cedes, that whatever modifies the density of the lung substance, and changes its proper elasticity, will cause a corresponding modification in the normal pulmonary resonance; for as the lung texture is rendered more dense, or less so, than natural, the percussion sound passes through every gradation from marked resonance to complete dullness. These modifications, caused by disease, we would classify under the following heads; viz., Exaggerated Pulmonary Resonance, Dulness, Flatness, Tympanitic Resonance, Vesiculo-Tympanitic Resonance, Amphoric Resonance, and Cracked-Pot Resonance. Exaggerated Pulmonary Resonance consists in an increase of the intensity of the sound; the pitch being slightly lower, while the quality remains unchanged. This sign may exist to a slight degree over the whole, or over a portion of a lung which is performing more than its usual share of labor. Thus if one pleural cavity is filled with fluid, or if one lung is solidified by the exudation of pneumonia, or the seat of extensive tuberculous deposit, you will find the resonance of percussion increased on the opposite unaffected side, which is now doing double duty. Extensive anasmia, by lessening the quantity of blood in the lungs, may also give rise to slight extra resonance on percussion.
<Callout type="important" title="Key Sign">Exaggerated pulmonary resonance indicates that one lung or pleural cavity is working harder than usual due to disease affecting the opposite side.</Callout>
Dulness. — This consists in a diminution of the pulmonary resonance, and may be slight, considerable, or complete, according as more or less air enters the affected part. In dulness, the intensity is diminished, the pitch raised, the duration shortened, and the quality hardened. Dulness always indicates a decrease in the normal proportion of air in the part, and is an important physical sign in a number of diseases, as in pneumonia, tuberculosis, oedema of the lungs, etc.
Flatness. — This indicates the total absence of air, so that there is no proper pulmonary resonance, and its sound resembles that produced by percussing the thigh. We have examples of this when we percuss over fluid contained in the pleural or pericardial serous cavities, or when tumors are developed in the thorax, etc.
Tympanitic Resonance. — This is marked by the absence of proper pulmonary quality in the characters of its resonance; the type being the resonance of a tympanitic abdomen on percussion; in intensity it exceeds normal pulmonary percussion, and is higher in pitch. As a physical sign in thoracic affections it usually indicates the presence of air in the pleural cavity, as in pneumo-thorax. In this affection we have contained, not in small vesicles, but in a large free space, and hence we have not the vesicular, but the tympanitic quality in the sound.
Vesiculo-Tympanitic Resonance. — By this term (introduced by Prof. A. Flint), it is meant to denote a resonance in which we have both the tympanitic and vesicular qualities. It is higher pitched, but more intense than normal pulmonary resonance, and is present, when the increase of the volume of the lung, as in some cases of emphysema, is so great as to dilate and render extremely tense the thoracic walls.
Amphoric Resonance, unlike tympanitic resonance (which gives an impression of fullness), is suggestive of shallowness or emptiness; it resembles the sound produced by flapping the cheek when the mouth is closed, and fully but not forcibly inflated. It is most frequently heard over a large superficial cavity, having thin, tense walls, and hence is usually indicative of phthisis. In case of pleuro-pneumonia, a sound more or less amphoric in character is sometimes heard.
Cracked-Pot Resonance is usually, though not invariably, heard in connection with amphoric resonance. It resembles the sound produced by striking the hands, loosely folded across each other, against the knee, the contained air being suddenly forced out between the fingers. If there exists a pulmonary cavity of large size, with thin walls, communicating freely with a large bronchial tube, the chest walls being at the same time particularly yielding, forcible percussion, with the patient's mouth open, will yield cracked-pot resonance.
Auscultatory Percussion. — This is a combination of auscultation and percussion. It was first brought to the notice of the profession by Drs. Camman and Clark in 1840. Their method of performing it was as follows: Press the objective end of a stethoscope, constructed expressly for this purpose (while the ear-piece is accurately fitted to the ear), firmly and evenly on the surface, directly over that portion of the organ or tumor to be examined which is most superficial; then let percussion be performed in the usual way, one or two inches from the point at which the stethoscope is applied. The percussion sound communicated to the ear in this manner far exceeds in intensity and distinctness the same sound when communicated through the medium of the air. The slightest change in pitch and quality is also readily appreciated.
<Callout type="gear" title="Equipment Needed">A specialized stethoscope designed for auscultatory percussion can enhance diagnostic accuracy by amplifying subtle changes in resonance.</Callout>
The benefits claimed for auscultatory percussion by its originators are: 'First, That the heart can be measured in all but its antero-posterior diameters, under most, perhaps all circumstances of health and disease, with hardly less exactness than we should be able to do if the organ were exposed before us. Second, That the outlines of the liver can be traced with much greater certainty than by ordinary percussion, in circumstances of health; and to circumscribe it in many conditions of disease in which ordinary percussion is not applicable. Third, That the dimensions of the spleen can be ascertained in circumstances that baffle ordinary percussion. Fourth, That by it we can mark the superior, inferior, and external limits of the kidneys.'
Key Takeaways
- Identify different types of pulmonary resonance to diagnose lung conditions.
- Use auscultatory percussion for enhanced diagnostic accuracy.
- Recognize the significance of changes in respiratory sound intensity and quality.
Practical Tips
- Practice identifying subtle variations in respiratory sounds to improve diagnosis skills.
- Utilize specialized equipment like a stethoscope designed for auscultatory percussion.
- Compare corresponding parts of both sides of the chest during examination.
Warnings & Risks
- Incorrect interpretation of resonance can lead to misdiagnosis and improper treatment.
- Performing percussions too forcefully may cause patient discomfort or injury.
- Overlooking variations in respiratory sounds due to age or sex can result in inaccurate diagnosis.
Modern Application
While the techniques described here are foundational, modern medical imaging has greatly improved diagnostic accuracy. However, understanding these historical methods remains crucial for interpreting results and recognizing subtle signs that advanced technology might miss.
Frequently Asked Questions
Q: What does exaggerated pulmonary resonance indicate?
Exaggerated pulmonary resonance indicates an increase in the intensity of sound over a portion of a lung which is performing more than its usual share of labor, often due to disease affecting the opposite side.
Q: How can auscultatory percussion enhance diagnosis?
Auscultatory percussion enhances diagnostic accuracy by amplifying subtle changes in resonance and pitch when performed with a specialized stethoscope designed for this purpose.
Q: What does tympanitic resonance suggest about the condition of the lungs?
Tympanitic resonance usually indicates the presence of air in the pleural cavity, such as in pneumo-thorax, where the sound resembles that produced by percussing a tympanitic abdomen.