Bronchopulmonary Dysplasia (BPD)

BPD has a multifactorial etiology.

Significant risk factors include

Additional risk factors include

The lungs of preterm infants are more vulnerable to the inflammatory changes that result from mechanical ventilation. The development of normal lung architecture is interrupted; fewer and larger alveoli develop, and the interstitium is thickened. Also, the pulmonary vasculature develops abnormally, with fewer and/or abnormally distributed alveolar capillaries; pulmonary resistance may be increased and pulmonary hypertension Persistent Pulmonary Hypertension of the Newborn Persistent pulmonary hypertension of the newborn is the persistence of or reversion to pulmonary arteriolar constriction, causing a severe reduction in pulmonary blood flow and right-to-left... read more can develop (1 Etiology reference Bronchopulmonary dysplasia is chronic lung disease of the neonate that typically is caused by prolonged ventilation and is further defined by degree of prematurity and extent of supplemental... read more ).

BPD typically is suspected when a ventilated infant is unable to wean from oxygen therapy, mechanical ventilation, or both. Infants typically develop worsening hypoxemia, hypercapnia, and increasing oxygen requirements. Additionally, when an infant cannot be weaned within the expected time, possible underlying disorders, including patent ductus arteriosus Patent Ductus Arteriosus (PDA) Patent ductus arteriosus (PDA) is a persistence of the fetal connection (ductus arteriosus) between the aorta and pulmonary artery after birth. In the absence of other structural heart abnormalities... read more and nursery-acquired pneumonia Neonatal Pneumonia Neonatal pneumonia is lung infection in a neonate. Onset may be within hours of birth and part of a generalized sepsis syndrome or after 7 days and confined to the lungs. Signs may be limited... read more , should be considered.

For diagnosis of BPD, the patient has to have required at least 28 days of > 21% oxygen or has to have continued need for supplemental oxygen at ≥ 36 weeks postmenstrual age. Specific additional diagnostic criteria (see table ) have been developed by the NICHD; however, there is still a need for a standardized diagnostic definition of BPD.

Chest x-ray initially shows diffuse haziness due to accumulation of exudative fluid; appearance then becomes multicystic or spongelike, with alternating areas of emphysema, pulmonary scarring, and atelectasis. Alveolar epithelium may slough, and macrophages, neutrophils, and inflammatory mediators may be found in the tracheal aspirate.

Treatment of BPD is supportive and includes nutritional supplementation, fluid restriction, diuretics, and perhaps inhaled bronchodilators and, as a last resort, inhaled corticosteroids. Respiratory infections must be diagnosed early and treated aggressively. Weaning Mechanical Ventilation Initial stabilization maneuvers include mild tactile stimulation, head positioning, and suctioning of the mouth and nose followed as needed by Supplemental oxygen Continuous positive airway... read more from mechanical ventilation and supplemental oxygen should be accomplished as early as possible.

Feedings should achieve an intake of 150 calories/kg/day including protein 3.5 to 4 g/kg/day; caloric requirements are increased because of the increased work of breathing and to aid lung healing and growth.

Because pulmonary congestion and edema may develop, daily fluid intake is often restricted to about 120 to 140 mL/kg/day. Diuretic therapy transiently improves pulmonary mechanics but not long-term clinical outcome. Thiazide or loop diuretics can be used for short-term benefit in patients who do not respond adequately to or cannot tolerate fluid restriction. Oral chlorothiazide with or without oral spironolactone is often tried first. Furosemide (may be used for short periods, but prolonged use causes hypercalciuria with resultant osteoporosis, fractures, and renal calculi. If long-term diuretic use is required, chlorothiazide is preferred because it has fewer adverse effects. Hydration and serum electrolytes should be monitored closely during diuretic therapy.

Inhaled bronchodilators (eg, albuterol) do not appear to improve long-term outcome and are not used routinely. However, they may be helpful for acute episodes of bronchoconstriction.

Weeks or months of additional ventilator support, supplemental oxygen, or both may be required for advanced BPD. Ventilator pressures or volumes and fraction of inspired oxygen (FIO2) should be reduced as rapidly as tolerated, but the infant should not be allowed to become hypoxemic. The degree of lung inflation (tidal volume measured in mL/kg) carries a higher risk of BPD than does the degree of airway pressure as an absolute number in cm of H2O (1 Treatment references Bronchopulmonary dysplasia is chronic lung disease of the neonate that typically is caused by prolonged ventilation and is further defined by degree of prematurity and extent of supplemental... read more ). Arterial oxygenation should be continuously monitored with a pulse oximeter and maintained at ≥ 89% saturation. Respiratory acidosis may occur during ventilator weaning and treatment and is acceptable as long as the pH remains > 7.25 and the infant does not develop severe respiratory distress.

Passive immunoprophylaxis with palivizumab, a monoclonal antibody to RSV, decreases RSV-related hospitalizations and intensive care unit stays but is costly and is indicated primarily in high-risk infants (see prevention of RSV Prevention Respiratory syncytial virus and human metapneumovirus infections cause seasonal lower respiratory tract disease, particularly in infants and young children. Disease may be asymptomatic, mild... read more for indications). During RSV season (November through April), when indicated, children are given as prophylaxis against RSV infections. Infants > 6 months also should be vaccinated against influenza Influenza Vaccine Based on recommendations by the World Health Organization and the Centers for Disease Control and Prevention (CDC), vaccines for influenza are modified annually to include the most prevalent... read more .

Although systemic or inhaled corticosteroids may result in clinical improvement in BPD, concerns about adverse neurodevelopmental outcomes from repeated and/or prolonged courses of dexamethasone for BPD (2 Treatment references Bronchopulmonary dysplasia is chronic lung disease of the neonate that typically is caused by prolonged ventilation and is further defined by degree of prematurity and extent of supplemental... read more ) led to the reaffirmed American Academy of Pediatrics' 2014 policy statement discouraging the routine use of dexamethasone for BPD. More recent studies of hydrocortisone and inhaled budesonide in BPD found no long-term significant adverse neurodevelopmental outcomes (3 Treatment references Bronchopulmonary dysplasia is chronic lung disease of the neonate that typically is caused by prolonged ventilation and is further defined by degree of prematurity and extent of supplemental... read more ); however, because of concerns for other possible adverse effects (eg, hypertension, cardiomyopathy, worsening of retinopathy of prematurity), the current recommendation is to use systemic and inhaled corticosteroids only in cases where there is thought to be no other alternative.

Prognosis varies with severity. Most infants gradually transition from mechanical ventilation Mechanical Ventilation Initial stabilization maneuvers include mild tactile stimulation, head positioning, and suctioning of the mouth and nose followed as needed by Supplemental oxygen Continuous positive airway... read more to continuous positive airway pressure Continuous Positive Airway Pressure (CPAP) Initial stabilization maneuvers include mild tactile stimulation, head positioning, and suctioning of the mouth and nose followed as needed by Supplemental oxygen Continuous positive airway... read more to low-flow oxygen over 2 to 4 months. Infants who still depend on mechanical ventilation at 36 weeks gestation have a 20 to 30% mortality rate in infancy. Infants who develop pulmonary arterial hypertension also are at higher risk of mortality during the first year of life.

Infants with BPD have a 3- to 4-fold increased rate of growth failure and neurodevelopmental problems. For several years, infants are at increased risk of developing asthma later in life as well as lower respiratory tract infections (particularly pneumonia or bronchiolitis Bronchiolitis Bronchiolitis is an acute viral infection of the lower respiratory tract affecting infants < 24 months and is characterized by respiratory distress, wheezing, and/or crackles. Diagnosis is... read more ) and may quickly develop respiratory decompensation if pulmonary infection occurs. The threshold for hospitalization should be low if signs of a respiratory infection or respiratory distress develop.

Practices for prevention of BPD include

Inhaled nitric oxide has been studied and may help prevent BPD. However, optimal dosage, duration, and timing are unclear, so nitric oxide is not yet recommended outside of research protocols.

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