Effect of high-flow nasal oxygen on hypoxaemia during procedural sedation
A systematic review and meta-analysis
Anaesthesia
Submitted January 2023 by Dr Derek Rosen
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Overview
- Systematic review of the effect of high-flow nasal oxygen (NHFO2) vs conventional oxygen (nasal prongs, face mask, mouth guard) for procedural sedation in adults and children.
- Methods: Literature review of randomised controlled trials that reported the effects of high-flow nasal oxygen during procedural sedation. The primary outcome measure was hypoxaemia and the secondary outcomes were minimum oxygen saturation; hypercarbia; requirement for airway manoeuvres; and procedure interruptions.
- 19 RCTs published between 2015 and 2021 were included with a total of 4121 patients, of which 2059 received HFNO and 2062 received conventional oxygenation, deemed to be the control group. Included trials included 8 gastrointestinal, 5 bronchoscopy, 3 cardiology, 2 dental and 1 endovascular. 3 trials (cardiology, bronchoscopy and dental) included children. 16/19 used propofol based sedation techniques.
- Findings: NHFO2 use reduced hypoxaemia (RR 0.37), minor airway manoeuvres (0.26), procedural interruptions, and increased minimum oxygen saturations (mean difference 4.1%) when compared to conventional oxygen techniques. There was no impact on hypercarbia. Grading of recommendations, assessment, development and evaluation (GRADE) was used to categorise the certainty of evidence which was deemed moderate for all but procedural interruptions which was deemed low.
Commentary
Oxygen desaturation is the most prevalent adverse event during procedural sedation, followed by airway obstruction and apnoea. Risk factors for hypoxaemia include higher ASA, reduced cardiopulmonary reserve, obesity, sleep apnoea and prolonged procedural sedation.
This is a pertinent review as the high uptake of NHFO2 into procedural sedation is associated with increased consumables and costs and warrants ongoing evaluation. It supports the use of NHFO2 in high-risk patient groups.
The relevance to paediatrics is limited since paediatric studies in this review and they were not discussed separately from the pooled data. The definitions of hypoxaemia and sedation protocols varied between studies but the direction and size of the difference did not change.
