A patient who does not cough spontaneously should be asked to do so after the chest examination. Waiting until then is advisable because coughing earlier may dispel secretion sounds or crackles at the bases before they can be detected. Listening to the patient's lungs over the chest and at his open mouth both before and after the cough is useful because movement of secretions may alter physical findings dramatically. On the other hand, posttussive crackles may appear, particularly over tuberculous lesions in the upper lobes. A major function of the cough reflex is to help clear secretions from the airways, particularly to help expel them through the larynx.
Questions can help determine what the sputum looks like and how easily it is expelled.
Blood streaking and frank hemoptysis are important and likely to be noted by the patient. Gritty material in sputum, characteristic of broncholithiasis, may be less noticeable, and a patient may deny its presence when first asked but may later notice and report it. If possible, the patient should expectorate a sputum specimen during the evaluation. Its gross appearance should be observed. Neutrophils predominate more often in purulent sputum, indicating an inflammatory, usually infectious process.