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The perceived risk of nosocomial transmission of COVID-19 infection from administering nebulised therapies to patients with unknown infection status has generated plenty of debate.1 2 The absence of consensus recommendations and issues with availability of personal protective equipment (PPE) have resulted in health staff exploring non-nebuliser therapies for management of children presenting to emergency departments with acute wheeze/asthma. The Royal College of Paediatrics and Child Health (RCPCH) has raised concerns about children presenting late to the hospital, and it is imperative that asthma attacks are managed aggressively during the first hour of presentation. The risk to a child of an asthma attack is significant and can be fatal. Asthma attacks result in poor quality of life, missing home/school and the potential to adversely impact the child’s lung function trajectory.
Here we review the infection risks of viral aerosolisation from the nebuliser and the role of commonly used non-nebuliser therapies in acute childhood asthma in the context of the COVID-19 pandemic.
Nebulised bronchodilator therapy
The COVID-19 pandemic has resulted in stringent infection control measures, including use of full PPE while administering nebulised bronchodilators. Evidence of risk of infection spread by viral aerosolisation through a nebuliser itself is unclear.3 The advice from Public Health England (PHE) is that nebulisation is not a viral droplet-generating procedure: the droplets are from the machine (liquid bronchodilator drug particles), not the patient. The particles generated by the nebulisers are between 1 and 5 µm. The particle size is crucial for the lower airway deposition of the nebulised drug. An aerosol by definition comprises particles which remain suspended in air and are <10 µm in size. Under experimental conditions, the SARS-COV-2 virus has been shown to remain in aerosol for up to 3 hours.4 It is unknown if the nebuliser or cough during the nebuliser administration disperses the aerosolised virus into the environment. The protective advantage to the health workers of N95 respirators compared with surgical masks during nebuliser therapy has not been investigated. The perceived risks of nosocomial transmission of the SARS-COV2 are based on studies in adults or in the laboratory environment during previous viral pandemics, and there are no data in children on transmissibility or the viral load.5
The National Institute for Health and Care Excellence COVID-19 rapid guideline published in April 2020 on severe asthma is primarily aimed at adult asthmatics with very little paediatric guidance. For example, the advice regarding continued use of home nebulisers should be interpreted with caution. Adults with asthma may have nebulisers prescribed for airway clearance and at times for administration of asthma therapies. The use of nebulisers for bronchodilator therapies at home in asthmatic children is not recommended.6 The rapid review guidance published by the RCPCH concludes that there is no evidence for or against categorising nebuliser therapy as an aerosol-generating procedure.
The ongoing debate as to whether nebulisers generate aerosol or droplets is unlikely to yield a definite answer during the current pandemic, and there is a need for a pragmatic approach. Any child presenting with an asthma attack with saturations of <92% in room air should be administered nebulised bronchodilators as per the British Thoracic Society (BTS) guidelines. Moreover, in children with severe wheeze (ie, oxygen saturations of <92% and severe respiratory distress), the efficacy of nebulised salbutamol alone is inferior to nebulised salbutamol with ipratropium bromide (IB),7 and therefore, a combination of salbutamol and ipratropium should be administered. Although the risks of infection spread from a child undergoing nebuliser therapy to healthcare workers is not quantifiable, the current available evidence supports that the risks are very low as the droplets are presumed to originate from the nebuliser device and not from the patient.8 The current PHE guidance does not recommend additional PPE for administration of nebulised bronchodilator therapies.
Salbutamol administered via metered dose inhaler (MDI)
In children with mild to moderate asthma/wheeze attack defined by oxygen saturations of >92% in room air and mild to moderate respiratory distress, administration of up to 10 puffs of a short-acting β agonist inhaler via a spacer, according to the BTS/Scottish Intercollegiate Guidelines Network (SIGN) guidelines, is recommended. Pooled data have shown that in younger children with moderate asthma, salbutamol administered via MDI decreases hospital admission by 44%, supporting such an approach in children with saturations of >92% in room air but to administer nebulised bronchodilators if the oxygen saturations are <92%. As with administering nebulised therapies, PHE does not recommend additional PPE for administration of the MDI therapies.
Salbutamol+IB administered via MDI
Twenty-one good quality trials have shown that nebulised salbutamol administered with IB significantly reduces hospitalisation. However, these two drugs administered by MDI have not been shown to reduce hospital admissions. IB doses in these studies were 80–160 mcg three times an hour. An Australian study of 347 children with a median age of 4 years showed no reduction in admission rate, but increased side effects, including tremor, were noted in the group who received 84–168 mcg three times an hour (two to four times the usual dose).9 Another study from Japan also showed no benefit.10 In summary, there is no evidence to support the use of inhaled salbutamol or IB administered as MDI in the acute management of children with moderate to severe wheeze. The administration of two drugs by MDI may prolong the contact time between the healthcare professional and the patient.
Intravenous salbutamol, aminophylline and magnesium sulfate
Salbutamol and aminophylline carry significant side effect profiles and are recommended as second-line therapies in severe, life-threatening asthma. Moreover, they are recommended as add-on therapies to nebulised bronchodilators. A single dose of magnesium sulfate, although safe, remains second-line therapy in management of acute childhood wheeze/asthma and should not be used as a substitute for initial nebulised or inhaled bronchodilator therapies in children.
Increasing the dose of inhaled corticosteroids (ICS)
A 2016 Cochrane Review found no evidence to support reduced need for oral corticosteroids through increased ICS in three paediatric studies (n=422). Although a study of 1871 adults and adolescents (aged 16–94 years) demonstrated fewer severe exacerbations in those quadrupling their stable ICS dose, a study of quintupling ICS dose in children aged 5–11 years (n=254) demonstrated no significant reduction in exacerbations requiring oral corticosteroids.11 12 There is therefore no good evidence to support increasing ICS doses in children. Alternatively, if the adolescent (>12 years) takes a combined ICS and long-acting β agonist preparation, then maintenance and reliever therapy can be used according to their asthma action plan.
Advice to children and families at discharge
To reduce the child’s risk of asthma attack and to maintain good asthma control during the COVID-19 pandemic, healthcare professionals should provide the following information at the time of discharge, along with the standard discharge advice:
To wash their hands and clean equipment such as face masks, mouthpieces, spacers and peak flow metres regularly using a detergent (eg, washing-up liquid), and to follow the manufacturer's cleaning instructions.
To keep taking all asthma medications daily as prescribed. This will help cut the child's risk of an asthma attack being triggered by any respiratory virus, including coronavirus.
To continue using ICS because stopping can increase the risk of the asthma attack. Educate families and children that there is no evidence that ICS increase the risk of getting COVID-19.
To always have the reliever inhaler (usually blue) available.
Management of an acute attack should not rely solely on reliever inhaler monotherapy, so advise patients to follow their personal asthma action plan and continue ICS treatment.
To use the inhalers and spacers as advised. Please refresh the inhaler technique by watching the videos on the asthma UK website (https://www.asthma.org.uk/advice/inhaler-videos/pmdi/).
Not to share their inhalers and the spacer devices with anyone else.
Follow the asthma plan to recognise and manage symptoms and to seek urgent medical help, as advised.
To have enough asthma medicines to meet the patient's clinical needs for no more than 30 days' treatment. For inhalers, this depends on the type of inhaler and the number of doses in the inhaler. Storing larger quantities of asthma medicines puts the supply chain at risk.
To keep the telephone, video or face-to-face appointments with general practitioners or hospitals.
To strictly comply with the government advice on social distancing and, where applicable, shielding as advised by the healthcare professional.
In summary, we advocate that children with acute asthma/wheeze should be administered nebulised bronchodilators as per the BTS/SIGN recommendations. Assessment of asthma severity as moderate/severe/life-threatening should be made, and usual stepwise treatment should be initiated as summarised in figure 1. Early administration of oral steroids is recommended.
Although the COVID-19 infection risk from children presenting with wheeze is likely to be low, minimising staff contact with the families perhaps by involving the parents in administration of the initial therapies should be considered. Risk stratification of the healthcare staff and the patients should be emphasised. The risks to a child suffering a severe asthma attack are significant and can be fatal. Clinicians should focus on correct diagnosis and aggressive management of acute wheeze in children rather than considering therapies without proven benefit.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Provenance and peer review Not commissioned; externally peer reviewed.