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Asthma acute

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    This guideline has been adapted for statewide use with the support of the Victorian Paediatric Clinical Network

  • See also

    Asthma Resources

    Asthma puffers and spacers photoboard  



    Key Points

    1. Asthma increases the risk of fatal anaphylaxis. Treatment of both is critical.
    2. Children <12 months of age presenting with wheeze are likely to have Bronchiolitis
    3. Preschoolers should only be given steroids for wheeze that is bronchodilator responsive and requiring admission.


    Asthma is a chronic inflammatory disease of the airways characterized by reversible airways obstruction and bronchospasm.
    Exacerbations in children are often precipitated by a viral infection.



    • Duration and nature of symptoms
    • Treatments used (relievers, preventers)
    • Trigger factors (including upper respiratory tract infection, passive smoking). Sudden onset of symptoms after insect sting or ingestion of food/medication may suggest anaphylaxis, not just asthma
    • Pattern and course of previous episodes (e.g. frequency, need for admission, IV treatment or ICU admission)
    • Parental understanding of the treatment of acute episodes
    • Presence of interval symptoms (see long term asthma control below)

    Risk factors for severe disease

    • Previous ICU admission
    • Poor compliance to asthma treatment
    • Poorly controlled - significant interval symptoms
    • Past history of Anaphylaxis


    Wheeze is not a good marker of severity. See table below
    The most important parameters in the assessment of the severity of acute childhood asthma are:

    • general appearance/mental state and;
    • work of breathing (accessory muscle use, recession)

    Initial SpO2 in air, heart rate and ability to talk are helpful but less reliable additional features.
    Tachycardia can be a sign of severity but is also a side effect of beta agonists such as salbutamol.
    Wheeze intensity, pulsus paradoxus, and peak expiratory flow rate are NOT reliable. A silent chest with no wheeze may herald imminent respiratory collapse.
    Asymmetry on auscultation is often found due to mucous plugging, but warrants consideration of foreign body.


    Children with respiratory distress should have minimal handling.


     Signs of Severity 



    Normal mental state

    Subtle or no increased work of breathing.

    Able to talk normally

    Salbutamol by MDI/spacer - give one dose (see dosing below) and review after 20 mins. Ensure device / technique appropriate.  

    Good response

    • Discharge on short acting B2-agonist as needed 
    • Provide written advice on what to do if symptoms worsen. Consider overall control and family's knowledge. Arrange follow-up as appropriate

    Poor response:  treat as Moderate.

    Consider oral prednisolone (see below)


    Normal mental state

    Some increased work of breathing


    Some limitation of ability to talk

    Oxygen if O2 saturation is <90%.
    Ongoing need for oxygen should be reassessed regularly.
    Oxygen may be required for low saturations DO NOT give oxygen for wheeze or increased work of breathing. (See Additional notes: SpO2)

    Salbutamol by MDI/spacer - 1 dose every 20 minutes for 1 hour; review 10-20 min after 3rd dose to decide on timing of next dose. See doses below.

    Consider oral prednisolone (see below)




    Moderate-marked increased work of breathing accessory muscle use/recession.


    Marked limitation of ability to talk

    Note: wheeze is a poor predictor of severity.

    Other signs of Anaphylaxis

    Involve senior staff.

    Oxygen as above

    Salbutamol by MDI/spacer - 1 dose (see below) every 20 minutes for 1 hour; review ongoing requirements 10-20 min after 3rd dose. If improving, reduce frequency. If no change, continue 20 minutely. If deteriorating at any stage, treat as critical.

    Ipratropium by MDI/spacer - 1 dose every 20 minutes for 1 hour only.

    Oral prednisolone (see below);

    if vomiting give IV Methylprednisolone (1 mg/kg; maximum 60 mg) 6 hourly

    If poor response to above treatment give:
    Loading dose: 10 mg/kg IV (maximum dose 500 mg) over 60 min.
    Unless markedly improved following loading dose, give continuous infusion (usually in ICU), or 6 hourly dosing (usually in ward).

    Magnesium sulfate 50% (500 mg/mL = 2 mmol/mL) 
    Dilute to 0.8 mmol/mL (by adding 1.5 mLs of sodium chloride 0.9% to each 1 mL of Magnesium Sulfate) for intravenous administration

      • 0.2 mmol/kg over 20 mins (maximum 8 mmol)
      • If going to ICU, this may be continued with 0.12 mmol/kg/hour by infusion

    Consider Adrenaline. 10 microg/kg or 0.01 mL/kg of 1:1000 (maximum 0.5 mL) intramuscular, into lateral thigh which should be repeated after 5 minutes if the child is not improving.

    Arrange admission after initial assessment.




    Maximal work of breathing accessory muscle use/recession


    Marked tachycardia

    Unable to talk

    SILENT CHEST, wheeze may be absent if there is poor air entry.

    Other signs of Anaphylaxis

    Involve senior staff and consider transfer to an appropriate children’s facility/PICU


    Continuous nebulised salbutamol
    : use 2 x 5 mg nebules undiluted. Monitor for hypokalaemia and toxicity as discussed below table.

    Nebulised ipratropium 250 microg, added to salbutamol, every 20 minutes for 3 doses only. 

    Methylprednisolone 1 mg/kg (maximum 60 mg) IV 6-hourly.

    Aminophylline as above

    Magnesium sulfate as above. In ICU, children on magnesium sulfate infusion, aim to keep serum magnesium between 1.5 and 2.5 mmol/L.

    May also consider IV salbutamol. Limited evidence for benefit. 5 microg/kg/min for one hour as a load, followed by 1-2 microg/kg/min.

    Aminophylline, magnesium and salbutamol must be given via separate IV lines.


    Consider Adrenaline. 10 microg/kg or 0.01 mL/kg of 1:1000 (maximum 0.5 mL) intramuscular, into lateral thigh which should be repeated after 5 minutes if the child is not improving.

    Intensive care admission for respiratory support (facemask CPAP, BiPAP, or intubation/IPPV) may be needed.


    • Salbutamol: 
      • <6 years old: 6 puffs MDI
      • 6 years or older: 12 puffs MDI
    • Ipratropium bromide (21 mcg/puff) dose:
      • <6 years old: 4 puffs MDI
      • 6 years or older: 8 puffs MDI
    • Oral prednisolone
      • 2 mg/kg (max 60 mg) initially, only continuing with 1 mg/kg daily for further 1-2 days if there is ongoing need for regular salbutamol.

        Note: this dose differs from the current Australian Asthma Handbook recommendation.

    Other management considerations:

    • If there is any concern about Anaphylaxis give Adrenaline. See Anaphylaxis
    • Beware severe Hypokalaemia can occur with frequent Salbutamol use, as this draws Potassium into cells. Consider monitoring Potassium levels. If the child is on IV fluids, consider adding 20-40 mmol of Potassium Chloride to prevent hypokalaemia in children likely to require frequent Salbutamol  
    • Beware salbutamol toxicity: tachycardia, tachypnoea, metabolic acidosis. Can occur with both IV and inhaled treatment. Lactate commonly high. Consider stopping/reducing salbutamol as a trial, if you think this may be the problem 


    Chest x-ray is not generally required (discuss with senior doctor if considering). Arterial blood gas and spirometry are NOT required in the assessment of acute asthma in children.

    Blood gases are distressing and can cause a child with respiratory compromise to deteriorate further. They are not usually required and the child's clinical state is more important in guiding treatment.

    Electrolytes for potassium levels may be indicated, although most children will not need long periods of electrolyte monitoring due to rapid improvement and reduced Salbutamol requirements.

    Consider consultation with local paediatric team when 

    • Assessed as moderate or severe asthma
    • Poor response to inhaled salbutamol
    • Oxygen requirement

    Consider transfer when

    • Severe or critical asthma requiring intravenous treatment or respiratory support
    • Children with escalating O2 requirement
    • Children poorly salbutamol responsive or unable to wean salbutamol requirement
    • Children requiring care above the level of comfort of the local hospital

    For emergency advice and paediatric or neonatal ICU transfers, call the Paediatric Infant Perinatal Emergency Retrieval (PIPER) Service: 1300 137 650.

    Consider discharge from Emergency Department when

    • Children without risk factors may be discharged 1 hour after initiation of treatment if clinically well 
    • Adequate oxygenation: mild hypoxia (SpO2 90-94) should not preclude discharge if child is clinically well and has responded well to treatment
    • Adequate oral intake 
    • Adequate parental education and ability to administer salbutamol via spacer

    Discharge requirements:

    • Each child should have a written action plan. This can be generated using the online Asthma action plan.
    • Observe inhaler and spacer technique before discharge.
    • Advise parents to seek further medical attention (preferably from their GP) should the child's condition deteriorate or if there is no significant improvement within 48 hours.
    • At discharge, all children should have follow-up arranged with a GP and/or paediatrician.
    • Ensure parents have access to written information (see Parent Information)

    Information Specific to RCH

    • Consider Criteria Led Discharge
    • Children with asthma are usually admitted under a General Medicine Short stay or inpatient team.
    • Consider ICU review in children with severe and critical asthma.
    • Consider Community Asthma Program referral for those eligible in the Western region or the Northern region of Victoria



    Parent Information

    Kids Health Info 

    Additional notes

    Long term asthma control

    • The frequency of acute episodes and any interval or persistent symptoms should be reviewed
    • Specific questions should be asked about sleep disturbance (due to asthma), early morning symptoms, exercise induced cough or wheeze, parental smoking and frequency of bronchodilator use 

    Preventive Treatment

    • Consider preventive treatment if there are interval or persistent symptoms (more than one disturbed night per week, difficulty participating in physical activities, or bronchodilator use on more than one day per week). There is limited role in children with viral induced asthma even if frequent exacerbations
    • First line treatment: low dose inhaled corticosteroids or leukotriene inhibitors (montelukast). Combined steroids and long acting beta agonists (e.g. Fluticasone/Salmeterol should NOT be first line treatment
    • Careful attention must be paid to the delivery system chosen


    • A spacer device should be used for children of all ages whenever they use a metered dose inhaler (MDI, puffer) 
    • Small volume spacers are suitable for children of all ages 
    • Small volume spacers should be fitted with a well-sealing face mask for younger children who cannot reliably seal their lips around the mouthpiece

    Oxygen Saturations

    • Oxygen saturation (SpO2) may be reduced in the absence of significant airway obstruction due to factors such as atelectasis and mucous plugging of airways 
    • SpO2 is purely a measure of oxygenation, which may be preserved in the presence of deteriorating ventilation (with CO2 retention) 
    • Indiscriminate use of oxygen may also lead to drying of the upper airways leading to worsening broncho-constriction. The use of humidified O2 might mitigate this 

    Last updated June 2018