By now if you have a preterm infant in particular who has been born before 36 weeks you will have heard people talking about chronic lung disease (CLD). Sometimes they may also refer to it as bronchopulmonary dysplasia (BPD). The terms are really for all intents and purposes the same from a parent’s point of view. If you google CLD or BPD you may find stories of very cystic and damaged lungs with babies needing tracheostomies due to long term need for ventilation. While this can still happen, thankfully this new type of CLD we see is not like the one of old but rather is a newer entity that is more uniform and has less of a cystic nature. The “New BPD” is really more of a lung that has less air sacs (alveoli) than usual but the lung is less damaged than the BPD of old.
When your infant was born they may have had immature lungs without enough surfactant. Surfactant is kind of like the engine oil of a car. It helps to make the lungs less sticky and allows breathing to be a lot easier. Some babies are treated with CPAP while others need intubation and ventilation. While this positive pressure can be lifesaving, it also exacts a cost. We humans prefer to breathe using negative pressure meaning that we suck air into the lungs rather than have it pushed in. With each delivered breath the lungs of these fragile infants can be injured leading to the type of picture shown above.
This becomes a concern at 36 weeks. You may hear doctors talking about 36 weeks as if it is scary deadline that is on the horizon. We tend to obsess about that date. The big reason for this obsession is that units compare themselves across Canada and in other countries using the need for oxygen, nasal prongs, CPAP or ventilation at this time point. If your unit has a rate of CLD of 10% and another has 20% it tells the higher one that they better do something with their medical practice to lessen the incidence. In other words the 36 weeks is a marker.
As I have written about in another blog post, in 2020, 40 weeks may be the more relevant number as written in the post “The New BPD That Matters” the reality is that your baby is more likely to stay in hospital due to inability to feed orally or from apnea of prematurity. I am not saying that we as a team should not try and reduce the risk as much as possible for CLD but in case you were wondering what we are talking about when we talk about this condition this is it.
Blog posts of interest on CLD