O SHIT as in asthma but prednisolone dose is 30mg OD and give controlled oxygen, i.e. 24-28% (venturi mask), and do regular ABGs to determine further oxygen therapy (see prescribing notes on oxygen therapy)
Antibiotics: prescribe if any signs of infection as per local guidelines, e.g. doxycycline
Consider BiPAP in hypercapnic respiratory acidosis not responding to medical management (or if you achieve oxygen sats of 88-92%/PaO2 ≥8 without a hypercapnic respiratory acidosis despite medical management)
If hypoxaemia/hypercapnia is worsening despite maximal therapy, involve senior/anaesthetist with a view to intubation and ventilation.