Examination of the patient with suspected pulmonary disease includes inspection, palpation, percussion, and auscultation of the chest. An efficient approach begins with observing the pattern of breathing, auscultation of the chest, and inspection for extrapulmonary signs of pulmonary disease. More detailed examination follows from initial findings.
The pattern of breathing refers to the respiratory rate and rhythm,
the depth of breathing or tidal volume, and the relative amount
of time spent in inspiration and expiration. Normal values are a
rate of 12–14 breaths per minute, tidal volumes of 5 mL/kg, and
a ratio of inspiratory to expiratory time of approximately 2:3. Tachypnea is an increased rate of breathing
and is commonly associated with a decrease in tidal volume. Respiratory
rhythm is normally regular, with a sigh (1.5–2 times normal
tidal volume) every 90 breaths or so to prevent collapse of alveoli
and atelectasis. Alterations in the rhythm of breathing include
rapid, shallow breathing, seen in restrictive lung disease and as
a precursor to respiratory failure; Kussmaul breathing,
rapid large-volume breathing indicating intense stimulation of the
respiratory center, seen in metabolic acidosis; and Cheyne-Stokes respiration, a rhythmic
waxing and waning of both rate and tidal volumes that includes regular
periods of apnea. This last pattern is seen in patients with end-stage
left ventricular failure or neurologic disease and in many normal
persons at high altitude, especially during sleep.
During normal quiet breathing, the primary muscle of respiration is the diaphragm. Movement of the chest wall is minimal. The use of accessory muscles of respiration, the intercostal and sternocleidomastoid muscles, indicates high work of breathing. At rest, the use of accessory muscles is a sign of significant pulmonary impairment. As the diaphragm contracts, it pushes the abdominal contents down. Hence, the chest and abdominal wall normally expand simultaneously. Expansion of the chest but collapse of the abdomen on inspiration indicates weakness of the diaphragm. The chest normally expands symmetrically. Asymmetric expansion suggests unilateral volume loss, as in atelectasis or pleural effusion, unilateral airway obstruction, asymmetric pulmonary or pleural fibrosis, or splinting from chest pain.
The examiner may palpate as follows: the trachea at the suprasternal notch, to detect shifts in the mediastinum; on the posterior chest wall, to gauge fremitus and the transmission through the lungs of vibrations of spoken words; and on the anterior chest wall to assess the cardiac impulse. All these maneuvers are characterized by low interobserver agreement.
Chest percussion identifies dull areas that correspond to lung consolidation or pleural effusion or hyperresonant areas suggesting emphysema or pneumothorax. Percussion has a low sensitivity (10–20% in several studies) compared with chest radiographs to detect abnormalities. Specificity is high (85–99%). Since an insensitive test is a poor screening examination, percussion and palpation are not necessary in every patient. These techniques do serve as important confirmatory tests in specific patients when the prior probability of a finding is increased. For example, in a patient with a suspected tension pneumothorax, the finding of tracheal shift and hyperresonance can be lifesaving, permitting immediate decompression of the affected side.
Vesicular breath sounds recorded in a person with normal lungs. (Reproduced, with permission, from Raymond L.H. Murphy, Jr., MD: A Simplified Introduction to Lung Sounds [audio tape], 1977.)
Recording of normal vesicular lung sounds. (Reproduced, with permission, from Raymond L.H. Murphy, Jr., MD: A Simplified Introduction to Lung Sounds [audio tape], 1977.)
Bronchial breath sounds recorded over an area of consolidation in a person with pneumonia. Note the loud expiratory phase, which helps to clarify these sounds as bronchial. (Reproduced, with permission, from Raymond L.H. Murphy, Jr., MD: A Simplified Introduction to Lung Sounds [audio tape], 1977.)
Recording of breath sounds in a person with emphysema. Note the diminished intensity of breath sounds in emphysema. The obstruction to air flow is more severe in expiration than in inspiration, and expiration is prolonged. (Reproduced, with permission, from Raymond L.H. Murphy, Jr., MD: A Simplified Introduction to Lung Sounds [audio tape], 1977.)
Abnormal lung sounds (“adventitious” breath sounds) may be continuous (> 80 ms in duration) or discontinuous (< 20 ms). Continuous lung sounds are divided into wheezes , which are high-pitched, musical, and have a distinct whistling quality; and rhonchi , which are lower-pitched, sonorous, and may have a gurgling quality. Wheezes occur in the setting of bronchospasm, mucosal edema, or excessive secretions. In each case, the airway is narrowed to the point where adjacent airway walls flutter as airflow is limited. Rhonchi originate in the larger airways when excessive secretions and abnormal airway collapsibility cause repetitive rupture of fluid films. Rhonchi frequently clear after cough.
Lung sound: sibilant rhonchus, often called "wheezes." (Reproduced, with permission, from Raymond L.H. Murphy, Jr., MD: A Simplified Introduction to Lung Sounds [audio tape], 1977.)
Lung sound: sonorous rhonchus. (Reproduced, with permission, from Raymond L.H. Murphy, Jr., MD: A Simplified Introduction to Lung Sounds [audio tape], 1977.)