As a fetus grows and develops in the womb, the lungs are among the last organs to become fully functional. For this reason,
lung problems are some of the most common complications of prematurity. In many cases, a premature baby may have trouble breathing
normally not because there is something wrong, but rather because the lungs are immature and have not had time to fully develop.
This section examines how the most common lung complications are diagnosed. As with all complications of prematurity, the
more immature a baby is, the more likely she is to develop complications and the more severe those complications are likely
to be.
All premature babies with breathing problems are carefully monitored to assess the severity of the breathing problem, to detect
changes in the severity of the problem, and to follow progress. The blood gas test measures the amount of oxygen, carbon dioxide,
and acid in the blood. These three measures indicate the severity of the baby’s respiratory distress. The blood gas specimen
is obtained from an artery or by heel prick. It is also possible to estimate the oxygen and carbon dioxide in the blood by
using “transcutaneous” devices that make these measurements through the skin. Transcutaneous measurements may be inaccurate
if the skin is too thick, contains too much fluid, or has a reduced blood flow.
Pulse oximetry, or the transcutaneous measurement of oxygen saturation, is another non-invasive approach to monitoring. A
small light is attached to one of the baby’s extremities, usually finger or toe. As the light passes through the body, the
light is measured to indicate how much oxygen is in the blood. Oximetry can confirm that a baby is breathing the appropriate
amount of oxygen.
