Abstract
Background:
Acute severe asthma (ASA) is a leading cause of hospital attendance in children. Standard first line therapy consists of high dose inhaled bronchodilators plus oral corticosteroids. Treatment for children who fail to respond to first line therapy is problematic: use of intravenous agents is inconsistent and side effects are frequent. High flow humidified oxygen (HiFlo) is widely used in respiratory conditions, and is increasingly being used in ASA, but with little evidence for its effectiveness. A well-designed, adequately powered RCT of HiFlo in ASA is urgently needed, and to plan such an RCT, feasibility data are required. We describe the protocol of a feasibility study designed to fill this knowledge gap.
Objective:
The objectives were to establish whether a full randomised controlled trial (RCT) of early HiFlo in children with ASA can be conducted successfully and safely, whether recruitment using deferred consent is practicable, and to define appropriate outcome measures and sample size for definitive RCT. The underlying hypothesis is that early HiFlo in ASA will reduce the need for more invasive treatments, allow faster recovery and discharge from hospital, and in both these ways reduce distress to children and their families.
Methods:
We carried out a feasibility randomised controlled trial with deferred consent to assess use of early HiFlo in children aged 2 to 11 years with acute severe wheeze not responding to ‘burst’ therapy (high dose inhaled salbutamol ± ipratropium). Children with PRAM score 5 or more after ‘burst’ were randomised to commence HiFlo or follow standard care. Candidate primary outcomes assessed were: treatment failure requiring escalation, and time to meeting hospital discharge criteria. Patient and parent experience were also assessed by questionnaire and telephone interview.
Results:
The trial opened to recruitment in February 2020, but was then paused for 15 months due to the COVID pandemic. The trial reopened at the lead site in July 2021 and opened at the other 3 sites during 2022. Recruitment was completed in June 2023.
Conclusions:
This feasibility RCT of early HiFlo in ASA in children recruited to target despite major disturbance due to the COVID pandemic. The data are currently being analysed and will be published separately. Clinical Trial: Registered with ISRCTN registry. ISRCTN Number 78297040 https://doi.org/10.1186/ISRCTN78297040