Experience with home oxygen in the management of infants with bronchopulmonary dysplasia

Pulmonary hypertension in the child with bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease of prematurity resulting from complex interactions of perinatal factors that often lead to prolonged respiratory support and increased pulmonary morbidity. There is also growing appreciation for the dysmorphic pulmonary bed characterized by vascular growth arrest and remodeling, resulting in pulmonary vascular disease and its most severe form, pulmonary hypertension (PH) in children with BPD. In this review, we comprehensively discuss the pathophysiology of PH in children with BPD, evaluate the current recommendations for screening and diagnosis of PH, discern associated comorbid conditions, and outline the current treatment options.

Pediatric Pulmonary Hypertension: Definitions, Mechanisms, Diagnosis, and Treatment

Pediatric pulmonary hypertension (PPH) is a multifactorial disease with diverse etiologies and presenting features. Pulmonary hypertension (PH), defined as elevated pulmonary artery pressure, is the presenting feature for several pulmonary vascular diseases. It is often a hidden component of other lung diseases, such as cystic fibrosis and bronchopulmonary dysplasia. Alterations in lung development and genetic conditions are an important contributor to pediatric pulmonary hypertensive disease, which is a distinct entity from adult PH. Many of the causes of pediatric PH have prenatal onset with altered lung development due to maternal and fetal conditions. Since lung growth is altered in several conditions that lead to PPH, therapy for PPH includes both pulmonary vasodilators and strategies to restore lung growth. These strategies include optimal alveolar recruitment, maintaining physiologic blood gas tension, nutritional support, and addressing contributing factors, such as airway disease and gastroesophageal reflux. The outcome for infants and children with PH is highly variable and largely dependent on the underlying cause. The best outcomes are for neonates with persistent pulmonary hypertension (PPHN) and reversible lung diseases, while some genetic conditions such as alveolar capillary dysplasia are lethal. © 2021 American Physiological Society. Compr Physiol 11:2135-2190, 2021.

Predictors of home oxygen duration in chronic neonatal lung disease

AIMS

In infants with chronic neonatal lung disease (CNLD), we aimed to identify predictors of home oxygen duration, predictors of discharge oxygen flow rates, and the association of oxygen flow rates with respiratory outcomes.

METHODS

Infants with CNLD requiring home oxygen in 2016 and 2017 were retrospectively reviewed. Hazard ratios (HR) were estimated from Cox proportional hazards regression models in the cohort. A multinomial logistic regression model examined the effects of maternal and infant variables on discharge oxygen flow rates. Kruskal-Wallis test with univariate linear regression and Fisher's exact test with binomial univariate logistic regression were used to examine associations between oxygen flow groups and post-discharge clinical variables.

RESULTS

One hundred and forty-nine infants were included. Median corrected gestational age (CGA) at oxygen cessation was 6.8 months (interquartile range, 4.4) with 87.2% of infants weaned by 12 months CGA. Shorter initial neonatal intensive care unit (NICU) stay predicted faster oxygen weaning at 9 months (HR, 0.99; 95% confidence interval [CI], 0.98-1.00, p = .02) and 12 months (HR, 0.99; 95% CI, 0.98-1.00, p = .02). Infants with hypercarbia at discharge or discharged from NICU at higher CGA had higher odds of requiring ≥ 200 ml/min relative to ≤ 125 ml/min oxygen. Infants discharged with > 250 ml/min oxygen were more likely to have a respiratory-related admission before 2 years chronological age.

CONCLUSION

Shorter initial NICU stay was the best predictor of earlier home oxygen cessation. At NICU discharge, infants with hypercarbia or a higher CGA may require more home oxygen and experience more respiratory-related hospital admission in the first 2 years of chronological age.

A rational approach to home oxygen use in infants and children

The provision of supplemental oxygen for infants and children with hypoxaemia is expensive but advantageous because it facilitates earlier discharge from hospital and enhances quality of life in the home setting. It is seen as potentially cost effective and family friendly. However, the prescription of supplemental oxygen varies greatly between neonatologists, paediatric respiratory physicians and paediatric cardiologists. There is a lack of consensus on appropriate indications for prescribing oxygen, desirable oxygen targets and clinically significant immediate and longer-term outcome measures. Of the limited studies available, most are small studies reporting the treatment of infants with chronic neonatal lung disease with inconsistent outcome measures. Such data are not readily extrapolated to older children, who are also poorly served by existing data in adult studies. Further delineation of the indications for home oxygen therapy is required together with appropriately designed and funded multicentre trials to provide evidence for optimal oxygen therapy.

Sevrage de l’oxygène

Oxygen weaning is a controversial problem which can be summarized in three questions: what do we expect from oxygen supplementation? what are the optimal targets? with what sort of monitoring? We shall try to evaluate these different questions assuming the uncertainty of the proposed answers and the short-lived character of them.

The pulmonary circulation in bronchopulmonary dysplasia

Abnormalities of the pulmonary circulation are increasingly being recognized as a major contributor to the high morbidity and mortality of bronchopulmonary dysplasia. Historically, studies have focused on the importance of pulmonary hypertension to the pathophysiology of BPD, with the assumption that pulmonary vascular abnormalities are a secondary consequence of primary injury to the airspace. Recent studies suggest, however, that abnormalities of the pulmonary vasculature, including altered growth and structure, may directly contribute to the abnormal alveolarization that characterizes the condition. In this article, we briefly outline mechanisms of pulmonary vascular injury in infants at risk of BPD. We then focus on the recognition and management of pulmonary hypertension in these infants. Finally, we review how disordered pulmonary vascular growth may contribute to the pathogenesis of BPD and emphasize the importance of the reciprocal development of the airspace and the pulmonary circulation.

Monitoring cardiovascular function in infants with chronic lung disease of prematurity

In addition to persistent airways disease, survivors of premature birth with chronic lung disease are at risk of cardiovascular sequelae, including pulmonary hypertension, systemic hypertension, left ventricular hypertrophy, and exercise intolerance. The major treatment of pulmonary hypertension is supplemental oxygen, but drugs such as calcium channel blockers may also be required. The use of inhaled nitric oxide for its long term management is being investigated

Oxygen therapy for infants with chronic lung disease

Supplemental oxygen is a safe and effective treatment for infants with established chronic lung disease who are not at risk of further progression of retinopathy of prematurity (ROP). Oxygen saturations of < 92% should be avoided and a target range of at least 94-96% aimed for. The saturation target range for very preterm infants at risk of developing ROP is more controversial, but the therapeutic index is probably considerably narrower.

Pulmonary function in technology-dependent children 2 years and older with bronchopulmonary dysplasia

Somatic and pulmonary growth coincide with resolution of hypoxemia by 2 years of age in most children with bronchopulmonary dysplasia (BPD). However, a distinct subgroup of children with BPD continue to require mechanical ventilation and/or supplemental oxygen beyond 2 years of age. This study tested the hypothesis that indices of pulmonary function would be significantly worse in children with BPD 2 years and older who remained technology-dependent secondary to hypoxemia, compared to those of age-matched children with BPD who were normoxemic. We measured pulmonary mechanics in 21 oxygen- or ventilator-dependent children with BPD 2 years and older (BPDO2 group; mean age+/-SD, 30.2+/-6.5 months) and in 19 children with BPD who had been weaned off mechanical ventilation and supplemental oxygen for at least 6 months (control group; mean age, 30.1+/-5.5 months). Respiratory rate and tidal volume were measured after sedation with chloral hydrate, and dynamic compliance and expiratory conductance were calculated using the esophageal catheter technique. Maximal flow at FRC (V'(maxFRC)) and ratio of forced-to-tidal flows at midtidal volume were obtained by the rapid thoracic compression technique. FRC was determined by nitrogen washout. There were no statistically significant differences in most measured indices of pulmonary mechanics between the BPDO2 and control groups. However, V'(maxFRC)/FRC was higher in controls compared to subjects in the BPDO2 group (0.81+/-0.40 sec(-1) vs. 0.34+/-0.21 sec(-1), P<0.003). We conclude that most indices of pulmonary function in children with BPD 2 years and older do not reflect the need for mechanical ventilation or supplemental oxygen. We speculate that measurements of lung elastic recoil and tests of distribution of ventilation and pulmonary perfusion may be more sensitive in differentiating normoxemic and hypoxemic children with BPD 2 years and older.

Home oxygen therapy in infants with bronchopulmonary dysplasia: assessment of parental anxiety

BACKGROUND

It is conceivable that a complicated recovery course in a high-risk premature infant managed at home generates apprehension and anxiety in parents.

AIMS

We attempted to define the evolution of anxiety levels in a population of parents of low-birth-weight premature infants with bronchopulmonary dysplasia enrolled in a prospective home O(2) therapy program.

STUDY DESIGN

In the immediate pre-discharge [mean postnatal age 95 (45-158) days], a questionnaire (State-Trait Anxiety Inventory form Y) was given to all parents of the premature infants [mean birth weight 1106 (0.610-1.770) kg; mean gestational age 27.1 (24-31) weeks] present for the discharge. Subsequently, the parents were assessed twice, initially after a week from the discharge of their infants and then at the end of the oxygen therapy phase [mean postnatal age 185 (60-361) days]. They included 10 mothers and 10 fathers, aged 33.5+/-0.5 and 37+/-0.2 years, respectively.

RESULTS

Our results indicate that these parents present an increased state anxiety level upon hospital discharge of their oxygen-dependent premature infants, which decreases as the improvement of respiratory status and the cessation of oxygen-dependency become evident [mean+/-S.D. related to age (T) maternal values 47.1+/-7.0, 41.8+/-5.6, 39.1+/-4.7, respectively; mean+/-S.D. related to age (T) paternal values 42.2+/-8.5, 41.1+/-8.1, 40.5+/-8.2, respectively]. When assessed separately by parental gender, in the maternal group, state anxiety decreased significantly (ANOVA, p<0.05).

CONCLUSIONS

These data indicate that although neonatologists generally define the discharge of prematures with chronic lung disease based upon the acquired stabilization of vital parameters, in the oxygen-dependent group, they should also pay special attention to the emotional support of the parents who we have identified as being at increased risk for pre-discharge anxiety.

Home oxygen management of neonatal chronic lung disease in Western Australia

OBJECTIVE

To describe the course and management of infants with neonatal chronic lung disease who were discharged home on low-flow supplemental oxygen.

METHODOLOGY

Retrospective case series in Western Australia.

RESULTS

Fifty-six neonates born in the 6 year period 1987-92 inclusive were discharged home on supplemental oxygen. The median gestational age was 27 weeks (range 22-40), median birthweight 865 g (range 450-3350), median oxygen flow rates 125 mL/min (range 30-850). The median corrected age at discharge was 1 month (range term-9.5) and this had decreased throughout the study period. Acute hospital readmissions were common (36 of 56, 64%). The majority of these admissions were for wheezing illnesses. Three infants died. The median corrected age at weaning from day oxygen was 4 months (range term-33) and from night oxygen was 6 months (range 2-38). Monitoring of oxygen saturation in air, in low-flow oxygen and in the overnight sleep study were important non-invasive guides in deciding when patients were ready for discharge, reducing the oxygen flow rate and when oxygen could be ceased, respectively.

CONCLUSIONS

The home oxygen programme enables infants with neonatal chronic lung disease to be discharged home earlier, is safe, and well accepted by parents and community health care workers.

Rehospitalization and growth of infants with bronchopulmonary dysplasia: a matched control study

OBJECTIVE

To determine the risk of hospitalization and the growth during the first year of life in infants with bronchopulmonary dysplasia (BPD) and birthweight matched controls.

METHODOLOGY

The study population consists of 78 infants of 26 to 33 weeks gestation with BPD of whom 20 were discharged on home oxygen therapy. The 78 control infants were matched with the study infants for broad based birthweight categories. Infants were reviewed at 4, 8 and 12 months corrected for prematurity at which time the history of rehospitalization was recorded and growth parameters were measured.

RESULTS

Infants with BPD were found to have a higher overall rate of rehospitalization (58 vs 35%, relative risk (RR) 1.7, 95% confidence interval (Cl) 1.2-2.4) and were more likely to be readmitted for respiratory illnesses (39 vs 20%, RR 1.9, 95% Cl 1.1-3.2) and for poor growth (14 vs 1%, RR 14, 95% Cl 1.7-82) than the control group. Many infants, both study and control, remained below the 10th percentile at 1 year of age. More BPD infants were below the 10th percentile in weight at the 4 month visit than the control infants (30 vs 15%, P = 0.034). This difference was neither present at subsequent visits nor in the other major growth parameters. The 20 BPD infants who were on home oxygen therapy were more frequently hospitalized for concerns with failure to thrive (30 vs 9%, RR 3.3, 95% Cl 1.2-8.9) than the remaining 58 BPD infants. No significant differences were detected in the overall rate of rehospitalization. Poor growth at the corrected age of 1 year was similar in the two subgroups of infants.

CONCLUSIONS

BPD infants are at increased for risk rehospitalization during the first year of life. While many infants with BPD have growth failure, it is suggested that the provision of appropriate supplemental oxygen at home may result in those infants having similar growth patterns when compared to birthweight matched preterm infants without BPD.

Pathophysiology and treatment of bronchopulmonary dysplasia. Current issues

Although much has been learned about BPD in the 25 years since its initial description, BPD remains a significant complication of prematurity. Substantial advances into the understanding of its pathophysiology and pathogenesis have been made and are reflected in new therapeutic interventions. Much current research is directed towards the role of prevention, exploring new approaches for accelerating lung maturation with combined maternal steroid and thyrotropin releasing hormone (TRH) therapy, surfactant replacement therapy, high frequency oscillatory ventilation, antioxidant administration, manipulation of endogenous antioxidants, and other pharmacologic strategies to minimize lung injury. The impact of other technologies, such as synchronized intermittent mandatory ventilation, perfluorocarbon (liquid) ventilation, and perhaps inhaled nitric oxide therapy may become additional parts of the clinical regimen for some cases of severe neonatal respiratory failure. Less information is available on mechanisms which can hasten lung healing. Ongoing studies of inflammatory products, growth factors, and cytokines may lead to new therapies which will favorably influence the fibroproliferative phase of disease. In the meantime, the medical and social impact of BPD continues to remain a significant problem not only during infancy but also throughout life. Mildred Stahlman, MD, recently wrote that (a)s sanguine as the future looks for surfactant therapy, it may leave us with more very low-birth weight infants who survive, whose potential for normal pulmonary growth and development is unknown, and whose very immature organ systems, besides the lung, are still susceptible to metabolic, neurologic, and other problems. As more survivors are reaching young adulthood, respiratory and neurodevelopmental complications persist. Thus, as advances in the care of the premature newborn with respiratory distress have dramatically improved survival, the management of chronic lung disease and related problems remains a continuing challenge.

Financial and emotional cost of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) in infants with neonatal respiratory disease significantly increases the duration of hospitalization and cost of medical care. Early discharge on home oxygen therapy results in cost savings for third-party payers and the hospital, but adds financial and emotional burdens for the family. The median cost of initial hospitalization for 59 infants was $173,160 each. The median duration of home oxygen therapy was 92 days; the median cost was $5,195, compared with a projected cost of $46,920 for hospitalization for the same period. Two thirds of the 59 families experienced increased financial stress associated with marital status, reduced income, type of health insurance, and/or lack of respite or nursing help. Emotional stress was assessed in 26 (44%) of the families; one half coped well. Parents' perception of adequate insurance and stable income was significantly associated with positive coping. Providing home care for an infant with BPD on oxygen therapy is rewarding in many respects, but success requires appreciating its financial and emotional impact on families and providing them with social and financial support.

Episodes of spontaneous desaturations in infants with chronic lung disease at two different levels of oxygenation

The optimal range of pulse oximeter oxygen saturation (SaO2) for infants with chronic lung disease (CLD) has not been well established. We quantified episodes of spontaneous desaturation, at two different ranges of SaO2. For 1 hr each, we alternatively administered inspired O2 concentrations (FiO2) necessary to maintain an SaO2 of 94-96% or 87-91% to 21 patients (mean birth weight, 865 g; gestational age, 27.3 weeks; postnatal age 40.6 days) with CLD (defined by FiO2 > 0.21 at > or = 28 days and radiographic evidence). SaO2 was monitored with the Nellcor N-200 oximeter and analyzed by a computer program (SatMaster). The percentage of time the infants desaturated to levels of SaO2 < 85 and < 80% revealed significantly fewer spontaneous episodes during the hour of higher baseline SaO2 (P < 0.0002). Comparison of episodes of spontaneous desaturation to SaO2 < 80 and < 85%, lasting 0-15, 16-30, 31-45 sec also showed significant differences between the two levels of SaO2. We conclude that when infants with CLD are maintained at a higher SaO2 they probably experience fewer episodes of spontaneous desaturations, because of less alveolar hypoxia. We believe that attempts at weaning the FiO2 should be tempered with the need of maintaining an adequate SaO2. Therefore, prolonged monitoring of oxygenation in infants with CLD at different levels of SaO2 could be helpful during the weaning process.

Home oxygen therapy following neonatal intensive care

In a 12-month period 28 of 164 consecutive very low birthweight (VLBW) infants receiving intensive care within 48 h of birth at King's College Hospital developed chronic lung disease, (oxygen dependence beyond 28 days of age). Fifteen of the 28 infants were eligible for home oxygen therapy, but this was only practical, because of home circumstances, in 8 infants (4.9%). These 8 infants received home oxygen therapy. One further infant, born at term and suffering from pulmonary hypoplasia was also discharged home on oxygen therapy. Two infants subsequently required readmission due to a deterioration in their respiratory status and died. Three others required re-admissions (total duration 32 days) for respiratory problems. The median duration of home oxygen therapy was 17 weeks (range 4-486 days). We conclude that home oxygen therapy is needed by only a very small number of preterm infants and is appropriate for only a proportion of them. Parents need to be counselled carefully regarding the possibility that the need for oxygen might be protracted.

Home oxygen therapy. Outcome of infants discharged from NICU on continuous treatment

Forty-four oxygen-dependent infants were discharged home in oxygen from an NICU during an 8-year period. Survivors were followed for 3 years. The infants' discharge diagnoses were bronchopulmonary dysplasia (BPD) (39), sleep apnea (2), and congenital cardiac defects (3). The five infants who had diagnoses other than BPD all died, but 34 of 39 infants with BPD survived. Supplemental oxygen was discontinued at a mean age of 13.4 months. The infants with BPD experienced health, growth, nutritional, neurodevelopmental and sensory problems that necessitated frequent rehospitalizations and utilization of a variety of medical and support services.

Role of respiratory syncytial virus in early hospitalizations for respiratory distress of young infants with cystic fibrosis

To determine the frequency of respiratory syncytial virus (RSV) as the cause of hospitalization for acute pulmonary exacerbations in young infants with cystic fibrosis (CF), and to assess the clinical effects of RSV infections, we prospectively followed 48 children with a diagnosis of CF after identification by newborn screening. At a mean follow-up age of 28.8 months (range 5 to 59), 18 infants (38%) had been hospitalized a total of 30 times for acute respiratory distress. At the time of admission, 18 infants (60%) were less than 12 months, 8 (27%) between 12 and 24 months, and 4 more than 2 years of age. The RSV was identified in seven hospitalized infants, as determined by fluorescent antibody, immunoassay, or culture. Before admission with RSV infection, one of the seven infants had chronic respiratory signs, none had Brasfield chest x-ray scores below 20, and a previous throat culture was positive for Staphylococcus aureus in one infant. Hospitalizations were prolonged (mean duration 22 days), and were characterized by significant morbidity, with three infants (43%) requiring mechanical ventilation and five infants (71%) requiring home oxygen therapy for persistent hypoxemia at discharge. At a mean follow-up age of 26 months, these infants more frequently have chronic respiratory signs (p less than 0.01) and lower chest radiograph scores (p less than 0.05) than other CF infants. These findings demonstrate that RSV is an important cause of early acute respiratory tract morbidity in young infants with CF, and suggest the need for studying new strategies to implement early and aggressive antiviral therapy in young infants with CF.

The needs of families of infants discharged home with continuous oxygen therapy

Forty-four parents of 48 infants who had been discharged home with continuous oxygen therapy described their experiences, needs, and resources in a semistructured interview. In addition, 20 professionals in contact with these infants were interviewed to determine their perceptions of discharge preparations, teaching, relief care, coordination of medical care, and expertise of community professionals regarding high-risk infants on oxygen. Both the professionals and parents reported a need for improved discharge teaching and community support services. Researchers concluded that individual needs must be considered in arranging supportive interventions, as needs vary across families, time, and geographic locations.

Continuing care for the preterm infant after dismissal from the neonatal intensive care unit

As more low-birth-weight babies survive, primary-care physicians are facing the responsibility of providing continuing care for those who have been dismissed from neonatal intensive-care units. Premature infants often require outpatient care for bronchopulmonary dysplasia, apnea, retinopathy of prematurity, intraventricular hemorrhage, hearing loss, hypothyroxinemia, anemia, neurodevelopmental sequelae, assessment of growth and nutrition, immunizations, and psychosocial stress. In this review, we present guidelines for the primary-care physician for the management of these conditions in preterm infants.

Home oxygen delivery system for infants

Home oxygen programs have evolved to facilitate the discharge of children who have bronchopulmonary dysplasia from neonatal intensive care units. This report describes a method of oxygen delivery for nighttime that is well suited to the home environment. It consists of an "inverted tent" that lines the walls and floor of the crib into which oxygen is flowed via an air entrainment device. This permits rapid equilibration of oxygen up to an FIO2 of 0.40 with a low flow oxygen source from a concentrator. The system is simple, safe, convenient, and economical.

Unsuspected cardiopulmonary abnormalities complicating bronchopulmonary dysplasia

Bronchopulmonary dysplasia is a serious chronic lung disease of infancy but despite numerous problems such as poor growth, recurrent lower respiratory tract infections, and cor pulmonale, steady improvement and recovery may generally be expected. We report four infants with bronchopulmonary dysplasia in whom the cardiopulmonary course did not show the usual steady improvement. Each infant was found to have an unsuspected cardiopulmonary lesion in addition to lung disease: two had congenital heart disease and two upper airway obstruction. Three improved after surgical intervention but one patient died immediately after this. Persistent right ventricular hypertrophy in patients with bronchopulmonary dysplasia maintained on supplemental oxygen, and a particularly slow rate of recovery from the need for supplemental oxygen are markers that should lead to evaluation for coexisting cardiopulmonary abnormalities.