Dr. Bob Underwood (Host): Welcome to Pediatrics in Practice, a CME podcast. I'm your host, Dr. Bob Underwood. Before we introduce our guest, I'd like to remind you to claim your CME credits after listening to today's podcast. You may do so by visiting cmkc.link/cmepodcast and then click the CME button.

With me today is the Director of Neonatal Outpatient Services from Children's Mercy, Dr. Winston Manimtim. Together, we will delve into the topic of bronchopulmonary dysplasia or BPD diagnosis and screening. Dr. Manimtim, welcome to Pediatrics in Practice.

Dr. Winston Manimtim: Thank you very much.

Host: So, you are also the Medical Director of Infant Tracheostomy and Home Ventilator Program and Professor of Pediatrics at the University of Missouri Kansas City School of Medicine. So, we're going to be calling on your extensive expertise to guide families in healthcare teams through some unique challenges of BPD, from diagnosis to long-term support. So, are you ready for us to ask you some questions here?

Dr. Winston Manimtim: Yes, sir.

Host: All right. Let's start with the basics. What is bronchopulmonary dysplasia or BPD, and how do you go about diagnosing it?

Dr. Winston Manimtim: Okay. So, bronchopulmonary dysplasia or BPD is sometimes called chronic lung disease of prematurity. This is a condition that occurs almost exclusively in infants born prematurely continue to require respiratory support or oxygen by the time these infants reach the 36 weeks corrected gestational age.

As you can see, this current definition of BPD is based only on the respiratory therapy and not on pathology, not on radiographic findings or presence of biologic markers. And therefore, this definition provides only minimal insight into the pulmonary abnormalities that are present in these infants. However, based on the degree of the respiratory support at 36 weeks corrected gestational age, BPD can be classified into mild, moderate, or severe.

Host: So, how do premature infants end up developing BPD?

Dr. Winston Manimtim: There remain major gaps in our understanding of the pathophysiology of BPD. However, the epidemiology of BPD is clear, and that is BPD is a lung injury syndrome that predominantly occurs in extremely low birth weight or extremely preterm infants. The lung injury that happens or that results in BPD is most likely multifactorial that begins as an altered lung development even before the baby is born. This is compounded sometimes by the initiation of resuscitation at birth, or this can also be amplified by postnatal exposures to oxygen, mechanical ventilation, infection, or even inflammation. There may also be some genetic component of this occurrence.

Conceptually, the events leading to BPD are the continued interplay of lung development, and it's altered progressively by injury and repair. So in as much as there is still ongoing development of the lungs, even after the baby's born, this is complicated by the altered development during this time period, and that results from all the other interventions like mechanical ventilation, infection, inflammation, or sometimes the use of oxygen that complicates this continuing insult to the lungs that results in bronchopulmonary dysplasia.

Host: Got it. So, I see where it is multifactorial. So, it's the underdeveloped respiratory structures as they are. And then, the normal things that we do in a premature infant, for example, oxygen supplementation or even intubation, those things can cause further injury, and then they become compounding upon one another.

Dr. Winston Manimtim: That is very accurate.

Host: So, how common is this?

Dr. Winston Manimtim: In the United States, the incidence of BPD in infants who were born at less than 28 weeks' gestation has been approximately 40% for the last 20 years. This is estimated to be about 50,000 infants every year, or one in every 80 live-born infant. It's pretty common. You may wonder why with all the advancement in neonatal care, why is the incidence of BPD remaining the same? The most possible explanation for that is because of the increased survival of the very or extremely preterm infants, which has increased with our modern neonatal care. So, the more extremely preterm infants survive, they are the ones who are at much higher risk to develop BPD. And so because their survival has been increasing, that translates to having more infants surviving with BPD.

Host: So, the fact that we've gotten so good at taking care of very premature infants has potentially actually increased the risk and likelihood of BPD development. So in a way, it's a good thing that we need to cope with.

Dr. Winston Manimtim: Yes. In fact, you may be aware that, in the last couple of years, there are babies who were born at 22 weeks' gestation, those we consider previable years ago, and they are now surviving if given intensive care from birth. And those are the same babies that if they survive, they will most likely develop BPD. So, that is why the more we have increased survival of extremely preterm infants, the incidence of BPD is remaining the same.

Host: So, the survivability of the premature infant is increasing or seemingly to increase, or at least hold steady BPD development. So, what are some promising developments in treatment or prevention of BPD? I know there's active research and work going on to try to help treat these patients. What's out there?

Dr. Winston Manimtim: So over the last many years actually, there have been great efforts made to prevent BPD or at least minimize its severity. Some of them include the more gentle ventilation strategies, especially soon after birth, or the use of non-invasive ventilation, meaning instead of intubating these infants right away, a non-invasive support can be initiated.

There is also a more recent push for minimally invasive administration of surfactant, instead of intubating the babies right away and giving surfactant. We now have a way of giving the surfactant in a much less invasive way. There is also a lot of work done on early and adequate nutritional support as well as in the treatment of comorbid conditions like patent ductus arteriosis, infection, prevention of intraventricular hemorrhage.

But despite all these efforts, as I mentioned, the incidence of BPD, at least here in the United States, has remained the same. So, we still have to find that magic bullet that would help us prevent BPD. I think prevention of preterm birth will make the greatest impact on BPD prevention, but we are not anywhere close to that.

Host: Right. And that makes sense because that's one of the biggest risk factors.

Dr. Winston Manimtim: Correct, that is the most consistent risk factor for infants developing BPD. And for those who have already developed, established BPD, prevention of complications, as well as maintenance of adequate growth and acquisition of developmentally appropriate milestones are the priority for their long-term care.

Host: So, let's talk about later in development. Let's talk about followup care. After the patient has been discharged, what are some of the complications associated with BPD that pediatricians really need to be aware of in that followup care?

Dr. Winston Manimtim: First, I'd like to address the misconception, I would say, that BPD goes away in early infancy or childhood. That is no longer the truth. In fact, BPD is now recognized as a disease that can persist the lifespan. The view that BPD, being the archetype of post-prematurity respiratory disease, as I mentioned, that results in early childhood is not accurate. There is evidence that although clinical symptoms improved during the first couple of years of life in infants with BPD, these same children had significant expiratory airflow limitation by pulmonary function testing. You know, several studies have already shown that this manifestation of post-prematurity respiratory disease can persist into early adulthood. While others with history of this disease may be at increased risk for more rapid decline in lung function as they get older, others have actually theorized that infants with a history of BPD are more susceptible to COPD as adults. We now have evidence that BPD is a lifelong disease condition.

So, it's very important, I believe, for the pediatricians to recognize that because screening for any type of pulmonary function abnormalities, particularly the expiratory flow limitation that are seen in these infants is very important. So, early involvement of a pediatric pulmonologist is very important, because they are the ones who are doing the pulmonary function testing on a regular basis.

Host: So, what advice based on that would you give pediatricians who are working with families of infants with BPD, especially regarding the long-term care and support of these children?

Dr. Winston Manimtim: So, for the pediatricians screening for such disease like post-prematurity respiratory disease is very important. So, the pediatricians should routinely obtain a history of prematurity and respiratory symptoms, especially during the neonatal period. And then, as I mentioned, periodic pulmonary function testing that can be done by the pulmonologist should also be planned.

And for those who are showing asthma-like symptoms, which is very prevalent among infants with BPD, they should be treated adequately with available bronchodilators and sometimes even with inhaled corticosteroids, although we don't have very solid evidence that these types of treatments for children with asthma works the same way for infants with BPD.

Another advice to the pediatricians, since, as I've mentioned, these infants most of them, if not all, have a history of prematurity, so screening for neurodevelopment as well as for their hearing, for their vision is very important so that we can assure that these infants will develop at their full potential.

Host: And that kind of gets into what my next question was going to be is what role do these different specialties play in the care of infants and children with BPD? I mean, pulmonologists, I think is the first one we would think of, but you mentioned some other types of screening and care that need to be involved.

Dr. Winston Manimtim: Correct. And so, in terms of time-wise, as soon as these babies are discharged from the nicu, they should be seen in a high risk followup clinic, usually by a pediatrician, sometimes working with a neonatologist, and at the same time with a nutritionist and developmental specialist. And this is to make sure that those developmental screening tests, attention to adequate growth and nutrition should be addressed during the first couple of years after discharging these patients to home.

Then, as I mentioned, involvement by the pulmonologist early as well as by other subspecialists, like a cardiologist may be involved in those infants with BPD who develop pulmonary hypertension. That is a common complication in this infant, especially those with severe BPD. The otolaryngologist may be involved in those infants with BPD, those with central airway problems as well as in those infants with tracheostomy for long-term ventilation. And gastroenterologists can also be involved in those infants with BPD who are not growing adequately or have growth failure.

And lastly, transition of care to an adult physician is very important because, as I mentioned, as these infants grow into their childhood, into their early adulthood and into their adult life, their pulmonary function may not necessarily be normal, even if they are not showing much symptoms at all. So, these are very important to be screened for those kinds of conditions.

Host: So, it really is a multidisciplinary approach. And you're right, you know, the common thought is that BPD is really a disease of infancy and early childhood. But as you've explained today, it is very long lasting in terms of the conditions and the way it presents it need to be addressed. So, thank you for that. Is there anything else you'd like to add before we close today?

Dr. Winston Manimtim: Well, there's a lot more, hopefully, as we are beginning to understand the different clinical types of BPD, that we would be able to tailor their therapy based on those clinical types so that we don't prescribe the same thing for everyone because our goal is to individualize our treatment, but we need to know what exactly these BPD infants have or at least have predominantly so that we can address those issues instead of just treating them all the same way.

Host: Absolutely. Dr. Manimtim, thank you so much for being with us today.

Dr. Winston Manimtim: It is my pleasure, and I thank you for the opportunity.

Host: And to our listeners, as a reminder, claim your CME credits after listening to this great episode. You can do so by visiting cmkc.link/cmepodcast and click the claim CME button. For more information and for other important topics you can visit that same site, cmkc.link/cmepodcast. If you enjoyed this podcast, please share it on your social channels and check out the entire podcast library for topics that interest you. I'm Dr. Bob Underwood, and this is Pediatrics in Practice, a CME Podcast.