High flow humidified oxygen as an early intervention in children with acute severe asthma: a randomised controlled trial (High flow humidified oxygen in paediatric severe asthma)
Acute severe asthma in children
Eligible children will be randomised using an online software application to the HiFlo or usual care arm. This will be performed by clinical staff using a computer desktop link and administered by the Clinical Trials Unit, as successfully piloted in the feasibility study. The randomisation list will be pre-generated by the Brighton and Sussex Clinical Trials Unit and uploaded to the randomisation system. The list will be block randomised with random block sizes, and stratified by age (2-4 years, 5-10 years, 11-18 years) and severity at study entry (oxygen saturation less than 92%, 92-94%). Randomised treatment will apply during the hospital admission, and follow-up will be for 48 hours after discharge from hospital (and only to measure the outcome of Readmission within 48 hours) HiFlo (Intervention) arm Children randomised to the HiFlo arm will be commenced on HiFlo by the clinical team immediately after randomisation (within a window of 30 minutes), and flow will be gradually increased to a target flow determined by body weight, using the targets published in the FIRST-ABC Study [36]. Inspired oxygen concentration will be adjusted to the minimum required to maintain oxygen saturation (by pulse oximeter) at 92% or higher. Other treatment for acute asthma will continue during HiFlo therapy. Inhaled bronchodilators will be administered via in-line vibrating mesh nebuliser (Aerogen Ltd), since this is the only effective way of administering inhaled bronchodilator on HiFlo. Children who have not already received an oral corticosteroid dose during burst therapy will receive a single dose of prednisolone or dexamethasone (according to local guidelines) at randomisation – further doses of oral corticosteroids during admission will be at the discretion of the clinical team. All treatment options will be allowed as clinically indicated, and further escalations of treatment will occur as judged necessary by the treating clinical team. These can include intravenous bronchodil
1. CYP aged 2-18 years (up to and including the day before 19th birthday) 2. Acute severe asthma (ASA) presenting to hospital, defined as respiratory distress and documented wheeze – formal prior diagnosis of asthma not required 3. Required high dose “burst” inhaled bronchodilator therapy – 3 doses of salbutamol ± ipratropium ± nebulised magnesium 4. Failure to respond, defined as persisting hypoxaemia (pulse oxygen saturation less than 95% in air) with moderate or severe respiratory distress, at any point 1 to 4 hours after commencing burst.
1. Clinical/radiological evidence of bacterial pneumonia: fever >38.5oC plus focal signs on auscultation or chest X-ray 2. Life-threatening asthma: signs of impending respiratory failure warranting imminent intubation 3. Impaired consciousness (AVPU score P or worse) 4. Contraindications to use of high flow humidified oxygen (HiFlo): air leak (pneumothorax, pneumomediastinum or subcutaneous emphysema), , recent (within 6 weeks) bowel surgery, intractable vomiting 5. Other major respiratory, cardiovascular or neurological condition 6. Previous participation in this study