Clinical Practice Guidelines

Asthma Acute

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

     RCH: Consider  Criteria Led Discharge  
    See also:

    Background to condition:

    • Asthma is a chronic inflammatory disease of the airways characterised by reversible airways obstruction and bronchospasm.
    • Exacerbations in children are often precipitated by viral infection
    • In children less than 12 months of age presenting with wheeze, consider the diagnosis of Bronchiolitis.

    History

    Inquire specifically about the duration and nature of symptoms, treatments used (relievers, preventers), trigger factors (including upper respiratory tract infection, allergy, passive smoking), pattern and course of previous acute episodes (eg. admission or ICU admissions), parental understanding of the treatment of acute episodes, and the presence of interval symptoms (see Long Term Asthma Control below).

    Risk Factors

    • Previous ICU admission
    • Poor compliance to asthma therapy
    • Poorly controlled - significant interval symptoms

    Examination

    Wheeze is not a good marker of severity.

    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), as indicated in the table. Initial SaO2 in air, heart rate and ability to talk are helpful but less reliable additional features. Wheeze intensity, pulsus paradoxus, and peak expiratory flow rate are not reliable.

    Asymmetry on auscultation is often found due to mucous plugging, but warrants consideration of foreign body.

    Assessment and Management

    Children with respiratory distress should have minimal handling.

    SaO2:  Oxygen may be required for low saturations, DO NOT give for wheeze or increased work of breathing. The arterial oxygen saturation (SaO2) may be reduced in the absence of significant airway obstruction by factors such as atelectasis and mucous plugging of airways. SaO2 is purely a measure of oxygenation, which may be preserved in the presence of deteriorating ventilation (with CO2 retention).

    Tachycardia can be a sign of severity - but is also a side effect of beta anagonists.

     Severity   Signs of Severity   Management
     Mild Normal mental state
    Subtle or no increased work of breathing accessory muscle use/recession.
    Able to talk normally
    Salbutamol by MDI/spacer (dose) - once and review after 20 mins. Ensure device / technique appropriate.

    Good response - discharge on B2-agonist as needed.

    Poor response - treat as moderate.

    Oral prednisolone (1 mg/kg daily for 1-3 days) if episode has persisted over several days.

    Provide written advice on what to do if symptoms worsen. Consider overall control and family's knowledge. Arrange follow-up as appropriate.

    (discharge pack)
     Moderate Normal mental state

    Some increased work of breathing accessory muscle use/recession

    Tachycardia

    Some limitation of ability to talk
    Give O2 if O2 saturation is < 92%. Need for O2 should be reassessed.

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

    Oral prednisolone (1 mg/kg daily for 3 days)
     Severe Agitated/distressed

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

    Tachycardia

    Marked limitation of ability to talk

    Note: wheeze is a poor predictor of severity.
    Oxygen.

    Salbutamol
    by MDI/spacer - 1 dose (drug dose)  every 20 minutes for 1 hour ; review on-going 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. If no improvement with salbutamol alone, consider intravenous treatments (see below)

    Ipratropium (drug dose) by MDI/spacer

    Oral prednisolone (1 mg/kg daily); if vomiting give i.v. methylprednisolone(1 mg/kg daily);

    Involve senior staff.

    Arrange admission after initial assessment.
     Critical  Confused/drowsy

    Maximal work of breathing accessory muscle use/recession

    Exhaustion

    Marked tachycardia

    Unable to talk

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

    Oxygen.

    Continuous nebulised salbutamol
    (0.5% undiluted) - see below re toxicity

    Nebulised ipratropium 250 mcg 3 times in 1st hr only, (20 minutely, added to salbutamol)

    Methylprednisolone 1 mg/kg i.v. 6-hourly.

    Aminophylline: If deteriorating or child is very sick.Loading dose: 10 mg/kg i.v. (maximum dose 500 mg) over 60 min. If currently taking oral theophylline, do not give i.v. aminophylline - take serum level.

    Unless markedly improved, following loading dose give continuous infusion (usually in ICU), or 6 hourly dosing (usually in ward). Drug doses

    Magnesium sulphate. Use 50% Mg Sulphate - 0.1ml/kg (50mg/kg) over 20 mins, then 0.06ml/kg/hr (30mg/kg/hour) by infusion.
    Aim to keep serum Mg between 1.5 and 2.5mmol/L.

    May also consider i.v. salbutamol. Limited evidence for benefit.

    5 mcg/kg/min for one hour as a load, followed by 1-2 mcg/kg/min.

    Beware salbutamol toxicity: tachycardia, tachypnoea, metabolic acidosis. Can occur with both IV and inhaled therapy. Lactate commonly high. Consider stopping/reducing salbutamol as a trial if you think this may be the problem.

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

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

    Salbutamol dose: 6 puffs if < 6 years old, 12 puffs if >6 years old

    Note: In hospital, the next dose of salbutamol should be given only when symptoms of asthma return. It does not need to be weaned.

    Ipratropium (Atrovent 20mcg/puff) dose: 4 puffs if < 6 years old, 8 puffs if >6 years old Drug doses

    Investigations

    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 therapy.

    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 therapy 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 advice and inter-hospital (including ICU level) transfers ring the Sick Child Hotline: (03) 9345 7007

    Consider discharge when:

    • Adequate oxygenation
    • Adequate oral intake
    • Anticipated salbutamol requirement weaned to 3-4 hourly
    • Adequate parental education and ability to administer salbutamol via spacer

    Discharge requirements:

    • Each child should have a written action plan. This can be generated on the intranet Asthma action plan.
    • Observe inhaler technique before discharge.
    • Advise parents to seek further medical attention (preferably from their GP) should the patient's condition deteriorate or if there is no significant improvement within 48 hours.
    • At discharge all patients should have an outpatient appointment or appropriate follow-up arranged with a paediatrician and/or GP.
    • Consider Community Asthma Program referral for those eligible (see here)
    • Parents should be informed of other sources of information about asthma such as the Asthma Foundation, and the Child Health Information Center (in RCH foyer)

     Information Specific to RCH

    Children with asthma are usually admitted under the General Paediatric Team.
    Consider ICU (5211) review in children with severe and critical asthma.

    RCH Criteria Led Discharge  form


    Resources:

    Additional Notes:

    Long Term Asthma Control

    • The frequency of acute episodes and any chronic symptoms should be reviewed.
    • Specific questions should be asked about sleep disturbance (due to asthma), early morning symptoms, exercise induced cough or wheeze, 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.
    • First line therapy : low dose inhaled corticosteroids or leukotriene inhibitors (montelukast). Combined steroids and long acting beta agonists (eg. Seretide) should NOT be first line therapy.
    • If commencing preventive treatment arrange early paediatric review.
    • Careful attention must be paid to the delivery system chosen -see below.

    Spacers:

    • A spacer device should be used for children of all ages whenever they use a metered dose inhaler (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..
    • Large volume spacers should not be used for children under 6 years - they can be used above this age but are more cumbersome and less convenient than the smaller ones.
    • We recommend small volume spacers for children of all ages.

    Last updated March 2014