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 oxygen requirement. Diagnosis is based on prolonged need for oxygen supplementation and sometimes ventilatory support. Treatment is supportive and includes nutritional supplementation, fluid restriction, diuretics, and perhaps inhaled bronchodilators and, as a last resort, systemic or inhaled corticosteroids.
(See also Overview of Perinatal Respiratory Disorders.)
Extensive physiologic changes accompany the birth process, sometimes unmasking conditions that posed no problem during intrauterine life. For that reason, a person with neonatal resuscitation skills must attend each birth. Gestational age and growth parameters help identify the risk of neonatal pathology.
Bronchopulmonary dysplasia (BPD) is considered present when there is prolonged need for supplemental oxygen in preterm infants after 28 days of age or after 36 weeks postmenstrual age and who do not have other conditions requiring oxygen (eg, pneumonia, congenital heart disease).
Etiology of Bronchopulmonary Dysplasia
BPD has a multifactorial etiology.
Significant risk factors include
Prolonged mechanical ventilation
High concentrations of inspired oxygen
Infection (eg, chorioamnionitis or sepsis)
Additional risk factors include
Pulmonary interstitial emphysema
High peak inspiratory pressures
Large end-tidal volumes
Repeated alveolar collapse
Increased airway resistance
Increased pulmonary artery pressures
Male sex
Intrauterine growth restriction
Genetic susceptibility
Maternal smoking
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 can develop (1).
Довідковий матеріал щодо етіології
1. Kalikkot Thekkeveedu R, Guaman MC, Shivanna B: Bronchopulmonary dysplasia: A review of pathogenesis and pathophysiology. Respir Med 132:170–177, 2017. doi: 10.1016/j.rmed.2017.10.014
Diagnosis of Bronchopulmonary Dysplasia
National Institute of Child Health and Human Development (NICHD) criteria
Characteristic findings on chest imaging
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 and nursery-acquired pneumonia, 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 National Institute of Child Health and Human Development Criteria for Diagnosis of Bronchopulmonary Dysplasia) 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.
Критерії діагностики бронхолегеневої дисплазії Національного інституту здоров'я дитини та людського розвитку*
< 32 Weeks Gestational Age† | ≥ 32 Weeks Gestational Age‡ | Diagnosis |
|---|---|---|
Breathing room air at 36 weeks PMA or discharge, whichever comes first | Breathing room air by 56 days postnatal age or discharge, whichever comes first | Mild BPD |
Need for < 30% oxygen at 36 weeks PMA or discharge, whichever comes first | Need for < 30% oxygen at 56 days postnatal age or discharge, whichever comes first | Moderate BPD |
Need for ≥ 30% oxygen, positive pressure, or both at 35 weeks PMA or discharge, whichever comes first | Need for ≥ 30% oxygen, positive pressure, or both at 56 days postnatal age or discharge, whichever comes first | Severe BPD |
* These criteria are in addition to the baseline diagnostic requirement of needing> 21% oxygen for at least 28 days or continued need for supplemental oxygen at ≥ 36 weeks PMA. | ||
† Assessed at 36 weeks PMA. | ||
‡ Assessed at age 29 to 55 days. | ||
BPD = bronchopulmonary dysplasia; PMA = postmenstrual age (gestational age plus chronological age (in weeks)). | ||
Treatment of Bronchopulmonary Dysplasia
Nutrition supplementation
Fluid restriction
Diuretics
Oxygen supplementation as needed
Respiratory syncytial virus (RSV) prophylaxis
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 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). 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.
Two monoclonal antibodies used for RSV prophylaxis in infants and young children are available in the United States. Nirsevimab is preferred but may not be available to some infants; if it is not available, eligible high-risk infants and children should receive palivizumab (see also Prevention of RSV for indications).
Infants > 6 months also should be vaccinated against influenza.
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) 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); 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.
Довідкові матеріали щодо лікування
1. Kalikkot Thekkeveedu R, Guaman MC, Shivanna B: Bronchopulmonary dysplasia: A review of pathogenesis and pathophysiology. Respir Med 132:170–177, 2017. doi: 10.1016/j.rmed.2017.10.014
2. Filippone M, Nardo D, Bonadies L, et al: Update on postnatal corticosteroids to prevent or treat bronchopulmonary dysplasia. Am J Perinatol 36(S 02):S58–S62, 2019. doi: 10.1055/s-0039-1691802
3. Aschner JL, Bancalari EH, McEvoy CT: Can we prevent bronchopulmonary dysplasia? J Pediatr 189:26–30, 2017. doi: 10.1016/j.jpeds.2017.08.005
Prognosis for Bronchopulmonary Dysplasia
Prognosis varies with severity. Most infants gradually transition from mechanical ventilation to continuous positive airway pressure 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) 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.
Prevention of Bronchopulmonary Dysplasia
Practices for prevention of BPD include
Use of antenatal corticosteroids as indicated
Prophylactic use of exogenous surfactant in selected high-risk infants (eg, weighing < 1000 g and requiring ventilator support)
Early therapeutic continuous positive airway pressure
Early use of surfactant for treatment of respiratory distress syndrome (RDS)
Prophylactic use of methylxanthines (eg, caffeine 5 to 10 mg/kg orally once/day), particularly when birth weight is < 1250 g
Permissive hypercarbia and hypoxemia to achieve low ventilator pressures, volumes, or both
Prophylactic use of vitamin A for infants with birth weight < 1000 g (not widely used because of high cost, limited availability, and need for frequent IM injections; 1)
Avoidance of large volumes of fluid
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.
Довідковий матеріал щодо профілактики
1. Aschner JL, Bancalari EH, McEvoy CT: Can we prevent bronchopulmonary dysplasia? J Pediatr 189:26–30, 2017. doi: 10.1016/j.jpeds.2017.08.005
Ключові моменти
Bronchopulmonary dysplasia (BPD) is chronic lung disease of preterm infants.
BPD develops in neonates who required prolonged mechanical ventilation and/or oxygen supplementation, which can disrupt normal lung development.
Diagnosis is based on prolonged (≥ 28 days or ≥ 36 weeks postmenstrual age) need for oxygen supplementation and sometimes ventilatory support.
Wean from respiratory support as soon as possible and use nutritional supplementation, fluid restriction, and sometimes diuretics.
Prevent by using antenatal corticosteroids, surfactant, caffeine, and vitamin A, avoiding excess fluid intake early in life, and using the lowest FIO2 levels, tidal volumes, and airway pressures as possible.
Додаткова інформація
The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
American Academy of Pediatrics: Policy statement: Postnatal corticosteroids to prevent or treat bronchopulmonary dysplasia (2014)
