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.