PHARMACOLOGICAL TREATMENT OF ACUTE SEVERE ASTHMA ( BASED ON 2014 BTS GUIDELINES)

✔️Supplementary oxygen to all hypoxaemic patients with acute severe asthma to maintain an SpO2 level of 94-98%

✔️Nebulisers for giving nebulised β2 agonist bronchodilators should preferably be driven by oxygen. A flow rate of 6 l/min is required to drive most nebulisers

✔️High-dose inhaled β2 agonists as first line agents in patients with acute asthma. Repeat doses of β2 agonists at 15–30 minute intervals or give continuous nebulisation of salbutamol at 5–10 mg/hour (requires appropriate nebuliser) if there is an inadequate response to initial treatment. Higher bolus doses, for example 10 mg of salbutamol, are unlikely to be more effective (2.5–5 mg salbutamol in children >2 years).

✔️There is no evidence for any difference in efficacy between salbutamol and terbutaline. Nebulised adrenaline (epinephrine), a non-selective β2 agonist, does not have significant benefit over salbutamol or terbutaline.

✔️Add nebulised ipratropium bromide (0.5 mg 4-6 hourly) to β2 agonist treatment for patients with acute severe or life-threatening asthma or those with a poor initial response to β2 agonist therapy. ( 250 micrograms/dose in children >2 years).

✔️Consider giving a single dose of IV magnesium sulphate (1.2-2 g IV infusion over 20 minutes) to patients with acute severe asthma who have not had a good initial response to inhaled bronchodilator therapy.

✔️Nebulised magnesium is not recommended for treatment in adults with acute asthma. Consider adding 150 mg magnesium sulphate to each nebulised salbutamol and ipratropium in the first hour in children >2 years with a short duration of acute severe asthma symptoms presenting with an oxygen saturation less than 92%.

✔️Routine prescription of antibiotics is not indicated for patients with acute asthma.

SECOND LINE TREATMENT OF ACUTE ASTHMA

✔️Consider early addition of a single bolus dose of intravenous salbutamol (15 micrograms/kg over 10 minutes) in a severe asthma attack where the patient has not responded to initial inhaled therapy.

✔️Consider aminophylline for children >2 years with severe or life-threatening asthma unresponsive to maximal doses of bronchodilators and steroids. A 5 mg/kg loading dose should be given over 20 minutes with ECG monitoring (omit in those receiving maintenance oral theophyllines) followed by a continuous infusion at 1 mg/kg/hour. Measure serum theophylline levels in patients already receiving oral treatment and in those receiving prolonged treatment.

NOTE:

✔️Give steroids in adequate doses in all cases of acute asthma attack.

✔️Prednisolone 40–50 mg daily or parenteral hydrocortisone 400 mg daily (100 mg six-hourly in adults and 4 mg/kg repeated four hourly in children >2 years ) are as effective as higher doses. Continue prednisolone 40–50 mg daily for at least five days or until recovery. ( In children >2 years, treatment for up to three days is usually sufficient).

✔️Following recovery from the acute asthma attack steroids can be stopped abruptly. Doses do not need tapering provided the patient receives Inhaled Corticosteroids

✔️In adults with an acute asthma attack, i.v. aminophylline is not likely to result in any additional bronchodilation compared to standard care with inhaled bronchodilators and steroids. Side effects such as arrhythmias and vomiting are increased if Iv aminophylline is used

✔️Heliox is not recommended for use in patients with acute asthma outside a clinical trial setting

✔️Although theoretically furosemide may produce bronchodilation, a review of three small trials failed to show any significant benefit of treatment with nebulised furosemide compared to β 2 agonists