A Case for Patience

By Heidi Morris, MMS, PA-C, Physician Assistant and Research Coordinator

Following an emergency C-section for intrauterine growth restriction (IUGR) and fetal distress, CM was born very preterm at just over 28 weeks’ gestation. Weighing little more than 700 grams at birth, she required extensive neonatal resuscitation (NRP) and intubation for survival. At 5 days old, CM was transferred to Children’s Hospital of Philadelphia (CHOP) and treated for medical necrotizing enterocolitis (NEC). After 2 months at CHOP, she was diagnosed with bronchopulmonary dysplasia (BPD), but was stable enough to transfer back to her home hospital. There, she was weaned off invasive mechanical ventilation, but continued to require high levels of CPAP and began to show signs of pulmonary hypertension (PH) on echocardiogram (ECHO).

By 3.5 months of life, CM’s PH was so severe that she required emergent intubation and transfer back to CHOP. To manage her PH and BPD, CM required prolonged intubation and initiation of pulmonary vasodilators. She was followed by the CHOP Newborn and Infant Chronic Lung Disease Program (NeoCLD) and cared for by a multidisciplinary team, including CHOP’s dedicated Pulmonary Hypertension Program. After an additional 2 months of intubation and medical treatment, CM’s PH was controlled enough to successfully extubate to noninvasive support. While it took many more months to slowly wean her off respiratory support, she was ultimately discharged home on oxygen, nasogastric feeds, and medications for the management of her PH and BPD. As an outpatient she was followed closely by CHOP’s Pulmonary Hypertension Program as well as a BPD specialized Pulmonologist. CM successfully weaned off all respiratory support (to room air) by 1 year of age and is doing well from a developmental standpoint at home.

According to CHOP PH specialist Jennifer Tingo, MD, “CM has thrived as an outpatient. While she remains on pulmonary vasodilator medications, our experience is that many times these medications can eventually be discontinued on the outpatient side. Our pulmonary hypertension team has extensive expertise to care for patients like CM as they graduate from the NICU and grow up.”

BPD related pulmonary hypertension

Approximately 25% and 40% of infants with BPD also develop PH, a complication which carries significant morbidity and mortality. Preterm birth, lung disease, and growth restriction are important risk factors for the development of PH. The pathophysiology of PH in infants with BPD is different than in that of adults and is characterized by a decrease in the number and size of pulmonary blood vessels, as well as increased reactivity of the vessels.

In preterm infants with evolving lung disease, chronic inadequate respiratory support can lead to hypoxia and hypercarbia that even while subtle, contributes to the development or exacerbation of PH. Even infants with normal pulse oximeter values can experience regions of alveolar hypoxia and acidosis leading to vasoconstriction and remodeling of the pulmonary vessels. Many infants with developing BPD may not show any, or only subtle, signs of PH, until their pulmonary pressures reach a critical threshold. In addition, it can be challenging to assess the adequacy of support if infants are examined largely while at rest, but develop work of breathing with any activity. Even modest work of breathing is a sign that there may be inadequate support. Additional signs are limited reserve off a noninvasive interface, frequent desaturations, evolving tachypnea, or failure of linear growth.

An infant with BPD requires uniquely specialized care that includes surveillance for PH. An infant with BPD should have a screening echocardiogram to assess for PH.

Once an infant meets a diagnosis of BPD, particularly the severe form, their management requires a frame shift from acute care to a more chronic care model. This can be quite nuanced and requires much patience on the part of the provider, as well as the parents. Some providers will recommend tracheostomy to a family if the infant remains on positive pressure past term.

In our experience, a portion of these infants will go on to wean off positive pressure, albeit perhaps over many months. In addition, having a child at home with a tracheostomy is not without risk of mortality from an unanticipated loss of the airway; as a result, the resources required to support a child at home with a tracheostomy are significant and may preclude some infants to transitioning to the home environment.

The NeoCLD Program at CHOP uses its diverse multidisciplinary team to assess trajectory of weaning from positive pressure over time, while providing the adequate respiratory support to promote the growth and development of these infants.

Access current CHOP recommendations for PH screening ECHOs at www.chop.edu/bpdpathwayph.