Asthma Guideline

Royal Children’s Hospital,
Melbourne
Australia

Asthma Guideline

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 due to 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 agonists such as salbutamol.

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 below table) - give 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 for acute episodes which do not respond to bronchodilator alone - 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. 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	Oxygen if O2 saturation is < 92%. Need for Oxygen should be reassessed. Salbutamol by MDI/spacer - 1 dose ( dose below ) every 20 minutes for 1 hour ; review 10-20 min after 3rd dose to decide on timing of next dose. 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.
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 as above Salbutamol by MDI/spacer - 1 dose (dose 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 (dose below) very 20 minutes for 1 hour only. Aminophylline If deteriorating or child is very sick.   Loading dose: 10 mg/kg i.v. (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).  Drug doses  Magnesium sulphate 50% (500 mg/mL) Dilute to 200 mg/mL (by adding 1.5mls of sodium chloride 0.9% to each 1ml of Mg Sulphate) for intravenous administration 50 mg/kg over 20 mins If going to ICU, this may be continued with 30 mg/kg/hour by infusion  Oral prednisolone (2 mg/kg); if vomiting give i.v. methylprednisolone (1 mg/kg) 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 (use 2 x 5mg/2.5L nebules 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 as above Magnesium sulphate as above. In ICU patients on Mg 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