The normal lung produces approximately 20 – 30 millilitres of mucus per day to assist with the functioning of the muco-ciliary escalator.
Mucus is called sputum when an excess amount is produced within the airways and needs to be expectorated. The quantity, colour and texture are variable and can be an indicator of an exacerbation .
The effectiveness of an airway clearance program may be assisted by monitoring these factors:
Quantity may be recorded in millilitres but most patients find it easier to describe their daily amount in teaspoons, tablespoons, egg cups and cups. An increase in sputum may be a sign of infection.
Colour of sputum reflects neutrophil influx into the secretions. The purulence of sputum can therefore be used as a guide to the presence of infection (Stockley et al 2001) .
Increased tenacity of sputum may also be an indication of the presence of infection.
A sputum colour chart can be a useful objective tool to record the sputum colour (Fig. 1)
Fig. 1 Sputum colour chart – Murray et al 2009