During these flows images will be captured using videolaryngoscope.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Quality of view	Percentage of glottic opening (POGO score) assessed from recorded videolaryngoscopic images.	From induction of general anesthesia to completion of orotracheal intubation (not longer than 10 minutes).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cormack-Lehane classification	Ordinal grading of glottic view using Cormack- Lehane classification.	From induction of general anesthesia to completion of orotracheal intubation (not longer than 10 minutes).
Subjective image quality (Likert scale)	Subjective assessment of laryngoscopic image quality rated on a 5-point Likert scale (1 = very poor, 5 = excellent) by independent evaluators blinded to HFNO flow conditions	From induction of general anesthesia to completion of orotracheal intubation (not longer than 10 minutes).

Collaborators and Investigators

• Sponsor: Masarykova Nemocnice v Usti nad Labem, Krajska Zdravotni a.s.

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: May 4, 2026
• First Submitted That Met QC Criteria: May 4, 2026
• First Posted (Actual): May 8, 2026

Study Record Updates

• Last Update Posted (Actual): May 8, 2026
• Last Update Submitted That Met QC Criteria: May 4, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: anaesthesia; airway management; difficult airway; high flow nasal canula; thrive
• Other Study ID Numbers: HFNORCT

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No