Lung Examination: Lung Surface and Breath Sounds – Lung Disease

by Jeremy Brown, PhD

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    00:01 Now when we move onto auscultation of the lung, we need to know about the lung surface markings. And what I mean by that is: where you’re listening, which lobe are you going to be listening to? So, if you look at this diagram – this picture of the anterior chest – you can see that the upper lobe, which is shown on the left-hand side of the picture, is most of the anterior chest. So, when you listen – and the green circles show where you should place you stethoscope during the examination process – you’re mostly, when you’re listening to the anterior chest, listening to the upper lobe, both on the right side and the left side.

    00:36 If you want to listen to the middle lobe, then it’s the lower part of the anterior examination that you need to concentrate on.

    00:44 These divisions that you see the lines are important when describing things. So the anterior axillary line is basically the line that is at the beginning of the armpit. The midclavicular line is half-way across the clavicle. And that’s important because we use that as a marker for where we insert the needle during treatment for tension pneumothorax and similar situations to that.

    01:13 Now an important thing on this is that the costophrenic pleural recess you can see hangs below the level of the lung. And that is important because it does mean that, if you’re doing a biopsy perhaps of the liver on the right-hand side or the kidney on either side, then there is a chance that if you’re not careful that the biopsy needle will go for the costophrenic pleural recess and cause a pneumothorax.

    01:39 Another important thing about examination is don’t forget the axilla. It represents quite a large surface area of the lung where there might be a pleural rub or some crackles that you won’t hear elsewhere. So you need to examine the axilla, twice in men because of the size and maybe only once depending on the size of the woman.

    01:59 Examination of the back of the chest: similarly, this diagram shows that most of the back of the chest is actually the lower lobe. You can see it’s only the very top of the examination, the first part where you might listen with a stethoscope where you’ll hear the upper lobe when you examine the back of the chest. And it largely represents the lower lobe.

    02:21 So, when you find crackles posteriorly but not anteriorly, that suggests it’s a lower-lobe problem. If you find crackles anteriorly and only at the very top of the lung, then that will suggest it’s an upper-lobe problem.

    02:35 An important aspect of this diagram is the T10 vertebral body. That is the level at which the lungs stop in a normal person. If you have hyperexpanded lungs, then they might go below that level. So normally when you percuss somebody’s chest, at that level – T10 – the resonance becomes dull thereafter. If the lung has been expanded, then the resonance of the lung will go below that level. But vice versa occurs: if you’ve lost volume within that lung – hemidiaphragm paralysis, for example, would bring up the bottom of the lung. Or if you have bilateral fibrosis actually, it might shrink both lungs quite substantially. Then the point where you get the end of the lung – the resonance becoming dull – goes higher up the thoracic vertebrae.

    03:24 Okay. So the next slide. It’s about percussion note. So in the previous two slides, the green circles identify where you percuss the patient, where you auscultate – where you listen with your stethoscope – and where you do your vocal resonance.

    03:41 Percussion note is designed to identify areas which have been – because the lungs are normally air filled and therefore should be resonant. And percussion is used to identify areas in which that air has been replaced by another material. The best example of that is probably going to be a pleural effusion where, instead of having a nice resonant note, it will be incredibly dull over the area where the pleural effusion is. Similarly, you’ll get dullness to percussion over areas of total lung collapse, where the aerated lung has now become solid. A previous pneumonectomy or lobectomy where the – especially with pneumonectomy – the removed lung is replaced by fluid. And occasionally we’ve very extensive consolidation due to pneumonia. Because the consolidation has replaced the air in that lung, it will be dull to percussion.

    04:27 In fact, probably the commonest cause of dullness to percussion is poor technique. If you try this at home, you can percuss on the table and it will sound nice and resonant. Then if you lift up the finger that you’re percussing on slightly so it’s not directly apposed to the table, then that note will certainly become quite dull. And the same happens when you examine a patient as well. You must make sure that the finger that’s being used as the sounding board is firmly adhered to the chest.

    05:00 Other causes of increased dullness to percussion is pleural thickening. Obesity – now it’s a practical thing really. It’s quite hard to hear a nice resonant note on somebody who is particularly large. The raised hemidiaphragm – because, as I discussed a few minutes ago, that increases the height where the lung ends and the abdomen starts.

    05:19 And if a patient should be a little dull over the right costochondral margin and the left parasternal edge, that’s because that’s where the liver and the heart are. And it’s the loss of that dullness to percussion over these areas that occurs in patients with hyperexpanded lungs.

    05:36 When you percuss and you hear resonance, it’s actually quite hard to know whether that’s hyper-resonance. Hyper-resonance is increased resonance. It’s much more resonant than normal. It’s very hard to detect that. But that occurs in patients with pneumothoraxes or very large cavities because you’re percussing over an area with just air, with no tissue in it. But that is not common, not common at all.

    05:58 Breath sounds: we’re all used to putting a stethoscope on the chest and listening for added sounds. But in fact, when you’re listening to the chest with your stethoscope, there are three things you’re looking for. One is the breath-sound intensity. And I’ll come back to that in a little bit. The most important thing about that is that vocal resonance is used to support whatever data you get from breath-sound intensity. Two, you’re looking at the inspiratory/expiratory ratio. And we’ve already discussed that in the general examination because that identifies patients with airways disease without even having to listen for added sounds. And then the third component is the added sounds. And essentially there are three added sounds that we listen to in lung disease: crackles or crepitations, or rales if you’re American, wheeze, or rhonchi if you’re American – they’re the same thing – and pleural rubs. There are other rarer noises – squeaks for example – but they’re very – they are unusual. We don’t need to describe those today.

    06:56 Inspiratory/expiratory ratio: when you’re listening to the chest with the stethoscope, it’s quite easy to hear the duration of inspiration versus expiration and therefore identify patients who may have airways disease with prolonged expiration compared to inspiration.

    07:15 Added sounds: I’ve already mentioned the crackles, wheeze and pleural rub are the normal added sounds that we listen for in lung disease. A pleural rub occurs in pleural disease. A wheeze is normally a sign of airways disease. Crackles or crepitations is normally a sign of alveolar or interstitial disease, the one exception being bronchiectasis. And that makes life easier for the examining person to identify what the problem might be affecting the patient and the causes of each of these abnormal sounds.

    07:47 So, for example, crepitations suggest there might be consolidation due to pneumonia present.

    07:52 Those would be asymmetric. Pulmonary fibrosis and other interstitial lung diseases will cause fine bibasal or bilateral crepitations depending on the cause. Pulmonary oedema also causes fine lateral crepitations. And bronchiectasis causes coarse crepitations.

    08:12 Wheeze is a sign of airways disease that you found during exacerbations of asthma, patients with COPD, patients with bronchiectasis with associated airways disease, occasionally because of partial obstruction of a major bronchus due to a tumour and that causes what we call a monophonic wheeze because there’s only one source of the wheeze. The bronchus has been obstructed, rather than airways disease where there’s multiple different tubes which are – multiple different bronchi which are partially obstructed. Occasionally, a patient with pulmonary oedema may sound wheezy when you listen to them. That’s called cardiac asthma. And, of course, other airways obstructions. But that’s usually an inspiratory wheeze – stridor.

    08:50 Pleural rub equals pleural inflammation. That occurs in infection over consolidated lungs during pneumonia or pulmonary emboli and, occasionally, in other inflammatory conditions causing pleural – pleural disease. Dressler’s syndrome for example. And if you drain somebody with a pleural effusion, actually frequently afterwards you can hear a pleural rub over the drained effusion.

    09:14 The intensity of the breath sounds and the vocal resonance and the tactile vocal fremitus all give similar information. You don’t need to do vocal resonance and tactile vocal fremitus. You don’t need to do both of those. And, in general, I’d probably generally stick to just doing vocal resonance because it’s a big easier and a bit clearer about what the results are.

    09:36 And what we’re listening for with breath-sound intensity is whether the intensity has been increased or decreased. So, for example, patients who have a pleural effusion, a pneumothorax, pleural thickening, lobar collapse, or bulla, they will have reduced breath-sound intensity over the affected area. That’s because there’s a big area of abnormal substance – air, fluid, thickening – between your stethoscope and the movement of the air in the lungs.

    10:09 Generalised quiet breath sounds is a sign of airways disease: less air being shifted through the bronchial tree. And that is probably the commonest sign you actually hear when you’re listening to the lungs of patients with COPD. It also occurs in asthma but usually in asthma it’s a late sign. That means the patient is imminently going to have a respiratory arrest.

    10:33 Now the breath-sound intensity can also be increased. And normally that’s because noise in the airways is being conducted to a stethoscope more readily. And that occurs when you have lung consolidation and overlarge cavities. In addition, you can hear it at the top of pleural effusions for reasons which I don’t fully understand. And one catch that often occurs is that, if somebody has a deviated trachea – for example, they have a pneumothorax pushing the trachea over to the left-hand side – when you listen to the apex of the left lung, you’re actually listening over the trachea. And therefore that sounds like they may have bronchial breathing at the top of their left lung. But actually what you’re listening to is the trachea itself. And that’s a trick – a situation where you can easily be caught out.

    11:20 The sort of epitome of increased breath-sound intensity is bronchial breathing. And that occurs over dense pulmonary consolidation. But it really has to be quite dense consolidation for you to hear bronchial breathing.

    About the Lecture

    The lecture Lung Examination: Lung Surface and Breath Sounds – Lung Disease by Jeremy Brown, PhD is from the course Introduction to the Respiratory System.

    Included Quiz Questions

    1. Pneumothorax
    2. Paralysis of the right phrenic nerve
    3. Right pleural effusion
    4. Atelectasis of the right base
    1. Tension pneumothorax
    2. Pneumonia
    3. Flail chest
    4. Atelectasis
    5. Pulmonary tuberculosis
    1. The lower lobes of the lungs
    2. The upper lobes of the lungs
    3. The pericardium
    4. The mediastinum
    5. The ribs
    1. T10
    2. T2
    3. T4
    4. T8
    5. T12
    1. Pulmonary embolism
    2. Bronchiectasis
    3. Pulmonary edema
    4. COPD
    5. Asthma

    Author of lecture Lung Examination: Lung Surface and Breath Sounds – Lung Disease

     Jeremy Brown, PhD

    Jeremy Brown, PhD

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