Study identifies new method for improving lung growth and function in preterm infants

Adding two weeks of continuous positive airway pressure for preterm infants in the hospital substantially improves lung growth and function, according to new research from Oregon Health & Science University.

The study, published in the American Journal of Respiratory and Critical Care Medicine, found that extending nasal continuous positive airway pressure (CPAP) in preterm infants beyond the usual time used in current clinical practice significantly improves lung growth and development.

OHSU physician-scientists say the extended use of a common, accessible tool in the neonatal intensive care unit (NICU) may result in healthier respiratory development through childhood.

Preterm birth affects 10% of births in the United States—about 400,000 infants per year—and is the most common cause of altered lung development, which poses potential lifelong respiratory consequences. Following discharge from the NICU, infants born preterm have an increased risk of wheezing, asthma and respiratory illness hospitalizations compared with full-term infants. Additionally, reduced airway function during infancy persists into adulthood and is associated with increased respiratory complications.

Early application of CPAP after preterm delivery is the standard of care for infants experiencing respiratory distress. However, the optimal duration of this treatment remains unknown, with most NICUs stopping CPAP when the infant no longer shows signs of breathing problems.

This study was the first to describe new targets for this common therapy by investigating how a longer duration of treatment would affect infant lung growth.

“Lower lung function early in life often tracks and remains low into adulthood, so it’s critical we identify early interventions to address these risks,” said the study’s principal investigator, Cindy McEvoy, M.D., professor of pediatrics in the OHSU School of Medicine, OHSU Doernbecher Children’s Hospital.

“Our findings suggest that implementing slight adjustments to our current common practice of CPAP in the NICU may be a safe and non-pharmacologic intervention to improve a child’s lifelong trajectory of lung function and overall respiratory health. We hope extending CPAP is a simple intervention that can soon be applied globally.”

In a randomized controlled trial of 100 preterm infants, OHSU researchers found that among stable preterm infants using CPAP in the NICU, an extended two weeks of treatment with CPAP beyond usual care resulted in significantly larger lung volumes—a key indicator of lung growth and development—when the infants were assessed following NICU discharge at 6 months of age.

The infants’ lungs could more effectively diffuse oxygen and carbon dioxide and showed signs of better airway function. Importantly, through 12 months of age, there was evidence of less wheezing in the infants who received the extended CPAP in the NICU.

OHSU Doernbecher Children’s Hospital is now implementing this practice for preterm infants in its NICU and continues to see positive results. Many NICUs around the country are also evaluating the amount of time preterm infants are kept on CPAP based on the study findings.

Researchers say future studies must further evaluate the optimal duration of CPAP treatment for preterm infants, especially for infants with very low birth weight. Additionally, longer-term follow-up with patients is needed to determine whether this treatment will improve the longer-term respiratory health of children born preterm, including protecting them against common lung conditions such as asthma and chronic obstructive pulmonary disease as adults.

McEvoy’s research team plans to continue to study the children from the randomized trial at OHSU through age 10, with yearly lung function tests to investigate the duration of the benefit of extended CPAP given in the NICU.

“CPAP treatment is something every NICU has in use, which makes this intervention very accessible and easy to implement,” said Dmitry Dukhovny, M.D., M.P.H., professor of pediatrics in the OHSU School of Medicine and medical director of the neonatal intensive care unit at OHSU Doernbecher Children’s Hospital.

“Our goal is to give children the best possible start to a full and healthy life, so it’s exciting to see that we’re able to significantly improve lung growth and function in preterm infants by simply altering the duration of an already standard treatment.”