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preterm baby

Validating a better way to stratify BPD risk in vulnerable newborns

preterm baby

Factoring in the total number of days that extremely preterm infants require supplemental oxygen and tracking this metric for weeks longer than usual improves clinicians’ ability to predict respiratory outcomes according to bronchopulmonary dysplasia severity.

Factoring in the total number of days that extremely preterm infants require supplemental oxygen and tracking this metric for weeks longer than usual improves clinicians’ ability to predict respiratory outcomes according to bronchopulmonary dysplasia (BPD) severity, a research team led by Children’s National Hospital writes in Scientific Reports. What’s more, the researchers defined a brand-new category (level IV) for newborns who receive supplemental oxygen more than 120 days as a reliable way to predict which infants are at the highest risk of returning to the hospital due to respiratory distress after discharge.

About 1 in 10 U.S. infants is born preterm, before 37 weeks gestation, according to the Centers for Disease Control and Prevention. That includes extremely preterm infants who weigh about 1 lb. at birth. These very low birthweight newborns have paper thin skin, frail hearts and lungs that are not yet mature enough to deliver oxygen throughout the body as needed. Thanks to advances in neocritical care, an increasing number of them survive prematurity, and many develop BPD, a chronic lung disease characterized by abnormal development of the lungs and pulmonary vasculature.

“About half of the babies born prematurely will come back to the hospital within the first year of life with a respiratory infection. The key is identifying them and, potentially, preventing complications in this high-risk population,” says Gustavo Nino, M.D., a Children’s National pulmonologist and the study’s lead author.

For decades, the most common way to stratify BPD risk in these vulnerable newborns has been to see if they require supplemental oxygen at 36 weeks corrected gestational age.

“The problem with this classification is it doesn’t take into account the very premature babies who are on oxygen for much longer than other babies. So, we asked the question: Can we continue risk stratification beyond 36 weeks in order to identify a subset of babies who are at much higher risk of complications,” Dr. Nino says.

The longitudinal cohort study enrolled 188 infants born extremely preterm who were admitted to the neonatal intensive care unit (NICU) at Children’s National and tracked their data for at least 12 months after discharge. The team used a multidimensional approach that tracked duration of supplemental oxygen during the newborns’ NICU stay as well as scoring lung imaging as an independent marker of BPD severity. To validate the findings, these U.S.-born newborns were matched with 130 infants who were born preterm and hospitalized at two NICUs located in Bogotá, Colombia.

“Babies who are born very preterm and require oxygen beyond 120 days should have expanded ventilation of the lungs and cardiovascular pulmonary system before going home,” he notes. “We need to identify these newborns and optimize their management before they are discharged.”

And, the babies with level IV BPD risk need a different type of evaluation because the complications they experience – including pulmonary hypertension – place them at the highest risk of developing sleep apnea and severe respiratory infection, especially during the first year of life.

“The earlier we identify them, the better their outcome is likely to be,” Dr. Nino says. “We really need to change the risk stratification so we don’t call them all ‘severe’ and treat them the same when there is a subset of newborns who clearly are at a much higher risk for experiencing respiratory complications after hospital discharge.”

In addition to Dr. Nino, Children’s National study co-authors include Awais Mansoor, Ph.D., staff scientist at the Sheikh Zayed Institute for Pediatric Surgical Innovation (SZI); Geovanny F. Perez, M.D., pediatric pulmonologist; Maria Arroyo, M.D., pulmonologist; Xilei Xu Chen, M.D., postdoctoral fellow; Jered Weinstock, pediatric pulmonary fellow; Kyle Salka, MS, research technician; Mariam Said, M.D., neonatologist, and Marius George Linguraru, DPhil, MA, MSc, SZI principal investigator and senior author. Additional co-authors include Ranniery Acuña-Cordero, Universidad Militar Nueva Granada, Bogotá, Colombia; and Monica P. Sossa-Briceño and Carlos E. Rodríguez-Martínez, both of Universidad Nacional de Colombia.

Funding for research described in this post was provided by the National Institutes of Health (NIH) under award Nos. HL145669, AI130502 and HL141237. In addition, the NIH has awarded Dr. Nino an RO1 grant to continue this research.

Michael Tsifansky

Lung transplant expert Michael Tsifansky, M.D., F.A.A.P., joins Children’s

Michael Tsifansky

Earlier this year Michael Tsifansky, M.D., F.A.A.P., joined Children’s National Hospital as an attending physician in the Cardiac Intensive Care Unit and in the Division of Pulmonology and Sleep Medicine. He brings to Children’s National a unique mix of expertise in critical care and pulmonary medicine. That passion for these two subspecialties has also made him one of the country’s leading experts in lung transplant procedures and the recovery from them.

Dr. Tsifansky shared more information about caring for patients with complex lung diseases, especially those with end-stage lung disease. He outlines the patient population for pediatric lung transplants and the arduous process patients endure while waiting for a transplant, undergoing this major procedure, and then recovering from it.

What types of patients undergo lung transplant surgeries?

Lung transplantation in children is indicated when the following criteria are met:

  • End-stage lung disease
  • No reasonable alternative to the established diagnosis
  • No medical or surgical alternative to the current course of treatment
  • No other organ failure
  • Stable social environment

Could you describe the surgery process?

Pediatric lung transplantation may be performed on cardiopulmonary bypass, on extracorporeal membrane oxygenation (ECMO) or off extracorporeal cardiopulmonary support (ECS). The donor’s lungs are kept chilled prior to transplantation and should be transplanted within six to eight hours after removal from the donor. The donor’s main-stem bronchi and pulmonary arteries are connected to those of the recipient, and the donor’s pulmonary venous drainage is connected to the recipient’s left atrium using the donor’s left atrial roof tissue. This procedure typically takes six to eight hours.

Could you describe the recovery process?

Typically, pediatric lung transplant recipients are extubated and encouraged to sit up four to six hours after the transplant procedure and walk soon afterward. It is important that they be out of bed and moving as soon as possible, and our colleague from Rehabilitation Services (physical and occupational therapists and rehabilitation physicians) will be working with the children toward these goals. After transplantation, pediatric patients will be given discharge instructions with individualized guidelines for a healthy lifestyle. Patients should return to near-normal life approximately three to six months after transplantation.

How long does the recovery process take?

The patient will remain hospitalized for 11-14 days following surgery for acute rehab, titration of antirejection meds and initial healing.

You’ve mentioned that it’s important for transplant patients to get moving as part of recovery. When can a patient begin walking again?

Lung recipients will be assisted into a chair soon after the transplant. Within the first 24-36 hours, the patient is encouraged to take short walks, increasing the distance each day. A physical therapist will work with the patient during their hospitalization to meet their goals. We also encourage patients to exercise on the treadmill regularly while hospitalized. By the time the patient is ready to go home, he or she will be able to easily move around by themselves and do most of their care without assistance. They feel so much better than before transplant and have so much energy that we almost always have to gently limit their activity for a short while to allow their chest incision to heal properly.

What do you see as the next step in pulmonary care for end stage lung disease at Children’s National Hospital?

The development of a pediatric-specific lung transplant and respiratory failure program is the natural extension of the hospital’s cystic fibrosis program, heart transplant program and programs in pulmonary hypertension, bronchopulmonary dysplasia and extracorporeal membrane oxygenation for respiratory failure.

At present, there is no local option for a pediatric-specific program that can perform the transplant and provide the necessary comprehensive wrap-around services for patients in infancy up to age 18. As a top children’s hospital, Children’s National is uniquely positioned to provide the highest level of pediatric-specific care to this patient population and allow patients and their families to spend more time at home while undergoing this and other lifesaving treatments.

Dr. Tsifansky hopes to launch a comprehensive pediatric lung transplant and respiratory failure program at Children’s National in the very near future. Stay tuned for future developments from this area.

chromosome

X-linked genes help explain why boys of all ages face higher respiratory risk

chromosome

A multi-institution research team that includes Children’s National Health System attempted to characterize gender-based epigenomic signatures in the human airway early in children’s lives with a special attention to defining DNA methylation patterns of the X chromosome.

Human airways already demonstrate gender-based differences in DNA methylation signatures at birth, providing an early hint of which infants may be predisposed to develop respiratory disorders like asthma later in life, a research team reports in a paper published online April 3, 2018, in Scientific Reports.

It’s clear that boys and young men are more likely to develop neonatal respiratory distress syndrome, bronchopulmonary dysplasia, viral bronchiolitis, pneumonia, croup and childhood asthma. Unlike boys, girls have an additional copy of the X chromosome, which is enriched with immune-related genes, some of which play key roles in the development of respiratory conditions. Methylation prevents excessive gene activity in X-linked genes, however much remains unknown about how this process influences infants’ risk of developing airway diseases.

A multi-institution research team that includes Children’s National Health System attempted to characterize gender-based epigenomic signatures in the human airway early in children’s lives with a special attention to defining DNA methylation patterns of the X chromosome.

“It’s clear as we round in the neonatal intensive care unit that baby boys remain hospitalized longer than girls and that respiratory ailments are quite common. Our work provides new insights about gender differences in airway disease risk that are pre-determined by genetics,” says Gustavo Nino, M.D., a Children’s pulmonologist and the study’s senior author.

“Characterizing early airway methylation signatures holds the promise of clarifying the nature of gender-based disparities in respiratory disorders and could usher in more personalized diagnostic and therapeutic approaches.”

The research team enrolled 12 newborns and infants in the study and obtained their nasal wash samples. Six of the infants were born preterm, and six were born full term. The researchers developed a robust gender classification algorithm to generate DNA methylation signals. The machine learning algorithm identified X-linked genes with significant differences in methylation patterns in boys, compared with girls.

As a comparison group, they retrieved pediatric nasal airway epithelial cultures from a study that looked at genomic DNA methylation patterns and gene expression in 36 children with persistent atopic asthma compared with 36 heathy children.

The team went on to classify X-linked genes that had significant gender-based X methylation and those genes whose X methylation was variable.

“These results confirm that the X chromosome contains crucial information about gender-related genetic differences in different airway tissues,” Dr. Nino says. “More detailed knowledge of the genetic basis for gender differences in the respiratory system may help to predict, prevent and treat respiratory disorders that can affect patients over their entire lifetimes.”

In addition to Dr. Nino, study co-authors include Lead Author Cesar L. Nino, bioinformatics scientist, Pontificia Universidad Javeriana; Geovanny F. Perez, M.D., co-director of Children’s Severe Bronchopulmonary Dysplasia Program; Natalia Isaza Brando, M.D., Children’s neonatology attending; Maria J. Gutierrez, Johns Hopkins University School of Medicine; and Jose L. Gomez, Yale University School of Medicine.

Financial support for this research was provided by the National Institutes of Health under award numbers
AI130502-01A1, HL090020, HL125474-03, HD001399, UL1TR000075 and KL2TR000076.