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SOP 2.16 Life Threatening Asthma Copyright Magpas of 9

Standard Operating Procedure 2.16

Life Threatening Asthma

Position Responsible: Medical Director CGC Approved: October 2018

Issue Date : 2018 Review Date : November 2019

Related Documents BTS/SIGN Guidelines 21 Sep 16 JRCALC 2016

This Policy is the intellectual property of Magpas

1.0 Background

1.1 Acute asthma still takes the life of around 1300 people every year in the UK, and the majority of these deaths are of people with acute pre-hospital deterioration of chronic asthma. The early recognition and aggressive management of acute severe asthma attacks aims to prevent progression of the patient to life-threatening/near-fatal asthma.

1.2 All Magpas personnel should be familiar with the classification and management of acute asthma - see appendix 2 from BTS/SIGN guideline Sep 2016.

1.3 This SOP may not apply to the patient suffering with exacerbation of COPD, however similar

features, i.e. bronchospasm, might be present. A key difference in management is the targeting of SpO2 88-92% in patients with COPD versus 94-98% in patients with asthma.

2.1 Assessment

2.1 A focused history and clinical examination should supplement any information available from those already with the patient in order to identify early those patients with acute severe, life threatening or near-fatal asthma. Patients with severe asthma and one or more adverse psychosocial factors are at risk of death (see Appendix 1 for more details). Examination should include:

respiratory rate;

SpO2;

Peak Expiratory Flow (PEF);

chest auscultation.

2.3 Life threatening asthma. In the prehospital phase, life threatening asthma can be recognised by any one of the following features in adults or children (aged one year and over):

- PEF <33% best or predicted - SpO2 <92%

- silent chest - cyanosis - poor respiratory effort - hypotension

- exhaustion - confusion/altered conscious level

- arrhythmia

https://www.brit-thoracic.org.uk/standards-of-care/guidelines/btssign-british-guideline-on-the-management-of-asthma/


Acute severe asthma. Acute severe asthma is diagnosed in the absence of life-threatening features, and the presence of any one of the following: PEF 33-50% (best or predicted); inability to complete sentences in one breath (adult) or too breathless to talk or feed (children); physiological variables as listed below:

Child aged 1-5 Child aged >5 Adult Heart Rate/min >140 >125 >110 Resp Rate/min >40 >30 >25 2.4 Children. The assessment of wheezing attacks in children under five can be difficult, the

differential includes viral induced wheeze; aspiration pneumonitis; pneumonia; bronchiolitis; tracheomalacia; cystic fibrosis and congenital anomalies. Alternative diagnoses to asthma

should be considered if there is a poor initial response to inhaled 2 agonist.

3.0 Management 3.1 Oxygen. Give oxygen to all hypoxaemic patients with acute severe asthma at flow rate to

maintain SpO2 of 94-98%. Patients with exacerbation of chronic COPD may benefit from targeting 88-92%

3.2 2 agonist. 2 agonists such as salbutamol are the first line treatment for acute asthma in all patients aged two years and older. Inhaled agents are as efficacious and preferable to parenteral agents for adult acute asthma in the majority of cases. Give nebulised salbutamol 5 mg (or 2.5 mg for 0-5 years of age).

3.3 Ipratropium bromide. For adults and children with acute severe or life threatening asthma

or those with a poor initial response to 2 agonist therapy give nebulised ipratropium bromide up to every 20-30 minutes: adults 0.5 mg; children 0.25 mg.

3.4 Steroids. Parenteral steroids should be given if oral steroids are unable to be swallowed or

retained. Give hydrocortisone adults 100 mg; children 4 mg/kg. 3.5 Magnesium sulphate. A single dose of intravenous magnesium sulphate is safe and may

improve lung function and reduce intubation rates in patients with acute severe asthma. For adults give magnesium sulphate 2 g (diluted into 0.9% saline) over 20 minutes and for children give 40 mg/kg as per Magpas aide-memoire. Consider adding 150 mg magnesium sulphate to each nebulised salbutamol and ipratropium in the first hour in children with a short duration of acute severe asthma symptoms presenting with an SpO2 <92%

3.6 Adrenaline 1:1,000 IM. IM adrenaline is recommended by JRCALC 2016 at the following

doses: >12 years 0.5 mg; 6-11 years 0.3 mg; <5 years 0.15 mg. Also consider 1:100,000 adrenaline titrated intravenous to effect.

3.7 Intravenous fluids and electrolytes. BTS/SIGN note that some patients require rehydration

and correction of electrolyte imbalance. 3.8 Prehospital Emergency Anaesthetic (PHEA). Indications for PHEA in the setting of acute

asthma may include: persisting or worsening hypoxia; exhaustion, feeble respiration; drowsiness, confusion, altered conscious state; respiratory arrest. Anaesthesia should be induced and maintained with Ketamine due to its bronchodilatory effects. The following considerations may apply in addition to the PHEA SOP:


- Pre-oxygenation may be difficult, be prepared for post induction desaturation. - Pressure – start with default Duopap PInsip 25 and PEP 5 cm H2O - TInsp – reduce to give a I:E ratio of 1:4. This will reduce risk of hyperinflation by allowing

sufficient time for passive exhalation to occur through bronchoconstricted respiratory pathways.

- Respiratory rate – 10/min. It is not necessary to target a particular EtCO2 range as for head injured patients, a raised EtCO2 can be tolerated safely.

- PEEP < 5 or remove to maintain driving pressure. - Tidal volume – keep below 6 ml/kg to reduce risk of barotrauma. - Post intubation hypotension should prompt exclusion/treatment of

o dynamic hyperinflation – consider disconnecting circuit and manually compressing chest

o hypovolaemia – give fluid bolus o tensioning pneumothorax – consider bilateral thoracostomies (also consider for

arrest/peri-arrest patients) - Remember that expired tidal volumes may not correlate well with inspired tidal volumes in

patients with severe bronchospasm.

3.9 Children. Inhaled 2 agonists delivered via an inhaler + spacer are less likely to have tachycardia and hypoxia than when the same drug is given via a nebuliser. Children with severe or life threatening asthma should receive frequent doses of 2.5 – 5 mg salbutamol nebulised through oxygen. Consider adding 150 mg magnesium sulphate to each nebulised salbutamol and ipratropium in the first hour in children with a short duration of acute severe asthma symptoms presenting with an SpO2 <92%

4.0 Disposition 4.1 Patients should be transported to the nearest Emergency Department. 4.2 If a child is receiving positive pressure ventilation, and it is safe to do so, consideration

should be given to transporting directly to the nearest Emergency Department with PICU on site. This must be agreed by the receiving Emergency Physician.


Appendix 1 – BTS/SIGN Guidelines 21 Sep 16 p.91


Appendix 2 – BTS/SIGN Guideline 21 Sep 16 – Quick Reference Guide p.15-16


Appendix 3 – BTS/SIGN Guideline 21 Sep 16 – Quick Reference Guide p.17-18


Appendix 4 – Magpas Emergency Action Card – Acute asthma