Bronchopulmonary Dysplasia/Chronic Lung Disease BPD

Bronchopulmonary Dysplasia/Chronic Lung Disease BPD, a type of chronic lung disease, commonly occurs in preterm and low-birth-weight infants who have experienced a lung injury resulting in the need for continued use of oxygen after the initial neonatal period (28 days of life). The cause is related to high concentrations of oxygen exposure and prolonged mechanical ventilation. Approximately 10,000 to 15,000 new cases of BPD occur each year in the United States. White male infants seem to be at greatest risk for developing BPD (American Lung Association [ALA], 2020). The average length of intensive in-hospital care for infants with BPD is 120 days. The overall costs of treating BPD in the United States are estimated to be $2.4 billion annually (ALA, 2020). Newborns with BPD need intensive hospital care and home oxygen therapy after being discharged. Pathophysiology BPD results from an underlying lung injury. However, the etiology of the lung injury is multifactorial, complex, and remains incompletely understood. It is associated with surfactant deficiency, genetic predisposition, prematurity, oxygen toxicity, pulmonary edema, lung immaturity, lung injury from mechanical ventilation, inflammation, and fluid overload. Lung injury commonly occurs secondary to mechanical ventilation and oxygen toxicity, usually in infants who have had RDS. This lung damage results from the complex interplay between impairments in the premature lung such as surfactant deficiency, perinatal insults such as infection, and damage resulting from supportive care of the infant due to mechanical ventilation and oxygen toxicity from supplemental oxygen administration. These factors trigger an inflammatory cascade in the infant lung with recurring cycles of lung damage and repair that may impair alveolarization and vascularization in the developing lungs. High levels of inspired oxygen concentrations cause an inflammatory process in the lungs that leads to parenchymal damage. Various toxic factor exposure can injure small airways, which interferes with alveolarization (alveolar septation), leading to a reduction in the overall surface area for gas exchange (Stark & Eichenwald, 2020b). This damage includes epithelial stretching, invasion by macrophages and polymorphonuclear leukocytes, airway edema interfering with the growth and development of lung structures, loss of cilia, and a decrease in the number of alveoli. Therapeutic Management BPD remains the most common severe adverse pulmonary outcome of preterm birth. It is associated with significant mortality, morbidity, and resource utilization. Low gestational age and birth weight are the strongest risk factors for the development of BPD, but the pathogenesis is complex. The strategy for respiratory support immediately after birth and during the initial neonatal period may have a critical impact on the development of BPD. The preterm lung is highly susceptible to injury. Excessive oxygen use in preterm infants increases the risk of BPD. The recently developed practices for oxygen saturation levels during the neonatal transition phase have become part of the newly revised resuscitation guidelines. For term neonates, starting resuscitation with room air or nitric oxide, rather than 100% oxygen, is now advised. Preterm infants may require a higher initial inspiratory oxygen concentration than term infants; however, the ideal level is not yet defined. Mechanical ventilation stretches the airways, causing airway injuries and diffuse lung inflammation. Primary intubation is no longer a prerequisite for preterm survival. Recent studies have demonstrated that even very preterm infants can be safely stabilized after birth with CPAP and later be selectively treated with surfactant for RDS. This initially less invasive strategy has the advantage of reducing the need for mechanical ventilation and thereby the risk of lung injury. Only infants who do not respond to positive-pressure ventilation delivered through a face mask or nasal prongs should undergo intubation (European Society of Pediatric Research, 2019). BPD can frequently be prevented by administering steroids to the mother in the prenatal period and exogenous surfactant to the newborn to help reduce the risk for RDS and its severity. In addition, the following practices may help reduce the incidence of BPD: Use lower target oxygen saturation levels or room air. Close the patent ductus arteriosus early, either medically or surgically. Monitor and minimize tidal volumes on ventilators. Use postnatal steroid therapy judiciously. Administer stem cell therapy using mesenchymal stem cells. Inspired oxygen tensions should be kept as low as possible. Use inhaled nitric oxide to provide pulmonary vasodilation. Maintain adequate nutritional status (Mandell et al., 2019). Supplemental oxygen, antibiotics, and fluid restriction and diuretics to decrease fluid accumulation in the lungs are used. Bronchodilators are used to open the airways. IV feedings are given to meet the infant’s nutrition needs, and physical therapy is used to improve muscle performance and to help the lungs expel mucus. Nursing Assessment Although BPD is most common in preterm newborns, it can also occur in full-term newborns who had respiratory problems during their first days of life. Thus, it is essential to assess the newborn’s history for risk factors, including male gender, preterm birth (earlier than 32 weeks), nutritional deficiencies, white race, pulmonary hypertension, excessive fluid intake during the first few days of life, presence of patent ductus arteriosus, anemia, low Apgar score, severe RDS treated with mechanical ventilation, oxygen toxicity, inflammation, and sepsis (MacKenzie et al., 2019). Also review the history for use of supplemental oxygen, the length of exposure to oxygen therapy, and the use of ventilatory support. Assess the infant for signs and symptoms of BPD. These may include tachypnea, poor weight gain related to the increased metabolic workload, tachycardia, sternal retractions (see Fig. 24.2), episodes of cyanosis, nasal flaring, and bronchospasm with abnormal breath sounds (crackles, rhonchi, and wheezes). Hypoxia, as evidenced by abnormal blood gas results, acidosis, and hypercapnia also are noted. Chest x-rays will show hyperinflation, infiltrates, and cardiomegaly. Nursing Management The focus of management is to improve supportive care and minimize additional lung injury by decreasing the workload of breathing and normalizing gas exchange, thus promoting growth and development of the respiratory system. Nursing care includes providing continuous ventilatory and oxygen support and optimal nutrition to support growth, and administering bronchodilators, antiinflammatory agents, and diuretics as ordered. Continuously monitor the newborn’s respiratory status to determine the need for continued ventilatory assistance. When the newborn is clinically stable and ready, expect to wean them slowly so that they can compensate for the changes. Supplemental oxygen may be needed after discharge from the hospital. Provide a high caloric intake to promote growth and to compensate for the calories expended due to the increased work of breathing. Some infants may require high-calorie formulas to foster adequate growth. Newborns with BPD may require continued care at home. When planning for discharge, educate the family caregiver about how to manage a chronically ill child who may be oxygen-dependent for an extended time. Successful discharge is greatly influenced by how prepared the family is to take an infant home on oxygen. Provide ongoing support to parents as they learn to meet their infant’s needs. Also instruct the family about the safe use of oxygen in the home, including the need to notify emergency medical services and utility companies that a technology-dependent child is living in their district. In addition, initiate a social service referral to help the family access community resources and obtain necessary support (Anderson & Hillman, 2019). Despite decades of promising research, primary prevention of BPD has proven elusive. Future management of BPD will involve strategies that emphasize prevention. Because few accepted therapies currently prevent BPD, many therapeutic modalities are used to treat it, which may in fact exacerbate it. Further research is needed to find better therapeutic interventions.