The instant babies gasp their first breaths, their lungs undergo a crucial change: The pulmonary vasculature, constricted in the womb, begins to open up for the transition to air breathing. For a number of possible reasons, this change fails to occur in some infants, resulting in persistent pulmonary hypertension of the newborn (PPHN).
The treatment for the condition is well established. Developed in the early 1990s by neonatologist John Kinsella, MD, and pediatric pulmonologist Steven Abman, MD, at Children's Hospital Colorado, inhaled nitric oxide (iNO) is now the international standard of care, widely celebrated for its safety, effectiveness and localized effects.
Turning attention to bronchopulmonary dysplasia (BPD)
"After demonstrating the role of iNO in near-term and term newborns with PPHN," says Dr. Kinsella, "we turned our attention to the potential effects of iNO in preventing bronchopulmonary dysplasia (BPD) in premature babies."
Common in premature infants, BPD occurs when mechanical ventilation, needed to support underdeveloped lungs, damages and inflames lung tissue. Early data suggested iNO might have some anti-inflammatory effects.
"But it turned out that in the smallest preemies, there are so many factors in lung development that the signals weren't strong enough to prove that iNO reduced the incidence of BPD," says Dr. Kinsella.
However, some premature infants also suffer from PPHN, and preemies with PPHN responded just as well as the full-term infants to iNO.
The use of iNO
Here, Dr. Kinsella and his team believe iNO is the best treatment for PPHN in both term and premature newborns. The problem is that, because the initial research focused on BPD, there's little data supporting the use of iNO to treat PPHN in preemies specifically, as well as a lack of clinical consensus — all of which makes it difficult to study with a conventional randomized trial today.
In an article published in the 2016 Journal of Pediatrics, Dr. Kinsella described a registry he and his team are developing to study the various ways iNO is currently used in premature newborns around the country, along with their results.
"It's not a formal randomized trial, but it's almost a randomization by practice pattern. There's a lot we can learn."
—John Kinsella, MD
Learn more about our neonatal intensive care unit (NICU).