Читать книгу Respiratory Medicine - Stephen J. Bourke - Страница 68

In normal individuals, at auscultation, the inspiratory phase of respiration seems longer than the expiratory phase. Prolongation of the expiratory phase is a feature of airway obstruction and is often accompanied by wheeze (‘rhonchi’ is redundant and should be avoided): a high‐pitched whistling or sighing sound. Diffuse wheeze is a feature of asthma. Despite the presence of airway obstruction, wheeze is unusual in COPD; diminished breath sounds are more common.

Wheeze localised to one side, or one area of the lung, suggests obstruction of a bronchus by a carcinoma or foreign body (e.g. an inhaled peanut). Remember, inspiratory wheeze is not wheeze, it’s stridor. Stridor indicates the site of obstruction as being in the trachea or main bronchi.

Avoid the term ‘crepitations’ or ‘crepes’ when describing crackles; the existence of two terms only causes confusion. (Most people have a clear idea of the difference in meaning between the two terms; unfortunately, everyone’s idea is different.) Language should facilitate communication, so keep it simple. If the crackles are coarse, they should be described as coarse crackles; if they are fine, they should be called fine crackles. (Reserve the term ‘crepes’ for those thin pancakes you get in France.) It is thought that crackles are produced by the opening of previously closed bronchioles. Early inspiratory crackles are sometimes heard in patients with a little excess airway mucus (e.g. COPD), but these may diminish or even disappear when the patient is asked to cough. Late inspiratory crackles can sometimes be heard at the lung bases in obese individuals as the poorly ventilated areas open at the end of a deep breath. Paninspiratory crackles can be fine (like Velcro), representing lung fibrosis or pulmonary oedema. Coarse paninspiratory crackles usually imply excess purulent airway secretions, as seen in bronchiectasis. Remember: distinguishing coarse from fine is much easier if you remembered to ask the patient to cough at the start of the examination.

Pleural rubs are ‘creaking’ sounds. They are often quite localised and indicate roughening of the normally slippery pleural surfaces. They are heard in the context of pleural inflammation due to either infection or infarction (pulmonary embolism).