Louis Kirton ,1,2 Julie Cook,1 Rowan Hamill,1 Tanira Kingi,1,3 Neakiry Kivi,1,3 Allie Eathorne,1 Alice Rogan ,3 Mark Weatherall,3 Richard Beasley
ABSTRACT 
Background When delivering nasal high flow (NHF) therapy in a medical ward, a high dependency unit or an intensive care unit, automated oxygen titration increases time spent within a target oxygen saturation (SpO2 ) range compared with standard, manually titrated oxygen. This study explores whether this improvement is also seen when titrating oxygen with NHF in an emergency department (ED). Method This open-label, parallel groups, randomised controlled trial compared automated to manual oxygen titration using NHF therapy in hypoxaemic adult patients in the Wellington Regional Hospital ED between October 2022 and December 2023. Participants with a prescribed target SpO2 range who demonstrated a minimum oxygen requirement were eligible for inclusion. A rank-based comparison was used for the primary outcome, the proportion of time spent within the target SpO2 range of 92%–96%, or 88%–92% if at risk of hypercapnia, among participants achieving ≥30min of therapy. An interaction term was applied to assess whether the proportion of time spent within target SpO2 range depended on the prescribed target range itself (SpO2 92%–96% or 88%–92%). Results 83 participants were screened, 52 were randomised and 49 had data for the primary endpoint. Median (IQR) proportion of time spent within the target SpO2 range with automated oxygen (n=25) was 96.4% (92.5% to 99.4%) compared with 89.9% (69.8% to 97.2%) with manually adjusted oxygen (n=24); difference (95%CI) 8.0% (1.7% to 16.9%), p=0.01. There was no evidence that the proportion of time spent within target SpO2 range depended on the selected target SpO2 range, P-interaction 0.60. Conclusion Automatically titrated oxygen therapy significantly increased time spent within a target SpO2 range, compared with manual oxygen titration in adult patients receiving NHF therapy in the ED.
