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NCT Number: NCT07575776

Effect of High-Flow Nasal Oxygen on Laryngoscopic View

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.

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Key information

Conditions

High Flow Nasal Canula Airway Anesthesia Airway Complication of Anaesthesia Difficult / Failed Intubation Difficult Airway Laryngoscopy

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

About this study

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).

Who can participate

Healthy volunteers accepted: No

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

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

Treatment and study plan

HFNO flow 0

Device

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.

HFNO flow 40

Device

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.

HFNO 60

Device

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.

Primary outcomes

  1. Quality of view

    Time frame: From induction of general anesthesia to completion of orotracheal intubation (not longer than 10 minutes).

    Percentage of glottic opening (POGO score) assessed from recorded videolaryngoscopic images.

Secondary outcomes

  1. Cormack-Lehane classification

    Time frame: From induction of general anesthesia to completion of orotracheal intubation (not longer than 10 minutes).

    Ordinal grading of glottic view using Cormack- Lehane classification.

  2. Subjective image quality (Likert scale)

    Time frame: From induction of general anesthesia to completion of orotracheal intubation (not longer than 10 minutes).

    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

Sponsors and collaborators

Lead sponsor

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

Other

Registry information

Official study title

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

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
May 8, 2026
Registry last updated
May 8, 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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