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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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420 oracic ultrasound
e most interesting aspect, is that lung ultrasound has the ability to quickly distinguish
critical similar situations requiring rapid differential diagnosis, in particular TTN and HMD.
Figure 20 – Meconium aspiration: radiological signs of infiltration in the right upper lobe.
➣ Bronchopulmonary dysplasia
Bronchopulmonary dysplasia (BPD) is a chronic lung disease that develops in preterm neonates treated with oxygen and positive pressure ventilation38.
BPD was first described by Northway in 1967. He defined the clinical, radiological and
histological characteristics of newborns with HMD treated with oxygen and mechanical
ventilation39. is definition was subsequently modified by Bancalari, that considered the
ventilation, the need for oxygen (at 28 days, able to maintain a pressure above 50 mmHg),
and the importance of chest x-ray abnormalities
need for oxygen at 36 weeks was a more accurate parameter in predicting the outcome42.
is led to a significant reduction of the cases that were included according to Bancalari’s
criteria. In 2001, the definition of BPD was further modified by introducing criteria based
on gestational age (less than or more than 32 weeks) and severity38.
BPD is generally rare in newborn weighing more than 1200 g and in those born after the
30th week of gestation. e antenatal use of corticosteroids43, the surfactant therapy and
less aggressive ventilation methods have reduced the severity of lung injury, especially in the
most premature infants.
e pathophysiology of BPD is multifactorial and the organs involved are mainly lungs
and heart. e bronchi show a marked reduction of epithelial metaplasia associated with
fibrosis and hypertrophy of smooth muscle cells. e alveoli are less numerous and larger,
and microcirculation appears to be less developed. In cases of severe BPD there is pulmonary
hypertension and an abnormal development of the pulmonary circulation44.
It has been shown that mechanical ventilation and oxygen interfere with alveolar and vascular
development.
e routine use of surfactant has helped the survival of many immature infants. In addition, the
knowledge of neonatal physiology has improved and many technologies have been developed.
For this reason, BPD today is a less severe disease than it was in past years. However, BPD
remain an important disease in the first 2 years of life, with high morbidity and mortality.
40-41
. In 1988, Shennan suggested that the
Pleural and lung ultrasound in the neonatal period and in childhood 421
e etiology of BPD is not yet fully clarified. In addition to barotrauma and oxygen toxicity, other factors favoring the development of this disease have been identified (activation
of inflammatory mediators such as prostaglandins and prostacyclins, respiratory infections,
inadequate nutrition, genetic factors)
45-50
.
Chest radiograph is useful in assessing the severity of BPD and for differentiating it from
atelectasis, pneumonia, and air leak syndrome.
Recently, CT and MRI have allowed to obtain very detailed images of the lung injury.
➣ Lung ultrasound in bronchopulmonary dysplasia
e sonographic findings in BPD involve both the pleural line and the lung parenchyma.
e pleural line is thickened, hyperechoic, irregular and fragmented. ese aspects can be
diffuse or localized.
A more or less extensive interstitial syndrome is always present, with compact B Lines in some
areas, and less compact in others. e presence of small subpleural consolidations is constant.
ey are responsible for the characteristically fragmented appearance of the pleural line. e
picture of BPD is always bilateral and asymmetrical (Figs. 21-25).
RX LX
B Lines
Fragmentation
of the pleaural line
Figure 21 – BPD: to the left, evidence of interstitial syndrome. To the right: presence of white lung with
thickening of the pleural line, which has a fragmented appearance for the presence of multiple small
subpleural consolidations.
Thickened and irregular pleural line
Figure 22 – BPD: bilateral white lung and thickened and irregular pleural line.
422 oracic ultrasound
Jagged pleural line
Figure 23 – BPD: jagged and irregular pleural line due to the presence of small and multiple subpleural
consolidations in the context of extended interstitial syndrome.
Jagged pleural line
Irregular and jagged pleural line
Figure 24 – BPD: markedly thickened and irregular pleural line. Compact B Lines (white lung).
Pulmonary involvement highlighted with lung ultrasound correlates well with the chest xray severity.
Lung ultrasound could be a useful tool in the early identification of infants who subsequently
develop BPD. In this regard, we found that the persistence of the interstitial syndrome, and
especially the changes in the pleural line at the 30th gestational week, most probably correlate
with a higher risk of subsequent BPD.
➣ Lung ultrasound in pulmonary atelectasis
Pulmonary atelectasis (PA) is frequent in infants undergoing mechanical ventilation.
Sometimes its diagnosis can be difficult because the pulmonary opacities detectable on chest
radiography may be attributed to an underlying disease. In infants with HMD and air leak
syndrome, for example, in order to minimize damages from barotrauma and volutrauma, a
ventilation with low volumes and pressures is implemented. is obviously exposes to the
risk of atelectasis and to the development of pulmonay opacities.
Pleural and lung ultrasound in the neonatal period and in childhood 423
Irregular and jagged pleural line
Figure 25 – BPD: irregular and thickened pleural line with numerous but not compact B Lines.
In adults with complete atelectasis, Lichtenstein has described a very specific sign, defined
lung pulse, which consists of the pulsation of the pleural line synchronously with the cardiac
activity35. is sign is also present in the complete atelectasis of newborns and, as described
in the specific chapter, in the case of alveolar collapse of pulmonary hemorrhage.
Unlike pneumonia, in case of atelectasis lung volume decreases, and this involves the loss of
the normal treelike appearance of air bronchograms, that become parallel
51-53
. is sign is
useful in differentiating lobar atelectasis from pneumonia (Figs. 26-27).
e evidence of dynamic air bronchograms (air moving in the bronchi synchronously with
the respiratory activity) categorically excludes atelectasis due to bronchial obstruction54.
Lung ultrasound also allows to check in real time the re-expansion of the lung (pulmonary
recruitment) after removing the cause of atelectasis (Fig. 28) (Clips 27-31).
Clips 27, 28 – Pulmonary atelectasis: longitudinal scan of the right lung
(see chest X-ray radiography, Fig. 25). Lung hepatization. There is lung
pulse. Bronchi (white linear formations) develop in parallel.
424 oracic ultrasound
Clip 29 – Pulmonary atelectasis: detail of the same case: air moving in the
bronchi during oscillatory ventilation at high frequency. The bronchogram is
dynamic, bronchial obstruction can be excluded with certainty. The lung is
completely hepatized.
Clips 30, 31 – Pulmonary atelectasis: partial re-expansion of the lung after
increase in mean airway pressure, confirming the diagnosis of atelectasis
secondary to hypoventilation.
Atelectasis: parallel development
of bronchi
Figure 26 – Atelectasis: parallel development of air bronchograms in the case of atelectasis.
Lobar pneumonia: bronchi
maintain their treelike appearance
Figure 27 – Treelike appearance of air bronchograms in case of lobar pneumonia.
Pleural and lung ultrasound in the neonatal period and in childhood 425
RX
Figure 28 – Atelectasis: chest radiograph of infant with HMD subjected to mechanical ventilation. The
left lung is completely opaque. Air bronchograms. No significant asymmetries of the intercostal spaces.
➣ Lung ultrasound in PNX
Pneumothorax (PNX) is a frequent occurrence in newborns, as a complication of pathological
conditions (air leak syndrome complicating HMD, meconium aspiration syndrome, etc.) or
as a result of mechanical ventilation. e diagnosis is not always easy when the pneumothorax
is small, and chest radiography may not highlight it. e sensitivity of lung ultrasound is far
superior to that of chest radiograph.
e sonographic features of PNX are the same in newborns and adults. e main signs are the
absence of pleural sliding, the lack of B Lines and the lung point (see Chapter 6). e absence
of pleural sliding is due to the lack of visualization of the visceral pleura for the interposition
of air between the pleural layers. For the same reason it is not possible to see any B Lines, as
these originate from the subpleural lung parenchyma9 (Clips 32-33).
Clip 32 – PNX: pulmonary apex scan. Normal pleural sliding.
Clip 33 – PNX: pulmonary apex scan. Absence of normal pleural sliding
and B Lines.
426 oracic ultrasound
e lung point has been described by Lichtenstein in cases of not massive pneumothorax. is
sign has a specificity of 100% and it corresponds to the display of the point where visceral
and parietal pleura are losing their contact
55-56
. In a representative picture showing the lung
point, normal pleural aspects and pleural aspects typical of PNX coexist (Clip 34) (Fig. 29).
In extended PNX (anterolateral PNX) the pleural sliding is erased laterally and at the lung
bases (Clip 35).
Figure 29 – PNX: infant with anterior pneumothorax, not evident on chest radiographs: to the right,
normal lung with B Lines; to the left, PNX area with no B Lines.
Clip 34 – PNX: lung point. To the left: lung with the characteristics of PNX;
to the right: aerated lung with B Lines and sliding preserved.
Clip 35 – Right anterolateral PNX. The movements of the liver, consensual to
the respiratory acts in the absence of pleural basal sliding are evident.
➣ Lung ultrasound in the diagnosis of pneumonia in children
At present, chest radiograph is considered the gold standard for the diagnosis of pneumonia
in pediatric age57. Lung ultrasound is slowly emerging as a very accurate and reliable method
both in adults and children
Chest radiograph shows some major limits: in adults it is not a particularly accurate method
because, when compared to the gold standard represented by CT, a percentage of pneumonia
58-62
.
Pleural and lung ultrasound in the neonatal period and in childhood 427
ranging between 25% and 30% is not detected
63-64
. Second, there is the not negligible problem
of exposure to ionizing radiation. Finally, the variability of inter- and intraobserver interpretation is very high, especially when the lesion is located in the retrocardiac area, rather than in
the classical framework of pulmonary consolidation65.
Pneumonia always reaches the pleural line and can then be visualized by ultrasound. e
concept of “central” pneumonia is derived from X-ray images that do not allow adequate
spatial assessment of the consolidations. In our experience, an inflammatory process not
reaching the pleural line in some point has never been seen.
ere is no doubt about the fact that lung ultrasound is far superior to chest radiography in
the diagnosis of pneumonia.
In the clinical context the interpretation of the images is simple and less operator-dependent
compared to X-ray. e examination may be repeated without the risk associated with radiation
exposure. Moreover, as mentioned in the section on pulmonary atelectasis, lung ultrasound
is useful in differentiating inflammatory consolidations from segmental or total atelectasis.
Pneumonia has the same sonographic appearance in children and in adults, and it appears as a
hypoechoic area with irregular and ill-defined limits, often surrounded by B Lines. Posteriorly
the presence of vertical compact artifacts is constant. is acoustic reinforcement could be
the expression of a rear wall enhancement, typically seen in fluid lesions. e pleural line in
the part that overhangs the consolidation is less echogenic or erased. Air bronchograms are
constantly visible in the context of pneumonia (Figs. 30-31) (Clip 36).
Hypoechoic pleural line
Pneumonia
Pneumonia
Figure 30 – Pneumonia is represented by the hypoechoic area. The pleural line is less echogenic.
Inside the consolidation small hyperechoic spots are obvious expression of air trapped in the bronchi.
Clip 36 – Pneumonia: extended hypoechoic area, moderate number of B
Lines and attenuation of the pleural line.
428 oracic ultrasound
In extended pneumonia, treelike hyperechoic structures due to air bronchograms are evident
(Fig. 32).
Pneumonia
Spleen
Diaphragm
Figure 31 – Pneumonia: lung hepatization at level of the left costophrenic angle.
Pneumonia
Air bronchograms
Figure 32 – Pneumonia with extended lung hepatization with air bronchograms with their typical
treelike appearance.
Pneumonia
Air bronchograms
Sometimes the presence of so-called “dynamic air bronchograms”, caused by the movements
of air within the bronchi, is evident (Clip 37).
Clip 37 – Dynamic air bronchogram: zoom on extensive pneumonia with
air bronchograms. In the centre: dynamic air bronchogram represented by
the air moving through the bronchus synchronously with breaths.
Pleural and lung ultrasound in the neonatal period and in childhood 429
is finding rules out the possibility of an atelectatic consolidation secondary to bronchial
obstruction. Fluid bronchograms are frequent in pneumonia in the pediatric age (whereas
they are rare in adults) and appear as anechoic tubular structures with hyperechoic walls,
that allow to distinguish them from the vascular structures (Fig. 33). e presence of any
pleural effusion is easily identifiable as anechoic area in the pleural space (Fig. 34) (Clip 38).
FLUID BRONCHOGRAMS
Figure 33 – Pneumonia: anechoic tubular structures referable to fluid bronchograms in a case of
postobstructive pneumonia.
Pleural eusion
Pneumonia
Spleen
Figure 34 – Pleural effusion in pneumonia.
Clip 38 – Extended left basal pneumonia complicated by pleural effusion.
Pleural eusion
Pneumonia
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