Determinants of chronic lung disease severity in the first year of life; A population based study

Comparison of New Bronchopulmonary Dysplasia Definitions on Long-Term Outcomes in Preterm Infants

OBJECTIVE

To compare the discriminative performances of the 2018 National Institutes of Health (NIH) and the 2019 Jensen definitions of bronchopulmonary dysplasia (BPD) with the 2001 NIH definition on adverse neurodevelopmental and respiratory outcomes at 2 years and 5 years corrected age.

STUDY DESIGN

In this single-center retrospective cohort study, outcomes of infants born at <30 weeks of gestational age were collected. The 3 definitions of BPD were compared by adding the different definitions to the National Institute of Child Health and Human Development's outcome prediction model for neurodevelopmental impairment (NDI) or death. Discriminative performance was compared for both outcomes at 2 years and 5 years corrected age by calculating the areas under the receiver operating characteristic curve and z-statistics.

RESULTS

The presence of BPD and its severity were determined in 584 infants. There were considerable shifts in BPD grading among the different definitions. At both time points, all BPD definition models had comparable discriminating power for NDI and respiratory morbidity, with one exception. Compared with the 2001 NIH definition, the 2018 NIH definition had less predictive power for the neurologic outcome at 2 years corrected age.

CONCLUSIONS

Our comparison of the 3 BPD definitions shows similar discriminative performance on long term neurodevelopmental and respiratory outcomes at 2 years and 5 years corrected age.

Development of a severity scale to assess chronic lung disease after extremely preterm birth

OBJECTIVE

Chronic lung disease of prematurity (CLDP) is a frequent complication of prematurity. We aimed to identify what clinicians believe are the most important factors determining the severity of CLDP in extremely preterm infants (<28 weeks gestational age) after discharge from the neonatal intensive care unit (NICU) through 12 months corrected age (CA), and to evaluate how these factors should be weighted for scoring, to develop a CLDP severity scale.

STUDY DESIGN

Clinicians completed a three-round online survey utilizing Delphi methodology. Clinicians rated the importance of various factors used to evaluate the severity of CLDP, from 0 (not at all important) to 10 (very important) for the period between discharge home from the NICU and 12 months CA. Fourteen factors were considered in Round 1; 13 in Rounds 2 and 3. The relative importance of factors was explored via a set of 16 single-profile tasks (i.e., hypothetical patient profiles with varying CLDP severity levels).

RESULTS

Overall, 91 clinicians from 11 countries who were experienced in treating prematurity-related lung diseases completed Round 1; 88 completed Rounds 2 and 3. Based on Round 3, the most important factors in determining CLDP severity were mechanical ventilation (mean absolute importance rating, 8.89), supplemental oxygen ≥2 L/min (8.49), rehospitalizations (7.65), and supplemental oxygen <2 L/min (7.56). Single-profile tasks showed that supplemental oxygen had the greatest impact on profile classification.

CONCLUSION

The most important factors for clinicians assigning CLDP severity during infancy were mechanical ventilation, supplemental oxygen ≥2 L/min, and respiratory-related rehospitalizations.

Newer bronchopulmonary dysplasia definitions and prediction of health economics impacts in very preterm infants

OBJECTIVE

To compare the abilities of bronchopulmonary dysplasia (BPD) definitions to predict hospital charges as a surrogate of disease complexity.

METHODS

Retrospective study of infants admitted to the neonatal intensive care unit (NICU) less than 32 weeks gestational age. Subjects were classified according to the Canadian Neonatal Network (CNN), the National Institute of Child Health and Human Development (NICHD) (2018), and Jensen BPD definitions as none, mild (1), moderate (2), or severe (3) BPD. Spearman's correlation was performed to evaluate the association of BPD definitions with health economics outcomes.

RESULTS

One hundred and sixty-eight infants were included with mean birth weight of 1197 g and mean gestational age of 28.4 weeks. More infants were classified as no BPD according to CNN definition (79%) in comparison to NICHD 2018 (64.3%) and Jensen (59.5%) definitions. There were fewer infants as the grade of severity increased for all definitions, this was most linear for Jensen definition with Grade 1 present in 25%, Grade 2 in 12.5%, and Grade 3 in 3%. A stronger correlation with NICU length of stay, NICU hospital charges, NICU charges per day, and first year of life hospital charges was detected for Jensen definition (correlation coefficient of 0.58, 0.66, 0.64, 0.67, respectively) in comparison to CNN and NICHD 2018 definitions (p < .0001).

CONCLUSION

Jensen BPD definition had the strongest correlation with first year health economics outcomes in our study. Validating recent BPD definitions using population-based data is imperative to improve family counseling and enhance the designs of quality improvement initiatives and therapeutic research studies targeting patient-centric outcomes.

Effects of neonatal lung abnormalities on parenchymal R2 * estimates

Infants admitted to the neonatal intensive care unit (NICU) often suffer from multifaceted pulmonary morbidities that are not well understood. Ultrashort echo time (UTE) magnetic resonance imaging (MRI) is a promising technique for pulmonary imaging in this population without requiring exposure to ionizing radiation. The aims of this study were to investigate the effect of neonatal pulmonary disease on R₂ * and tissue density and to utilize numerical simulations to evaluate the effect of different alveolar structures on predicted R₂ *.This was a prospective study, in which 17 neonatal human subjects (five control, seven with bronchopulmonary dysplasia [BPD], five with congenital diaphragmatic hernia [CDH]) were enrolled. Twelve subjects were male and five were female, with postmenstrual age (PMA) at MRI of 39.7 ± 4.7 weeks. A 1.5T/multiecho three-dimensional UTE MRI was used. Pulmonary R₂ * and tissue density were compared across disease groups over the whole lung and regionally. A spherical shell alveolar model was used to predict the expected R₂ * over a range of tissue densities and tissue susceptibilities. Tests for significantly different mean R₂ * and tissue densities across disease groups were evaluated using analysis of variance, with subsequent pairwise group comparisons performed using t tests. Lung tissue density was lower in the ipsilateral lung in CDH compared to both controls and BPD patients (both p < 0.05), while only the contralateral lung in CDH (CDHc) had higher whole-lung R₂ * than both controls and BPD (both p < 0.05). R₂ * differences were significant between controls and CDHc within all tissue density ranges (all p < 0.05) with the exception of the 80%-90% range (p = 0.17). Simulations predicted an inverse relationship between alveolar tissue density and R₂ * that matches empirical human data. Alveolar wall thickness had no effect on R₂ * independent of density (p = 1). The inverse relationship between R₂ * and tissue density is influenced by the presence of disease globally and regionally in neonates with BPD and CDH in the NICU. LEVEL OF EVIDENCE: 2. TECHNICAL EFFICACY STAGE: 2.

Pediatric Modification of the Medically Necessary, Time-Sensitive Scoring System for Operating Room Procedure Prioritization During the COVID-19 Pandemic

BACKGROUND

The COVID-19 pandemic forced surgeons to reconsider concepts of "elective" operations. Perceptions about the time sensitivity and medical necessity of a procedure have taken on greater significance during the pandemic. The evolving ethical and clinical environment requires reappraisal of perioperative factors, such as personal protective equipment conservation; limiting the risk of exposure to COVID-19 for patients, families, and healthcare workers; preservation of hospital beds and ICU resources; and minimizing COVID-19-related perioperative risk to patients.

STUDY DESIGN

A scaffold for the complex decision-making required for prioritization of medically necessary, time-sensitive (MeNTS) operations was developed for adult patients by colleagues at the University of Chicago. Although adult MeNTS scoring can be applied across adult surgical specialties, some variables were irrelevant in a pediatric population. Pediatric manifestations of chronic diseases and congenital anomalies were not accounted for. To account for the unique challenges children face, we modified the adult MeNTS system for use across pediatric subspecialties.

RESULTS

This pediatric MeNTS scoring system was applied to 101 cases both performed and deferred between March 23 and April 19, 2020 at the University of Chicago Comer Children's Hospital. The pediatric MeNTS scores provide a safe, equitable, transparent, and ethical strategy to prioritize children's surgical procedures.

CONCLUSIONS

This process is adaptable to individual institutions and we project it will be useful during the acute phase of the pandemic (maximal limitations), as well as the anticipated recovery phase.

Predicting Lung Health Trajectories for Survivors of Preterm Birth

Rates of preterm birth (<37 weeks of gestation) are increasing worldwide. Improved perinatal care has markedly increased survival of very (<32 weeks gestation) and extremely (<28 weeks gestation) preterm infants, however, long term respiratory sequalae are common among survivors. Importantly, individual's lung function trajectories are determined early in life and tend to track over the life course. Preterm infants are impacted by antenatal, postnatal and early life perturbations to normal lung growth and development, potentially resulting in significant shifts from the "normal" lung function trajectory. This review summarizes what is currently known about the long-term lung function trajectories in survivors of preterm birth. Further, this review highlights how antenatal, perinatal and early life factors are likely to contribute to individual lung health trajectories across the life course.

Characterization of R 2 ∗ and tissue density in the human lung: Application to neonatal imaging in the intensive care unit

PURPOSE

Novel demonstration of R 2 ∗ and tissue density estimation in infant lungs using 3D ultrashort echo time MRI. Differences between adult and neonates with no clinical indication of lung pathology is explored, as well as relationships between parameter estimates and gravitationally dependent position and lung inflation state. This provides a tool for probing physiologic processes that may be relevant to pulmonary disease and progression in newborns.

METHODS

R 2 ∗ and tissue density were estimated in a phantom consisting of standards allowing for ground truth comparisons and in human subjects (N = 5 infants, N = 4 adults, no clinical indication of lung dysfunction) using a 3D radial multiecho ultrashort echo time MRI sequence. Whole lung averages were compared between infants and adults. Dependence of the metrics on anterior-posterior position as well as between end-tidal inspiration and expiration were explored, in addition to the general relationship between R 2 ∗ and tissue density.

RESULTS

Estimates in the phantom did not differ significantly from ground truth. Neonates had significantly lower mean R 2 ∗ (P = .006) and higher mean tissue density (P = 1.5e-5) than adults. Tissue density and R 2 ∗ were both significantly dependent on anterior-posterior position and lung inflation state (P < .005). An overall inverse relationship was found between R 2 ∗ and tissue density, which was similar in both neonates and adults.

CONCLUSION

Estimation of tissue density and R 2 ∗ in free breathing, nonsedated, neonatal patients is feasible using multiecho ultrashort echo time MRI. R 2 ∗ was no different between infants and adults when matched for tissue density, although density of lung parenchyma was, on average, lower in adults than neonates.

Bronchopulmonary dysplasia

In the absence of effective interventions to prevent preterm births, improved survival of infants who are born at the biological limits of viability has relied on advances in perinatal care over the past 50 years. Except for extremely preterm infants with suboptimal perinatal care or major antenatal events that cause severe respiratory failure at birth, most extremely preterm infants now survive, but they often develop chronic lung dysfunction termed bronchopulmonary dysplasia (BPD; also known as chronic lung disease). Despite major efforts to minimize injurious but often life-saving postnatal interventions (such as oxygen, mechanical ventilation and corticosteroids), BPD remains the most frequent complication of extreme preterm birth. BPD is now recognized as the result of an aberrant reparative response to both antenatal injury and repetitive postnatal injury to the developing lungs. Consequently, lung development is markedly impaired, which leads to persistent airway and pulmonary vascular disease that can affect adult lung function. Greater insights into the pathobiology of BPD will provide a better understanding of disease mechanisms and lung repair and regeneration, which will enable the discovery of novel therapeutic targets. In parallel, clinical and translational studies that improve the classification of disease phenotypes and enable early identification of at-risk preterm infants should improve trial design and individualized care to enhance outcomes in preterm infants.

The Diagnosis of Bronchopulmonary Dysplasia in Very Preterm Infants. An Evidence-based Approach

Rationale: Current diagnostic criteria for bronchopulmonary dysplasia rely heavily on the level and duration of oxygen therapy, do not reflect contemporary neonatal care, and do not adequately predict childhood morbidity.Objectives: To determine which of 18 prespecified, revised definitions of bronchopulmonary dysplasia that variably define disease severity according to the level of respiratory support and supplemental oxygen administered at 36 weeks' postmenstrual age best predicts death or serious respiratory morbidity through 18-26 months' corrected age.Methods: We assessed infants born at less than 32 weeks of gestation between 2011 and 2015 at 18 centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network.Measurements and Main Results: Of 2,677 infants, 683 (26%) died or developed serious respiratory morbidity. The diagnostic criteria that best predicted this outcome defined bronchopulmonary dysplasia according to treatment with the following support at 36 weeks' postmenstrual age, regardless of prior or current oxygen therapy: no bronchopulmonary dysplasia, no support (n = 773); grade 1, nasal cannula ≤2 L/min (n = 1,038); grade 2, nasal cannula >2 L/min or noninvasive positive airway pressure (n = 617); and grade 3, invasive mechanical ventilation (n = 249). These criteria correctly predicted death or serious respiratory morbidity in 81% of study infants. Rates of this outcome increased stepwise from 10% among infants without bronchopulmonary dysplasia to 77% among those with grade 3 disease. A similar gradient (33-79%) was observed for death or neurodevelopmental impairment.Conclusions: The definition of bronchopulmonary dysplasia that best predicted early childhood morbidity categorized disease severity according to the mode of respiratory support administered at 36 weeks' postmenstrual age, regardless of supplemental oxygen use.

How best to capture the respiratory consequences of prematurity?

Chronic respiratory morbidity is a common complication of premature birth, generally defined by the presence of bronchopulmonary dysplasia, both clinically and in trials of respiratory therapies. However, recent data have highlighted that bronchopulmonary dysplasia does not correlate with chronic respiratory morbidity in older children born preterm. Longitudinally evaluating pulmonary morbidity from early life through to childhood provides a more rational method of defining the continuum of chronic respiratory morbidity of prematurity, and offers new insights into the efficacy of neonatal respiratory interventions. The changing nature of preterm lung disease suggests that a multimodal approach using dynamic lung function assessment will be needed to assess the efficacy of a neonatal respiratory therapy and predict the long-term respiratory consequences of premature birth. Our aim is to review the literature regarding the long-term respiratory outcomes of neonatal respiratory strategies, the difficulties of assessing dynamic lung function in infants, and potential new solutions.

Better measures are needed to predict chronic respiratory morbidity in survivors born prematurely http://ow.ly/1L3n30ihq9C

Bronchopulmonary Dysplasia and Perinatal Characteristics Predict 1-Year Respiratory Outcomes in Newborns Born at Extremely Low Gestational Age: A Prospective Cohort Study

OBJECTIVE

To assess the utility of clinical predictors of persistent respiratory morbidity in extremely low gestational age newborns (ELGANs).

STUDY DESIGN

We enrolled ELGANs (<29 weeks' gestation) at ≤7 postnatal days and collected antenatal and neonatal clinical data through 36 weeks' postmenstrual age. We surveyed caregivers at 3, 6, 9, and 12 months' corrected age to identify postdischarge respiratory morbidity, defined as hospitalization, home support (oxygen, tracheostomy, ventilation), medications, or symptoms (cough/wheeze). Infants were classified as having postprematurity respiratory disease (PRD, the primary study outcome) if respiratory morbidity persisted over ≥2 questionnaires. Infants were classified with severe respiratory morbidity if there were multiple hospitalizations, exposure to systemic steroids or pulmonary vasodilators, home oxygen after 3 months or mechanical ventilation, or symptoms despite inhaled corticosteroids. Mixed-effects models generated with data available at 1 day (perinatal) and 36 weeks' postmenstrual age were assessed for predictive accuracy.

RESULTS

Of 724 infants (918 ± 234 g, 26.7 ± 1.4 weeks' gestational age) classified for the primary outcome, 68.6% had PRD; 245 of 704 (34.8%) were classified as severe. Male sex, intrauterine growth restriction, maternal smoking, race/ethnicity, intubation at birth, and public insurance were retained in perinatal and 36-week models for both PRD and respiratory morbidity severity. The perinatal model accurately predicted PRD (c-statistic 0.858). Neither the 36-week model nor the addition of bronchopulmonary dysplasia to the perinatal model improved accuracy (0.856, 0.860); c-statistic for BPD alone was 0.907.

CONCLUSION

Both bronchopulmonary dysplasia and perinatal clinical data accurately identify ELGANs at risk for persistent and severe respiratory morbidity at 1 year.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01435187.

Pulmonary MRI of neonates in the intensive care unit using 3D ultrashort echo time and a small footprint MRI system

PURPOSE

To determine the feasibility of pulmonary magnetic resonance imaging (MRI) of neonatal lung structures enabled by combining two novel technologies: first, a 3D radial ultrashort echo time (UTE) pulse sequence capable of high spatial resolution full-chest imaging in nonsedated quiet-breathing neonates; and second, a unique, small-footprint 1.5T MRI scanner design adapted for neonatal imaging and installed within the neonatal intensive care unit (NICU).

MATERIALS AND METHODS

Ten patients underwent MRI within the NICU, in accordance with an approved Institutional Review Board protocol. Five had clinical diagnoses of bronchopulmonary dysplasia (BPD), and five had putatively normal lung function. Pulmonary imaging was performed at 1.5T using 3D radial UTE and standard 3D fast gradient recalled echo (FGRE). Diagnostic quality, presence of motion artifacts, and apparent severity of lung pathology were evaluated by two radiologists. Quantitative metrics were additionally used to evaluate lung parenchymal signal.

RESULTS

UTE images showed significantly higher signal in lung parenchyma (P < 0.0001) and fewer apparent motion artifacts compared to FGRE (P = 0.046). Pulmonary pathology was more severe in patients diagnosed with BPD relative to controls (P = 0.001). Infants diagnosed with BPD also had significantly higher signal in lung parenchyma, measured using UTE, relative to controls (P = 0.002).

CONCLUSION

These results demonstrate the technical feasibility of pulmonary MRI in free-breathing, nonsedated infants in the NICU at high, isotropic resolutions approaching that achievable with computed tomography (CT). There is potential for pulmonary MRI to play a role in improving how clinicians understand and manage care of neonatal and pediatric pulmonary diseases. J. Magn. Reson. Imaging 2016.

LEVEL OF EVIDENCE

2 J. Magn. Reson. Imaging 2017;45:463-471.