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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5769_Библиотеки_им_академика_М_И_Перельмана
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280 oracic ultrasound
e posterior localization of blood in a supine patient, hides many hemothoraces to radiography, but makes them clearly visible in ultrasound and CT (occult hemothoraces). However,
the occult hemothorax does not possess the critical potential of the occult PNX, but from
a practical point of view a quantitative estimate of it is useful to determine the need for a
drainage.
In the supine position, a thickness of blood less than 1.5 cm corresponds to an average of
250-300 ml; a moderate hemothorax (300-1000 ml) shows a thickness of 1.5-4.5 cm; a large
hemothorax, with a volume of over 1000 ml, has a thickness greater than 4.5 cm54. It is likely
that hemothoraces thicker than 1 cm need drainage with greater frequency55. Finally, during
abdominal imaging of the liver and spleen, the effusion may appear immediately above the
diaphragm or in the posterior costophrenic angle. FAST can identify this picture and makes
the intercostal acquisition unnecessary52 (Clip 4).
Clip 4 – Longitudinal scan of the spleen in polytrauma: left hemothorax.
An effusion above the diaphragm is differentiated from the single or coexisting intraperitoneal
effusion through the clear demonstration of the diaphragm domes. Finally, the attenuation
and the mirror effect that often occur above the diaphragmatic domes when making coronal
scans oriented upward, should not be confused with a pleural effusion (Fig. 16).
DIAPHRAGM
HEMOTHORAX
Figure 16 – Polytrauma: coexistence of right hemothorax and hemoperitoneum.
HEMOPERITONEUM
In the majority of cases, the therapy for hemothorax is the drainage with tube, traditionally
36-42F55, and the strategy is to evacuate the pleural cavity in the first seven days56. Table 2
illustrates the indications for urgent surgical treatment (thoracotomy) of a hemothorax.
Table 2 – Indications for thoracotomy in traumatic hemothorax
Immediate evacuation with tube of more than 1500 ml of blood
Persistent bleeding of the chest of 150-200 ml/h for 2-4 hours
Need for continuous blood transfusions to maintain an appropriate hematocrit
oracic trauma 281
Some authors have debated how much blood can be left in the pleural cavity
57,58
, identifying
a “secure” thickness for the effusion in CT less than 1.5 cm.
However, the incomplete drainage of blood from the pleural cavity is a risk factor (33%) for
empyema. is is induced by pleuropulmonary inflammation, favored by lesions and possibly
by the action of bacteria59. At present it remains uncertain whether an aggressive approach
to hemothorax may reduce the most common complications.
A thoracostomic tube does not ensure the complete evacuation of a hemithorax, if the blood
determines the sedimentation of fibrin and clots that transform the fluid collection in a
complex mass. When the transonic component is minimal and inhomogeneous because of
corpuscular or areolar components or clots the drainage may be unsuccessful. A clot can
show a low echogenicity, and may be confused with a collapsed lung. e resulting picture
is called retained hemothorax60.
In every hemothorax ultrasound has a high diagnostic power and in our opinion it can easily
replace traditional radiography for the diagnosis and for detecting the correct position of a
tube or its draining effectiveness.
Table 3 lists EAST recommendations for traumatic hemothorax.
Table 3 – Recommendations for the treatment of traumatic hemothorax
Massive hemothorax Hemothorax
• The primary indication for surgery follows
from the conditions of the patient and his
physiology, rather than from the blood output
from the chest (Level II)
• Surgical exploration is indicated by the issue
of 1,500 ml of blood from the pleural tube
within 24 hours, regardless of the bleeding
mechanism (Level II)
Mowery NT, Gunter OL, Collier BR
pneumothorax.
J Trauma
2011; 70: 510-518.
et al.
Practice management guidelines for of hemothorax and occult
• All hemothoraces, regardless of volume, must
be drained (Level III)
• A persistent retained hemothorax must not to
be treated with a second tube but with videothoracoscopic surgery (VATS) (Level I)
• VATS should be performed between the
third and seventh day of hospitalization
to minimize the risk of empyema and
thoracotomy (Level II)
• The intrapleural thrombolysis can be used
to improve the drainage of circumscribed or
dense effusions (6-13 days of life), in subjects
in whom a thoracotomy is burdened with a
high risk (Level III)
➣ Pleural empyema
Early onset pneumonia is a critical event in the chest-injured patient, which takes place
within 72 hours after admission. Predisposing factors are the need for intubation, aspiration,
pulmonary contusion and hemothorax61. Approximately 3% of patients with chest trauma
develops a pleural empyema. e diagnosis of this complication has clinical (fever, signs and
symptoms of sepsis), objective (purulent material from the thoracostomic tube) and instrumental basis. Ultrasound is accurate to define the presence, persistence and structure of the
effusion, which in these cases is always complex (echogenic, pseudosolid, areolar, fibrinous).
282 oracic ultrasound
Many studies have identified factors predisposing posttraumatic empyema, such as effusion
or persistent hemothorax, prolonged drainage with tube or the application of many tubes.
ese data are the basis of early indications to the use of Video Assisted oracoscopy
(VATS)
62,63
.
➣ Haemopericardium
e occupation of the pericardial cavity from the blood is usually caused by penetrating
trauma, contusion or rupture of the heart64. If the blood determines a significant increase of
pressure in the pericardial cavity, it produces an obstacle to the diastolic filling of the heart
resulting in a cardiac tamponade. Under conditions of rapid filling, the inextensibility of
the serous membrane allows a small amount of blood (100-150 cc) to determine the conditions for the tamponade. e net result is the decreased cardiac output evolving in a state of
obstructive shock65.
It is therefore necessary to promptly identify the early signs of tamponade, differentiate them
from hypertensive pneumothorax and prepare appropriate measures. ese can be temporary such as pericardiocentesis or a pericardial window, or definitive as surgical repair of the
causal lesion66. Echographic scans useful to highlight the haemopericardium are the subcostal
epigastric scan, used in FAST67, and the classic cardiologic scans (parasternal long-axis or
apical four chambers)68.
e findings of hemopericardium and cardiac tamponade in trauma are similar to that of
the common pericardial effusions, which are treated in the chapter on echocardiography.
➣ Pulmonary contusion
e pulmonary contusion is a typical injury in closed chest trauma. A blunt chest trauma
rarely induces injuries such as ruptures of the lung parenchyma or intrapulmonary hematomas.
Pulmonary lacerations with or without hemo or pneumothorax are rather characteristic of
open thoracic injuries. e therapeutic approach is different.
Among patients undergoing thoracotomy for trauma, 40% of those with penetrating trauma
requires some form of lung resection, compared with only 17% of patients with blunt trauma,
and this reflects the different anatomy of the injury related to the traumatic mechanism69. In
the common emergency practice, outside of urban realities with high index of crime or war
situations, most of the lung contusions or lacerations can be treated conservatively70.
From the dynamic point of view, the mechanical energy exerted on the rib cage, especially
when it exerts a parietal deformation, fractures the ribs and/or the sternum. is is true in
adults, but not in children, where rib fractures are relatively rare.
It is now established that the lung contusion is the most frequent manifestation in closed chest
trauma and occurs in 30-70% of the victims
detected as a result of clinically irrelevant traumas, thus not easy to be diagnosed73. Wagner74
described with accuracy the pathogenesis of lung injury. Table 4 summarizes this classification.
Obviously, the mechanisms of contusions are not mutually excluding each other. In contusions,
the lung suffers injuries ranging from edema to blood suffusion, from the simple rupture of
the tissue to complex lacerations. Parenchymal ruptures may involve the tracheobronchial
tree, with or without hemothorax and/or PNX. Microscopically, edema, blood extravasation, alveolar damage, airspace consolidation, vascular, bronchial and tissue laceration are
the hallmarks of the contusion75.
71,72
. Moreover, pulmonary contusions may be
oracic trauma 283
Table 4 – Types of lung injury in relation to the pathogenesis
Type 1 - Compressive: due to compression of the rib cage against the lung. Direct trauma
Type 2 - Indirect posterior: due to sliding of the lung parenchyma against the vertebrae
Type 3 - Direct: due to drilling of fractured rib
Type 4 - Due to sprain: secondary to pleural adhesions
ese features influence the clinical imaging generating ultrasound artifacts and consolidations. However, edema and interstitial extravasation of blood do not alter the geometry of
the subpleural air spaces. On the contrary, lacerations, consolidations and hematomas cause
large increases in density and a geometrical subversion of the distal air spaces.
Another point deserves attention. For many reasons, ventilation abnormalities are a corollary
to the lung trauma. Chest splinting due to reflexes elicited by pain leads to obvious supradiaphragmatic hypoventilation. Moreover, bronchial hypersecretion or bleeding in the airspace
produce obstruction, which configures lamellar, segmental or major atelectasis. Finally, the
blood inhibits the alveolar surfactant, and/or its production is decreased for lung damage. In
trauma patients, the pathological pulmonary attitude is toward regional or focal hypoventilation. e deflated lung tissue may produce artifacts indistinguishable from those produced
by interstitial damage with edema or blood extravasation.
In trauma patients, the traditional radiological imaging is not very sensitive to minor or
initial alterations (the interstitial stage of tissue damage) and it highlights, often too late, irregular lung consolidations, sometimes coexisting with pneumo- and hemothorax. Computed
Tomography, on the other hand, is very accurate toward these lesions, and identifies them in
the earliest stages as areas of ground glass.
Many contusive lesions often undergo exacerbations related to the occurrence of exudation,
pulmonary edema, micro and macro consolidations, infection, inflammation or abnormalities
of distal ventilation. eir evidence, especially on chest X-ray, is thus better in the following
71,76-78
days
(Figs. 17-19).
Figure 17 – Pulmonary contusions are detected with difficulty in chest radiography in the emergency
department and they tend to worsen over time. A: antero-posterior scan showing rib fractures on the
right. B: a particular of the right hemithorax showing a faint basal lung opacity.
284 oracic ultrasound
Figure 18 – A CT scan obtained in the same subject a few minutes after is much more informative, as
it shows the real injury and the presence of an occult pneumothorax.
Figure 19 – Pulmonary contusion. Left: CT findings. Right: radiography of the same case is uninformative.
In this regard, in 1999 it was found that about 35% of lung injury did not appear in the initial
chest X-ray and the time of radiological opacification of a contusion influenced a diagnostic
delay of a minimum of 6 hours up to 48 hours. Schild79 reports that in an experimental
animal context, as opposed to 100% of parenchymatous lung lesions detected by CT, only
38% had radiographic relevance.
e stereotype behavior of lung ultrasound investigation already described with regard to
pathology also occurs in the case of trauma. e normal lung parenchyma does not have a
real echographic representation80. Its existence is masked by a field of reverberation artifacts
(the specular effect).
However, whenever its surface is acoustically affected in terms of density and geometry (interstitial infiltration, edema, alveolar exudation or hemorrhage), windows (micro- or macroholes)
are produced. If the lung injury is able to produce superficial density and geometric variations,
then the pleural surface is not more specular and the A Lines pattern is lost.
e traumatic interstitial edema is recognized by the variation of acoustic permeability of the
superficial lung, that generates multiple B Lines or white lung81 (Figs. 20-23).
oracic trauma 285
Figure 20 – The first suspect of the existence of a lung contusion arises from a focal interstitial syndrome,
related to the site of the trauma.
Figure 21 – Lesional edema from a trauma thickens inter- and intralobular septa of the lung up to the
expression of compact B Lines. The image illustrates an interstitial syndrome in the lung contusion.
Figure 22 – Left parasternal pulmonary contusion. The X-ray is not diagnostic. The ultrasound
examination shows the presence of a mild interstitial syndrome. The arrows indicate mammary vessels.
e widespread presence on the lung fields of B Lines indicates diffuse pulmonary interstitial
involvement, while if localized it indicate inflammatory or traumatic edema. An important
286 oracic ultrasound
Figure 23 – Mild pulmonary contusion explored
with 10 MHz linear probe. An interstitial syndrome
with B Lines is evident. There is inconsistency of
interstitial disease with spared areas, white lung
(thin arrow) and microconsolidations (large arrows).
The pleura is linear (acute illness).
difference between hydrostatic and traumatic edema, apart from the focality of
the latter, is the appearance of confluent B
Lines, which can form an extensive pattern
of white lung82. is aspect draws ARDS
edema and it is probably related to an interstitial (or interstitial-alveolar) flooding
inside the lobules, and not to a predominant expansion of subpleural interlobular
septa, as it can occur in the early stages
of hydrostatic edema83. In trauma, as in
ARDS, the pleura appears in echography
with an irregular surface84.
When a massive filling of the acinar structures occurs, the tissue becomes hepatized,
thus solid. It generates a hypoechoic image
of variable shape, that in the case of contusion, is irregular, and it does not respect
segmental or lobar limits (Figs. 24-29).
Figure 24 – The initial hepatization of the
acinar structures in a pulmonary contusion can
be highlighted with the appearance of multiple
small consolidation areas, on a background of
compact B Lines.
Figure 25 – A well-defined pulmonary
contusion may be indistinguishable from a
pulmonary consolidation of a different nature.
oracic trauma 287
Figure 26 – Pulmonary contusion at the left base due to car accident. Hemodynamically stable,
eupneic subject, saturation 98%. A: Normal X-ray at the admission. B: particular of the left base. C:
CT performed immediately after the X-ray. Evident areas of ground glass on the left lung and a small
hemothorax. D: X-ray after six hours from the injury. There is only a faint opacity at the left base. Note
the massive pneumoperitoneum by small bowel laceration (arrow).
Figure 27 – Thoracic ultrasound (longitudinal scans at the left base) of the subject of Figure 26. A:
ultrasound at the admission. Interstitial syndrome with many B Lines. B: after 2 hours tiny subpleural
areolas of consolidation (surface alveologram), that progress in the following four hours to produce a
sharply interrupted and irregular pleural line (C-D).
288 oracic ultrasound
Figure 28 – The right lung base of the patient in the preceding figures (no contusion) shows no
ultrasound abnormalities. The arrow indicates the pleural line.
Figure 29 – A: small alveolar consolidation in a ground glass area due to contusion. B: In the same
position, evidence of subpleural consolidation with B Lines.
CONSOLIDATION
CONSOLIDATED ECHOES
BEHIND
THE CONSOLIDATION
HEMOTHORAX
Figure 30 – Pulmonary contusion. A consolidation inside dense B Lines. There is also a small
hemothorax.
oracic trauma 289
Consolidations consequent to contusions may contain tubular anechoic structures, that
can be formed by bronchioles filled with liquid (fluid bronchogram), or, if there are aerated
bronchioles, they can show multiple small hyperechoic spots.
Usually the rear limit of these lesions is marked by echoes, which generate a posterior enhancement that, in this specific case, does not indicate the presence of a cystic structure
(Figs. 30-32) (Clip 5).
CONSOLIDATION
B LINES
Figure 31 – Pulmonary contusion. A scan adjacent to the consolidation highlight the presence of
compact B Lines.
B LINES
Figure 32 – Pulmonary contusion. Interstital syndrome at the right base.
Clip 5 – Pulmonary contusion. Small subpleural consolidations inside a focal
interstitial syndrome.
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