This is a single centre, crossover study to compare the use of two nebulisers in the sputum induction procedure. 54 participants with stable asthma or COPD will be recruited and will attend 2 visits, at least 48 hours apart. Differences in the quality and quantity of samples and the time taken to produce a sample will be described. The main purpose is to explore the optimum device to perform the procedure, whilst protecting the safety of participants and maximising their comfort.
If participants are unable to produce a sputum sample after completion of the induction procedure, physiotherapy techniques may be performed. This is an exploratory objective to establish whether these techniques may help in the event of unsuccessful procedures.
