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Examination of the patient with suspected pulmonary disease includes inspection, palpation, percussion, and auscultation of the chest.
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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 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 as seen in end-stage LV failure, neurologic disease, and high altitude, especially during sleep.
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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 increased work of breathing and is a sign of pulmonary impairment. As the diaphragm contracts, it pushes the abdominal contents down. Hence, the chest and abdominal wall normally expand simultaneously. 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.
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The examiner may palpate the trachea at the suprasternal notch, to detect shifts in the mediastinum; the posterior chest wall, to gauge fremitus and the transmission through the lungs of vibrations of spoken words; and the anterior chest wall to assess the cardiac impulse.
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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 but high specificity, therefore it is not necessary in every patient. However, perfusion may serve as a confirmatory test in patients with high pretest probability, such as in suspected tension pneumothorax; the combination of tracheal shift and hyperresonance can be lifesaving, permitting immediate decompression.
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Auscultation of the chest depends on a reliable and consistent classification of auditory findings. Normal lung sounds heard over the periphery of the lung are called vesicular. They have a gentle, rustling quality heard throughout inspiration that fades during expiration. Normal sounds heard over the suprasternal notch are called tracheal or bronchial sounds. They are louder, higher-pitched, and have a hollow quality that tends ...