Lung ultrasound
LUS was performed with the ultrasound machine ESAOTE MyLab ™ 40, which
complies with the Medical Device Directive (MDD) 93 \ 42
\ EEC and subsequent amendments. In accordance with this
directive, Esaote has classified it as Class IIa devices. The preset
used was small parts. Linear probe (12 - 6 MHz) was used in preschool
children. In older children, we used a curved probe (8 - 5 MHz). The
focus was always positioned at the level of the pleural line. Images and
clips were stored and archived. The ultrasound scans were performed by
pediatricians and pediatric residents with certifications and / or with
an experience of at least 3 years of practice with LUS.
The scans were made by investigating the anterior, lateral and posterior
regions of the bilaterally thorax and placing the probe transversally
and longitudinally along the lines considered traditional ultrasound
findings: the parasternal line, the axillary line and the paravertebral
line so as to fully explore the chest wall according to a methodical
scheme first described by Copetti et al.22
To investigate the anterior and lateral lung fields patients were
positioned, according to age, in a seated or supine position. The
posterior lung fields have been explored in lateral decubitus and in
sitting position.
LUS was performed at the time of first evaluation - and before the start
of any treatment - of all children with acute or previous history of
heart disease (with and without signs and symptoms of respiratory
distress) or with signs and symptoms of suspected disease. systemic
inflammatory/sepsis (with and without signs and symptoms of respiratory
distress).
All lung regions were scanned with LUS to assess pleural slip and
pleural line regularity, presence of A lines, density and
characteristics of B lines or vertical artifacts, pleural effusion, and
presence of subplerural lung consolidations.
The regular movement of the pleura during breathing defines the pleural
sliding which in some circumstances may be absent or have irregularities
of the hypercogeneity of the pleruic line. 23
The A lines were horizontal, regularly spaced, hyperechoic lines
representing reverberations of the pleural line (repetition artifacts):
this model is considered the physiological lung
model.23
B lines or vertical artifacts were defined as vertical lines arising
from the pleural line. These artifacts show a narrow base, extend to the
bottom of the screen without fading, and move synchronously with the
lung slide.23 However, according to the evidence that
the B lines appear different in different pathological and deflationary
conditions, depending on the variable distribution of the full-to-void
ratio along the pleural line7,24,25, in this study the
presence of short B lines also have been considered.
Finally, a fluid-filled anechoic space between the parietal and visceral
pleura identified the trasudative pleural
effusion1,3,26 and lung consolidations were diagnosed
by the presence of poorly ventilated or solid images adjacent to the
pleura, according to the usual descriptions in the
literature. 1,3,26
The following lung ultrasound finding were detected (Figures 1, 2 and
3):
- the presence of short vertical artifacts;
- the presence of long vertical artifacts, their characteristics
(multiple or single, confluent or non-confluent, without or with spared
areas) and their position (predominantly localized to the pulmonary
bases or widespread also in other fields; unilateral or bilateral);
- the presence of anechoic pleural effusion and its location (at the
unilateral or bilateral bases);
- the presence of subpleural consolidations;
- the characteristics of the pleural line (regular, irregular, regular
with areas of irregularity).