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Lungs diagnosis illness health care medi


Study aim

The aim of this study is to compare LFNO versus HFNOI in infants and children requiring microlaryngoscopy.



HFNOI is superior to LFNOI and HFNOI will reduce the incidence of hypoxia requiring rescue oxygenation by 20% compared to alternative anaesthesia methods not using high-flow nasal oxygen insufflation.


Study design

A randomised controlled trial (RCT) to demonstrate superiority of HFNOI compared to alternative anaesthesia practices without high-flow nasal oxygen insufflation. Participants will be randomised individually, to either anaesthesia using HFNOI or alternatively to anaesthesia without high-flow technique. Due to the nature of the procedure it is not possible to have blind operators or outcome assessors.

Sample size


QCH will be recruiting 496 patients who will be randomized in a 1:1 ratio stratified by age (<1 year, 1-5 year and 5-16 year of age), with randomly varied block sizes within each stratum.

Outcomes, significance and innovation

Primary outcome


The primary outcome is defined as successful anaesthesia without any rescue oxygenation attempt for a hypoxic event.


Secondary outcomes

  1. Total length of time patient experiences hypoxemia [seconds].

  2. Minor adverse events: occurrence of epistaxis, laryngospasm, bronchospasm, coughing at any time during procedure.

  3. Major adverse events: occurrence of hypotension requiring treatment, bradycardia requiring treatment, cardiac arrest with or without return of spontaneous circulation at any time during procedure.

  4. Requirement for unexpected paediatric intensive care admission.

  5. Requirement for unanticipated post-operative mechanical ventilation or any other form of non-invasive ventilation including HFNO.

  6. Length of PICU and/or hospital stay.

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