Bronchoscopy in neonates with severe bronchopulmonary dysplasia in the NICU

Structural and functional stenosis of the upper airway in Crouzon syndrome patients: A computational fluid dynamics analysis

OBJECTIVES

This study aimed to simulate the aerodynamics and to identify the spatial correlation between anatomical and functional stenoses in Crouzon syndrome patients.

METHODS

Six patients of Crouzon syndrome were included. Computational fluid dynamics (CFD) was utilized to simulate airflow dynamics, and characteristics, including the velocity, pressure intensity, wall shear stress, airflow resistance and streamline, were extracted for quantitative analysis both in overall and regionally. Structural stenosis was defined at the minimum cross-sectional area, while functional stenosis was identified at the point of maximum airflow velocity. The spatial distances between the Frankfurt plane and structural/functional stenosis were calculated and compared.

RESULTS

Structural stenosis occurred in the palatopharynx, while the highest inspiratory resistance and peak airflow velocity during expiration identified the glossopharynx as the functional stenosis site. A steep increase in negative pressure and a significant increase in wall shear stress could be observed surrounding the functional stenosis. The intensity and diffusion range of wall shear stress are positively correlated with age. Notably, the functional stenosis was consistently 5 mm below the structural stenosis (P < 0.05).

CONCLUSIONS

CFD effectively visualized both overall and regional aerodynamics of Crouzon syndrome, providing a novel method for functional airway evaluation. The spatial distributions of structural and functional stenoses did not strictly correspond; the structural stenosis was located on the palatopharynx, while the functional stenosis was on the glossopharynx. The wall shear stress worsens pathologically with age, aggravating functional stenosis to structural stenosis. Therefore, functional stenosis should also be addressed in airway management to ensure therapeutic effectiveness.

Current and Emerging Therapies for Prevention and Treatment of Bronchopulmonary Dysplasia in Preterm Infants

Although advances in the care of extremely preterm born infants have yielded improvements in survival and reductions in important morbidities, rates of bronchopulmonary dysplasia (BPD) have remained relatively unchanged. As BPD can have a long-lasting impact on the quality of life for survivors of prematurity and their families, this remains a continuing challenge. Treatments that have consistently shown efficacy in preventing either BPD or the composite outcome of BPD and death prior to 36 weeks post menstrual age (PMA) in large-scale randomized clinical trials (RCTs) include caffeine [adjusted odds ratio aOR for BPD, 0.63; 95% confidence interval (95% CI) 0.52-0.76; p < 0.001)], vitamin A [relative risk (RR) for death or BPD 0.89; 95% CI 0.80-0.99], low-dose hydrocortisone in the first week of life [OR for survival without BPD, 1.45; 95% CI 1.11-1.90; p = 0.007], and post-natal dexamethasone [RR for BPD or mortality; 0.76; 95% CI 0.66-0.87]. Although early caffeine therapy is now a widely used strategy to prevent BPD, the potentially severe side effects of post-natal glucocorticoids and the concerns regarding the cost-benefit of vitamin A have led to inconsistent use of these drugs in clinical practice. Inhaled bronchodilators and diuretics provide differing degrees of symptomatic relief for patients according to their phenotypic pattern of lung injury; however, these medications do not prevent BPD. Currently available pharmaceuticals do not sufficiently address the degree of structural immaturity and immune dysregulation that is present in the growing population of survivors born prior to 25 weeks gestational age. In this article, we provide both an evidence-based summary of pharmacological treatments currently available to prevent and manage BPD and a discussion of emerging therapies that could help preserve normal lung development in infants born preterm.

Predicting Clinical Outcomes of Severe Bronchopulmonary Dysplasia through New Definitions and Phenotypes

This study aimed to compare the accuracy of three newly proposed definitions of bronchopulmonary dysplasia (BPD) in predicting outcomes, and to investigate the impact of large airway versus parenchymal versus vascular BPD phenotypes on BPD outcomes.Retrospective chart review of 100 infants with severe BPD discharged from a Children's hospital between 2020 and 2021. Multivariable models evaluated the associations between BPD definitions and phenotypes with tracheostomy and death at 6 months and 1 year after NICU discharge. Secondary outcomes included the need for respiratory support, the use of pulmonary medications, and the need for long-term gastrostomy feeding.Neonatal research network (NRN) and BPD collaborative criteria best-predicted outcomes associated with tracheostomy and/or death (p < 0.001). Among the three BPD phenotypes, large airway disease was independently associated with death or tracheostomy (odds ratios [OR]: 10.5; 95% confidence interval [CI]: 1.6, 68.1). The combination of all three phenotypes was also associated with death or tracheostomy (OR: 9.8; 95% CI: 1.0, 93.5). Both NRN and BPD collaborative definitions showed an association with the need for respiratory support, medication use, and need for long-term gastrostomy tube feeding. Among the 29 infants for whom complete information was available, 18 (62%), 20 (69%), and 18 (62%) had parenchymal, central airway and pulmonary vascular phenotype, respectively.Our results indicate that newer definitions of BPD may better predict the severity of BPD and the need for long-term invasive ventilation support compared with the 2001 National Institute of Health definition of BPD phenotypes impacting mortality and short-term outcomes. These data may be useful for counseling families and developing phenotype-based individualized treatment plans. · The current definition of BPD has limitations.. · New definitions of BPD better predict outcomes.. · BPD phenotypes can better predict outcomes..

Clinical Outcomes Through Two Years for Infants With Bronchopulmonary Dysplasia and Tracheomalacia

BACKGROUND

Tracheomalacia (TM) is common in infants with bronchopulmonary dysplasia (BPD) and associated with respiratory morbidity. Assessment of TM was historically via bronchoscopy, but recent studies demonstrate that ultrashort echo-time (UTE) magnetic resonance imaging (MRI) can accurately assess TM in neonates.

RESEARCH QUESTION

Do neonates with MRI-identified TM and BPD have increased respiratory morbidity through age 2 years?

METHODS

We performed an observational cohort study of 54 subjects with BPD and assessed TM using UTE MRI at term-equivalent age. TM was defined as an airway minor/major axis ratio (rd,min) of < 0.7. Outcomes through 2 years of life were evaluated via electronic medical record review.

RESULTS

There were 23 subjects (43%) with TM. Modified Ochiai MRI scores were similar between the subjects with and without TM (7.3 ± 4.1 vs. 7.4 ± 4.1). Subjects with TM were more likely to require respiratory support at age 2 years (62% vs. 30%, p = 0.04) and be prescribed systemic corticosteroids (71% vs. 27%, p = 0.004). Most patients with TM were prescribed bronchodilators (90% vs. 60%, p = 0.04). A 10% increase in tracheal collapse correlated with a 28-day increased hospital length of stay (p = 0.047), increased likelihood of pneumonia (p = 0.05), and treatment with antibiotics (p = 0.04) and systemic steroids (p = 0.008).

CONCLUSIONS

TM in the neonatal period was associated with increased respiratory morbidity through age 2 years, demonstrated by increased respiratory support and more frequent usage of systemic corticosteroids and bronchodilators, independent of the severity of BPD. These results highlight the significance of central airway disease in neonates with BPD.

Airway diseases in very low birth weight infants

OBJECTIVE

To identify the incidence and characteristics of airway diseases in very low birth weight infants (VLBWIs).

METHODS

A retrospective study of 214 inborn VLBWIs admitted to our NICU between April 2009 and March 2022 (approval no: 2023-0008). Neonatologists ourselves performed bronchoscopy to diagnose airway diseases.

RESULTS

Symptomatic airway diseases were present in 36/214 (16.8%) of VLBWIs. Common airway diseases were tracheobronchomalacia (TBM) and pharyngomalacia. Infants with airway diseases had shorter gestational age, lower birth weight, more boys, and more moderate/severe bronchopulmonary dysplasia (BPD). Regarding treatment, more infants with airway diseases required intubation were intubated longer, used more dexamethasone, were on ventilators and oxygen longer, and were hospitalized longer.

CONCLUSION

We found that VLBWIs were more frequently complicated with airway diseases, especially TBM. We also observed many pharyngeal lesions, which have not been previously reported. Intensity of prematurity, BPD, and the need for stronger respiratory management were risks for airway diseases. In VLBWIs, bronchoscopy should be actively performed because airway diseases are important complications.

The potential therapeutic effect of human umbilical cord mesenchymal stem cell-derived exosomes in bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of preterm infants, with its incidence rising due to improved survival rates of these infants. BPD results from a combination of prenatal and postnatal factors, such as mechanical ventilation, oxygen toxicity, and infections, all of which significantly impact the prognosis and growth of affected infants. Current treatment options for BPD are largely supportive and do not address the underlying pathology. Exosomes are cell-derived bilayer-enclosed membrane structures enclosing proteins, lipids, RNAs, growth factors, cytokines and metabolites. They have become recognized as crucial regulators of intercellular communication in various physiological and pathological processes. Previous studies have revealed the therapeutic potential of human umbilical cord mesenchymal stem cells-derived exosomes (HUCMSCs-Exos) in promoting tissue repair and regeneration. Therefore, HUCMSCs-Exos maybe a promising and effective therapeutic modality for BPD. In this review, we firstly provide a comprehensive overview of BPD, including its etiology and the mechanisms of lung injury. Then we detail the isolation, characterization, and contents of HUCMSCs-Exos, and discuss their potential mechanisms of HUCMSCs-Exos in BPD treatment. Additionally, we summarize current clinical trials and discuss the challenges in translating these findings from bench to bedside. This review aims to lay the groundwork for future clinical applications of HUCMSCs-Exos in treating BPD.

Flexible bronchoscopy in preterm infants with bronchopulmonary dysplasia: findings and complications in a matched control study

Bronchopulmonary dysplasia (BPD) poses a significant challenge as the most common late morbidity of preterm infants. This study aimed to evaluate airway abnormalities in infants with BPD who underwent flexible bronchoscopy (FB) to gain insights into the prevalence of upper airway obstruction and associated complications. A retrospective case-control study was conducted on BPD patients who underwent FB at a tertiary center between 2013 and 2023. BPD patients were matched (1:3) with a reference group based on age, gender, and ethnicity, who also had undergone FB. Demographic data, comorbidities, indications for FB, findings, and complications during and after FB were collected. The study included 50 BPD patients (mean age 1.26 ± 0.9 years, 58% males), and 150 controls. As expected, BPD patients had a lower gestational age, lower birth weight, and longer hospitalizations and were treated with more medications. Abnormal bronchoscopy findings were significantly more common in the BPD group compared to the reference group, with an increased rate of turbinate hypertrophy (OR [95% CI]: 3.44 [1.27-9.37], P = 0.014), adenoid hypertrophy (OR: 2.7 [1.38-5.29], P = 0.004), lingual tonsils (OR: 5.44 [1.29-27.4], P = 0.0024), subglottic stenosis (OR: 6.95 [2.08-27.1], P = 0.002), and tracheomalacia (OR: 2.98 [1.06-8.19], P = 0.034). Complications including desaturation (OR: 3.89 [1.32-11.7], P = 0.013) and PICU admission (OR: 16.6 [2.58-322], P = 0.011) were more frequent in the BPD than in the reference group.

CONCLUSION

The study revealed a high prevalence of structural anomalies leading to upper airway obstruction and complications in infants with BPD undergoing FB. These findings emphasize the importance of careful consideration and preparation for bronchoscopic procedures in this vulnerable population.

WHAT IS KNOWN

• Bronchopulmonary dysplasia (BPD) represents the most prevalent late morbidity among preterm infants. • Preterm infants diagnosed with BPD frequently undergo diagnostic procedures, including flexible and rigid bronchoscopies, to identify structural pathologies within the respiratory tract.

WHAT IS NEW

• A significantly higher prevalence of structural anomalies leading to upper airway obstruction was observed in the BPD group compared to controls. • The incidence of complications during flexible bronchoscopy was higher in the BPD group than in controls.

Airway Anomalies in Pediatric Patients After Surgery for Congenital Heart Disease: Single-Center Retrospective Cohort Study, Taiwan, 2017-2020

OBJECTIVES

Airway anomalies increase risk of morbidity and mortality in postoperative pediatric patients with congenital heart disease (CHD). We aimed to identify airway anomalies and the association with intermediate outcomes in patients undergoing surgery for CHD.

DESIGN

Single-center, hospital-based retrospective study in Taiwan, 2017-2020.

SETTING

A tertiary referral hospital in Taiwan.

PATIENTS

All pediatric patients who underwent surgery for CHD and were admitted to the PICU and had data about airway evaluation by cardiopulmonary CT scan or bronchoscopy.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Among 820 CHD patients identified as having undergone airway evaluation in the PICU, 185 (22.6%) were diagnosed with airway anomalies, including structural lesions in 146 of 185 (78.9%), and dynamic problems were seen in 87 of 185 (47.0%). In this population, the explanatory factors associated with greater odds (odds ratio [OR]) of airway anomaly were premature birth (OR, 1.90; p = 0.002), genetic syndromes (OR, 2.60; p < 0.001), and in those with preoperative ventilator use (OR, 4.28; p < 0.001). In comparison to those without airway anomalies, the presence of airway anomalies was associated with higher hospital mortality (11.4% vs. 2.7%; p < 0.001), prolonged intubation days (8 d [1-27 d] vs. 1 d [1-5 d]; p < 0.001), longer PICU length of stay (23 d [8-81 d] vs. 7 d [4-18 d]; p < 0.001), and greater hazard of intermediate mortality (adjusted hazard ratio, 2.60; p = 0.001).

CONCLUSIONS

In our single-center retrospective study, 2017-2020, between one-in-five and one-in-four of our postoperative CHD patients undergoing an airway evaluation had airway anomalies. Factors associated with greater odds of airway anomaly included, those with premature birth, or genetic syndromes, and preoperative ventilator use. Overall, in patients undergoing airway evaluation, the finding of an airway anomalies was associated with longer postoperative intubation duration and greater hazard of intermediate mortality.

Clinical application of flexible fiberoptic bronchoscopy in neonatal respiratory diseases

BACKGROUND

Respiratory disease is a predominantly observed problem in neonates. Moreover, the application of flexible bronchoscopy in newborns is gradually increasing. This study aimed to investigate the value of bronchoscopy in neonates respiratory abnormalities and evaluate the safety of bronchoscopy application.

METHODS

Clinical data and outcomes of 56 neonates who underwent flexible bronchoscopy were retrospectively analyzed. Correlations among indications for bronchoscopy, findings, and clinical diseases were assessed.

RESULTS

A total of 56 neonates had a minimum weight of 1200 g at the time of bronchoscopy, while the minimum gestational age at birth was 26 + 1 weeks. A total of 22 cases (39.3%) had two or more clinical indications; the five most common indications were respiratory distress in 24 (42.9%), stridor in 22 (39.3%), pulmonary atelectasis in 10 (17.6%), feeding difficulty in 10 (17.6%), and difficult weaning from mechanical ventilation in 6 (10.7%) cases. A total of 13 types of abnormalities were detected in the respiratory tract. The most common abnormalities were laryngomalacia in 29 (59.2%), tracheobroncomalacia in 8 (16.3%), and vocal cord paralysis in 6 (12.2%) cases. Bronchoalveolar lavage was performed in 39 cases. Eight cases were diagnosed by bronchoscopy and then treated with surgery in the Thoracic Surgery/Otolaryngology Department; all of them were cured and discharged from the hospital after surgery. No serious complications, such as pneumothorax or shock, occurred in any of the children, of whom none died.

CONCLUSIONS

Flexible bronchoscopy could play an important role in diagnosing and identifying respiratory disorders in neonates and be safely used with few serious complications.

Tracheomalacia Reduces Aerosolized Drug Delivery to the Lung

Rationale: Neonates with respiratory issues are frequently treated with aerosolized medications to manage lung disease or facilitate airway clearance. Dynamic tracheal collapse (tracheomalacia [TM]) is a common comorbidity in these patients, but it is unknown whether the presence of TM alters the delivery of aerosolized drugs. Objectives: To quantify the effect of neonatal TM on the delivery of aerosolized drugs. Methods: Fourteen infant subjects with respiratory abnormalities were recruited; seven with TM and seven without TM. Respiratory-gated 3D ultrashort echo time magnetic resonance imaging (MRI) was acquired covering the central airway and lungs. For each subject, a computational fluid dynamics simulation modeled the airflow and particle transport in the central airway based on patient-specific airway anatomy, motion, and airflow rates derived from MRI. Results: Less aerosolized drug reached the distal airways in subjects with TM than in subjects without TM: of the total drug delivered, less particle mass passed through the main bronchi in subjects with TM compared with subjects without TM (33% vs. 47%, p = 0.013). In subjects with TM, more inhaled particles were deposited on the surface of the airway (48% vs. 25%, p = 0.003). This effect becomes greater with larger particle sizes and is significant for particles with a diameter >2 μm (2-5 μm, p ≤ 0.025 and 5-15 μm, p = 0.004). Conclusions: Neonatal patients with TM receive less aerosolized drug delivered to the lungs than subjects without TM. Currently, infants with lung disease and TM may not be receiving adequate and/or expected medication. Particles >2 μm in diameter are likely to deposit on the surface of the airway due to anatomical constrictions such as reduced tracheal and glottal cross-sectional area in neonates with TM. This problem could be alleviated by delivering smaller aerosolized particles.

The effect of bethanechol on tracheobronchomalacia in preterm infants with bronchopulmonary dysplasia: a retrospective cohort study

OBJECTIVE

Bethanechol has demonstrated improvement in trachealis tone in animal models, but no trials have studied efficacy in infants. This study aimed to examine if bethanechol improves a standardized pulmonary severity score (PSS) in infants with severe bronchopulmonary dysplasia with a diagnosis of tracheobronchomalacia (TBM).

STUDY DESIGN

This retrospective cohort study evaluated cases treated with bethanechol matched with controls who did not receive bethanechol. TBM was diagnosed by dynamic computography. Daily PSS was recorded for each infant from 40 to 55 weeks post-menstrual age.

RESULTS

Cases' mean PSS change was 21% lower than the controls' mean PSS change pre- and post-bethanechol (95% CI -40%, -2%) by paired t-test (p = 0.03). Matched differences (controls' PSS - cases' PSS) demonstrated greater mean PSS difference post-bethanechol compared to pre-bethanechol 0.17, (95% CI 0.05, 0.29) by paired t-test (p = 0.009).

CONCLUSION

Infants with TBM treated with bethanechol compared to those not treated had a lower PSS reflecting improved respiratory status.

Dynamic computed tomography for evaluation of tracheobronchomalacia in premature infants with bronchopulmonary dysplasia

INTRODUCTION

Dynamic computed tomography (dCT) gives real-time physiological information and objective descriptions of airway narrowing in tracheobronchomalacia (TBM). There is a paucity of literature in the evaluation of TBM by dCT in premature infants with bronchopulmonary dysplasia (BPD). The aim of this study is to describe the findings of dCT and resultant changes in management in premature infants with TBM.

METHODS

A retrospective study of 70 infants was performed. Infants included were <32 weeks gestation without major anomalies. TBM was defined as ≥50% expiratory reduction in cross-sectional area with severity defined as mild (50%-75%), moderate (≥75%-90%), or severe (≥90%).

RESULTS

Dynamic CT diagnosed malacia in 53% of infants. Tracheomalacia was identified in 49% of infants with severity as 76% mild, 18% moderate, and 6% severe. Bronchomalacia was identified in 43% of infants with varying severity (53% mild, 40% moderate, 7% severe). Resultant management changes included PEEP titration (44%), initiation of bethanechol (23%), planned tracheostomy (20%), extubation trial (13%), and inhaled ipratropium bromide (7%).

CONCLUSION

Dynamic CT is a useful noninvasive diagnostic tool for airway evaluation of premature infants. Presence and severity of TBM can provide actionable information to guide more precise clinical decision making.

Pulmonary phenotypes of bronchopulmonary dysplasia in the preterm infant

Bronchopulmonary dysplasia (BPD) remains the most common complication of premature birth, imposing a significant and potentially life-long burden on patients and their families. Despite advances in our understanding of the mechanisms that contribute to patterns of lung injury and dysfunctional repair, current therapeutic strategies remain non-specific with limited success. Contemporary definitions of BPD continue to rely on clinician prescribed respiratory support requirements at specific time points. While these criteria may be helpful in broadly identifying infants at higher risk of adverse outcomes, they do not offer any precise information regarding the degree to which each compartment of the lung is affected. In this review we will outline the different pulmonary phenotypes of BPD and discuss important features in the pathogenesis, clinical presentation, and management of these frequently overlapping scenarios.

Tracheostomy in Severe Bronchopulmonary Dysplasia-How to Decide in the Absence of Evidence

Infants with the most severe forms of bronchopulmonary dysplasia (BPD) may require long-term invasive positive pressure ventilation for survival, therefore necessitating tracheostomy. Although life-saving, tracheostomy has also been associated with high mortality, postoperative complications, high readmission rates, neurodevelopmental impairment, and significant caregiver burden, making it a highly complex and challenging decision. However, for some infants tracheostomy may be necessary for survival and the only way to facilitate a timely and safe transition home. The specific indications for tracheostomy and the timing of the procedure in infants with severe BPD are currently unknown. Hence, centers and clinicians display broad variations in practice with regard to tracheostomy, which presents barriers to designing evidence-generating studies and establishing a consensus approach. As the incidence of severe BPD continues to rise, the question remains, how do we decide on tracheostomy to provide optimal outcomes for these patients?

Development and Disorders of the Airway in Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD), a disorder characterized by arrested lung development, is a frequent cause of morbidity and mortality in premature infants. Parenchymal lung changes in BPD are relatively well-characterized and highly studied; however, there has been less emphasis placed on the role that airways disease plays in the pathophysiology of BPD. In preterm infants born between 22 and 32 weeks gestation, the conducting airways are fully formed but still immature and therefore susceptible to injury and further disruption of development. The arrest of maturation results in more compliant airways that are more susceptible to deformation and damage. Consequently, neonates with BPD are prone to developing airway pathology, particularly for patients who require intubation and positive-pressure ventilation. Airway pathology, which can be divided into large and small airways disease, results in increased respiratory morbidity in neonates with chronic lung disease of prematurity.

Hemosiderin-Laden Macrophages in Bronchoalveolar Lavage Samples of Children with Bronchopulmonary Dysplasia

OBJECTIVES

To evaluate the prevalence of hemosiderin-laden macrophages in children with bronchopulmonary dysplasia (BPD) and assess for an association between hemosiderin-laden macrophages and pulmonary arterial hypertension.

STUDY DESIGN

Retrospective case-control study of infants and children with and without BPD who underwent bronchoscopy with bronchoalveolar lavage (BAL) the at Children's Hospital of Philadelphia between 2012 and 2021.

RESULTS

BAL from 205 children with BPD and 106 controls without BPD matched for tracheostomy, infection, and age were reviewed for hemosiderin-laden macrophages. Seventy-one individuals (34.6%) with BPD had a BAL with 10% or more hemosiderin-laden macrophages compared with 3 (2.8%) controls (P < .0001; OR, 18.19; 95% CI, 5.57-59.41). Patients with pulmonary hypertension by echocardiogram (P = .04; OR, 3.69; 95% CI, 1.05-12.96) or an elevated mean pulmonary artery pressure during cardiac catheterization, r_s (14) = 0.56, P = .04, were more likely to have elevated hemosiderin-laden macrophages on BAL samples less than 60 days from bronchoscopy. After adjusting for birth weight, gestational age, BPD grade, and age at the time of bronchoscopy using logistic regression, pulmonary hypertension was associated with a higher odds of hemosiderin-laden macrophages of 10% or more (P = .02; OR, 6.37; 95% CI, 1.28-31.87). No association was observed between hemosiderin-laden macrophages and sex, race, gestational age, birth weight, tracheostomy, or infectious studies.

CONCLUSIONS

This retrospective study revealed increased hemosiderin-laden macrophages in BAL samples from patients with BPD and a significant association with pulmonary arterial hypertension. It is unclear whether elevated hemosiderin-laden macrophages within BPD contributes to the pathogenesis of lung and pulmonary vascular disease or is simply a biomarker of pulmonary arterial hypertension.

Imaging in neonatal respiratory disease

The purpose of this review is to describe the current state of the art in clinical imaging for NICU patients, divided into major areas that correspond to likely phenotypes of neonatal respiratory disease: airway abnormalities, parenchymal disease, and pulmonary vascular disease. All common imaging modalities (ultrasound, X-ray, CT, and MRI) are discussed, with an emphasis on modalities that are most relevant to the individual underlying aspects of disease. Some promising aspects of dynamic and functional imaging are included, where there may be future clinical applicability.

Bronchoscopy in the management of children from developing countries undergoing congenital heart surgery

OBJECTIVES

To study the clinical characteristics and impact of bronchoscopy in children from developing countries, referred for cardiac surgery, through the "Save a Child's Heart" (SACH) organization.

METHODS

We performed a retrospective hospital-chart review of SACH children (0-18 years old) referred between 2006 and 2021 who underwent fiberoptic bronchoscopy. We examined demographics, congenital-heart-disease (CHD) types, bronchoscopy's indications and findings, subsequent recommendations, number of ventilation, and intensive-care-unit days. The primary outcome was percent changes in management and diagnosis, following the bronchoscopy. We included a control group matched-for-age and CHD type, who did not undergo bronchoscopy.

RESULTS

We performed 82 bronchoscopies in 68 children: 18 (26.5%) preoperatively; 46 (67.6%) postoperatively; and four (5.9%) both. The most prevalent CHDs were Tetralogy-of-Fallot (27.9%) and ventricular-septal-defect (19.1%). The main indications were persistent atelectasis (41%) and mechanical ventilation/weaning difficulties (27.9%). Bronchoscopic evaluations revealed at least one abnormality in 51/68 (75%) children. The most common findings were external airway compression (23.5%), bronchomalacia (19.1%), and mucus secretions (14.7%). Changes in management were made in 35 (51.4%) cases, with a major change made in 14/35 (40%) children. Compared to the control group, the children undergoing bronchoscopy were both ventilated longer (median 6 vs. 1.5 days, p < 0.0001) and stayed longer in the intensive care unit (median 1.5 vs. 18.5 days, p < 0.0001).

CONCLUSION

A bronchoscopy is an important tool in the diagnosis and management of the unique group of children from developing countries with CHD referred for cardiac surgery. The results of our study, reveal a more complicated clinical course in children requiring bronchoscopy compared to controls.

Dynamic PEEP Study: A Non-invasive Diagnostic Exam to Assess for Effective PEEP in Children with Severe BPD

OBJECTIVE

Tracheobronchomalacia (TBM) is common in neonates with bronchopulmonary dysplasia (BPD) and is associated with higher morbidity. This study evaluates the value of a CT protocol to assess the degree of TBM and gauge the adequacy of prescribed PEEP.

STUDY DESIGN

Four infants with severe BPD on invasive mechanical ventilation underwent a chest CT protocol, including limited reduced-dose expiratory scans with varying PEEP levels.

RESULTS

Baseline PEEP was adjusted in all subjects after performing the Dynamic PEEP CT. In two infants, the PEEP was increased due to significant TBM and in the other two without signs of TBM PEEP was decreased. The clinical course improved in all patients after adjusting PEEP.

CONCLUSION

A "Dynamic PEEP" study may be reliable and non-invasive imaging modality for the evaluation of adequate ventilator settings in infants with severe BPD who are not optimal candidates for bronchoscopy.

Flexible Endoscopy With Non-invasive Ventilation Enables Clinicians to Assess and Manage Infants With Severe Bronchopulmonary Dysplasia

OBJECTIVES

The objectives of the study were to determine the efficacy of flexible endoscopy (FE) to assess the approachable aeroesophageal tract (AET) and subsequent changes in clinical management in infants with severe bronchopulmonary dysplasia (sBPD).

METHODS

This retrospective study investigated sBPD infants who received FE measurement from 2011 to 2020. FE was supported with non-invasive ventilation (FE-NIV) of pharyngeal oxygen with nose closure and abdominal compression without any mask or laryngeal mask airway. Data on AET lesions, changes in subsequent management, and FE therapeutic interventions were collected and analyzed.

RESULTS

Forty-two infants were enrolled in the study. Two thin scopes (1.8- and 2.6-mm outer diameter) were used. FE analysis revealed 129 AET lesions in 38 (90.5%) infants. Twenty-eight infants (66.7%) had more than one lesion. Thirty-five (83.3%) infants had 111 airway lesions where bronchial granulations (28, 25.2%), tracheomalacia (18, 16.2%), and bronchomalacia (15, 13.5%) were the main complications. Eighteen esophageal lesions were found in 15 (35.7%) infants. No significant FE-NIV complications were observed. The FE findings resulted in changes in management in all 38 infants. Thirty-six (85.7%) infants underwent altered respiratory care with pressure titrations (29, 45.3%), shortened suction depth (17, 26.6%), immediate extubation (8, 12.5%), changed insertion depth of endotracheal tube (7, 10.9%) and tracheostomy tube (3, 4.7%). Twenty-one (50%) infants had 50 pharmacotherapy changes, including added steroids, anti-reflux medicine, antibiotics, and stopped antibiotics. Eighteen (42.8%) infants received 37 therapeutic FE-NIV procedures, including 14 balloon dilatations, 13 laser-plasty, and 10 stent implantations. Seven (16.7%) infants underwent surgeries for four tracheostomies and three fundoplications.

CONCLUSION

Flexible endoscopy with this non-invasive ventilation could be a safe and valuable technique for direct and dynamic visual measurement of AET, which is essential for subsequent medical decision making and management in infants with sBPD.

Outpatient Respiratory Management of Infants, Children, and Adolescents with Post-Prematurity Respiratory Disease: An Official American Thoracic Society Clinical Practice Guideline

Background: Premature birth affects millions of neonates each year, placing them at risk for respiratory disease due to prematurity. Bronchopulmonary dysplasia is the most common chronic lung disease of infancy, but recent data suggest that even premature infants who do not meet the strict definition of bronchopulmonary dysplasia can develop adverse pulmonary outcomes later in life. This post-prematurity respiratory disease (PPRD) manifests as chronic respiratory symptoms, including cough, recurrent wheezing, exercise limitation, and reduced pulmonary function. This document provides an evidence-based clinical practice guideline on the outpatient management of infants, children, and adolescents with PPRD. Methods: A multidisciplinary panel of experts posed questions regarding the outpatient management of PPRD. We conducted a systematic review of the relevant literature. The Grading of Recommendations, Assessment, Development, and Evaluation approach was used to rate the quality of evidence and the strength of the clinical recommendations. Results: The panel members considered the strength of each recommendation and evaluated the benefits and risks of applying the intervention. In formulating the recommendations, the panel considered patient and caregiver values, the cost of care, and feasibility. Recommendations were developed for or against three common medical therapies and four diagnostic evaluations in the context of the outpatient management of PPRD. Conclusions: The panel developed recommendations for the outpatient management of patients with PPRD on the basis of limited evidence and expert opinion. Important areas for future research were identified.

Wheezing in preterm infants and children

Wheezing is a common outcome of preterm birth. This article will review the mechanisms, epidemiology, and treatment of wheezing in preterm children with and without a history of bronchopulmonary dysplasia.

Central airway issues in bronchopulmonary dysplasia

While there is a very large focus on the abnormalities of parenchymal lung development and extensive efforts to minimize alveolar damage with "gentle ventilation" and noninvasive respiratory support for neonates with bronchopulmonary dysplasia (BPD), there is relatively little consideration for the implications of central airway disease in this patient population. There are significant changes in the structure and conformation of the central airway during the last half of gestation, and premature birth disrupts this natural developmental process. The arrest of maturation results in a smaller airway that is more compliant, easier to deform, and more susceptible to damage. Consequently, neonates with BPD are prone to developing central airway pathology, particularly for patients who require intubation and positive pressure ventilation. Central airway disease can be divided into dynamic and fixed airway obstruction and results in increased respiratory morbidity in neonates with chronic lung disease of prematurity.

Human upper-airway respiratory airflow: In vivo comparison of computational fluid dynamics simulations and hyperpolarized 129Xe phase contrast MRI velocimetry

Computational fluid dynamics (CFD) simulations of respiratory airflow have the potential to change the clinical assessment of regional airway function in health and disease, in pulmonary medicine and otolaryngology. For example, in diseases where multiple sites of airway obstruction occur, such as obstructive sleep apnea (OSA), CFD simulations can identify which sites of obstruction contribute most to airway resistance and may therefore be candidate sites for airway surgery. The main barrier to clinical uptake of respiratory CFD to date has been the difficulty in validating CFD results against a clinical gold standard. Invasive instrumentation of the upper airway to measure respiratory airflow velocity or pressure can disrupt the airflow and alter the subject's natural breathing patterns. Therefore, in this study, we instead propose phase contrast (PC) velocimetry magnetic resonance imaging (MRI) of inhaled hyperpolarized 129Xe gas as a non-invasive reference to which airflow velocities calculated via CFD can be compared. To that end, we performed subject-specific CFD simulations in airway models derived from 1H MRI, and using respiratory flowrate measurements acquired synchronously with MRI. Airflow velocity vectors calculated by CFD simulations were then qualitatively and quantitatively compared to velocity maps derived from PC velocimetry MRI of inhaled hyperpolarized 129Xe gas. The results show both techniques produce similar spatial distributions of high velocity regions in the anterior-posterior and foot-head directions, indicating good qualitative agreement. Statistically significant correlations and low Bland-Altman bias between the local velocity values produced by the two techniques indicates quantitative agreement. This preliminary in vivo comparison of respiratory airway CFD and PC MRI of hyperpolarized 129Xe gas demonstrates the feasibility of PC MRI as a technique to validate respiratory CFD and forms the basis for further comprehensive validation studies. This study is therefore a first step in the pathway towards clinical adoption of respiratory CFD.

Role of Flexible Bronchoscopy in Ventilator-Dependent Neonates

Objective

To assess the usefulness and safety of flexible bronchoscopy in ventilated neonates with extubation failure.

Method

This was a prospective observational study. Flexible bronchoscopy was done in eligible patients with failure of extubation form invasive ventilation. The main outcome measure was to find the presence of any anatomic or dynamic abnormalities of the airways of these patients and the organism profile of bronchoalveolar lavage (BAL) fluid.

Results

Forty-eight babies (68.8% preterm) were enrolled in the study. The most common finding on bronchoscopy was airway edema seen in 13 (27%) patients. BAL culture was positive in 29 (74%) patients. Overall treatment was modified in 35 (73%) patients based on bronchoscopy findings/BAL culture. Majority of infants (83.3%) tolerated the procedure very well.

Conclusion

Flexible bronchoscopy provides useful information in the management of newborn babies with extubation failure.

Outcomes of infants with severe bronchopulmonary dysplasia in the pediatric intensive care unit

BACKGROUND

Some infants with severe bronchopulmonary dysplasia (sBPD) are referred to higher-level centers for multidisciplinary care, including the pediatric intensive care unit (PICU). However, information regarding these infants is limited in PICUs.

METHODS

We investigated the characteristics and outcomes of preterm infants with sBPD referred to the PICU of a tertiary hospital. This retrospective cohort study included 14 preterm infants with sBPD who were transferred to the PICU beyond 40 weeks' postmenstrual age (PMA) because of weaning failure, from January 1, 2014, to September 30, 2018.

RESULTS

The median age at referral was 47.1 weeks (range, 43.6-55.9 weeks), and the median length of stay in the previous neonatal intensive care unit was 154 days (range, 105.8-202.3 days) after birth. After referral the following major comorbidities were found in the patients: large airway malacia, n = 7 (50.0%); significant upper airway obstruction, n = 3 (21.4%); and pulmonary arterial hypertension, n = 8 patients (57.1%). Finally, eight patients (57.1%) were successfully extubated without tracheostomy. Final respiratory support of the patients was determined at a median PMA of 56 weeks (range, 48-63 weeks). Age at referral (P = 0.023) and large airway obstruction (P = 0.028) were significantly related to a decrease in successful extubation.

CONCLUSION

Based on a timely and individualized multidisciplinary approach, some of the prolonged ventilator-dependent infants, even those beyond term age, could be successfully extubated.

Pediatric bronchoscopy: recent advances and clinical challenges

Introduction: During the last 40 years equipment has been improved with smaller instruments and sufficient size working channels. This has ensured that bronchoscopy offers therapeutic and interventional options.Areas covered: We provide a review of recent advances and clinical challenges in pediatric bronchoscopy. This includes single-use bronchoscopes, endobronchial ultrasound, and cryoprobe. Bronchoscopy in persistent preschool wheezing and asthma is included. The indications for interventional bronchoscopy have amplified and included balloon dilatation, endoscopic intubation, the use of airway stents, whole lung lavage, closing of fistulas and air leak, as well as an update on removal of foreign bodies. Others include the use of laser and microdebrider in airway surgery. Experience with bronchoscope during the COVID-19 pandemic has been included in this review. PubMed was searched for articles on pediatric bronchoscopy, including rigid bronchoscopy as well as interventional bronchoscopy with a focus on reviewing literature in the past 5 years.Expert opinion: As the proficiency of pediatric interventional pulmonologists continues to grow more interventions are being performed. There is a scarcity of published evidence in this field. Courses for pediatric interventional bronchoscopy need to be developed. The COVID-19 experience resulted in safer bronchoscopy practice for all involved.

Respiratory, growth, and survival outcomes of infants with tracheostomy and ventilator dependence

BACKGROUND

Outcome of infants with tracheostomy have not been well described in the literature. Our objective was to describe the respiratory, growth, and survival outcomes of infants with tracheostomy.

METHODS

A retrospective study was conducted on 204 infants born between 2005 and 2015 with tracheostomy at <1 year of age and follow-up in the Infant Tracheostomy and Home Ventilator Clinic up to 4 years of age.

RESULTS

The mean age at tracheostomy was 4.5 months with median age of 3 months. Median age of decannulation was 32 months. The time from tracheostomy placement to complete discontinuation of mechanical ventilation was 15.4 months and from tracheostomy to decannulation was 33.8 months. Mortality rate was 21% and median age of death was 18 months. Preterm infants with acquired airway and lung disease (BPD) and born at <28 weeks' gestation had a significantly higher survival rate compared to term infants. The z-scores for weight and weight for length improved from the time of discharge (mean chronological age 6.5 months) to first year and remained consistent through 3 years.

CONCLUSIONS

Premature infants had a higher rate of discontinuation of mechanical ventilation and decannulation compared to term infants. These infants showed consistent growth and comparable survival rate.

IMPACT

Infants with tracheostomy and ventilator dependence followed in a multidisciplinary clinic model may have improved survival, growth, and earlier time to decannulation. Preterm infants with acquired airway and lung disease (BPD) with tracheostomy had a higher survival rate compared to term infants with various tracheostomy indications. The age at tracheostomy in infants was 4.5 months and of decannulation was 37 months. Time from tracheostomy to complete discontinuation of mechanical ventilation was 15.4 months. Addition of this data to the sparse literature will be crucial in counseling the families and education of medical staff.

Subglottic Stenosis Position Affects Work of Breathing

OBJECTIVES

Subglottic stenosis (SGS) is the most common type of laryngeal stenosis in neonates. SGS severity is currently graded based on percent area of obstruction (%AO) via the Myer-Cotton grading scale. However, patients with similar %AO can have widely different clinical courses. Computational fluid dynamics (CFD) based on patient-specific imaging can quantify the relationship between airway geometry and flow dynamics. We investigated the effect of %AO and axial position of SGS on work of breathing (WOB) in neonates using magnetic resonance imaging.

METHODS

High-resolution ultrashort echo-time MRI of the chest and airway was obtained in three neonatal patients with no suspected airway abnormalities; images were segmented to construct three-dimensional (3D) models of the neonatal airways. These models were then modified with virtual SGSs of varying %AO and axial positioning. CFD simulations of peak inspiratory flow were used to calculate patient-specific WOB in nonstenotic and artificially stenosed airway models.

RESULTS

CFD simulations demonstrated a relationship between stenosis geometry and WOB increase. WOB rapidly increased with %AO greater than about 70%. Changes in axial position could also increase WOB by approximately the same amount as a 10% increase in %AO. Increased WOB was particularly pronounced when the SGS lumen was misaligned with the glottic jet.

CONCLUSION

The results indicate a strong, predictable relationship between WOB and axial position of the stenotic lumen relative to the glottis, which has not been previously reported. These findings may lead to precision diagnosis and treatment prediction tools in individual patients.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E1220-E1226, 2021.

Bronchopulmonary Dysplasia: Then, Now, and Next

Bronchopulmonary dysplasia (BPD) has evolved considerably since its first description over 50 years ago. This review aims to provide a historical framework for conceptualizing BPD and a current understanding of the changing definition, epidemiology, pathophysiology, treatment, and outcomes of BPD. The transdisciplinary approach that led to the initial phenotypic description of BPD continues to hold promise today. Investigators are refining the definition of BPD in light of changes in clinical care and increasing survival rates of very preterm infants. Despite improvements in perinatal care the incidence of BPD continues to increase. There is growing recognition that antenatal risk factors play a key role in the development of BPD. Strategies designed to prevent or limit neonatal lung injury continue to evolve. Defining the phenotype of infants with BPD can meaningfully direct treatment. Infants with BPD benefit from an interdisciplinary approach to longitudinal care with a focus on growth and neurocognitive development. While the ultimate impact of BPD on long-term pulmonary morbidity remains an active area of investigation, current data indicate that most children and adolescents with a history of BPD have a quality of life comparable to that of other preterm infants.

The Clinical Evaluation of Severe Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia is a common disease of prematurity that presents along a wide spectrum of disease severity. Infants with high severity require prolonged hospitalizations and benefit from multidisciplinary care. We describe our approach to the evaluation of infants with severe bronchopulmonary dysplasia. Important considerations include the phenotypic heterogeneity in clinical presentation that necessitates individualized care, the common presence of comorbidities and importance of a comprehensive multisystem evaluation, and the value of applying a chronic care model that prioritizes long-term respiratory and neurodevelopmental goals. Key features of the history, physical examination, and diagnostic studies are discussed with these considerations in mind.

Differences in Flexible and Rigid Bronchoscopy for Assessment of Tracheomalacia

OBJECTIVES/HYPOTHESIS

Both flexible and rigid bronchoscopy can be used to assess tracheomalacia; however, there is limited evidence comparing the two techniques. The objective of this study was to compare flexible and rigid bronchoscopy for evaluating the location and severity of tracheomalacia in children.

STUDY DESIGN

Retrospective case series.

METHODS

This was a retrospective study of children with both flexible and rigid bronchoscopy under the same sedation. All bronchoscopies were reviewed by three bronchoscopists for the location and severity of tracheomalacia. The location of collapse was defined as upper, middle, or lower trachea, and the severity of collapse was defined as none (0%-25% collapse), mild/moderate (26%-75% collapse), and severe (>75% collapse).

RESULTS

Twenty-one patients were recruited for this study with a variety of neonatal respiratory diseases. There was 94% agreement (κ = 0.64) for assessment of tracheomalacia in the upper trachea. However, agreement was only 75% (κ = 0.50) in the middle trachea and 76% (κ = 0.52) in the lower trachea. In the subset of patients without tracheostomy, agreement improved to 100%, 88%, and 82% for the upper, middle, and lower trachea, respectively. There was poor correlation for tracheomalacia severity in the middle trachea (ρ = 0.30, P = .2) and moderate in the lower trachea (ρ = 0.63, P = .002).

CONCLUSIONS

Although there is moderate agreement between flexible and rigid bronchoscopy for evaluating the presence of tracheomalacia, there can be differences in the two techniques, particularly when assessing severity of airway collapse. Future studies will be needed to understand factors that result in the discordance of flexible and rigid bronchoscopy for assessing airway dynamics.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:201-204, 2021.

Ultrashort Echo-Time MRI for the Assessment of Tracheomalacia in Neonates

BACKGROUND

Bronchoscopy is the gold standard for evaluating tracheomalacia; however, reliance on an invasive procedure limits understanding of normal airway dynamics. Self-gated ultrashort echo-time MRI (UTE MRI) can assess tracheal dynamics but has not been rigorously evaluated.

METHODS

This study was a validation of UTE MRI diagnosis of tracheomalacia in neonates using bronchoscopy as the gold standard. Bronchoscopies were reviewed for the severity and location of tracheomalacia based on standardized criteria. The percent change in cross-sectional area (CSA) of the trachea between end-inspiration and end-expiration was determined by UTE MRI, and receiver-operating curves were used to determine the optimal cutoff values to predict tracheomalacia and determine positive and negative predictive values.

RESULTS

Airway segments with tracheomalacia based on bronchoscopy had a more than threefold change in CSA measured from UTE MRI (54.4 ± 56.1% vs 14.8 ± 19.5%; P < .0001). UTE MRI correlated moderately with bronchoscopy for tracheomalacia severity (ρ = 0.39; P = .0001). Receiver-operating curves, however, showed very good ability of UTE MRI to identify tracheomalacia (area under the curve, 0.78). A "loose" definition (> 20% change in CSA) of tracheomalacia had good sensitivity (80%) but low specificity (64%) for identifying tracheomalacia based on UTE MRI, whereas a "strict" definition (> 40% change in CSA) was poorly sensitive (48%) but highly specific (93%).

CONCLUSIONS

Self-gated UTE MRI can noninvasively assess tracheomalacia in neonates without sedation, ionizing radiation, or increased risk. This technique overcomes major limitations of other diagnostic modalities and may be suitable for longitudinal population studies of tracheal dynamics.

A novel approach using volumetric dynamic airway computed tomography to determine positive end-expiratory pressure (PEEP) settings to maintain airway patency in ventilated infants with bronchopulmonary dysplasia

BACKGROUND

Positive end-expiratory pressure (PEEP) is a key mechanical ventilator setting in infants with bronchopulmonary dysplasia (BPD). Excessive PEEP can result in insufficient carbon dioxide elimination and lung damage, while insufficient PEEP can result in impaired gas exchange secondary to airway and alveolar collapse. Determining PEEP settings based on clinical parameters alone is challenging and variable.

OBJECTIVE

The purpose of this study was to describe our experience using dynamic airway CT to determine the lowest PEEP setting sufficient to maintain expiratory central airway patency of at least 50% of the inspiratory cross-sectional area in children with BPD requiring long-term ventilator support.

MATERIALS AND METHODS

We retrospectively identified all infants with BPD who underwent volumetric CT with a dynamic airway protocol for PEEP optimization from December 2014 through April 2019. Sixteen infants with BPD underwent 17 CT exams. Each CT exam consisted of acquisitions spanning the trachea and mainstem bronchi. We measured cross-sectional area of the trachea and mainstem bronchi and qualitatively assessed the amount of atelectasis. We documented changes in management as a result of the CT exam.

RESULTS

The average effective dose was 0.1-0.8 mSv/scan. Of 17 CT exams, PEEP was increased in 9, decreased in 3 and unchanged after 5 exams.

CONCLUSION

Dynamic airway CT shows promise to assist the clinician in determining PEEP settings to maintain airway patency in infants with BPD requiring long-term ventilator support. Further evaluation of the impact of this maneuver on gas exchange, cardiac output and other physiological measures is needed.