PHYSICAL EXAMINATION



The physical examination of the chest remains a cornerstone of the diagnostic process, and it is wise to follow a set system to avoid inadvertently neglecting some aspects of the examination (Table 18-1). Unobtrusive observation of the patient as he breathes quietly is important. A respiratory rate above 22 breaths per minute suggests under­lying lung disease. Normally the ribcage and abdomen move synchronously on respiration, both moving out on inspiration and in on expiration. Inward motion of the abdomen during inspiration suggests paralysis or dysfunction of the dia­phragm, while chaotic in and out movements of the abdominal wall during inspiration may be an early sign of impending respiratory muscle fa­tigue. Retraction of the intercostal, supraclavi­cular, and suprasternal spaces reflects the gen­eration of increased negative intrathoracic pressure in the presence of lung disease. Down­ward pull of the trachea—tracheal tug—is com­monly observed in obstructive lung disease. The distance between the cricoid cartilage and the sternal notch is less than the usual three to four finger breadths in patients with hyperinflation.
Cyanosis is a bluish discoloration of the skin, generally indicating an 02 saturation of 80 per cent or less, representing about 3g/dl, rather than the usually stated 5 g/dl, of reduced hemoglobin. Accuracy diminishes in the presence of inade­quate capillary blood flow or anemia. Finger club­bing is recognized by loss of the angle between the nail and the nail bed. It may be associated with painless swelling of tissues of the terminal phal­anx and/or arthralgias of the wrist and ankles (hy­pertrophic pulmonary osteoarthropathy). Com­mon causes include chronic suppurative diseases, chronic interstitial lung disease, pulmonary ma­lignancy, cyanotic congenital heart disease, en­docarditis, chronic liver and bowel disease, as well as a congenital idiopathic form.
Contraction of the sternomastoid muscles dur­ing resting breathing is an important indicator of respiratory distress. Patients with obstructive lung disease often derive symptomatic benefit from pursed-lip breathing, but the mechanism of this improvement is unknown. A “barrel-shaped” chest wall is seen in emphysema, while deformity of the chest wall may explain a restrictive pattern on pulmonary function testing.

Reduction in movement of one side of the chest on palpation indicates the presence of ipsilateral lung disease. Deviation of the trachea from the midline may reflect a shift in the mediastinum and is helpful in the diagnosis of a pneumothorax (Table 18-2). Vocal fremitus is the palpable vi­bration associated with transmission of the spo­ken word to the chest wall. It is increased with consolidation and decreased if fluid or air is pres­ent in the pleural space. Its absence helps to dif­ferentiate pleural effusion from dense parenchy­mal infiltrates seen on x-ray.

Percussion helps in detecting the interface be­tween the aerated lung and solid structures (liver, pleural fluid, or consolidation). Determination of heart and mediastinal size and probably also the extent of diaphragmatic movement is better done radiographically.

During auscultation, the observer needs to com­pare the two sides of the chest at equidistant points from the midline and while listening an­swer only two questions: (1) what is the character of the breath sounds? and (2) are added sounds present, and if so what is their nature?

Breath sounds are caused by turbulent air flow, with the intensity depending on the flow rate. They are produced almost entirely in the trachea and large airways and transmitted to the chest wall initially by the smaller airways and finally through the lung parenchyma. The passage through the lung filters out the high frequencies and accounts for the differences in normal breath sounds heard at different places.

Bronchial breath sounds are essentially unal­tered, and both inspiration and expiration are clearly heard. These are heard normally over the trachea and the central airways in the back. As we move away from the central airways to the pe­riphery of the lung, the filtering effect serves to diminish the inspiration and almost eliminate the expiratory noise. This is the normal vesicular breath sound.

The breath sounds can only be normal, de­creased, or increased. Decreased intensity of the breath sounds is due to either (1) impaired move­ment of air that normally generates the breath sounds, such as in emphysema, diaphragmatic paralysis, or bronchial obstruction, or (2) im­paired transmission from the lung to the chest wall due to pneumothorax or pleural effusion or thickening. An increased transmission of the breath sounds is characterized by the finding of bronchial breath sounds (similar to the sound nor­mally heard over the trachea) over the peripheral lung fields. Bronchial breathing is most com monly found with consolidation but can also occur at the interface with a pleural effusion where the lung is compressed. Upon completion of initial auscultation, the examiner can verify the presence of bronchial breathing by demonstrating the presence of the associated features: increased vocal resonance, whispering pectoriloquy (whis­pered sounds are heard more clearly), and ego­phony (the phonated e is heard as a).
Added sounds can be of only three types: wheezes, crackles, and pleural sounds. Wheezes are continuous, musical sounds thought to occur as air passes through a narrowed airway, setting up oscillations in the walls. They are more com­mon during expiration, since dynamic compres­sion exaggerates the constriction. Wheezes may be diffuse in asthma or chronic bronchitis, or local­ized in the case of a partially obstructed bronchus (tumor, secretions, or foreign body).

Crackles, formerly called rales or crepitations, are short sequences of discontinuous sounds that may be heard during inspiration or expiration. Very coarse crackles heard over the large airways are thought to result from air moving through se­cretions. However, most crackles are generated further out in the lung as a result of the popping open of small airways that were closed during the previous expiration owing to low lung volumes, alterations in lung compliance, or increases in in­terstitial pressure. These factors are magnified in the bases, and they are more common there even if the underlying process is diffuse. When fine, the sound is mimicked by rubbing hair close to the ear between the thumb and finger, while the coarse crackle is like the sound of a Velcro fas­tener opening. The finding of crackles is a non­specific indicator of pulmonary parenchyma] dis­ease, and the crackles of congestive failure cannot be differentiated from those of pulmonary infec­tion.

Pleural sounds may be a rub, like the creaking of leather, found with pleural inflammation or the mediastinal crunching sound synchronous with systole found with a pneumomediastinum and likened to the sound created while walking through snow.
The typical physical findings in the major pul­monary disorders are outlined in .