Static impedance tomography in diagnostics of respiratory disorders
of newborn infants.
V. Cherepenin *, V. Bardin **, A. Karpov ***, A. Korjenevsky*
*Institute of Radio-Engineering and Electronics of Russian Academy of Sciences,
Russia
** Yaroslavl State Medical Academy, Russia
*** Clinical Hospital * 9, Yaroslavl, Russia
Among the existing modern methods of diagnostics of newborns’
respiratory disorders, there is none, which is capable of providing efficient
diagnostics and at the same as being safe. The electric static impedance
tomography meets these requirements
The purpose of the present work is to reveal distinctions in the electric
impedance image of lungs and impedance pneumogramme at respiratory
impairment of newborns.
We have carried out examination of 69 healthy newborns and 36
newborns with respiratory impairment of various genesis: aspiration syndrome 6, a pneumonia - 24, hyaline membranes syndrome - 6. Besides, 6 newborns
were subjected to the examination while undergoing artificial pulmonary
ventilation. We utilized the sixteen-electrode, single-frequency (8 kHz, 0,5 ma)
single-channel electric impedance tomograph, capable of obtaining the static
image, developed in the Research Institute of Radio-Engineering and
Electronics of Russian Academy of Sciences. Computer scanning the
newborns’ thorax organs was performed in 4th intercostals zone. The
examination was carried out utilizing round steel electrodes (6 mm diameter),
which were fixed around the thorax of a newborn with the help of a rubber belt
Measurements were taken during independent breathing as well as during
artificial pulmonary ventilation of the newborn’s lungs. In order to estimate the
electric impedance image of the chest organs we used the following criteria:
visualization of anatomic structures, their topographic interrelation,
particularities of the anatomic structures. In order to describe the impedance
pneumogramme we used the following criteria: respiratory amplitude and
variability, variance of pneumogrammes, respiration rate.
Results.
1. Norm. An electric impedance image of
anterior
thorax organs. The electric impedance
tomogram (EIT) of a newborn is characterized
by visualization of all standard anatomic
right
left
structures: lungs, a mediastinum, a spinal
column. Correct topographical interrelation of
the organs can be determined (fig. 1).
posterior
Impedance pneumogramme. The impedance
Figure 1 Electro impedance
pneumogramme is characterized by high
tomogram of the thorax organs of
a healthy newborn; 2 days.
respiratory amplitude with low variability,
Figure of 2 Impedance pneumogrammes of a healthy newborn. Respiration rate 36 respirations per
minute. Conductivity: max=3,896, min=3,172.
2.
insignificant variation and the respiration rate of 30-50 respirations per
minutes (fig. 2).
Aspiration syndrome. Aspiration syndrome is collection of a significant
amount of waters mixed with meconium in the
anterior
newborn respiratory ways and stomach. The
electric impedance image of the thorax
organs. The EIT of a newborn, as well as the
right
left
one of a normal infant, is characterized by
visualization of all typical anatomic structures
of
the
thorax.
Correct
topographical
posterior
interrelation of the organs can be determined
Figure 3. Electro impedance
as well. The following particular feature of the
tomogram of the thorax
anatomic structures can be observed: the
organs
of
a
newborn.
Aspiration syndrome. 2 days.
hyperimpedance areas corresponding to the
lungs on both sides of the mediastinum are
fairly well defined, which is not typical for the 1st – 2nd day of the
noncomplicated neonatal period (fig. 3). Impedance pneumogramme. The
Figure of 4 Impedance pneumogramme of a newborn. Aspiration syndrome. Respiration rate of 60
respirations per minutes. Conductivity: max=0,743, min=0,224.
impedance pneumogramme is characterized by reduced respiratory
amplitude and its high variability, pronounced variation and the respiration
rate, exceeding 60 respirations per minute (fig. 4)
3. Pneumonia. The electric impedance image of the thorax organs.
Pneumonia is a development of an inflammatory
anterior
process in the newborn’s lungs, which took
place either within the uterus or against the
right
left
background of meconium aspiration. The
electric impedance tomography of the newborn
is characterized by absence of the airways
posterior
visualization in the affected lung. The changes
of the normal topographical interrelation of the
Figure 5. Electro impedance
organs depend on the affected side. The
tomogram of a newborn’s
thorax organs. 4 days.
following particular feature of the anatomic
Bilateral pneumonia.
structures
can
be
observed:
the
Figure of 6 Impedance pneumogrammes of a newborn infant. Bilateral pneumonia. Respiration rate - 80
respirations per minutes. Oxygen tent. Conductivity: max=7,610, min=5,012.
hyperimpedance areas corresponding to airways on both sides of the
mediastinum are fairly prominent (fig. 5). Impedance pneumogramme.
The impedance pneumogramme is characterized by reduced respiratory
amplitude and its high variability, pronounced variation and the respiration
rate of up to 90 respirations per minute (fig. 6).
4. Syndrome of hyaline membranes. The electric impedance image of the
thorax organs. Syndrome of hyaline
anterior
membranes is a respiratory distress syndrome,
which developed due to insufficient maturity of
a newborn’s lung tissue. The EIT of the
right
left
newborn is characterized by absence of the
airways visualization of the affected lung
similar to pneumonia. Correct topographical
interrelation of the organs can be determined.
posterior
The following particular feature of the anatomic
Figure 7 Electro impedance
structures can be observed: apparent bilateral
tomogram of a newborn’s thorax
increase of electroconductivity in the zone of
organs; 2 days. Period of
gestation 30 weeks. The
the airways and respiratory zone, on both side
hyaline membranes syndrome.
of the mediastinum (fig. 7). Impedance
pneumogramme.
The
impedance
pneumogramme is characterized by sharply reduced respiratory amplitude
Figure of 8 Impedance pneumogrammes of a newborn. The hyaline membranes syndrome. Rate of
respiration 80 respirations per minute. Conductivity: max=4,710, min=3,212.
5.
and its high variability, pronounced variation and tachypnea. (fig. 8).
Artificial lungs ventilation. The electric impedance of the thorax
organs. The EIT of the newborn shows
anterior
rhythmical changes of the colour scale in the
zone the airways as well as the respiratory
zone. The correct topographical interrelation of
right
left
the organs (fig. 9) can be determined.
Impedance pneumogramme During artificial
lungs ventilation rhythmical changes of
posterior
electroconductivity in the airways and as well as
Figure 9. Electro impedance
the respiratory zone take place: reduction of
tomograms of a newborn’s
electroconductivity during inhalation
and
thorax
organs.
Artificial
ventilation of lungs.
increase during exhalation; the respiratory
Figure of 10 Impedance pneumogrammes of a newborn. Artificial ventilation of lungs. Rate of respiration - 44
respiration per minute. Conductivity: max=1,712, min=1,320.
amplitude of different degree is observed as well (fig. 10).
Further development of the electric impedance static tomography (tools,
software) will make it possible to acquire a safe and informative method for
diagnostics of respiratory disorders of newborns.