Definition Of Bronchopulmonary Dysplasia Research Articles

Validation of the National Institutes of Health Consensus Definition of Bronchopulmonary Dysplasia

A number of definitions of bronchopulmonary dysplasia (BPD), or chronic lung disease, have been used. A June 2000 National Institute of Child Health and Human Development/National Heart, Lung, and Blood Institute Workshop proposed a severity-based definition of BPD for infants <32 weeks' gestational age (GA). Mild BPD was defined as a need for supplemental oxygen (O2) for > or =28 days but not at 36 weeks' postmenstrual age (PMA) or discharge, moderate BPD as O2 for > or =28 days plus treatment with <30% O2 at 36 weeks' PMA, and severe BPD as O2 for > or =28 days plus > or =30% O2 and/or positive pressure at 36 weeks' PMA. The objective of this study was to determine the predictive validity of the severity-based, consensus definition of BPD. Data from 4866 infants (birth weight < or =1000 g, GA <32 weeks, alive at 36 weeks' PMA) who were entered into the National Institute of Child Health and Human Development Neonatal Research Network Very Low Birth weight (VLBW) Infant Registry between January 1, 1995 and December 31, 1999, were linked to data from the Network Extremely Low Birth Weight (ELBW) Follow-up Program, in which surviving ELBW infants have a neurodevelopmental and health assessment at 18 to 22 months' corrected age. Linked VLBW Registry and Follow-up data were available for 3848 (79%) infants. Selected follow-up outcomes (use of pulmonary medications, rehospitalization for pulmonary causes, receipt of respiratory syncytial virus prophylaxis, and neurodevelopmental abnormalities) were compared among infants who were identified with BPD defined as O2 for 28 days (28 days definition), as O2 at 36 weeks' PMA (36 weeks' definition), and with the consensus definition of BPD. A total of 77% of the neonates met the 28-days definition, and 44% met the 36-weeks definition. Using the consensus BPD definition, 77% of the infants had BPD, similar to the cohort identified by the 28-days definition. A total of 46% of the infants met the moderate (30%) or severe (16%) consensus definition criteria, identifying a similar cohort of infants as the 36-weeks definition. Of infants who met the 28-days definition and 36-weeks definition and were seen at follow-up at 18 to 22 months' corrected age, 40% had been treated with pulmonary medications and 35% had been rehospitalized for pulmonary causes. In contrast, as the severity of BPD identified by the consensus definition worsened, the incidence of those outcomes and of selected adverse neurodevelopmental outcomes increased in the infants who were seen at follow-up. The consensus BPD definition identifies a spectrum of risk for adverse pulmonary and neurodevelopmental outcomes in early infancy more accurately than other definitions.

Physiologically Redefining Bronchopulmonary Dysplasia

To the Editor .— I was initially excited after reading the multicenter study published in the November 2004 issue of Pediatrics by Walsh et al, “Impact of a Physiologic Definition on Bronchopulmonary Dysplasia Rates.”1 After more careful thought, I wished to express my concerns about the limitations of the authors' proposed “physiologic definition” of bronchopulmonary dysplasia (BPD) and the potential implications on infant morbidity and mortality. The general pediatrician and the pediatric pulmonologist are the physicians who are most frequently responsible for the follow-up and long-term care of high-risk postneonatal infants who have BPD and respiratory control disorders. After leaving the security of the NICU or “step-down” unit, in which they are closely monitored and observed, they are often discharged to high-risk home environments. Their morbidity and mortality rates, in at least the first year of life, remain high. Some succumb to episodes of acute cardiorespiratory failure, while others may die, suddenly and unexpectedly, in homes or in day care centers in which they may be poorly supervised and/or exposed to stresses such as viral infections or continued tobacco smoke or are left sleeping on unsafe surfaces and positions. I am afraid that limiting the definition of BPD to those infants who can maintain …

Physiologically Redefining Bronchopulmonary Dysplasia: In Reply

In Reply .— We agree entirely with Dr Beckerman's concern that a 30-minute trial of room air should not be the basis for continued treatment of recovering very low birth weight infants with room air. The physiologic definition of bronchopulmonary dysplasia was developed to …

Is the New Definition of Bronchopulmonary Dysplasia More Useful?

To determine the incidence of bronchopulmonary dysplasia (BPD) in low birth weight (LBW) infants <1251 g managed with early bubble nasal continuous positive airway pressure (NCPAP) and a gentle ventilation strategy using the newly proposed definition for BPD and the previous definitions. Needs for supplemental oxygen and positive pressure (positive pressure ventilation or NCPAP) during initial hospitalization were evaluated in 266 inborn LBW infants (birth weight <1251 g). The data were categorized in three weight groups, <751, 751 to 1000 and 1001 to 1250 g and the incidence of BPD was computed in survivors based on oxygen need at 28 days, 36 weeks postmenstrual age (PMA) and the new severity of BPD criteria, that is, mild BPD: need for supplemental oxygen > or =28 days, but not at 36 weeks PMA; moderate BPD: need for supplemental oxygen > or =28 days and <30% at 36 weeks PMA and severe BPD: need for supplemental oxygen > or =28 days, and >30% at 36 weeks PMA and/or positive pressure at 36 weeks PMA. Further, BPD-associated comorbidities and short-term outcome data during hospitalization were compared among the groups, defined by severity of BPD. Among LBW infants <1251 g, the incidences of BPD at 28 days and 36 weeks PMA were 21.1 and 7.4% respectively. Using the newly defined criteria, the incidences of mild, moderate and severe BPD were 13.5, 4.8 and 2.6%, respectively. In total, 64.6% of these infants had mild BPD and 70.8% weighed <751 g at birth. Associated comorbidities correlated significantly with grades of underlying pulmonary disease. Also, significantly longer hospital stay, discharge at a higher PMA and lower growth velocity was observed with increasing grades of BPD. The new system for grading the severity of BPD offers a better description of underlying pulmonary disease and correlates with the infant's maturity, growth and overall severity of illness. Whether it will have a role in predicting long-term outcome remains to be determined.

Impact of a Physiologic Definition on Bronchopulmonary Dysplasia Rates

Bronchopulmonary dysplasia (BPD) is the endpoint of many intervention trials in neonatology, yet the outcome measure when based solely on oxygen administration may be confounded by differing criteria for oxygen administration between physicians. We previously reported a technique to standardize the definition of BPD between sites by using a timed room-air challenge in selected infants. We hypothesized that a physiologic definition of BPD would reduce the variation in observed rates of BPD among different neonatal centers. Methodology. A total of 1598 consecutive inborn premature infants (501-1249 g birth weight) who remained hospitalized at 36 weeks' postmenstrual age were prospectively assessed and assigned an outcome with both a clinical definition and physiologic definition of BPD. The clinical definition of BPD was oxygen supplementation at exactly 36 weeks' postmenstrual age. The physiologic definition of BPD was assigned at 36 +/- 1 weeks' postmenstrual age and included 2 distinct subpopulations. First, neonates on positive pressure support or receiving >30% supplemental oxygen with saturations between 90% and 96% were assigned the outcome BPD and not tested further. Second, those receiving < or =30% oxygen or effective oxygen >30% with saturations >96% underwent a room-air challenge with continuous observation and oxygen-saturation monitoring. Outcomes of the room-air challenge were "no BPD" (saturations > or =90% during weaning and in room air for 30 minutes) or "BPD" (saturation <90%). At the conclusion of the room-air challenge, all infants were returned to their baseline oxygen levels. Safety (apnea, bradycardia, increased oxygen use) and outcomes of the physiologic definition versus the clinical definition were assessed. A total of 560 (35.0%) neonates were diagnosed with BPD by the clinical definition of oxygen use at 36 weeks' postmenstrual age. The physiologic definition diagnosed BPD in 398 (25.0%) neonates in the cohort. All infants were safely studied. There were marked differences in the impact of the definition on BPD rates between centers (mean reduction: 10%; range: 0-44%). Sixteen centers had a decrease in their BPD rate, and 1 center had no change in their rate. The physiologic definition of BPD reduced the overall rate of BPD and reduced the variation among centers. Significant center differences in the impact of the physiologic definition were seen, and differences remained even with the use of this standardized definition. The magnitude of the change in BPD rate is comparable to the magnitude of treatment effects seen in some clinical trials in BPD. The physiologic definition of BPD facilitates the measurement of BPD as an outcome in clinical trials and the comparison between and within centers over time.

Safety, reliability, and validity of a physiologic definition of bronchopulmonary dysplasia.

Bronchopulmonary dysplasia (BPD) is the focus of many intervention trials, yet the outcome measure when based solely on oxygen administration may be confounded by differing criteria for oxygen administration between physicians. Thus, we wished to define BPD by a standardized oxygen saturation monitoring at 36 weeks corrected age, and compare this physiologic definition with the standard clinical definition of BPD based solely on oxygen administration. A total of 199 consecutive very low birthweight infants (VLBW, 501 to 1500 g birthweight) were assessed prospectively at 36+/-1 weeks corrected age. Neonates on positive pressure support or receiving >30% supplemental oxygen were assigned the outcome BPD. Those receiving < or =30% oxygen underwent a stepwise 2% reduction in supplemental oxygen to room air while under continuous observation and oxygen saturation monitoring. Outcomes of the test were "no BPD" (saturations > or =88% for 60 minutes) or "BPD" (saturation < 88%). At the conclusion of the test, all infants were returned to their baseline oxygen. Safety (apnea, bradycardia, increased oxygen use), inter-rater reliability, test-retest reliability, and validity of the physiologic definition vs the clinical definition were assessed. A total of 199 VLBW were assessed, of whom 45 (36%) were diagnosed with BPD by the clinical definition of oxygen use at 36 weeks corrected age. The physiologic definition identified 15 infants treated with oxygen who successfully passed the saturation monitoring test in room air. The physiologic definition diagnosed BPD in 30 (24%) of the cohort. All infants were safely studied. The test was highly reliable (inter-rater reliability, kappa=1.0; test-retest reliability, kappa=0.83) and highly correlated with discharge home in oxygen, length of hospital stay, and hospital readmissions in the first year of life. The physiologic definition of BPD is safe, feasible, reliable, and valid and improves the precision of the diagnosis of BPD. This may be of benefit in future multicenter clinical trials.

Bronchopulmonary dysplasia: changes in pathogenesis, epidemiology and definition

Bronchopulmonary dysplasia (BPD) continues to be one of the most common long-term complications associated with preterm birth. Its incidence is increasing as the survival of extreme premature infants improves, but its clinical presentation is milder than the original description of Northway and collaborators. In contrast to the classic BPD that was strongly related to mechanical injury and oxygen toxicity, current forms of the condition are more related to immaturity, perinatal infection and inflammation, persistent ductus arteriosus and disrupted alveolar and capillary development. Many different definitions of BPD have been proposed, most of which are based on the duration of supplemental oxygen requirement. The different definitions can produce strikingly different incidence figures, which may account for the wide variations in the condition reported in the literature. Some of the limitations of the criteria most commonly used to diagnose BPD are discussed in this article.

Bronchopulmonary dysplasia: an enduring challenge.

1. Yvonne E. Vaucher, MD, MPH* 1. *Clinical Professor of Pediatrics, Division of Neonatology, University of California, San Diego, Calif. After completing this article, readers should be able to: 1. Describe the most common cause of chronic lung disease during infancy. 2. Explain the importance of a history of bronchopulmonary dysplasia throughout childhood. 3. Identify infants at high risk for developing bronchopulmonary dysplasia. 4. List the adverse effects associated with postnatal corticosteroids. Despite clinical advances in antepartum, intrapartum, and neonatal care, bronchopulmonary dysplasia (BPD) continues to challenge infants who have been in neonatal intensive care units and their caretakers. BPD is the most common cause of chronic respiratory disease during infancy and remains a major cause of long-term medical, pulmonary, and neurodevelopmental morbidity, increasing the cost of health care and the utilization of medical and educational resources throughout childhood. BPD is a clinical diagnosis, defined by oxygen dependence for a specific period of time after birth and accompanied by characteristic radiographic findings that correspond to anatomic abnormalities. Thus far, a precise physiologic definition of BPD is lacking. As the clinical presentation has evolved over the past 30 years, so has the definition. As originally described by Northway in the 1960s, the diagnosis of classic BPD was based on progressive radiographic changes in preterm infants who were treated for severe respiratory distress syndrome (RDS) immediately after birth and had prolonged ventilator and oxygen dependence. This form of BPD occurred in larger, relatively mature preterm infants, who required treatment with high-pressure mechanical ventilation and high concentrations of oxygen. Although the acute respiratory disease initially improved in these infants, oxygen requirements increased 7 to 10 days after birth and persisted for at least 28 days. The definition of BPD subsequently was modified by Bancalari to include preterm infants who had less severe RDS that initially required short-term mechanical ventilation, but who also developed persistent respiratory symptoms and an oxygen requirement for at least 28 days after birth …

Evaluating “old” definitions for the “new” bronchopulmonary dysplasia

Objectives: To examine the accuracy of different criteria for the diagnosis of bronchopulmonary dysplasia (BPD), based on the final age at which oxygen therapy was stopped, in predicting pulmonary and neurologic outcomes at 18-month corrected age. Study design: Data were collected prospectively on infants with birth weights between 500 and 999 g enrolled in the Trial of Indomethacin Prophylaxis in Preterms (TIPP) who survived to discharge home. Differing postnatal ages and postmenstrual ages at which supplemental oxygen therapy was no longer required formed the criteria for defining BPD. Diagnostic accuracy of each criterion for defining BPD was calculated for both poor pulmonary and poor neurosensory outcomes. Results: The prevalence of poor pulmonary outcome was 54% and of poor neurosensory outcome was 34% in the 956 infants who were eligible for this analysis. Accuracy of different definitions of BPD was limited but greatest when using supplemental oxygen requirement at 36 weeks' postmenstrual age to predict long-term pulmonary outcome (63%) and 40 weeks to predict long-term neurosensory outcome (68%). Conclusions: Poor pulmonary outcome and poor neurosensory outcome are common late adverse outcomes in this population. BPD as defined by duration of oxygen therapy is a less accurate surrogate currently than in previous eras. (J Pediatr 2002;140:555-60)

Bronchopulmonary dysplasia: prevention, management and long-term outlook

Despite major advances in neonatology over the last few years, neonatal intensive care units continue to care for a number of infants with ventilator and oxygen dependency or bronchopulmonary dysplasia (BPD). In 1967 Northway first described a chronic lung disease which developed after recovery from respiratory distress syndrome (RDS). 1 The original description was of a progressive illness culminating at 30 days in severe lung disease with oxygen dependency and a characteristic chest X-ray. The definition of BPD has evolved to the criteria currently used in Table 1. 36 weeks gestation is a more useful cut off when considering extremely preterm babies and is more predictive of final outcome than respiratory status at 28 days of life. The typical chest X-ray of BPD is seen in Figure 1. There are two variants which are sometimes seen in clinical practice. In the first the clinical criteria are similar but the lung appearance on chest radiograph is relatively normal or shows minor bilateral diffuse opacities. In the second the nonventilated preterm infant develops a persistent oxygen requirement commencing in the second week of life or later (Wilson Mikity syndrome). The prognosis in these two groups is better than in classical BPD. Although definitions of BPD are useful for statistics and comparisons, they are less useful clinically. BPD is more of a continuum of lung insult, injury and repair from birth. The absence of a diuresis classically present in the recovery phase of RDS, the development of pulmonary interstitial emphysema or pneumothoraces on the chest radiograph and the inability to wean the infant from the ventilator by day 7 of life are all early signs that chronic lung disease is likely to be established and the infant will continue to require respiratory support. The incidence of BPD from published studies varies considerably and is partly dependent on the definition. It varies from 3 0 4 0 % in mechanically ventilated newborns. 2~ Over the last 3 years a reduction in the number of babies with BPD on our Unit has been noted with an incidence of 15% in infants under 1500 g in 1995. Other units in the UK are reporting an increase. Good epidemiological studies are required to explain these differences.

Home oxygen therapy

Long term oxygen therapy may be administered in hospital or at home. It can be difficult to make decisions about which babies should remain in 02, for how long and where the therapy should be administered, not least because decisions about continuing need for 02 may affect timing of discharge home. As the survival of very low birth weight infants is increasing so is the number of infants with chronic lung disease, whether described by the continuing need for 02 supplementation at a month from birth, at 36 weeks gestation or by Northway's definition of bronchopulmonary dysplasia (BPD) 1 with its evidence of significant ongoing respiratory dysfunction. Neonates surviving a variety of other early illnesses such as severe meconium aspiration syndrome, cardiac or neuromuscular diseases may also require prolonged 02 therapy.

Neurodevelopmental Outcome in Infants with Bronchopulmonary Dysplasia

It appears that the survivor of BPD is at risk for neurodevelopmental compromise but not necessarily to any greater extent than are prematurely born infants in general. What appears to be true is that as the neonatal course becomes more complicated, and the birth weight drops, the risk increases. If a BPD survivor sustains a moderate to severe IVH, particularly if accompanied by periventricular leukomalacia, the risk of significant handicap increases substantially. Effects of socioeconomic status (SES) are also important, and become more evident over time with a direct correlation between SES and outcome. Maximizing the environmental conditions while in the special care nursery, and reducing stress on the infant during the illness, may help to reduce risk of a compromised developmental outcome in the survivors. Careful monitoring of oxygen saturation postdischarge may similarly have a positive effect on outcome. Although direct comparability among studies is not possible, it appears that most reports suggest about half the survivors are free of any handicapping condition at follow-up, and about half are either moderately or severely impaired. Cerebral palsy is the most frequently reported handicapping condition. Since the presence or absence of significant IVH is not consistently reported across studies, it is not possible to know if infants who subsequently develop CP sustained a bleed, in addition to BPD, in the neonatal period. In studies in which this is more carefully delineated, that appears to be the case. In studies in which infants with significant hemorrhage were either excluded or dropped out, no survivors with cerebral palsy are reported. Approximately 4% of survivors across all studies reviewed were blind as a result of severe retinopathy of prematurity. Several studies excluded infants who developed significant ROP from their follow-up, so this percentage may be an underestimate of the actual incidence across all BPD survivors. With a greater number of gestationally younger infants surviving, this is one area of handicap that may increase in the years to come. Not all studies report on the presence of sensorineural hearing loss in survivors, but there is the suggestion this may occur perhaps in up to 4% of survivors. This is an area that future research should address. For infants who fall in the moderately handicapped category, typically defined as more than one standard deviation below the mean on a standardized developmental examination, that rating may change over time in either direction.(ABSTRACT TRUNCATED AT 400 WORDS)

Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is the most common chronic respiratory disease that results from complications related to the lung injury during the treatment of respiratory distress syndrome, or develops in older infants when abnormal lung growth occurs. The definition and classification of BPD have changed since the original diagnosis was established many years ago. The incidence of BPD continues to grow as lower-birth-weight infants continue to survive. The primary focus of all treatment associated with premature infants is on prevention of BPD. Surfactant replacement, invasive and noninvasive ventilation techniques, management of the patent ductus arteriosus, cautious management of oxygen therapy, caffeine, inhaled nitric oxide, and changes in delivery room practices have been studied to assess their effects on the development of the disease. Other strategies used to reduce the long-term effects of this chronic lung disease include bronchodilators, inhaled and systemic steroids, nutrition management, and selected ventilator strategies. The prevention of BPD is targeted at minimizing effects of this pulmonary disease and preventing the long-term sequelae associated with its treatment.