This is a new guideline from NICE on when to prescribe antibiotics in an acute exacerbation. It was published in Dec 18. It should be read alongside their updated guideline on COPD.
The most interesting bit for me about this new guideline was that only 50% of COPD exacerbations are thought to be caused by bacterial infections. The rest are caused mainly by viral infections or smoking. Unfortunately there is no good evidence on what signs or symptoms we can use to differentiate between a bacterial and non-bacterial exacerbation.