Asthma - life threatening
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Recognition of Life-threatening Asthma
- Deterioration despite maximal therapy on severe asthma pathway
- Respiratory - cyanosis/exhaustion
- Neurological - confusion/drowsiness.
- Cardiovascular - pulsus paradoxus
- Consider diagnoses other than asthma, especially in infants with poorly responsive respiratory distress. No infant (< 1 year) should be started on intravenous bronchodilators without discussion with a consultant.
If the patient's condition is improving therapy can be de-escalated at any stage - see Asthma - Management of Acute Guideline.
- Call for assistance - request urgent review with PICU/CED Senior
- OXYGEN - use high flow oxygen via mask (e.g. 15L/min).
- IV access
- Give Hydrocortisone 4 mg/kg IV as soon as possible.
- Nebulised bronchodilators - Continuous nebulised salbutamol 5 mg/dose for all ages. Add ipratropium bromide 0.25 mg to the second nebuliser, if there is inadequate response to the first salbutamol nebule. Repeat ipratropium every 20 minutes for 3 doses, then every 4 hours.
- IV salbutamol bolus Give 10 micrograms/kg (single dose maximum 500 micrograms). Over 2 minutes. Give in a minimum volume of 5ml (can be diluted with 0.9% Saline). Repeat dose at 10 minutes if still not improving
- IV magnesium sulphate bolus. Use magnesium sulphate 49.3% (493mg/ml). Give 0.1 ml/kg (approx 50mg/kg) over 20 minutes (dilute to 20mls with normal saline and infuse via syringe driver). Maximum dose 5 mls (2.5 g).
- IV aminophylline bolus. Give 10 mg/kg IV (maximum dose 500 mg) over 1 hour (dilute to 1mg/ml - the total volume will be 10ml/kg, compatible with fluid containing Sodium chloride and/or Dextrose and/or Potassium). If the child is already on oral theophylline, do not give IV aminophylline unless you have obtained a baseline serum level and can calculate a reduced loading dose. If patient is on any other medications you must check for potential interactions and adjust dose accordingly (see below).
- If inadequate response to bolus therapy then start further IV therapy in form of salbutamol +/- aminophylline infusion(s). These children require admission to PICU.
Remember if child is improving therapy can be de- escalated at any stage
5 -10 microgram/kg/min for 1 hour then reduce to 1 - 2 microgram/kg/min
If Patient Weight < 16kg
Add 3 mg/kg of IV salbutamol solution (1 mg/ml) to a 50 ml syringe and make up to 50 ml with 5% dextrose
Then 1 ml/hr = 1 microgram/kg/min
If Patient Weight > 16kg
Draw up neat IV salbutamol solution (1 mg/ml) into a 50ml syringe (i.e. not diluted)
Then rate (ml/hr) = 0.06 x weight (kg) x dose (microgram/kg/min)
For example if you have a 20 kg child and want to infuse salbutamol at 5 microgram/kg/min then set rate at 0.06 x 20 x 5 = 6 ml/hr
|IV Salbutamol infusion chart for patients >16kg|
|Wt(kg)||1 microgram/kg/min||2 microgram/kg/min||5 microgram/kg/min||10 microgram/kg/min|
|Dose if patient aged 1 - 9 years
Add 55 mg/kg of IV aminophylline solution (25 mg/ml) to a 50 ml syringe and make up to 50 ml with 5% dextrose
Then infuse at 1 ml/hr
If weight between 23-30kg (50th centile for 9 year olds) then use neat IV aminophylline solution (25mg/ml) in a 50ml syringe and run at 1ml/hr.
|Dose if patient aged 10 - 15 years and weight < 35
Add 35 mg/kg of IV aminophylline solution (25 mg/ml) to a 50 ml syringe and make up to 50 ml with 5% dextrose
Then infuse at 1 ml/hr
|Dose if patient aged 10 - 15 years and weight > 35
Draw up neat IV Aminophylline solution (25 mg/ml) into a 50 ml syringe
Then infuse at 0.028 ml/kg/hr
For example if you have a 40 kg child then infusion rate will be 40 x 0.028 = 1.12 ml/hr
|Dose adjustment for obesity
Use 50th percentile of expected weight for age
|Factors increasing Aminophylline clearance
|Factors decreasing Aminophylline clearance
Hepatic or renal dysfunction
British Guideline on the Management of Asthma (http://www.sign.ac.uk/guidelines/published/support/guideline63/download.html)
Advanced Paediatric Life Support, BMJ Book - Third Edition
Browne GJ, Trieu L, Van Asperen P. Randomized, double blind, placebo-controlled trial of intravenous salbutamol and nebulized ipratropium bromide in early management of severe acute asthma in children presenting to an emergency department. Crit Care Med 2002 Feb; 30(2): 448-53
Cheuk DKL, Chau TCH, Lee SL. A meta-analysis on intravenous magnesium sulphate for treating acute asthma. Arch Dis Child 2005; 90: 74-77
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- Date last published: 01 April 2007
- Document type: Clinical Guideline
- Services responsible: Children’s Emergency Department
- Author(s): Fran Settle
- Editor: Greg Williams
- Review frequency: 2 years
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