Respiratorycommon
A 34-year-old woman with asthma remains breathless in the emergency department after three nebulised doses of salbutamol and ipratropium and intravenous hydrocortisone. She speaks in short phrases, has a respiratory rate of Thirty-two per minute and a peak expiratory flow rate of 32% of her predicted value. Chest examination reveals widespread polyphonic wheeze with poor air entry. Which one of the following is the most appropriate next treatment?