Now, the difficulty arises if a child is born prematurely.
This can give rise to the condition known
as respiratory distress syndrome. What’s happening
here is that the lungs are not sufficiently
well developed to support respiration on their
own. At this stage of development of the lungs
is the primary determining factor in whether
the baby will survive or not. As we indicated,
between 26 weeks and birth, there is a respectable
chance of survival even in premature babies,
as the lungs are sufficiently differentiated
and there are adequate amounts of
surfactant present. If not, then chances of survival
may be poorer, and there may be significant
negative consequences such as brain damage
arising from birth in these very early periods.
So, for example, a child born at 23 weeks
would clinically show laboured breathing if
breathing was possible at all, and threatening
the child with immediate asphyxiation.
The breathing rate would also be increased and
as a consequence, it might be necessary to
have mechanical ventilation to support the
baby’s breathing. But this in turn can damage
the alveolar lining, and what happens is that
fluid in proteins will actually leak into
the alveolus. And if this process continues,
then the alveolar lining itself may detach
and the baby will be unable to transfer blood
across the blood-air barrier. This chronic
lung injury in premature infants can cause this
bronchopulmonary dysplasia as a consequence.
There may be some actions that we can take.
It’s possible that glucocorticoid treatment
can accelerate the foetal lung development
and assist in the production of surfactant.
And it may be possible to add artificial surfactant,
and this is effective if added with additional
proteins which mimics the natural proteins
as closely as possible There is, in fact,
a surfactant B deficiency disease, which is
a fatal genetic disease, an autosomal recessive,
which is, therefore, hereditary, and this
would cause serious problems to a baby even
born closer to term. Now, let’s look at
some common abnormalities of lung development