Asthma

Disclaimer These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common-sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline.  Read the full PCH Emergency Department disclaimer.

Aim

To guide staff with the assessment and management of acute asthma.

Definition

Asthma is a chronic inflammatory disease of the lower respiratory tract that leads to acute episodes of bronchospasm leading to cough and wheezing.

Background

General

• Around 14-16% of Australian children are currently living with asthma.
• This guideline applies to children 12 months of age and over and addresses the Emergency Department Management of acute asthma in the first hour of presentation.
• Potential triggers for an acute asthma exacerbation can include:
  • Allergy (there is a strong link between asthma and atopy).
  • Viral upper and lower respiratory tract infections
  • Environmental: cigarette smoke including passive smoking, air pollution, cold air
  • Drugs
  • Exercise

Recent changes in practice

• In the treatment of asthma / wheezing, the use of pressurised metered dose inhalers (pMDIs) with spacer devices has to a large extent superseded the use of nebulisers as the preferred means of delivery of inhaled aerosol solutions.
• Perth Children's Hospital uses the small volume spacer for all ages.

Assessment

• Continue reassessing the patient’s condition and their response to treatment.
• A deteriorating patient needs to be identified early and treated more aggressively.
• It is not necessary for all clinical criteria to be met for a patient to be considered ‘severe’ or ‘critical’.
• Wheeze is not an indicator of severity.

History

• Asthma classification: infrequent or frequent intermittent, persistent.
• Potential triggers.
• Previous Paediatric Intensive Care Unit admissions.
• Medications recently used: reliever, preventer, steroids.
• Symptoms of a viral upper respiratory tract infection.
• Symptoms such as wheezing, cough, chest tightness, dyspnoea.
• Personal or family history or atopy or eczema.

Examination

• Observations: pulse rate, respiratory rate, temperature, oxygen saturations.
• Mental status: lethargic, drowsy.
• Ability to talk in sentences, phrases or single words.
• Evidence of a viral upper or lower respiratory tract infection.
• Chest hyperinflation.
• Work of breathing: degree and type of recession (eg: mild, moderate, severe; subcostal, intercostal, sternal, tracheal tug), and use of accessory muscles, head bobbing, nasal flaring.
• Chest auscultation: air entry (normal, reduced, equal on both sides), wheeze, crackles. Beware the SILENT CHEST.
• Unequal air entry is often due to mucus plugging.

Investigations

• Peak expiratory flow rate (PEFR) measurements are not routinely performed for children who are acutely unwell or unfamiliar with having their PEFR measured (usually older than 7 years).
• Chest X-rays are not routinely required in children with acute wheeze.
• Indications for a chest X-ray may include:
  • deteriorating clinical state
  • poor response to treatment.
• Blood gases are not routinely done unless patients are critical and going to a Paediatric Intensive Care Unit – in this case consider a venous blood gas.

Differential diagnoses

• Viral induced wheeze, viral pneumonitis.
• Inhaled foreign body.
• Recurrent cough (post viral, non-specific). 

Management

Initial management

• pMDIs are used to deliver medication with a spacer
• It is reasonable to change to a nebuliser if the patient is unable to cooperate with a spacer or the patient is deteriorating clinically.

Further management

• Reassess the patient’s condition within 20 minutes following salbutamol to assess for responsiveness. 
• If responding observe for 1-1.5 hours post salbutamol and then review to determine need for admission to either ESSU or inpatient ward 
• Patients who are not responding to treatment, or who are deteriorating, need to be identified early and treated more aggressively.
• ESSU admission criteria includes: 
  • Frequency of salbutamol administration via puffer and spacer >45 minutely.
  • Receiving no more than 2L of oxygen via nasal prongs.
  • Likely to be discharged within 24 hours (Note: Seek early senior medical help with decision to admit).
• An admission to the medical ward at PCH or a peripheral hospital under the General Paediatric Team, for more prolonged treatment for patients not meeting ESSU criteria.

Medications

Acute dosing

pMDI’s:

Salbutamol = 100 micrograms per actuation. pMDIs are used via spacer with 1 actuation at a time, with 3 normal tidal breaths between each actuation. Protocol for salbutamol in acute asthma is:

• Children < 6 years: 6 puffs
• Children > 6 years: 12 puffs
• For moderate to severe asthma, pMDIs are given 20 minutely over 40 minutes (3 times). Then the patient should be reassessed to decide the timing for the next dose.

Ipratropium is no longer used for mild and moderate asthma.

Spacers

pMDIs must be used with a small volume spacer and mask for all children.

Nebulisers

Endorsed by:	Executive Director, Medical Services	Date:	Oct 2021
		Review date:	Apr 2022

This document can be made available in alternative formats on request for a person with a disability.