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Examination of the respiratory system should be preceded by a careful general examination. Dyspnea, cyanosis, digital clubbing and cervical or axillary lymphadenopathy may suggest a primary respiratory disorder.
For purposes of physical examination, the chest is divided into different areas with a view to enable anatomical localization of the lesion. The anterior part is divided into supraclavicular, infraclavicular, mammary and inframammary regions. The lateral aspect is divided into the axillary and infra-axillary regions and the back is divided into suprascapular, interscapular and infrascapular regions. Physical examination is carried out sequentially from inspection to palpation, percussion and auscultation. Measurement of the chest for its expansion is a simple and reliable clinical method for assessing the ventilatory capacity, normal expansion in an adult ranges from 6-8cm.
Percussion:
The note raised by percussion and the vibration felt by the pleximeter finger gives valuable clues to the state of the underlying lung and pleura. By percussion it is possible to assess the relative proportion of air, solid tissue or fluid underlying the area.
Clinical significance of alteration in percussion note
Normal lung - Resonant normally
Hollow viscus, penumothorax - Tympanitic
Moderate pneumothorax, emphysema, bullae - Hyper-resonant
Consolidation, collapse, fibro-thorax - Impaired resonance to moderate dullness
Pleural effusion, emphysema, thick fibrothorax - stony dullness.
Special forms of percussion include "tidal percussion" and the "elicitation of shifting dullness". The former is employed to distinguish dullness caused by the upper border of the liver from that caused by pleural fluid or consolidation of the lower portion of the lungs. Shifting dullness occurs when there is fluid which is free to move with changing positions of the patient. This occurs in hydropneumothorax or in a large cavity containing fluid and air.
Auscultatory findings:
Breath sounds, vocal resonance and whispering pectoriloquy are elicited by auscultation. Breath sounds are produced by oscillation set up in the larger air passages (trachea and larger bronchi) by turbulent flow of air. Over the larger air passages the character of breath sounds is bronchial. In the lower regions of the lungs, the parenchyma acts as a low pass filter which filters off the higher frequency components (200 Hz and above) and this changes the character of the breath sounds to vesicular. When this filtering effect is lost, the sounds are directly transmitted to the chest wall and the breath sounds become bronchial. This occurs in consolidation of the lungs. This is the acoustic basis of bronchophony and whispering pectoriloquy as well. Adventitious sounds heard during auscultation may be "wheezes" (previously called 'rhonchi') and "crackles" (used to be known as "crepitations").
The breath sounds:
Normal breath sounds are vesicular. This is characterized by the phase of inspiration, closely followed by a short expiratory phase (one-third of the inspiration) and the quality being rustling. In bronchial breathing the expiratory and inspiratory phases are equal with a pause in between and the quality is guttural or aspirate. Normally bronchial breathing is heard over the trachea, when auscultated over the front and back of the neck. Pathological associations of a bronchial breathing include pulmonary consolidation, collapse adjoining a patent bronchus or rarely other conditions. Based on the pitch, bronchial breathing has been described as "tubular" (high pitched), "cavenous" (low pitched) and "amphoric" (low pitched breath sounds with high pitched overtones). "Tubular breathing" is heard over pneumonic consolidation, "cavenous breathing" over communicating cavities and large air passages, and "amphoric breathing" over open pneumothorax and large communicating cavities. "Bronchophony" (increased vocal resonance) occurs over areas of consolidation, "whispering pectoriloquy (whispered sounds being heard distinctly on auscultating the chest) can be elicited over areas of bronchial breathing. When only high frequency sounds of a spoken voice are transmitted to the chest wall, the vocal resonance attains a nasal quality and this is termed "aegophony". This may be elicited above the level of a pleural effusion.
Adventitious sounds may be continuous or interrupted. "Continuous adventitious sounds" include:
• Stridor occurring in laryngeal and bronchial obstruction and
• "wheezes" arising from narrowed air passages interrupted adventitious sounds are crackles (which may be fine, medium or coarse), and pleural rubs. Crackles (crepitations) are produced by explosive equilibration of gas pressure between boluses of air in the air passage and the sequestial opening up of airways during respiratory cycles. Coarse crepitations may be due to the presence of exudates in the larger air passages and these disappear with coughing and expectoration.
Physical examination in pulmonary clinical cases is quite an interesting one nevertheless, not as simple as they may sound. They require a of technicalities.
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