Is the new definition of bronchopulmonary dysplasia more useful?

Echocardiography parameters used in identifying right ventricle dysfunction in preterm infants with early bronchopulmonary dysplasia: A scoping review

Background

Bronchopulmonary Dysplasia (BPD) is a chronic condition that affects preterm infants and is associated with long-term complications. Haemodynamic effects of BPD can lead to right ventricular (RV) dysfunction.

Objective

To synthesise and map the evidence of echo parameters used in identifying RV dysfunction in the first two weeks-after-birth (WAB) of preterm infants with early BPD.

Information Sources

This scoping review included the databases: Medline, CINAHL, PubMed, EMBASE, Scopus, ProQuest, Web of Science, Cochrane Library, JBI Evidence-Based Practise and Gray Literature.

Search Strategy

The search utilised Boolean operators and descriptors registered in Medical Subject Headings.

Inclusion and exclusion criteria

Included were studies utilising echo parameters to examine RV function in preterm infants with early BPD in the first two WAB.

Synthesis of results

The results are presented as a map of the extracted findings in a tabular format with a narrative summary.

Results

Eight studies were included. Differences were observed in the number and timing of echo scans performed in the first two WAB and the variations in the echo parameters used to compare preterm infants with and without early BPD. Only echo scans performed at the end of the first WAB, demonstrated significant differences in the echo parameters measurements between preterm infants with and without BPD. Studies using RV Myocardial Performance Index (MPI) to identify RV-dysfunction associated with early BPD demonstrated similar findings. The Pulsed-Wave Doppler technique identified differences in RV-MPI between preterm infants with and without BPD, while Tissue-Doppler-Imaging did not demonstrate similar results. Speckle tracking can measure strain (S) and strain rate (SR) and diagnose RV-dysfunction. However, the findings of studies that utilised speckle tracking varied. Finally, two of the included studies added blood tests to their diagnostic model of early BPD, which was able to demonstrate significant differences in blood test results between BPD-affected and control preterm infants.

Conclusion

BPD could adversely affect the myocardium function of the RV; these negative influences can be captured in the first two WAB. However, there are still knowledge gaps regarding the appropriate number, timing and the most suitable echo parameters to assess RV function.

The challenge of accurately describing the epidemiology of bronchopulmonary dysplasia (BPD) based on the various current definitions of BPD

Despite marked improvements in the survival of extremely low birth weight preterm infants, bronchopulmonary dysplasia (BPD) remains a prevalent morbidity. BPD has evolved pathologically and epidemiologically but the definition has failed to keep up. The majority of the definitions of BPD still use the respiratory support provided to the infants at a single timepoint. The lack of a uniform definition of BPD presently reflects the changing BPD pathogenesis and phenotype and limits defining the epidemiology. To address the epidemiology of BPD, the definition should be clarified; even the newer definitions have not been validated entirely. The definition needs to be meaningful clinically and be predictive of long-term respiratory outcomes. We believe the definition should have a composite assessment like a score (quantitative measurement) and include the different phenotypes (qualitative measurements) so that optimally they can be applied to the different phases of BPD and at different timepoints. Furthermore, the definitions need to be easy to measure and assess so that generalizability is enhanced.

Right ventricular function and vasoactive peptides for early prediction of bronchopulmonary dysplasia

BACKGROUND

To assess the prognostic value of early echocardiographic indices of right ventricular function and vasoactive peptides for prediction of bronchopulmonary dysplasia (BPD) or death in very preterm infants.

METHODS

Prospective study involving 294 very preterm infants (median [IQR] gestational age 28.4 [26.4-30.4] weeks, birth weight 1065 [800-1380] g), of whom 57 developed BPD (oxygen supplementation at 36 weeks postmenstrual age) and 10 died. Tricuspid annular plane systolic excursion (TAPSE), right ventricular index of myocardial performance (RIMP), plasma concentrations of mid-regional pro-atrial natriuretic peptide (MR-proANP) and C-terminal pro-endothelin-1 (CT-proET1) were measured on day 7 of life.

RESULTS

RIMP was significantly increased (median [IQR] 0.3 [0.23-0.38] vs 0.22 [0.15-0.29]), TAPSE decreased (median [IQR] 5.0 [5.0-6.0] vs 6.0 [5.4-7.0] mm), MR-proANP increased (median [IQR] 784 [540-936] vs 353 [247-625] pmol/L), and CT-proET1 increased (median [IQR] 249 [190-345] vs 199 [158-284] pmol/L) in infants who developed BPD or died, as compared to controls. All variables showed significant but weak correlations with each other (rS -0.182 to 0.359) and predicted BPD/death with similar accuracy (areas under receiver operator characteristic curves 0.62 to 0.77). Multiple regression revealed only RIMP and birth weight as independent predictors of BPD or death.

CONCLUSIONS

Vasoactive peptide concentrations and echocardiographic assessment employing standardized measures, notably RIMP, on day 7 of life are useful to identify preterm infants at increased risk for BPD or death.

Revisiting the definition of bronchopulmonary dysplasia in premature infants at a single center quaternary neonatal intensive care unit

OBJECTIVE

To compare the incidence of bronchopulmonary dysplasia (BPD) based on the 1988 Vermont Oxford Network (VON) criteria, National Institutes of Health (NIH) 2001 definition, and NIH 2018 definition.

METHODS

BPD incidence by each definition was compared in premature infants born at a single center between 2016 and 2018. Comorbidities were compared between those with and without BPD according to the newest definition.

RESULTS

Among 352 survivors, BPD incidence was significantly different at 9%, 28% and 34% according to VON, NIH 2001 and NIH 2018 definitions, respectively (p < 0.05). According to the newest definition, any grade of BPD was associated with more co-morbidities than those without BPD (P < 0.001).

CONCLUSION

At a center that emphasizes use of early noninvasive respiratory support, the incidence of BPD was significantly higher according to the NIH 2018 definition compared to other two definitions. The relationship between BPD diagnosis and long-term clinical outcomes remains unclear.

Bronchopulmonary dysplasia: Rationale for a pathophysiological rather than treatment based approach to diagnosis

Bronchopulmonary dysplasia (BPD), also known as Chronic Lung Disease (CLD), is a chronic respiratory condition of prematurity with potential life-long consequences for respiratory well-being. BPD was first described by Northway in 1967, when the mean gestation of preterm infants with BPD was 34 weeks' postmenstrual age (PMA). Survival of preterm infants at lower gestational ages has increased steadily since 1967 associated with marked improvements in respiratory management of respiratory distress syndrome. Currently, BPD develops in approximately 45 % of all infants born extremely preterm (Stoll et al., 2015). These smaller and more immature babies are born during the late canalicular or early saccular period of lung development. Not surprisingly, the pathophysiology of BPD also evolved since classical BPD was described. As the nature and our understanding of BPD evolved, so too the definitions and classification of BPD changed over time. These differing and ever-changing definitions hamper clinical benchmarking as they are interpreted and applied inconsistently, and define BPD and its severity by non-standardised treatments rather than independent evaluations of structure or function. A standardised, unambiguous definition and classification of BPD is essential for evaluation and improvement in clinical practice, both within an individual unit, as well as across and between neonatal networks. The determination and implementation of diagnostic criteria and severity classification that is standardised, globally applicable, and that has prognostic utility for clinical outcomes and guidance of ongoing respiratory management remain of utmost importance. This review describes the evolution of BPD definitions, evaluates the benefits and limitations of each approach, and discusses alternative approaches that may improve the functional assessment of BPD severity.

Bronchopulmonary dysplasia: risk prediction models for very-low- birth-weight infants

OBJECTIVE

Our objective is to develop risk prediction models for moderate/severe bronchopulmonary dysplasia (BPD) and BPD and/or death in very-low-birth-weight infants (VLBWI) at birth, 3, 7, and 14 postnatal days.

STUDY DESIGN

It is a multicenter study including 16,407 infants weighing 500-1500 g (2001-2015) from the Neocosur Network. BPD was defined as oxygen dependency at 36 weeks. Variables were selected using forward logistic regression models. Predictive values were evaluated using the ROC curve.

RESULTS

In total, 2580 (15.7%) presented BPD and 6121 (37.3%) BPD/death. The AUC values for the BPD models were 0.788, 0.818, 0.827, and 0.894 respectively. For BPD/death, the AUC values were 0.860, 0.869, 0.867, and 0.906. BW and gestational age had higher contribution at birth; at later ages, the length of oxygen therapy and ventilation had the highest contribution. All AUC values were statistically significant when compared with a neutral value of 0.5 (p-value < 0.001).

CONCLUSIONS

We developed high predictive power models for moderate/severe BPD and BPD/death at four postnatal ages.

Effectiveness of Respiratory Syncytial Virus Immunoprophylaxis in Reducing Bronchiolitis Hospitalizations Among High-Risk Infants

We sought to determine the real-world effectiveness of respiratory syncytial virus (RSV) immunoprophylaxis in a population-based cohort to inform policy. The study population included infants born during 1996-2008 and enrolled in the Kaiser Permanente Northern California integrated health-care delivery system. During the RSV season (November-March), the date of RSV immunoprophylaxis administration and the following 30 days were defined as RSV immunoprophylaxis protected period(s), and all other days were defined as unprotected period(s). Numbers of bronchiolitis hospitalizations were determined using International Classification of Diseases, Ninth Revision, codes during RSV season. We used a proportional hazards model to estimate risk of bronchiolitis hospitalization when comparing infants' protected period(s) with unprotected period(s). Infants who had ever received RSV immunoprophylaxis had a 32% decreased risk of bronchiolitis hospitalization (adjusted hazard ratio = 0.68, 95% confidence interval: 0.46, 1.00) when protected periods were compared with unprotected periods. Infants with chronic lung disease (CLD) had a 52% decreased risk of bronchiolitis hospitalization (adjusted hazard ratio = 0.48, 95% confidence interval: 0.25, 0.94) when protected periods were compared with unprotected periods. Under the new 2014 American Academy of Pediatrics (AAP) guidelines, 48% of infants eligible for RSV immunoprophylaxis on the basis of AAP guidelines in place at birth would no longer be eligible, but nearly all infants with CLD would remain eligible. RSV immunoprophylaxis is effective in decreasing hospitalization. This association is greatest for infants with CLD, a group still recommended for receipt of RSV immunoprophylaxis under the new AAP guidelines.

Relevance of clinical features in the prognosis of bronchopulmonary dysplasia in premature infants

The aim of this study is to determine the accuracy rate of bronchopulmonary dysplasia (BPD) diagnosis and risk factors of short-term poor prognosis for premature infants. This study analyzed the clinical data of 81 premature infants (<32 weeks gestational age) with BPD, who were on oxygen therapy >28 days, and survived >36 weeks (corrected age). Outcome measures included treatments, conditions on the 28th day after birth, oxygen therapy conditions at the 36th week, occurrence of any serious complications during hospital stay. The major risk factors affecting prognosis were ventilation duration, duration of oxygen therapy, application of steroids, hypothyroidism and severity of BPD (all P<0.05). Interventions for complications (n=53) resulted in ceased inhalation of oxygen in 12 infants, improvement of symptoms in 26 infants, and were ineffective in 15 infants. BPD prognosis can be improved by shortening the duration of invasive ventilation and correcting thyroid function.

Scoping review shows wide variation in the definitions of bronchopulmonary dysplasia in preterm infants and calls for a consensus

The use of different definitions for bronchopulmonary dysplasia (BPD) has been an ongoing challenge. We searched papers published in English from 2010 and 2015 reporting BPD as an outcome, together with studies that compared BPD definitions between 1978 and 2015. We found that the incidence of BPD ranged from 6% to 57%, depending on the definition chosen, and that studies that investigated correlations with long-term pulmonary and/or neurosensory outcomes reported moderate-to-low predictive values regardless of the BPD criteria.

CONCLUSION

A comprehensive and evidence-based definition for BPD needs to be developed for benchmarking and prognostic use.

Chorioamnionitis and subsequent bronchopulmonary dysplasia in very-low-birth weight infants: a 25-year cohort

OBJECTIVE

To determine whether chorioamnionitis (CA) or sepsis were associated with bronchopulmonary dysplasia (BPD) in a 25-year cohort of very-low-birth weight (VLBW) infants.

STUDY DESIGN

VLBW infants ⩽32 weeks gestation admitted to the neonatal intensive care unit between 1989 and 2014 were reviewed. BPD was defined using the National Institutes of Health consensus definition. CA was defined clinically. Logistic regression models were used for BPD prediction.

RESULTS

One thousand six hundred and eighty-seven infants were included; 44% (n=740) had moderate or severe BPD. In multivariable analysis, lower gestational age (odds ratio (OR) 1.12 per week (95% confidence interval (CI) 1.11, 1.14)), sepsis (OR 2.03 (95% CI 1.49, 2.77)) and birth year ⩾1995 (OR 1.49 (95% CI 1.09, 2.04)) were significant predictors of BPD. CA was not associated with BPD (OR 1.18 (95% CI 0.66, 2.11)).

CONCLUSION

Sepsis, but not CA, is associated with the development of moderate or severe BPD in VLBW infants after controlling for gestational age.

Persistently elevated right ventricular index of myocardial performance in preterm infants with incipient bronchopulmonary dysplasia

OBJECTIVES

Elevated pulmonary vascular resistance occurs during the first days after birth in all newborn infants and persists in infants at risk for bronchopulmonary dysplasia (BPD). It is difficult to measure in a non-invasive fashion. We assessed the usefulness of the right ventricular index of myocardial performance (RIMP) to estimate pulmonary vascular resistance in very low birth weight infants.

STUDY DESIGN

Prospective echocardiography on day of life (DOL) 2, 7, 14, and 28 in 121 preterm infants (median [quartiles] gestational age 28 [26]-[29] weeks, birth weight 998 [743-1225] g) of whom 36 developed BPD (oxygen supplementation at 36 postmenstrual weeks).

RESULTS

RIMP derived by conventional pulsed Doppler technique was unrelated to heart rate or mean blood pressure. RIMP on DOL 2 was similar in infants who subsequently did (0.39 [0.33-0.55]) and did not develop BPD (0.39 [0.28-0.51], p = 0.467). RIMP declined steadily in non-BPD infants but not in BPD infants (DOL 7: 0.31[0.22-0.39] vs. 0.35[0.29-0.48], p = 0.014; DOL 14: 0.23[0.17-0.30] vs. 0.35[0.25-0.43], p<0.001; DOL 28: 0.21[0.15-0.28] vs. 0.31 [0.21-0.35], p = 0.015).

CONCLUSIONS

In preterm infants, a decline in RIMP after birth was not observed in those with incipient BPD. The pattern of RIMP measured in preterm infants is commensurate with that of pulmonary vascular resistance.

Nasal respiratory support through the nares: its time has come

Respiratory distress syndrome (RDS) is the most common respiratory morbidity in preterm infants. Surfactant therapy and invasive mechanical ventilation through the endotracheal tube (ETT) have been the cornerstones in RDS management. Despite improvements in the provision of mechanical ventilation, bronchopulmonary dysplasia (BPD), a multifactorial disease in which invasive mechanical ventilation is a known contributory factor, remains an important cause of morbidity among preterm infants. Barotrauma, volutrauma or oxygen-induced lung inflammation (oxy-trauma) contributes significantly to the development of BPD in neonates ventilated through an ETT. Recently, nasal respiratory support has been increasingly used in preterm infants in an attempt to decrease post-extubation failure and, perhaps, BPD, and for the treatment of apnea of prematurity in nonventilated neonates. Observational studies using noninvasive respiratory support, such as nasal continuous positive airway pressure (NCPAP), have shown a decrease in the incidence of BPD when used to avoid intubation or minimize the duration of invasive mechanical ventilation through the ETT. Moreover, synchronized as well as nonsynchronized nasal intermittent positive-pressure ventilation (NIPPV) have been shown to significantly decrease post-extubation failure compared with NCPAP and their use has been associated with a reduced risk of BPD in small randomized controlled clinical trials. More recently, early surfactant administration followed by extubation to NIPPV has been suggested to be synergistic in decreasing BPD. Although these findings are promising, additional studies evaluating different nasal interfaces, flow synchronization, synchronization using neurally adjusted ventilatory assist mode, and closed loop control of oxygen during nasal ventilation to minimize lung injury are needed in an attempt to further decrease the incidence of lung injury in preterm neonates requiring respiratory support.

Lack of association between FXIII-Val34Leu, FVII-323 del/ins, and transforming growth factor beta1 (915G/T) gene polymorphisms and bronchopulmonary dysplasia: a single-center study

Bronchopulmonary dysplasia (BPD) is a multifactorial disease of preterm infants that is characterized by airway injury, inflammation, and parenchymal remodeling. Extravascular fibrin deposits in septae and alveoli due to the altered fibrin turnover are the pathological hallmarks of BPD that strongly indicates the importance of the imbalance in the competing activities of coagulation and fibrinolysis. Activation of the coagulation cascade leads to intraalveolar fibrin deposition in many inflammatory pulmonary disorders. Increased fibrin formation or decreased fibrinolysis may cause extravascular fibrin deposition. We evaluated the association between FXIII-Val34Leu, FVII-323 del/ins, and transforming growth factor beta1 (TGF-beta(1)) (915G/T) gene polymorphisms in patients with BPD. The study group consisted of 98 preterm infants with BPD. Ninety-four of the 192 preterm neonates were without BPD and sampled for the control group. Restriction fragment size analyses were performed by examining digested PCR products for FXIII-Val34Leu, FVII-323 del/ins, and TGF-beta(1) (915G/C) genotypes. No significant associations were found between FXIII-Val34Leu, FVII-323 del/ins, TGF-beta(1) (915G/C) gene polymorphisms and BPD phenotype in our population. Further studies with other genes are required for the identification of molecular predisposing factors for BPD that may help in the development of new treatments and hence might allow for targeting of this treatment to a "high-risk" subgroup, reducing unnecessary exposure to potentially harmful therapies.

[Bronchopulmonary dysplasia and prematurity. Short-and long-term respiratory changes]

Bronchopulmonary dysplasia (BPD) is the most frequent chronic lung disease in premature children. With the inclusion of antenatal steroid therapy, surfactant use and novel mechanical ventilation strategies, survival of premature newborns has increased, whereupon the incidence of BPD has not only decreased but has also risen in extremely premature newborns. This has led to a high respiratory morbidity in the first 2-3 years of life, with numerous admissions to hospital and respiratory exacerbations mostly due to viral infections. Although there is a trend towards improvement, during school age and adolescence, respiratory symptoms may persist, due to changes in pulmonary function often showing a lower exercise capacity. Although BPD symptoms are similar to those of asthma, as there is limitation in airflow and bronchial hyperresponsiveness (BHR), pathophysiological mechanisms could be different in both diseases. On the other hand, isolated prematurity plays an important role in the child's respiratory pathology, proving that pulmonary function alterations in preterm children are present since the first months of life. A higher respiratory morbidity has also been observed in these children when compared to full-term newborns, not only during the first years of life but also subsequently. In this study, different aspects of chronic respiratory disease associated with prematurity will be analysed, drawing special attention to clinical symptoms, respiratory function changes, BHR and exercise capacity. All these aspects will be reviewed from early childhood until adolescence and young adult age. Similarities and differences between BPD and asthma will also be discussed.

Pathogenesis and prevention of chronic lung disease in the neonate

Often used interchangeably, chronic lung disease (CLD) or bronchopulmonary dysplasia (BPD) develops primarily in extremely low birth weight infants weighing <1000 g who receive prolonged oxygen therapy and or positive pressure ventilation. CLD, which occurs in as many as 30 percent of infants born weighing <1000 g, contributes significantly to the morbidity and mortality seen in very low birth weight infants. Despite extensive research aimed at identifying risk factors and devising preventative therapies, many questions about the etiology and pathogenesis of BPD remain. This article reviews the embryologic development of the lung and the pathogenesis of CLD or BPD. The authors discuss some of the measures that have been used in an attempt to both prevent and treat BPD.

Chronic wet cough: Protracted bronchitis, chronic suppurative lung disease and bronchiectasis

The role of persistent and recurrent bacterial infection of the conducting airways (endobronchial infection) in the causation of chronic respiratory symptoms, particularly chronic wet cough, has received very little attention over recent decades other than in the context of cystic fibrosis (CF). This is probably related (at least in part) to the (a) reduction in non-CF bronchiectasis in affluent countries and, (b) intense focus on asthma. In addition failure to characterize endobronchial infections has led to under-recognition and lack of research. The following article describes our current perspective of inter-related endobronchial infections causing chronic wet cough; persistent bacterial bronchitis (PBB), chronic suppurative lung disease (CSLD) and bronchiectasis. In all three conditions, impaired muco-ciliary clearance seems to be the common risk factor that provides organisms the opportunity to colonize the lower airway. Respiratory infections in early childhood would appear to be the most common initiating event but other conditions (e.g., tracheobronchomalacia, neuromuscular disease) increases the risk of bacterial colonization. Clinically these conditions overlap and the eventual diagnosis is evident only with further investigations and long term follow up. However whether these conditions are different conditions or reflect severity as part of a spectrum is yet to be determined. Also misdiagnosis of asthma is common and the diagnostic process is further complicated by the fact that the co-existence of asthma is not uncommon. The principles of managing PBB, CSLD and bronchiectasis are the same. Further work is required to improve recognition, diagnosis and management of these causes of chronic wet cough in children.

Lung protective ventilatory strategies in very low birth weight infants

Respiratory distress syndrome (RDS) is the most common respiratory diagnosis in preterm infants. Surfactant therapy and mechanical ventilation using conventional or high-frequency ventilation have been the standard of care in the management of RDS. Bronchopulmonary dysplasia (BPD) continues to remain as a major morbidity in very low birth weight infants despite these treatments. There is no significant difference in pulmonary outcome when an optimal lung volume strategy is used with conventional or high-frequency ventilation. Lung injury is directly related to the duration of invasive ventilation via the endotracheal tube. Studies using noninvasive ventilation, such as nasal continuous positive airway pressure and noninvasive positive pressure ventilation, have shown to decrease postextubation failures as well as a trend toward reduced risk of BPD. Lung protective ventilatory strategy may involve noninvasive ventilation as a primary therapy or following surfactant administration in very preterm infants with RDS. Initial steps in the management of preterm infants may also include sustained inflation to establish functional residual capacity, followed by noninvasive ventilation to minimize lung injury and subsequent development of BPD.

PCO2 and room air saturation values in premature infants at risk for bronchopulmonary dysplasia

OBJECTIVE

To determine the capillary partial pressure of carbon dioxide (PCO(2)) and room air transcutaneous hemoglobin saturation (RA SAT) at 36 weeks' postmenstrual age (PMA) in infants born with weight between 501 and 1250 g.

STUDY DESIGN

Multicenter, prospective investigation with primary data collection within 72 h of 36 weeks PMA or discharge, whichever first. PCO(2) and RA SAT determinations were done at rest on infants not requiring mechanical ventilation or nasal continuous positive airway pressure (NCPAP).

RESULT

A total of 220 infants were enrolled (mean gestational age 27.7 weeks, mean birthweight 951 g). In infants with traditionally defined chronic lung disease (CLD) compared to those without CLD, the mean PCO(2) was significantly higher (54 versus 45 mm Hg) and the median RA SAT significantly lower (<80 versus 97%). In infants with the new classification of bronchopulmonary dysplasia (BPD), there was a significant linear trend toward increasing PCO(2) with increasing severity of BPD (45, 47, 54 and 62 mm Hg in No, Mild, Moderate and Severe BPD). There was a significant linear trend toward decreasing RA SAT with increasing severity of BPD (97, 95 <80, <80% in No, Mild, Moderate and Severe BPD).

CONCLUSION

Defining CLD as BPD based upon a RA SAT test is a more discriminate, objective method to categorize lung injury. PCO(2) is an objective measure of lung function that inversely correlates with RA SAT. These determinations done together at 36 weeks PMA may provide more precise and accurate estimates of lung injury that might allow for better understanding of pulmonary therapies and clearer comparison of BPD rates and severities among NICUs.

Acquired Nonneoplastic Neonatal and Pediatric Diseases

The lung biopsy is an established procedure to procure a pathologic diagnosis in a child with a suspected pneumonic process of undetermined etiology. Improvements in pediatric anesthesia and surgery have reduced the operative complications to a minimum. A biopsy can usually be taken through a small intercostal incision when localization is not especially important in a patient with diffuse changes (see Chapter 1). The alternative method for tissue sampling is the endoscopic transbronchial biopsy. There is less risk to the patient, but the specimen is smaller and crush artifacts from the instrument are more common.

Outcomes of extremely low birth weight (<1 kg) and extremely low gestational age (<28 weeks) infants with bronchopulmonary dysplasia: effects of practice changes in 2000 to 2003

OBJECTIVE

The goal was to evaluate whether changes in neonatal intensive care have improved outcomes for children with bronchopulmonary dysplasia (oxygen dependence at corrected age of 36 weeks).

METHODS

We compared outcomes of extremely low birth weight (<1 kg) and extremely low gestational age (<28 weeks) infants with bronchopulmonary dysplasia between 2 periods (period I, 1996-1999: extremely low birth weight, n = 122; extremely low gestational age, n = 118; period II, 2000-2003: extremely low birth weight, n = 109; extremely low gestational age, n = 107).

RESULTS

For both groups, significant practice changes between period I and period II included increased prenatal and decreased postnatal steroid therapy and increased surfactant therapy, indomethacin therapy, and patent ductus arteriosus ligation. Significant morbidity changes included decreased rates of severe cranial ultrasound abnormalities and increased rates of ventilator dependence. Rates of bronchopulmonary dysplasia did not change (52% vs 53%). Follow-up evaluation revealed significantly lower rates of neurosensory abnormalities during period II (extremely low birth weight: 29% vs 16%; extremely low gestational age: 31% vs 16%). There were no changes in rates of Mental Developmental Index scores of <70 (extremely low birth weight: 42% vs 42%; extremely low gestational age: 37% vs 45%) or overall developmental impairment (extremely low birth weight: 51% vs 49%; extremely low gestational age: 50% vs 51%). For the extremely low gestational age group, predictors of neurosensory abnormalities were severe cranial ultrasound abnormality and postnatal steroid therapy. Predictors of overall impairment included severe cranial ultrasound abnormalities, ventilator dependence, postnatal steroid therapy, and patent ductus arteriosus ligation. For the extremely low birth weight group, the only predictor of neurosensory abnormalities was severe cranial ultrasound abnormality. Predictors of overall impairment included multiple birth, ventilator dependence, and severe cranial ultrasound abnormalities.

CONCLUSIONS

Neurosensory outcomes of infants with bronchopulmonary dysplasia improved during 2000 to 2003 but overall neurodevelopmental outcomes did not change.

Noninvasive ventilation in the neonate

One of the most common and concerning complications seen in low-birth-weight infants is chronic lung disease. A variety of factors have been implicated in the etiology of chronic lung disease including lung inflammation and injury. Noninvasive ventilation (NIV), a term applied to a variety of devices capable of supporting neonatal ventilation without the use of an endotracheal tube, is receiving increasing attention as means to reduce damage often incurred with mechanical ventilation. This article will review the history of continuous positive pressure ventilation and will provide an overview of some of the other types of NIV being used in neonates. The literature supporting the use of NIV is reviewed, and nursing care of the infant receiving NIV is examined.

Long-term outcomes: what should the focus be?

The neonatal intervention trials of the 1980s and early 1990s focused primarily on short-term outcomes. Contemporary clinical trials have recognized the importance of longer-term outcomes but have rarely been powered to achieve that aim. This review discusses important and clinically relevant outcomes that future trials should be powered to address and identifies the challenges facing the neonatal clinical trials community. These challenges include consensus definitions of relevant outcomes that are objective and validated, variability among centers in populations and practices, and the need for predictive surrogate markers of long-term outcomes. Future trials must be designed and powered to address the potential for harm as well as the prospect of benefit.

The role of chronic hypoxia in the development of neurocognitive abnormalities in preterm infants with bronchopulmonary dysplasia

Bronchopulmonary dysplasia is the most common pulmonary morbidity in preterm infants and is associated with chronic hypoxia. Animal studies have demonstrated structural, neurochemical and functional alterations due to chronic hypoxia in the developing brain. Long-term impairments in visual-motor, gross and fine motor, articulation, reading, mathematics, spatial memory and attention skills are prevalent in survivors of bronchopulmonary dysplasia, and impairments appear to correlate with the severity of hypoxia. However, due to the simultaneous occurrence of multiple neurodevelopmental risk factors, a primary or potentiating role for chronic hypoxia in these impairments has yet to be conclusively established.

Surfactant therapy in preterm infants with respiratory distress syndrome and in near-term or term newborns with acute RDS

Many different surfactant preparations derived from animal sources, as well as synthetic surfactants, are available for the treatment of preterm infants with respiratory distress syndrome (RDS). Natural, modified surfactants containing surfactant-associated proteins appear to be more effective than non-protein-containing synthetic surfactants. Comparative trials with poractant alfa at a higher initial dose of 200 mg/kg appear to be associated with rapid weaning of FiO2, less need for additional doses, and decreased mortality in infants <32 weeks gestation when compared with beractant. Early rescue (<30 min of age) surfactant therapy is an effective method to minimize over treatment of some preterm infants who may not develop RDS. Surfactant therapy followed by rapid extubation to nasal ventilation appears to be more beneficial than continued mechanical ventilation. In near-term or term newborns with acute RDS, surfactant therapy has been shown to be 70% effective in improving respiratory failure.

Serum levels of seven cytokines in premature ventilated newborns: correlations with old and new forms of bronchopulmonary dysplasia

OBJECTIVE

In addition to the previous classification of chronic lung disease (CLD) O2 dependency at 36 weeks of postmenstrual age, a new definition of CLD has recently been proposed: new bronchopulmonary-dysplasia (BPD). This uses total duration of O2 supplementation and positive pressure requirements to delineate three degrees of severity (mild, moderate, and severe) according to the respiratory status at 36 weeks postmenstrual age. We analyzed the balance of serum proinflammatory and profibrotic/angiogenic cytokine concentrations in relation to CLD and the new BPD definition.

DESIGN AND SETTING

Descriptive study in a third-level neonatal ICU.

PATIENTS

Thirty-one preterm neonates with a gestational age of 24-29 weeks were studied to evaluate their serum cytokine concentration; they were previously enrolled in a randomized clinical trial to compare the effects of high-frequency oscillatory ventilation vs. intermittent mandatory ventilation in terms of pulmonary mechanics and lung cytokines. Serum samples were collected on days 1, 3, and 5 after birth until extubation to detect the levels of three proinflammatory cytokines plus four profibrotic/angiogenic cytokines, and correlations were examined to old CLD and new BPD. Ventilation treatments were distributed homogeneously between the groups and did not interfere with the results presented here.

RESULTS AND CONCLUSIONS

Old CLD development, mainly corresponding to the moderate/severe forms of new BPD, was associated with increased proinflammatory and profibrotic/angiogenic cytokines, while mild forms of new BPD were characterized only by increases in profibrotic/angiogenic cytokines, suggesting a different balance of two pathogenic mechanisms in different phases of the disease.

Validation of the National Institutes of Health consensus definition of bronchopulmonary dysplasia

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

The consensus BPD definition identifies a spectrum of risk for adverse pulmonary and neurodevelopmental outcomes in early infancy more accurately than other definitions.

Mycoplasmas and ureaplasmas as neonatal pathogens

The genital mycoplasmas represent a complex and unique group of microorganisms that have been associated with a wide array of infectious diseases in adults and infants. The lack of conclusive knowledge regarding the pathogenic potential of Mycoplasma and Ureaplasma spp. in many conditions is due to a general unfamiliarity of physicians and microbiology laboratories with their fastidious growth requirements, leading to difficulty in their detection; their high prevalence in healthy persons; the poor design of research studies attempting to base association with disease on the mere presence of the organisms in the lower urogenital tract; the failure to consider multifactorial aspects of diseases; and considering these genital mycoplasmas only as a last resort. The situation is now changing because of a greater appreciation of the genital mycoplasmas as perinatal pathogens and improvements in laboratory detection, particularly with regard to the development of powerful molecular nucleic acid amplification tests. This review summarizes the epidemiology of genital mycoplasmas as causes of neonatal infections and premature birth; evidence linking ureaplasmas with bronchopulmonary dysplasia; recent changes in the taxonomy of the genus Ureaplasma; the neonatal host response to mycoplasma and ureaplasma infections; advances in laboratory detection, including molecular methods; and therapeutic considerations for treatment of systemic diseases.