Late Preterm Infants (Part 3)

Apologies for the long hiatus! I have not forgotten that we were last on the subject of late pretermers and hyperbilirubinemia; this time it's late pretermers and breathing.

Obviously, one can't survive extrauterine without oxygen-carbon dioxide exchange in the lungs, whether by natural respiration or mechanical ventilation. There is never a 100% guarantee that things will go as they should in any situation, but with a late pretermer, it is even less certain.

These babies are more likely to need resuscitation at birth as well as have periods of apnea after the initial transition period. Preterm infants are less likely to have fully developed alveolar sacs, which facilitate oxygen uptake, nor are they as likely to have the amount of lung surfactant necessary to maintain alveolar expansion.

Apnea is defined by Haws as "absence of breathing for 20 seconds or of shorter duration if the apnea is accompanied by cyanosis and/or bradycardia" (2004). This is generally caused by the lack of neural maturity in babies born before 37 completed weeks of gestation. Brainstem centers that trigger respiration may not have fully developed; thus the infant is more likely to have periods of apnea than an infant born at term.

Some other things to consider:
1) Late pretermers are also at risk for hypoglycemia related to poor feeding and immature liver glycogen stores; hypoglycemia can also cause respiratory distress.

2) Sepsis can also cause respiratory issues with late preterm kids, and because of the decreased maturity of their immune systems, they are at higher risk than a baby born at term.

At my facility, if a late preterm baby is receiving care in the newborn nursery (as opposed to the intensive care nursery), there are several things we watch out for.

First, we watch these kids like hawks in the immediate neonatal period - say, the first 3-4 hours. Often a baby will be born with great tone, great color, and screaming like a banshee. After about an hour or two, they run out of fuel, so to speak, and become floppy, gray, and less responsive to stimuli. Sometimes all they need is a bit of blow-by oxygen, positive-pressure ventilation, or a good feed (each case is obviously different). Other times, a transfer to intensive care is in order.

If they pass initial muster and can go to Mom's room, we round on them more frequently than we would a regular newborn. I like to encourage Mom (or Dad) to keep baby skin-to-skin. This helps baby stay warm, but numerous studies have also shown this to have positive effects on respiration as well as oxygen saturation. We do vital signs every four hours, and do our best to make sure baby is eating well (prevent hypoglycemia if we can).

These kids are so unpredictable. They can be fine for hours, even days, and BAM! They remind us that by rights, they don't HAVE to remember to breathe (or breathe well) because they're not supposed to be outside Mom yet. And there are others, that do just fine and never look back from Moment One. We watch them all and fortunately, most of the time they do well in the long run. But we cannot treat them like regular babies.