Infant Bronchiolitis Endotypes and the Risk of Developing Childhood Asthma: Lessons From Cohort Studies

Severe bronchiolitis (i.e., bronchiolitis requiring hospitalization) during infancy is a heterogeneous condition associated with a high risk of developing childhood asthma. Yet, the exact mechanisms underlying the bronchiolitis-asthma link remain uncertain. Birth cohort studies have reported this association at the population level, including only small groups of patients with a history of bronchiolitis, and have attempted to identify the underlying biological mechanisms. Although this evidence has provided valuable insights, there are still unanswered questions regarding severe bronchiolitis-asthma pathogenesis. Recently, a few bronchiolitis cohort studies have attempted to answer these questions by applying unbiased analytical approaches to biological data. These cohort studies have identified novel bronchiolitis subtypes (i.e., endotypes) at high risk for asthma development, representing essential and enlightening evidence. For example, one distinct severe respiratory syncytial virus (RSV) bronchiolitis endotype is characterized by the presence of Moraxella catarrhalis and Streptococcus pneumoniae, higher levels of type I/II IFN expression, and changes in carbohydrate metabolism in nasal airway samples, and is associated with a high risk for childhood asthma development. Although these findings hold significance for the design of future studies that focus on childhood asthma prevention, they require validation. However, this scoping review puts the above findings into clinical context and emphasizes the significance of future research in this area aiming to offer new bronchiolitis treatments and contribute to asthma prevention.

Cognitive, Functional, and Quality of Life Outcomes 6 Months After Mechanical Ventilation for Bronchiolitis: A Secondary Analysis of Data From the Randomized Evaluation of Sedation Titration for Respiratory Failure Trial ( RESTORE )

OBJECTIVES

To describe rates and associated risk factors for functional decline 6 months after critical bronchiolitis in a large, multicenter dataset.

DESIGN

Nonprespecified secondary analysis of existing 6-month follow-up data of patients in the Randomized Evaluation of Sedation Titration for Respiratory Failure trial ( RESTORE , NCT00814099).

SETTING

Patients recruited to RESTORE in any of 31 PICUs in the United States, 2009-2013.

PATIENTS

Mechanically ventilated PICU patients under 2 years at admission with a primary diagnosis of bronchiolitis.

INTERVENTIONS

There were no interventions in this secondary analysis; in the RESTORE trial, PICUs were randomized to protocolized sedation versus usual care.

MEASUREMENTS AND MAIN RESULTS

"Functional decline," defined as worsened Pediatric Overall Performance Category and/or Pediatric Cerebral Performance Category (PCPC) scores at 6 months post-PICU discharge as compared with preillness baseline. Quality of life was assessed using Infant Toddler Quality of Life Questionnaire (ITQOL; children < 2 yr old at follow-up) or Pediatric Quality of Life Inventory (PedsQL) at 6 months post-PICU discharge. In a cohort of 232 bronchiolitis patients, 28 (12%) had functional decline 6 months postdischarge, which was associated with unfavorable quality of life in several ITQOL and PedsQL domains. Among 209 patients with normal baseline functional status, 19 (9%) had functional decline. In a multivariable model including all subjects, decline was associated with greater odds of worse baseline PCPC score and longer PICU length of stay (LOS). In patients with normal baseline status, decline was also associated with greater odds of longer PICU LOS.

CONCLUSIONS

In a random sampling of RESTORE subjects, 12% of bronchiolitis patients had functional decline at 6 months. Given the high volume of mechanically ventilated patients with bronchiolitis, this observation suggests many young children may be at risk of new morbidities after PICU admission, including functional and/or cognitive morbidity and reduced quality of life.

Bronchiolitis hospital admission in infancy is associated with later preschool ventilation inhomogeneity

BACKGROUND

Rhinovirus (RV) positive bronchiolitis episodes in infancy confer a higher risk to develop asthma in later childhood with associated lung function impairments. We aimed to investigate the association between the type of virus causing a bronchiolitis hospitalization episode and lung ventilation inhomogeneities at preschool age.

METHODS

Infants hospitalized with a clinical diagnosis of moderate (ward admission) or severe (pediatric intensive care ward admission) bronchiolitis were prospectively followed-up at preschool age to assess nitrogen (N2 ) multiple breath washout (MBW). Lung clearance index (LCI), functional residual capacity (FRC), and concentration normalized phase III slope analysis (SnIII ) indices were reported from ≥2 technically acceptable trials. Differences between groups were calculated using logistic and linear regression and adjusted for confounders (sex, age at bronchiolitis admission, height at visit, maternal asthma, and doctor-diagnosed asthma, including interaction terms between the latter three). An interaction term was included in a regression model to test for an interaction between RV bronchiolitis severity and MBW parameters at preschool age.

RESULTS

One hundred and thirty-nine subjects attended preschool follow-up, of which 84 out of 103 (82%) performing MBW had technically acceptable data. Children with a history of RV positive bronchiolitis (n = 39) had increased LCI (adjusted β-coefficient [aβ] = 0.33, 95% confidence interval [CI] 0.02-0.65, p = 0.040) and conductive airways ventilation inhomogeneity [Scond ] (aβ = 0.016, CI 0.004-0.028, p = 0.011) when compared with those with a RV negative bronchiolitis history (n = 45). In addition, we found a statistical interaction between RV bronchiolitis and bronchiolitis severity strengthening the association with LCI (aβ = 0.93, CI 0.20-1.58, p = 0.006).

CONCLUSION

Children with a history of hospital admission for RV positive bronchiolitis in infancy might be at a higher risk of lung ventilation inhomogeneities at preschool age, arising from the peripheral conducting airways.

Predicting long-term neurocognitive outcome after pediatric intensive care unit admission for bronchiolitis-preliminary exploration of the potential of machine learning

PURPOSE

For successful prevention and intervention, it is important to unravel the complex constellation of factors that affect neurocognitive functioning after pediatric intensive care unit (PICU) admission. This study aims (1) to elucidate the potential relevance of patient and PICU-related characteristics for long-term adverse neurocognitive outcome after PICU admission for bronchiolitis, and (2) to perform a preliminary exploration of the potential of machine learning as compared to linear regression to improve neurocognitive outcome prediction in a relatively small sample of children after PICU admission.

METHODS

This cross-sectional observational study investigated 65 children aged 6-12 years with previous PICU admission for bronchiolitis (age ≤ 1 year). They were compared to demographically comparable healthy peers (n = 76) on neurocognitive functioning. Patient and PICU-related characteristics used for the prediction models were as follows: demographic characteristics, perinatal and disease parameters, laboratory results, and intervention characteristics, including hourly validated mechanical ventilation parameters. Neurocognitive outcome was measured by intelligence and computerized neurocognitive testing. Prediction models were developed for each of the neurocognitive outcomes using Regression Trees, k-Nearest Neighbors, and conventional linear regression analysis.

RESULTS

The patient group had lower intelligence than the control group (p < .001, d = -0.59) and poorer performance in neurocognitive functions, i.e., speed and attention (p = .03, d = -0.41) and verbal memory (p < .001, d = -0.60). Lower intelligence was predicted by lower birth weight and lower socioeconomic status (R2 = 25.9%). Poorer performance on the speed and attention domain was predicted by younger age at follow-up (R2 = 53.5%). Poorer verbal memory was predicted by lower birth weight, younger age at follow-up, and greater exposure to acidotic events (R2 = 50.6%). The machine learning models did not reveal added value in terms of model performance as compared to linear regression.

CONCLUSION

The findings of this study suggest that in children with previous PICU admission for bronchiolitis, (1) lower birth weight, younger age at follow-up, and lower socioeconomic status are associated with poorer neurocognitive outcome; and (2) greater exposure to acidotic events during PICU admission is associated with poorer verbal memory outcome. The findings of this study provide no evidence for the added value of machine learning models as compared to linear regression analysis in the prediction of long-term neurocognitive outcome in a relatively small sample of children.

WHAT IS KNOWN

• Adverse neurocognitive outcomes are described in PICU survivors, which are known to interfere with development in other major domains of functioning, such as mental health, academic achievement, and socioeconomic success, highlighting neurocognition as an important outcome after PICU admission. • Machine learning is a rapidly growing field of artificial intelligence that is increasingly applied in health care settings, with great potential to capture the complexity of outcome prediction.

WHAT IS NEW

• This study shows that lower birth weight, lower socioeconomic status, and greater exposure to acidotic events during PICU admission for bronchiolitis are associated with poorer long-term neurocognitive outcome after PICU admission. Results provide no evidence for the added value of machine learning models in a relatively small sample of children. • As bronchiolitis seldom manifests neurologically, the relation between acidotic events and neurocognitive outcome may reflect either potentially harmful effects of acidosis itself or related processes such as hypercapnia or hypoxic and/or ischemic events during PICU admission. This study further highlights the importance of structured follow-up to monitor long-term outcome of children after PICU admission.

Chest imaging classification in Mycoplasma pneumoniae pneumonia is associated with its clinical features and outcomes

BACKGROUND

The imaging findings of Mycoplasma pneumoniae pneumonia (MPP) vary; however, few studies have focused on the relationship of imaging classification with clinical manifestations and outcomes.

OBJECTIVE

To prospectively investigate whether chest imaging classification in Mycoplasma pneumoniae pneumonia (MPP) is associated with its clinical features and outcomes.

METHODS

A total of 1,401 hospitalized children with MPP were enrolled from January 2019 to December 2021. Imaging findings were categorized as bronchopneumonia and consolidation/atelectasis according to X-ray, and bronchopneumonia, consolidation/atelectasis, bronchiolitis, and mosaic pattern according to computed tomography (CT). Clinical characteristics and outcomes of patients with different imaging classifications were prospectively analyzed based on electronic medical records.

RESULTS

Bronchopneumonia was the most common finding (59.6%), while consolidation/atelectasis was the most severe group. Clinical manifestations and laboratory indicators for the consolidation/atelectasis group included serious abnormalities. Further, outcomes of the patients were worse, including having longer total durations of fever and hospitalization, greater hospitalization expenses, and a higher likelihood of developing refractory MPP, necrotizing pneumonia, and bronchiolitis obliterans (BO) in this group. The incidence of bronchiolitis, a disease characterized by a high prevalence of fever, moist rales, and an atopic constitution, tended to increase after the coronavirus disease pandemic and predisposed patients to BO. A mosaic pattern occurred in allergic and young individuals, with wheezing as the main manifestation, with patients having relatively mild symptoms and good outcomes.

CONCLUSION

Different imaging classifications have different clinical features and clinical outcomes; thus, formulating an imaging-based classification system is of great clinical value.

Low peripheral blood chemokine (C-C motif) ligand 5 and tumor necrosis factor α gene expression is associated with unfavorable progression of respiratory syncytial virus bronchiolitis in infants

OBJECTIVES

We aimed to analyze whether the expression of inflammatory and antiviral genes in respiratory syncytial virus (RSV)-infected infants' peripheral blood is associated with bronchiolitis progression.

METHODS

We conducted a prospective study on 117 infants between 2015 and 2023. The expression levels of nine genes were quantified by quantitative polymerase chain reaction. Infants were classified according to their clinical evolution during hospital admission: (i) non-progression (n = 74), when the RSV bronchiolitis severity remained stable or improved; (ii) unfavorable progression (n = 43), when the RSV bronchiolitis severity increased. The association analysis was performed by logistic regression, adjusted by age, gender, prematurity, and RSV bronchiolitis severity in the emergency room.

RESULTS

Infants were 57.3% male, and the median age of the study population was 61 days. Thirty-five infants (30.7%) were admitted to the intensive care unit after hospital admission. Univariate logistic models showed that tumor necrosis factor (TNFα) and chemokine (C-C motif) ligand (CCL5) gene expression at baseline were inversely associated with unfavorable progression, which was confirmed by multivariate analyses: TNFα (adjusted odds ratio = 0.8 [95% confidence interval = 0.64-0.99], P-value = 0.038) and CCL5 (adjusted odds ratio = 0.76 [95% confidence interval = 0.62-0.93], P-value = 0.007).

CONCLUSIONS

An inadequate immune response to RSV, characterized by reduced gene expression levels of CCL5 and TNFα in peripheral blood, was associated with an unfavorable progression of RSV bronchiolitis.

Association between goal nutrition and intubation in patients with bronchiolitis on noninvasive ventilation: A retrospective cohort study

BACKGROUND

Acute bronchiolitis causes many hospitalizations in children younger than 2 years. Early enteral nutrition is associated with improved outcomes in these patients. However, often nutrition is withheld when patients require noninvasive respiratory support because of the risk of aspiration worsening respiratory failure, possibly requiring intubation. We hypothesize that achieving goal energy intake is associated with a lower intubation rate in hospitalized children with bronchiolitis who require noninvasive ventilation.

METHODS

This retrospective cohort study examined the association between goal enteral nutrition (60% of dietary reference energy intake) and intubation rates. We grouped patients by severity of illness and compared intubation rates in those who met goal energy to those who did not. We use stratified analysis methods (for both level of respiratory support and feeding route) to evaluate progression to intubation.

RESULTS

Of the 272 patients, 215 met goal feeds. These groups had similar demographics, but the goal-feeds group started on higher respiratory support in the pediatric intensive care unit. We found that 4.65% of the patients who met goal feeds required intubation compared with 24.6% of patients who did not meet goal feeds (P < 0.0001), even after controlling for respiratory status at admission and time of feed initiation and feeding route.

CONCLUSION

We observed when adjusting for severity, feeding route, and respiratory support, achieving goal energy intake remained associated with a lower rate of intubation, without higher rates of aspiration. Confounding factors include practice variation and difference in severity of illness that objective scoring may have missed.

Environmental risk factors for respiratory infection and wheeze in young children: A multicentre birth cohort study

INTRODUCTION

Respiratory infections and wheeze have a considerable impact on the health of young children and consume significant healthcare resources. We aimed to evaluate the effect of environmental factors on respiratory infections and symptoms in early childhood.

METHODS

Environmental risk factors including: daycare attendance; breastfeeding; siblings; damp within the home; environmental tobacco smoke (ETS); child's bedroom flooring; animal exposure; road traffic density around child's home; and solid fuel pollution within home were assessed in children recruited to the GO-CHILD multicentre prospective birth cohort study. Follow-up information on respiratory infections (bronchiolitis, pneumonia, otitis media and cold or flu), wheeze and cough symptoms, healthcare utilisation and medication prescription was collected by postal questionnaires at 12 and 24 months. Log binomial and ordered logistic regression models were fitted to the data.

RESULTS

Follow-up was obtained on 1344 children. Daycare was associated with increased odds of pneumonia (odds ratio [OR] = 2.39, 95% confidence interval [CI]: 1.04-5.49), bronchiolitis (OR = 1.40, 1.02-1.90), otitis media (OR = 1.68, 1.32-2.14) and emergency department attendance for wheeze (RR = 1.81, 1.17-2.80). Breastfeeding beyond 6 months was associated with a reduced odds of bronchiolitis (OR = 0.55, 0.39-0.77) and otitis media (OR = 0.75, 0.59-0.99). Siblings at home was associated with an increased odds of bronchiolitis (OR = 1.65, 1.18-2.32) and risk of reliever inhaler prescription (RR = 1.37, 1.02-1.85). Visible damp was associated with an increased odds of wheeze (OR = 1.85, 1.11-3.19), and risk of reliever inhaler (RR = 1.73, 1.04-2.89) and inhaled corticosteroid prescription (RR = 2.61, 1.03-6.59). ETS exposure was associated with an increased odds of primary care attendance for cough or wheeze (OR = 1.52, 1.11-2.08). Dense traffic around the child's home was associated with an increased odds of bronchiolitis (OR = 1.32, 1.08-2.29).

CONCLUSION

Environmental factors likely influence the wide variation in infection frequency and symptoms observed in early childhood. Larger population studies are necessary to further inform and guide public health policy to decrease the burden of respiratory infections and wheeze in young children.

Asthmalitis? Diagnostic Variability of Asthma and Bronchiolitis in Children <24 Months

BACKGROUND AND OBJECTIVES

Bronchiolitis and asthma have similar acute clinical presentations in young children yet have opposing treatment recommendations. We aimed to assess the role of age and other factors in the diagnosis of bronchiolitis and asthma in children <24 months of age.

METHODS

We conducted a retrospective cross-sectional analysis of the Pediatric Health Information System database. We included children aged <2 years diagnosed with bronchiolitis, asthma, wheeze, or bronchospasm in emergency department or hospital encounters from 2017 to 2021. We described variation by age and between institutions. We used mixed-effects models to assess factors associated with a non-bronchiolitis diagnosis in children 12 to 23 months of age.

RESULTS

We included 554 158 encounters from 42 hospitals. Bronchiolitis made up 98% of encounters for children <3 months of age, whereas asthma diagnoses increased with age and were included in 44% of encounters at 23 months of age. Diagnosis patterns varied widely between hospitals. In children 12 to 23 months of age, the odds of a non-bronchiolitis diagnosis increased with month of age (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.12-1.13), male sex (OR 1.37, 95% CI 1.35-1.40), non-Hispanic Black race (OR 1.54, 95% CI 1.50-1.58), number of previous encounters (OR 2.73, 95% CI 2.61-2.86, for 3 or more encounters), and previous albuterol use (OR 2.24, 95% CI 2.16-2.32).

CONCLUSIONS

Non-bronchiolitis diagnoses and the use of inhaled bronchodilators and systemic steroids for acute wheezing respiratory illness increase with month of age in children aged 0 to 23 months. Better definitions of clinical phenotypes of bronchiolitis and asthma would allow for more appropriate treatment in acute care settings, particularly in children 12 to 23 months of age.

Respiratory Syncytial Virus Infection: An Update

Respiratory syncytial virus (RSV) is a highly contagious respiratory virus that can cause mild to severe illness in children. It is the leading cause of lower respiratory tract infections (LRTI) in children under the age of one year, and it can also affect older children and adults, especially those with underlying medical conditions. In the post-COVID period, there seems to be an increase in the incidence, possibly due to 'immunity debt'. Symptoms of RSV infection in children may include fever, runny nose, and cough. In severe cases, it can lead to bronchiolitis (inflammation of the small airways in the lungs) or pneumonia (infection of the lungs). Most children with RSV infection recover within a week or two, but some may require hospitalization, especially those who are premature or have underlying medical conditions. As there is no specific treatment for RSV infection, supportive care is the mainstay of management. In severe cases, oxygen therapy or mechanical ventilation may be necessary. High flow nasal cannula seems to be beneficial. There have been promising advances in development of RSV vaccines; few trials in adults and pregnant women have reported encouraging results. The US FDA has approved two RSV vaccines for use in older adults (GSK's Arexvy and Pfizer's ABRYSVO).

Effect Modifiers of the Association of High-Flow Nasal Cannula and Bronchiolitis Length of Stay

BACKGROUND AND OBJECTIVES

High-flow nasal cannula (HFNC) therapy for hospitalized children with bronchiolitis is associated with a longer length of stay (LOS) when used outside of the ICU. We sought to explore the association between HFNC and LOS to identify if demographic and clinical factors may modify the effect of HFNC usage on LOS.

METHODS

In this multicenter retrospective cohort study, we used a combination of hospital records and the Pediatric Health Information System. We included encounters from September 1, 2018 to March 31, 2020 for patients <2 years old diagnosed with bronchiolitis. Multivariable Poisson regression was performed for the association of LOS with measured covariates, including fixed main effects and interaction terms between HFNC and other factors.

RESULTS

Of 8060 included patients, 2179 (27.0%) received HFNC during admission. Age group, weight, complex chronic condition, initial tachypnea, initial desaturation, and ICU services were significantly associated with LOS. The effect of HFNC on LOS differed among hospitals (P < .001), with the estimated increase in LOS ranging from 32% to 139%. The effect of HFNC on LOS was modified by age group, initial desaturation, and ICU services, with 1- to 6-month-old infants, patients without initial desaturation, and patients without ICU services having the highest association between HFNC and LOS, respectively.

CONCLUSIONS

We identified multiple potential effect modifiers for the relationship between HFNC and LOS. The authors of future prospective studies should investigate the effect of HFNC usage on LOS in non-ICU patients without documented desaturation.

Long-Term Follow-Up of Daily Life Functioning After Pediatric Intensive Care Unit Admission

OBJECTIVE

To investigate the long-term impact of pediatric intensive care unit (PICU) admission on daily life functioning while exploring the potential mediating role of neurocognitive outcome.

STUDY DESIGN

This cross-sectional observational study compared children aged 6-12 years with previous PICU admission (age ≤1 year) for bronchiolitis requiring mechanical ventilation ("patient group," n = 65) to demographically comparable healthy peers ("control group," n = 76). The patient group was selected because bronchiolitis is not expected to affect neurocognitive functioning in itself. Assessed daily life outcome domains were behavioral and emotional functioning, academic performance, and health-related quality of life (QoL). The role of neurocognitive outcomes in the relationship between PICU admission and daily life functioning was assessed by mediation analysis.

RESULTS

The patient group did not differ from the control group regarding behavioral and emotional functioning but performed poorer on academic performance and school-related QoL (Ps ≤ .04, d = -0.48 to -0.26). Within the patient group, lower full-scale IQ (FSIQ) was associated with poorer academic performance and school-related QoL (Ps ≤ .02). Poorer verbal memory was associated with poorer spelling performance (P = .002). FSIQ mediated the observed effects of PICU admission on reading comprehension and arithmetic performance.

CONCLUSIONS

Children admitted to the PICU are at risk for long-term adverse daily life outcomes in terms of academic performance and school-related QoL. Findings suggest that lower intelligence may contribute to academic difficulties after PICU admission. Findings underline the importance of monitoring daily life and neurocognitive functioning after PICU admission.

Hypophosphatemia in infants with severe bronchiolitis and association with length of mechanical ventilation

OBJECTIVES

Electrolyte disorders occurs frequently in children with bronchiolitis. The aim of the present study was to describe the frequency of hypophosphatemia and to evaluate its association with length of mechanical ventilation in infants admitted to a pediatric intensive care unit (PICU) with bronchiolitis.

METHODS

This retrospective cohort study included infants aged between 7 days and 3 months admitted to a PICU between September 2018 and March 2020 and diagnosed with severe acute bronchiolitis requiring respiratory support. Infants with a chronic condition that could potentially be a confounding factor were excluded. The primary outcome was the frequency of hypophosphatemia (<1.55 mmol/L); the secondary outcomes were the frequency of hypophosphatemia during the PICU stay, and the association with length of mechanical ventilation (LOMV).

RESULTS

Among the 319 infants admitted 178 had at least one phosphatemia value and were included in the study. The frequency of hypophosphatemia was 41% at PICU admission (61/148) and 46% during the PICU stay (80/172). The median [IQR] LOMV was significantly longer in children with hypophosphatemia at admission (109 [65-195] h vs. 67 [43-128] h, p = 0.007), and in multivariable linear regression lower phosphatemia at admission was associated with longer LOMV (p < 0.001) after controlling for severity (PELOD2 score) and weight.

CONCLUSION

Hypophosphatemia was frequent in infants with severe bronchiolitis admitted to a PICU and was associated with a longer LOMV.

Pulmonary Hypertension Associated with Diffuse Panbronchiolitis That Improved with Erythromycin and Home Oxygen Therapy

Pulmonary hypertension (PH) often complicates chronic lung disease. However, there are few reports of PH associated with diffuse panbronchiolitis, and there is no effective treatment. We herein report a 64-year-old woman diagnosed with PH due to diffuse panbronchiolitis. She received erythromycin, carbocysteine, and home oxygen therapy (1 L O2/min). After 4 months of therapy, the respiratory function (diffusing capacity of the lungs for carbon monoxide: 23.3% to 76.1%) and PH (mean pulmonary arterial pressure: 50 to 28 mmHg; pulmonary vascular resistance: 680 to 518 dynes・sec・cm-5; pre- vs post-therapy, respectively) had improved markedly.

Role of Air Pollution in the Development of Asthma Among Children with a History of Bronchiolitis in Infancy

BACKGROUND

Infants experiencing bronchiolitis are at increased risk for asthma, but few studies have identified modifiable risk factors. We assessed whether early life air pollution influenced child asthma and wheeze at age 4-6 years among children with a history of bronchiolitis in the first postnatal year.

METHODS

Children with caregiver-reported physician-diagnosed bronchiolitis were drawn from ECHO-PATHWAYS, a pooled longitudinal cohort from six US cities. We estimated their air pollution exposure from age 1 to 3 years from validated spatiotemporal models of fine particulate matter (PM 2.5 ), nitrogen dioxide (NO 2 ), and ozone (O 3 ). Caregivers reported children's current wheeze and asthma at age 4-6 years. We used modified Poisson regression to estimate relative risks (RR) and 95% confidence intervals (CI), adjusting for child, maternal, and home environmental factors. We assessed effect modification by child sex and maternal history of asthma with interaction models.

RESULTS

A total of 224 children had caregiver-reported bronchiolitis. Median (interquartile range) 2-year pollutant concentrations were 9.3 (7.8-9.9) µg/m 3 PM 2.5 , 8.5 (6.4-9.9) ppb NO 2 , and 26.6 (25.6-27.7) ppb O 3 . RRs (CI) for current wheeze per 2-ppb higher O 3 were 1.3 (1.0-1.7) and 1.4 (1.1-1.8) for asthma. NO 2 was inversely associated with wheeze and asthma whereas associations with PM 2.5 were null. We observed interactions between NO 2 and PM 2.5 and maternal history of asthma, with lower risks observed among children with a maternal history of asthma.

CONCLUSION

Our results are consistent with the hypothesis that exposure to modest postnatal O 3 concentrations increases the risk of asthma and wheeze among the vulnerable subpopulation of infants experiencing bronchiolitis.

Risk factors for recurrent wheezing after bronchiolitis

BACKGROUND

This study aimed to determine whether there was an association between certain factors in patients with bronchiolitis and recurrent wheezing in childhood.

METHOD

In 2021 we tracked children hospitalized for bronchiolitis at Chengdu Women's and Children's Central Hospital in 2017. The patients were classified into recurrent wheezing group (RWG) and non-recurrent wheezing group (NRWG). Possible risk factors including maternal age, school-age siblings, allergic history, atopic dermatitis, allergic rhinitis, atopic family history, severity of the condition, duration of hospitalization, nasopharyngeal secretions culture, blood eosinophil counts, FeNO and skin prick test were compared between the two groups. Continuous variables were analyzed by independent sample t-test for normal distribution and Mann-Whitney U-test for non-normal distribution. Categorical variables were tested using chi-square tests. Multifactor analysis was conducted by stepwise logistics regression analysis.

RESULTS

In total 167 participants were included, of which 26 and 141 were in RWG and NRWG respectively. In RWG children represented higher maternal age (P = 0.02) and greater probability of allergic history, atopic dermatitis, allergic rhinitis, atopic family history (odds ratio [OR] = 4.0,3.7, 7.8, 10.9 respectively, P < 0.01). However, school-age siblings, severity of the condition, duration of hospitalization, blood eosinophil counts, fractional exhaled nitric oxide and skin prick test results seemed unrelated to recurrent wheezing. In the subgroup analysis of nasopharyngeal secretion culture, there were more Moraxella catarrhalis-positive in RWG(P = 0.043). Atopic dermatitis, allergic rhinitis and atopic family history were identified as independent risk factors for recurrent wheezing.

CONCLUSION

Some children with bronchiolitis will develop recurrent wheezing, and the risk factors are allergic history, Moraxella catarrhalis infection or colonization, atopic dermatitis, allergic rhinitis and atopic family history; the latter three are independent risk factors.

Elevated Diaphragmatic Tonic Activity in PICU Patients: Age-Specific Definitions, Prevalence, and Associations

OBJECTIVES

Tonic diaphragmatic activity (tonic Edi, i.e., sustained diaphragm activation throughout expiration) reflects diaphragmatic effort to defend end-expiratory lung volumes. Detection of such elevated tonic Edi may be useful in identifying patients who need increased positive end-expiratory pressure. We aimed to: 1) identify age-specific definitions for elevated tonic Edi in ventilated PICU patients and 2) describe the prevalence and factors associated with sustained episodes of high tonic Edi.

DESIGN

Retrospective study using a high-resolution database.

SETTING

Single-center tertiary PICU.

PATIENTS

Four hundred thirty-one children admitted between 2015 and 2020 with continuous Edi monitoring.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We characterized our definition of tonic Edi using data from the recovery phase of respiratory illness (i.e., final 3 hr of Edi monitoring, excluding patients with significant persistent disease or with diaphragm pathology). High tonic Edi was defined as population data exceeding the 97.5th percentile, which for infants younger than 1 year was greater than 3.2 μV and for older children as greater than 1.9 μV. These thresholds were then used to identify patients with episodes of sustained elevated tonic Edi in the first 48 hours of ventilation (acute phase). Overall, 62 of 200 (31%) of intubated patients and 138 of 222 (62%) of patients on noninvasive ventilation (NIV) had at least one episode of high tonic Edi. These episodes were independently associated with the diagnosis of bronchiolitis (intubated patients: adjusted odds [aOR], 2.79 [95% CI, 1.12-7.11]); NIV patients: aOR, 2.71 [1.24-6.0]). There was also an association with tachypnea and, in NIV patients, more severe hypoxemia.

CONCLUSIONS

Our proposed definition of elevated tonic Edi quantifies abnormal diaphragmatic activity during expiration. Such a definition may help clinicians to identify those patients using abnormal effort to defend end-expiratory lung volume. In our experience, high tonic Edi episodes are frequent, especially during NIV and in patients with bronchiolitis.

Are BMI and adipokines associated with asthma, atopy and lung function in young adults previously hospitalized for bronchiolitis?

BACKGROUND

Children hospitalized for bronchiolitis have increased risk of asthma and low lung function persisting into adulthood, but the underlying mechanisms are poorly understood. Body mass index (BMI) and adipokines are associated with respiratory morbidity. We aimed to investigate if associations between BMI and adipokines and the outcomes asthma, atopy, and lung function differed between young adults previously hospitalized for bronchiolitis and control subjects.

METHODS

This sub study of a historical cohort enrolled 185 young adults previously hospitalized for bronchiolitis and 146 matched control subjects. Exposures (BMI and the adipokines: adiponectin, leptin, resistin, and ghrelin) and outcomes (asthma, atopy, and lung function) were measured cross-sectionally at 17-20 years of age. Associations were tested in regression models, and differences between the post-bronchiolitis- and control group were tested by including interaction terms.

RESULTS

BMI was associated with asthma and lung function, but we did not find that the associations differed between the post-bronchiolitis- and control group. We also found some associations between adipokines and outcomes, but only associations between adiponectin and forced vital capacity (FVC) and between resistin and current asthma differed between the groups (p-value interaction term 0.027 and 0.040 respectively). Adiponectin tended to be positively associated with FVC in the post-bronchiolitis group, with an opposite tendency in the control group. Resistin was positively associated with current asthma only in the control group.

CONCLUSION

The increased prevalence of asthma and impaired lung function observed in young adults previously hospitalized for bronchiolitis do not seem to be related to growth and fat metabolism.

The impact of coronavirus disease 2019 pandemic on bronchiolitis (lower respiratory tract infection) due to respiratory syncytial virus: A systematic review and meta-analysis

The coronavirus disease 2019 (COVID-19) pandemic has changed the epidemiology of respiratory syncytial virus (RSV) infection which accounts for most bronchiolitis and viral pneumonias in infants. This systematic review and meta-analysis aimed to quantitatively assess the effect of the COVID-19 pandemic on RSV-associated bronchiolitis among hospitalized infants. The study protocol was registered in the PROSPERO database (CRD42022314000) and was designed based on Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines updated in May 2020. The meta-analysis component was modified appropriately to synthesize the pooled proportion of infants having RSV-associated bronchiolitis before the COVID-19 pandemic in 2019 and during the pandemic with 95% confidence interval (CI). We identified and screened 189 articles and systematically reviewed 50 full texts. Eight qualified studies from Europe and China, including 109,186 symptomatic cases of bronchiolitis before the pandemic in 2019 and 61,982 cases in 2020-2021 were pooled by random-effects meta-analysis. The quantitative analysis included laboratory-confirmed RSV infection in 7691 infants with bronchiolitis reported before the pandemic in 2019. Meanwhile, during the pandemic, 4964 bronchiolitis cases were associated with RSV infection. The pooled proportion of RSV-associated bronchiolitis cases before the pandemic in 2019 was 16.74% (95% CI 11.73, 22.43%, 95% prediction interval 0.032, 34.16). The pooled proportion of confirmed RSV cases during the pandemic in 2020/2021 was 19.20% (95% CI 12.01, 27.59%, 95% prediction interval 0.046, 42.35). There was an increase in RSV activity after the relaxation of stringent public health measures during the COVID-19 pandemic.

Antibiotic use in nonintubated children with bronchiolitis in the intensive care unit

INTRODUCTION

Antibiotic use may shorten mechanical ventilation duration and length of stay for patients with bronchiolitis that require intubation. The goals of this study were to describe antibiotic use in previously healthy children with bronchiolitis admitted to the intensive care unit (ICU) for noninvasive respiratory support and to describe associations of early antibiotic use with clinical outcomes.

METHODS

The Pediatric Health Information Systems database was queried for children <2 years of age without significant comorbidities admitted to the ICU for bronchiolitis. Children requiring mechanical ventilation on the first ICU day were excluded. Two groups were analyzed: those patients receiving antibiotics on the first day of their ICU stay (early antibiotics), and those receiving no antibiotics on their first ICU day (no antibiotics). Primary outcome was the length of ICU stay.

RESULTS

A total of 11,029 admissions met criteria, 2522 (22.9%) in the early antibiotic group, and 8507 (77.1%) in the no antibiotic group. The use of early antibiotics varied by center from 10% to 54%. In multivariate analysis, the early antibiotic group had similar ICU length of stay compared to the no antibiotic group (relative risk, RR [95% confidence interval, CI] 1.01 [0.98-1.05]). For patients on noninvasive ventilation, the first ICU day early antibiotics did not impact ICU length of stay (RR [95% CI] 0.97 [0.92-1.02]) or need for intubation (RR [95% CI] 1.11 [0.77-1.58]).

CONCLUSION

Early antibiotic use was common with significant variation between centers. Early antibiotic use was not associated with improved clinical outcomes in children admitted to the ICU for noninvasive respiratory support for bronchiolitis.

Oral Feeding on High-Flow Nasal Cannula in Children Hospitalized With Bronchiolitis

OBJECTIVE

Oral feeding by children with bronchiolitis on high-flow nasal cannula (HFNC) is questioned, resulting in high practice variability. Our objective was to determine the incidence of aspiration pneumonia and adverse feeding events in otherwise healthy children with bronchiolitis on HFNC who fed orally from admission.

METHODS

We conducted a single-center, retrospective chart review, in a tertiary children's hospital, of 876 children who were <24 months old, admitted for bronchiolitis, and treated with HFNC in the pediatric ward from March 2017 to May 2020. Primary outcomes included the incidence of aspiration pneumonia and adverse feeding events. Secondary outcomes included escalation of care, frequency and duration of nil per os status, length of stay, and 7-day readmission.

RESULTS

Most patients (77.2%) met inclusion criteria and were fed orally within 2 hours of admission. The average maximum HFNC flow rate was 8 L/min (1 L/kg/min); the average maximum respiratory rate was 62 ± 10. Adverse feeding events occurred in 11 patients (1.6%), of which 3 had a concern for possible microaspiration. None were diagnosed with or treated for aspiration pneumonia. Few patients (8.1%) were made nil per os while on HFNC but returned to oral feeding by discharge.

CONCLUSION

Among those with bronchiolitis on HFNC who received oral nutrition on admission, there were few incidences of adverse feeding events and no diagnoses of aspiration pneumonia, suggesting that oral feeding while on HFNC can be well-tolerated in similar populations. However, this study was limited by its single-center retrospective design, and future prospective studies are needed.

Overweight Infants Hospitalized for Bronchiolitis Associated With Severe Disease

OBJECTIVES

Overweight negatively affects pediatric respiratory function. In this study, we evaluate if overweight is associated with more severe bronchiolitis in hospitalized infants.

METHODS

This retrospective cohort study analyzed infants aged 30 to 365 days hospitalized for bronchiolitis from September 2019 to April 2020. Exclusion criteria included known risk factors for severe bronchiolitis, asthma treatment, or bacterial pneumonia. Weight-for-length z-score was categorized per the World Health Organization's growth assessments as overweight (z-score >2), underweight (z-score <-2), and standard weight (between -2 and ≤2). Primary outcomes included respiratory support, ICU stay, and local bronchiolitis score. Secondary outcomes included supplemental interventions.

RESULTS

After exclusion criteria, 385 of 644 infants were categorized as overweight (n = 24), standard (n = 335), or underweight (n = 26). There were differences in need for respiratory support (overweight, 100%; standard weight, 81.8%; underweight, 76.9%; P = .03), highest support of high-flow nasal cannula (overweight, 75%; standard weight, 48%; underweight, 42%; P = .03), admission to ICU (overweight, 54.2%; standard weight, 21.5%; underweight, 34.7%; P < .001), and median bronchiolitis score (overweight, 8 [interquartile range 5-10]; standard weight, 4 [3-7]; underweight, 4 [3-7]; P = .01). Findings remained significant after age adjustments. Additionally, overweight experienced higher frequency of certain treatments.

CONCLUSIONS

This study suggests overweight is associated with more severe bronchiolitis in hospitalized infants supported by increased respiratory support level, bronchiolitis scores, and interventions. Higher need for ICU admission may be related to high-flow nasal cannula limitations on the acute care floor.

Nasopharyngeal lipidomic endotypes of infants with bronchiolitis and risk of childhood asthma: a multicentre prospective study

BACKGROUND

Bronchiolitis is the leading cause of hospitalisation of US infants and an important risk factor for childhood asthma. Recent evidence suggests that bronchiolitis is clinically heterogeneous. We sought to derive bronchiolitis endotypes by integrating clinical, virus and lipidomics data and to examine their relationship with subsequent asthma risk.

METHODS

This is a multicentre prospective cohort study of infants (age <12 months) hospitalised for bronchiolitis. We identified endotypes by applying clustering approaches to clinical, virus and nasopharyngeal airway lipidomic data measured at hospitalisation. We then determined their longitudinal association with the risk for developing asthma by age 6 years by fitting a mixed-effects logistic regression model. To account for multiple comparisons of the lipidomics data, we computed the false discovery rate (FDR). To understand the underlying biological mechanism of the endotypes, we also applied pathway analyses to the lipidomics data.

RESULTS

Of 917 infants with bronchiolitis (median age, 3 months), we identified clinically and biologically meaningful lipidomic endotypes: (A) cinicalclassiclipidmixed (n=263), (B) clinicalseverelipidsphingolipids-high (n=281), (C) clinicalmoderatelipidphospholipids-high (n=212) and (D) clinicalatopiclipidsphingolipids-low (n=161). Endotype A infants were characterised by 'classic' clinical presentation of bronchiolitis. Profile D infants were characterised by a higher proportion of parental asthma, IgE sensitisation and rhinovirus infection and low sphingolipids (eg, sphingomyelins, ceramides). Compared with endotype A, profile D infants had a significantly higher risk of asthma (22% vs 50%; unadjusted OR, 3.60; 95% CI 2.31 to 5.62; p<0.001). Additionally, endotype D had a significantly lower abundance of polyunsaturated fatty acids (eg, docosahexaenoic acid; FDR=0.01). The pathway analysis revealed that sphingolipid metabolism pathway was differentially expressed in endotype D (FDR=0.048).

CONCLUSIONS

In this multicentre prospective cohort study of infants with bronchiolitis, integrated clustering of clinical, virus and lipidomic data identified clinically and biologically distinct endotypes that have a significantly differential risk for developing asthma.Delete.

Proteomics endotyping of infants with severe bronchiolitis and risk of childhood asthma

BACKGROUND

Bronchiolitis is the leading cause of hospitalization in U.S. infants and a major risk factor for childhood asthma. Growing evidence supports clinical heterogeneity within bronchiolitis. We aimed to identify endotypes of infant bronchiolitis by integrating clinical, virus, and serum proteome data, and examine their relationships with asthma development.

METHODS

This is a multicenter prospective cohort study of infants hospitalized for physician-diagnosis of bronchiolitis. We identified bronchiolitis endotypes by applying unsupervised machine learning (clustering) approaches to integrated clinical, virus (respiratory syncytial virus [RSV], rhinovirus [RV]), and serum proteome data measured at hospitalization. We then examined their longitudinal association with the risk for developing asthma by age 6 years.

RESULTS

In 140 infants hospitalized with bronchiolitis, we identified three endotypes: (1) clinicalatopic virusRV proteomeNFκB-dysregulated , (2) clinicalnon-atopic virusRSV/RV proteomeTNF-dysregulated , and (3) clinicalclassic virusRSV proteomeNFκB/TNF-regulated endotypes. Endotype 1 infants were characterized by high proportion of IgE sensitization and RV infection. These endotype 1 infants also had dysregulated NFκB pathways (FDR < 0.001) and significantly higher risks for developing asthma (53% vs. 22%; adjOR 4.04; 95% CI, 1.49-11.0; p = 0.006), compared with endotype 3 (clinically resembling "classic" bronchiolitis). Likewise, endotype 2 infants were characterized by low proportion of IgE sensitization and high proportion of RSV or RV infection. These endotype 2 infants had dysregulated tumor necrosis factor (TNF)-mediated signaling pathway (FDR <0.001) and significantly higher risks for developing asthma (44% vs. 22%; adjOR 2.71; 95% CI, 1.03-7.11, p = 0.04).

CONCLUSION

In this multicenter cohort, integrated clustering of clinical, virus, and proteome data identified biologically distinct endotypes of bronchiolitis that have differential risks of asthma development.

Respiratory virus type to guide predictive enrichment approaches in the management of the first episode of bronchiolitis: A systematic review

It has become clear that severe bronchiolitis is a heterogeneous disease; even so, current bronchiolitis management guidelines rely on the one-size-fits-all approach regarding achieving both short-term and chronic outcomes. It has been speculated that the use of molecular markers could guide more effective pharmacological management and achieve the prevention of chronic respiratory sequelae. Existing data suggest that asthma-like treatment (systemic corticosteroids and beta2-agonists) in infants with rhinovirus-induced bronchiolitis is associated with improved short-term and chronic outcomes, but robust data is still lacking. We performed a systematic search of PubMed, Embase, Web of Science, and the Cochrane’s Library to identify eligible randomized controlled trials to determine the efficacy of a personalized, virus-dependent application of systemic corticosteroids in children with severe bronchiolitis. Twelve studies with heterogeneous methodology were included. The analysis of the available results comparing the respiratory syncytial virus (RSV)-positive and RSV-negative children did not reveal significant differences in the associatons between systemic corticosteroid use in acute episode and duration of hospitalization (short-term outcome). However, this systematic review identified a trend of the positive association between the use of systematic corticosteroids and duration of hospitalization in RSV-negative infants hospitalized with the first episode of bronchiolitis (two studies). This evidence is not conclusive. Taken together, we suggest the design for future studies to assess the respiratory virus type in guiding predictive enrichment approaches in infants presenting with the first episode of bronchiolitis.

Severe bronchiolitis profiles and risk of asthma development in Finnish children

BACKGROUND

Recent studies support the existence of several entities under the clinical diagnosis of bronchiolitis. Among infants with severe bronchiolitis, distinct profiles have been differentially associated with development of recurrent wheezing by age 3 years. However, their associations with actual asthma remain unclear.

OBJECTIVE

Our aim was to study the association between severe bronchiolitis profiles identified by using a clustering approach and childhood asthma.

METHODS

Among 408 children (aged <2 years) hospitalized with bronchiolitis in Finland (in 2008-2010), latent class analysis identified 3 bronchiolitis profiles: profile A (47%), characterized by history of wheezing and/or eczema, wheezing during acute illness, and rhinovirus infection; profile BC (38%), characterized by severe illness and respiratory syncytial virus infection; and profile D (15%), characterized by the least severely ill children, including mostly children without wheezing and with rhinovirus infection. The children were followed by questionnaire 4 years later (86% [n = 348]) and through a nationwide social insurance database 7 years later (99% [n = 403]). Current asthma at the 4- and 7-year follow-ups was defined by regular use (according to parental report and medical records) or purchase (according to the social insurance database) of asthma control medication.

RESULTS

Compared with risk of current asthma associated with profile BC, we observed increased risk of current asthma associated with profile A both at the 4-year follow-up (age- and sex-adjusted odds ratio = 2.42 [95% CI = 1.23-4.75]) and at the 7-year follow-up (age- and sex-adjusted odds ratio = 3.14 [95% CI = 1.33-7.42]). No significant difference in asthma risk was observed between profile D and profile BC.

CONCLUSION

These longitudinal results provide further support for an association between a distinct severe bronchiolitis profile (characterized by a history of wheezing and/or eczema and rhinovirus infection) and risk of development childhood asthma.

Comparative Fecal Microbiota Analysis of Infants With Acute Bronchiolitis Caused or Not Caused by Respiratory Syncytial Virus

Bronchiolitis due to respiratory syncytial virus (RSV) or non-RSV agents is a health-menacing lower respiratory tract (LRT) disease of infants. Whereas RSV causes more severe disease than other viral agents may, genus-dominant fecal microbiota profiles have been identified in US hospitalized infants with bronchiolitis. We investigated the fecal microbiota composition of infants admitted to an Italian hospital with acute RSV (25/37 [67.6%]; group I) or non-RSV (12/37 [32.4%]; group II) bronchiolitis, and the relationship of fecal microbiota characteristics with the clinical characteristics of infants. Group I and group II infants differed significantly (24/25 [96.0%] versus 5/12 [41.7%]; P = 0.001) regarding 90% oxygen saturation (SpO₂), which is an increased respiratory effort hallmark. Accordingly, impaired feeding in infants from group I was significantly more frequent than in infants from group II (19/25 [76.0%] versus 4/12 [33.3%]; P = 0.04). Conversely, the median (IQR) length of stay was not significantly different between the two groups (seven [3–14] for group I versus five [5–10] for group II; P = 0.11). The 16S ribosomal RNA V3–V4 region amplification of infants’ fecal samples resulted in 299 annotated amplicon sequence variants. Based on alpha- and beta-diversity microbiota downstream analyses, group I and group II infants had similar bacterial communities in their samples. Additionally, comparing infants having <90% SpO₂ (n = 29) with infants having ≥90% SpO₂ (n = 8) showed that well-known dominant genera (Bacteroides, Bifidobacterium, Escherichia/Shigella, and Enterobacter/Veillonella) were differently, but not significantly (P = 0.44, P = 0.71, P = 0.98, and P = 0.41, respectively) abundant between the two subgroups. Overall, we showed that, regardless of RSV or non-RSV bronchiolitis etiology, no fecal microbiota-composing bacteria could be associated with the severity of acute bronchiolitis in infants. Larger and longitudinally conducted studies will be necessary to confirm these findings.

Hospital Charges Associated With Critical Bronchiolitis From 2009 to 2019

OBJECTIVES

To evaluate the contribution of PICU care to increasing hospital charges for patients with bronchiolitis over a 10-year study period.

DESIGN

In this retrospective multicenter study, changes in annual hospital charges (adjusted for inflation) were analyzed using linear regression for subjects admitted to the PICU with invasive mechanical ventilation (PICU + IMV) and without IMV (PICU - IMV), and for children not requiring PICU care.

SETTING

Free-standing children's hospitals contributing to the Pediatric Health Information System (PHIS) database.

SUBJECTS

Children less than 2 years with bronchiolitis discharged from a PHIS hospital between July 2009 and June 2019. Subjects were categorized as high risk if they were born prematurely or had a chronic complex condition.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

PICU patients were 26.5% of the 283,006 included subjects but accrued 66% of the total $14.83 billion in charges. Annual charges increased from $1.01 billion in 2009-2010 to $2.07 billion in 2018-2019, and PICU patients accounted for 83% of this increase. PICU + IMV patients were 22% of all PICU patients and accrued 64% of all PICU charges, but PICU - IMV patients without a high-risk condition had the highest relative increase in annual charges, increasing from $76.7 million in 2009-2010 to $377.9 million in 2018-2019 (374% increase, ptrend < 0.001).

CONCLUSIONS

In a multicenter cohort study of children hospitalized with bronchiolitis, PICU patients, especially low-risk children without the need for IMV, were the highest driver of increased hospital charges over a 10-year study period.

OUP accepted manuscript

Background

Methods

Results

Conclusions

SARS-CoV-2 acute bronchiolitis in hospitalized children: Neither frequent nor more severe

INTRODUCTION

Endemic coronaviruses have been found in acute bronchiolitis, mainly as a coinfecting virus. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been responsible for respiratory illness in hospitalized children. The characteristics of patients with bronchiolitis have not been extensively described.

METHODS

Cross-sectional study of patients with bronchiolitis and SARS-CoV-2 infection enrolled in a prospective multicenter cohort of children hospitalized with COVID-19 in Spain from March 1, 2020 to February 28, 2021.

RESULTS

Twelve of 666 children infected with SARS-CoV-2 who required hospital admission met the diagnostic criteria for bronchiolitis (1.8%). Median age was 1.9 months (range: 0.4-10.1). Six cases had household contact with a confirmed or probable COVID-19 case. Main complaints were cough (11 patients), rhinorrhea (10), difficulty breathing (8), and fever (8). Eleven cases were classified as mild or moderate and one as severe. Laboratory tests performed in seven patients did not evidence anemia, lymphopenia, or high C-reactive protein levels. Chest X-rays were performed in six children, and one case showed remarkable findings. Coinfection with metapneumovirus was detected in the patient with the most severe course; Bordetella pertussis was detected in another patient. Seven patients required oxygen therapy. Albuterol was administered in four patients. One patient was admitted to the pediatric intensive care unit. Median length of admission was 4 days (range: 3-14). No patient died or showed any sequelae at discharge. Two patients developed recurrent bronchospasms.

CONCLUSION

SARS-CoV-2 infection does not seem to be a main trigger of severe bronchiolitis, and children with this condition should be managed according to clinical practice guidelines.

Pneumococcal septic shock after neonatal respiratory syncytial virus bronchiolitis: A case report and literature review

BACKGROUND

Bronchiolitis is a common cause of hospitalisation of infants less than a year old, with most infants recovering without complications. Respiratory syncytial virus (RSV) is a leading cause of bronchiolitis. Antimicrobial stewardship programmes do not recommend antibiotics for viral infections in neonates unless documented evidence of secondary bacterial infection is present.

CASE REPORT

We present the case of a 7-day-old infant admitted to hospital with chest retractions and fever. The baby was hospitalised, empirical antibiotic therapy was administered, and non-invasive ventilation was started. When the viral aetiology was identified and clinical conditions improved, antibiotics were discontinued. However, after 48 hours, the newborn's condition worsened because of pneumococcal septic shock. Intravenous fluids, catecholamine support, and wide-spectrum antibiotics were administered. Non-invasive ventilation was re-started and continued until the full recovery.

CONCLUSIONS

There is increasing evidence that RSV and S. pneumoniae co-infect and interact with each other, thus increasing respiratory diseases' severity. We provide a brief overview of the main international guidelines for managing bronchiolitis. Guidelines suggest avoidance of antibiotics use when the diagnosis of viral bronchiolitis is confirmed. We discuss the uncertainties regarding antibiotic use, especially in younger infants, who are more exposed to risks of bacterial superinfection.

Acute viral bronchiolitis as a cause of pediatric acute respiratory distress syndrome

The Pediatric Acute Lung Injury Consensus Conference (PALICC) published pediatric-specific guidelines for the definition, management, and research in pediatric acute respiratory distress syndrome (PARDS). Acute viral bronchiolitis (AVB) remains one of the leading causes of admission to PICU. Respiratory syncytial virus (RSV) is the most common cause of AVB. We aimed to evaluate the incidence of PARDS in AVB and identify the risk of RSV as a trigger pathogen for PARDS. This study is a retrospective single-center observational cohort study including children < 2 years of age admitted to the pediatric intensive care unit at St Mary's Hospital, London, and presented with AVB in 3 years (2016-2018). Clinical and demographic data was collected; PALICC criteria were applied to define PARDS. Data was expressed as median (IQR range); non-parametric tests were used. In this study, 144 infants with acute viral bronchiolitis were admitted to PICU in the study period. Thirty-nine infants fulfilled criteria of PARDS with RSV as the most common virus identified. Bacterial infection was identified as a risk factor for development of PARDS in infants with AVB.Conclusion: AVB is an important cause of PARDS in infants. RSV is associated with a higher risk of PARDS in AVB. Bacterial co-infection is a significant risk factor for development of PARDS in AVB. What is Known: • Bronchiolitis is a common cause of respiratory failure in children under 2 years. • ARDS is a common cause of PICU admission. What is New: • Evaluation of bronchiolitis as a cause of PARDS according to the PALLIC criteria. • Evaluation of different viruses' outcome in PARDS especially RSV as a commonest cause of AVB.

Interleukin 8 Association with respiratory syncytial virus bronchiolitis: a systematic review and meta-analysis

Infants with the respiratory syncytial virus (RSV) and human rhinovirus respiratory infection (HRV) produce inflammatory interleukins (ILs) in the respiratory epithelium. The aim of this study was to evaluate the levels of interleukin-8 in RSV negative and RSV positive patients. This study search was conducted without a time limit until 2020 through the databases of PubMed, Wiley, Springer, ScienceDirect and Google Scholar search engines, by two researchers independently. The random-effects model was used to compare of interleukin-8 in RSV negative vs. RSV positive patients, using Revman software version 5 meta-analysis software. Totally, 921 patients were evaluated (207 RSV-negative and 714 RSV-positive). The mean concentration of IL8 in RSV positive patients was 15.02 pg/ml (95% CI: 13.68- 16.35%).  According to the meta-analysis results, the standardized mean difference (SMD) of IL8 concentration between RSV-positive and negative patients was 6.31 pg/ml) (95% confidence interval: 2.50- 10.13%). subtotal analysis of the IL8 laboratory assessment method revealed that there was no significant SMD deference in the studies that have used chemiluminescence (P=0.21). while IL8 concentrations were significantly higher in RSV positives in ELISA and Magnetic bead-based assays (P&lt;0.05).  It appears that RSV positive patients may have greater levels of IL8 than RSV negative ones; whereas the synthesis of IL8 tends to be more secreted into the nasopharyngeal space; whereas the evaluation approach can also affect the results.

Increased Moraxella and Streptococcus species abundance after severe bronchiolitis is associated with recurrent wheezing

BACKGROUND

The role of the airway microbiome in the development of recurrent wheezing and asthma remains uncertain, particularly in the high-risk group of infants hospitalized for bronchiolitis.

OBJECTIVE

We sought to examine the relation of the nasal microbiota at bronchiolitis-related hospitalization and 3 later points to the risk of recurrent wheezing by age 3 years.

METHODS

In 17 US centers researchers collected clinical data and nasal swabs from infants hospitalized for bronchiolitis. Trained parents collected nasal swabs 3 weeks after hospitalization and, when healthy, during the summer and 1 year after hospitalization. We applied 16S rRNA gene sequencing to all nasal swabs. We used joint modeling to examine the relation of longitudinal nasal microbiota abundances to the risk of recurrent wheezing.

RESULTS

Among 842 infants hospitalized for bronchiolitis, there was 88% follow-up at 3 years, and 31% had recurrent wheezing. The median age at enrollment was 3.2 months (interquartile range, 1.7-5.8 months). In joint modeling analyses adjusting for 16 covariates, including viral cause, a 10% increase in relative abundance of Moraxella or Streptococcus species 3 weeks after day 1 of hospitalization was associated with an increased risk of recurrent wheezing (hazard ratio [HR] of 1.38 and 95% high-density interval [HDI] of 1.11-1.85 and HR of 1.76 and 95% HDI of 1.13-3.19, respectively). Increased Streptococcus species abundance the summer after hospitalization was also associated with a greater risk of recurrent wheezing (HR, 1.76; 95% HDI, 1.15-3.27).

CONCLUSIONS

Enrichment of Moraxella or Streptococcus species after bronchiolitis hospitalization was associated with recurrent wheezing by age 3 years, possibly providing new avenues to ameliorate the long-term respiratory outcomes of infants with severe bronchiolitis.

Risk Factors for Functional Decline and Impaired Quality of Life after Pediatric Respiratory Failure

Rationale: Poor outcomes of adults surviving critical illness are well documented, but data in children are limited.Objectives: To identify factors associated with worse postdischarge function and health-related quality of life (HRQL) after pediatric acute respiratory failure.Methods: We assessed functional status at baseline, discharge, and 6 months after pediatric ICU discharge and HRQL 6 months after discharge in 2-week- to 17-year-olds mechanically ventilated for acute respiratory failure in the RESTORE (Randomized Evaluation of Sedation Titration for Respiratory Failure) trial. We assessed HRQL via Infant and Toddler Quality of Life Questionnaire-97 (<2 yr old) or Pediatric Quality of Life Inventory (≥2 yr old). We categorized patients with normal baseline function as having impaired HRQL if scores were greater than 1 SD below mean norms for Infant and Toddler Quality of Life Questionnaire-97 growth and development or Pediatric Quality of Life Inventory total score.Measurements and Main Results: One-fifth (n = 192) of 949 patients declined in function from baseline to postdischarge; 20% (55/271) had impaired growth and development; 19% (64/343) had impaired HRQL. In multivariable analyses, decline in function was associated with baseline impaired function, prematurity, cancer, respiratory failure etiology, ventilation duration, and clonidine (odds ratio [OR] = 2.14; 95% confidence interval [CI] = 1.22-3.76). Independent predictors of impaired growth and development included methadone (OR = 2.27; 95% CI = 1.18-4.36) and inadequate pain management (OR = 2.94; 95% CI = 1.39-6.19). Impaired HRQL was associated with older age, non-white or Hispanic race, cancer, and inadequate sedation management (OR = 3.15; 95% CI = 1.74-5.72).Conclusions: Postdischarge morbidity after respiratory failure is common and associated with admission factors, exposure to critical care therapies, and pain and sedation management.

Association of Serum Albumin With Apnea in Infants With Bronchiolitis: A Secondary Analysis of Data From the MARC-35 Study

IMPORTANCE

Apnea is a rare, life-threatening complication of bronchiolitis, the leading cause of infant hospitalization in the United States. Currently, no objective method exists for identifying which infants will become apneic.

OBJECTIVE

To investigate whether serum albumin levels are associated with apnea in infants with severe bronchiolitis.

DESIGN, SETTING, AND PARTICIPANTS

A secondary data analysis of the 35th Multicenter Airway Research Collaboration, an ongoing multicenter cohort study of infants hospitalized for bronchiolitis, was conducted from December 11, 2018, to May 30, 2019. Seventeen hospitals across the United States enrolled infants (n = 1016) during 3 consecutive bronchiolitis seasons (November 1 to April 30) between 2011 and 2014. Infants with heart-lung disease or a gestational age less than 32 weeks were excluded.

EXPOSURES

Serum albumin level was categorized as low (<3.8 g/dL) or normal (≥3.8 g/dL).

MAIN OUTCOMES AND MEASURES

Apnea during the hospitalization.

RESULTS

Of the 1016 infants hospitalized for bronchiolitis, the median (interquartile range [IQR]) age was 3 (2-6) months, 610 (60.0%) were male, and 186 (18.3%) were born preterm (32-37 weeks' gestation). Among the 25 infants (2.5%) with apnea while hospitalized, the median (IQR) serum albumin level was 3.5 (3.1-3.6) g/dL, and 22 (88.0%) had low serum albumin levels. The prevalence of apnea was 5.7% among all infants with low albumin levels, compared with 0.5% prevalence in infants with normal serum albumin levels. In unadjusted analyses, apnea was associated with younger age, preterm birth, weight-for-age z score, and low albumin (odds ratio [OR], 12.69; 95% CI, 3.23-49.82). After adjustment for age, preterm birth, and weight-for-age z score, low serum albumin levels remained statistically significantly associated with apnea (OR, 4.42; 95% CI, 1.21-16.18).

CONCLUSIONS AND RELEVANCE

Low serum albumin levels appeared to be associated with increased risk of apnea after adjustment for known apnea risk factors. This finding provides a path to potentially identifying apnea, a life-threatening complication of bronchiolitis.

Serum Na+ Level in Children Suffering from Acute Bronchiolitis: A Review

Bronchiolitis is the leading cause of lower respiratory tract infection (LRTI) in infants. Respiratory syncitial virus (RSV) is the most common cause of bronchiolitis in infants and young children. Hyponatremia is a commonly overlooked important extrapulmonary manifestation of bronchiolitis. It is now known that the syndrome of inappropriate anti diuretic hormone secretion (SIADH) occurs frequently in several pulmonary conditions including bronchiolitis which may lead to hyponatremia. In many studies,a good number of patients admitted with bronchiolitis were found to have hyponatremia e.g. Wilson et al. A high index of suspicion with prompt diagnosis and treatment can save life and prevent handicaps. Serum electrolyte level should be measured in all children hospitalized for bronchiolitis. Neurological complications may occur in hyponatremia and fluid therapy in vulnerable infants should be appropriately planned to reduce this risk.

Prognostic Value of Concomitant Bronchiectasis in Newly Diagnosed Diffuse Panbronchiolitis Patients on a Maintenance Therapy with Macrolides

Background

Factors determining the prognosis of diffuse panbronchiolitis (DPB) remain unclear at present. The objective of this study was to identify the prognostic value of concomitant bronchiectasis in the macrolide treatment efficacy and exacerbation risk in DPB patients.

Methods

Data of patients initially diagnosed with DPB at the Shanghai Pulmonary Hospital between January 2007 and December 2017 were retrospectively collected and analyzed. The patients were divided into two groups according to the existence of bronchiectasis. Clinical manifestations, laboratory findings, microbiological culture results, as well as exacerbation risks and treatment outcomes, were compared between these two groups. The survival curve and Cox regression analysis models were additionally constructed to further demonstrate the predicting role of bronchiectasis in DPB exacerbation.

Results

Baseline data revealed more respiratory symptoms, lower body mass index (BMI), and forced expiratory volume in one second (FEV1) as well as increased isolates of Pseudomonas aeruginosa (P. aeruginosa) in DPB subjects with bronchiectasis than those without. Furthermore, bronchiectasis was associated with a lower rate of responsiveness to macrolides and increased exacerbation frequency during follow-up. The survival curve and Cox regression analysis showed that comorbid bronchiectasis was linked to increased time to episode relapse, which remained significant even after controlling for BMI, FEV1, and P. aeruginosa culture results.

Conclusion

The coexistence of bronchiectasis predicted a poor outcome of maintenance macrolide therapy and an increased exacerbation risk in DPB subjects, possibly through its impacts on nutritional status, pulmonary function, and P. aeruginosa infections.

Vitamin D Status at the Time of Hospitalization for Bronchiolitis and Its Association with Disease Severity

OBJECTIVE

To investigate the association between circulating 25-hydroxyvitamin D [25(OH)D] status at admission and disease severity among infants hospitalized for bronchiolitis and to determine whether the association differs by the form of 25(OH)D-total, bioavailable or free 25(OH)D.

STUDY DESIGN

We conducted a 17-center prospective cohort study of 1016 US infants <12 months old hospitalized with bronchiolitis. Vitamin D status was defined by total 25(OH)D levels, and by calculated levels of bioavailable and free 25(OH)D. Bronchiolitis severity was defined by requirement for intensive care and hospital length-of-stay (LOS). Logistic and Poisson regression were used for unadjusted and multivariable analyses.

RESULTS

The median age of hospitalized infants was 3.2 months (IQR 1.6-6.0). The median total 25(OH)D was 26.5 ng/mL (IQR 18.0-33.1); 298 (29%) infants had total 25(OH)D <20 ng/mL. In multivariable models, infants with total 25(OH)D <20 ng/mL had higher risk of requiring intensive care (aOR 1.72, 95% CI 1.12-2.64) and longer LOS (adjusted rate ratio 1.39, 95% CI 1.17-1.65) compared with infants with total 25(OH)D ≥30 ng/mL. Infants with the lowest tertile of bioavailable 25(OH)D, compared with those with the highest tertile, had longer LOS (adjusted rate ratio 1.32, 95% CI 1.07-1.62); admission to the intensive care unit was not statistically significant in the adjusted model (aOR 1.39, 95% CI 0.96-2.64). Free 25(OH)D level was not associated with severity of bronchiolitis in either unadjusted or adjusted models.

CONCLUSION

In a large, multicenter cohort of US infants hospitalized for bronchiolitis, infants with total 25(OH)D <20 ng/mL had increased risk of intensive care and longer hospital LOS.

RSV-hRV co-infection is a risk factor for recurrent bronchial obstruction and early sensitization 3 years after bronchiolitis

To assess risk factors of recurrent bronchial obstruction and allergic sensitization 3 years after an episode of acute bronchiolitis, whether after ambulatory care treatment or hospitalization. A monocentric prospective longitudinal study including infants aged under 1 year with acute bronchiolitis was performed, with clinical (severity score), biological (serum Krebs von den Lungen 6 antigen), and viral (14 virus by naso-pharyngeal suction detection) assessments. Follow-up included a quaterly telephone interview, and a final clinical examination at 3 years. Biological markers of atopy were also measured in peripheral blood, including specific IgEs towards aero- and food allergens. Complete data were available for 154 children. 46.8% of them had recurrent wheezing (RW). No difference was found according to initial severity, care at home or in the hospital, respiratory virus involved, or existence of co-infection. A familial history of atopy was identified as a risk factor for recurrent bronchial obstruction (60% for RW infants versus 39%, P = 0.02), as living in an apartment (35% versus 15%, P = 0.002). 18.6% of the infants were sensitized, with 48.1% of them sensitized to aeroallergens and 81.5% to food allergens. Multivariate analysis confirmed that a familial history of atopy (P = 0.02) and initial co-infection RSV-hRV (P = 0.02) were correlated with the risk of sensitization to aeroallergens at 3 years. Familial history of atopy and RSV-hRV co-infection are risk factors for recurrent bronchial obstruction and sensitization.

IgG4-related lung disease presenting as interstitial lung disease with bronchiolitis: A case report

RATIONALE

IgG4-related disease is a rare and novel disease entity that tends to involve multiple organs. The pulmonary manifestation of this disease is highly variable and may mimic lung cancer, pneumonia, interstitial lung disease (ILD), sarcoidosis, and so forth. Small airway disease is rarely reported in IgG4-related lung disease (IgG4-RLD). In the current study, we describe a rare case of IgG4-RLD with patterns of ILD and bronchiolitis.

PATIENT CONCERN

A 43-year-old man had chronic cough and dyspnea on exertion for 4 years. Initial chest radiography showed diffuse interstitial infiltration. Follow-up chest computed tomography 4 years later revealed bilateral diffuse centrilobular nodules with tree-in-bud pattern, bronchial wall thickening, and mediastinal lymph nodes. Bilateral diffuse multifocal ground-glass opacities and mosaic attenuation were also observed. Pulmonary function test revealed mixed restrictive and obstructive ventilatory impairment.

DIAGNOSES

Video-assisted thoracoscopic surgery (VATS) lung biopsy showed interstitial fibrosis with lymphoplasmacytic infiltration rich in IgG4-positive plasma cells. Serum IgG4 level also showed remarkable elevation. Therefore, IgG4-RLD is confirmed.

INTERVENTION

VATS wedge resection of right upper lobe and mediastinal lymph node.

OUTCOMES

The patient responded well to steroid and immunosuppression therapy, and was regular followed-up in outpatient clinic.

LESSONS

IgG4-RLD should be considered not only in ILD, but also in small airway disease. Serum IgG4 level may be a useful tool for screening.

Complete heart block complicating the acute phase of respiratory syncytial virus bronchiolitis

Respiratory syncytial virus is the most common pathogen causing lower respiratory tract infection in infants. In recent years, the importance of extrapulmonary complications and longterm sequelae including those involving the cardiovascular system has become apparent. We report on a 10 month old infant with respiratory syncytial virus bronchiolitis, the acute phase of which was complicated by irreversible complete heart block, which was managed conservatively.

Risk Factors for Respiratory Decompensation Among Healthy Infants With Bronchiolitis

BACKGROUND

Although most children with bronchiolitis only require supportive care, some decompensate and require ventilatory support. We examined predictors of respiratory decompensation among hospitalized children to identify which patients may benefit from expectant monitoring.

METHODS

We examined children ≤24 months old with bronchiolitis admitted to the general infant and toddler floor. Children with pneumonia or comorbidities were excluded. Demographic and clinical characteristics were abstracted from a clinical database and medical records. Respiratory decompensation was defined as the need for initiating high-flow nasal cannula oxygen, continuous positive airway pressure, nasal intermittent mandatory ventilation, bilevel positive airway pressure, or intubation. A multivariable logistic regression model was constructed to identify independent predictors of respiratory decompensation.

RESULTS

A total of 1217 children were included. The median age was 6.9 months, 41% were girls, 49% were Hispanic, 21% were black, and 18% were premature. Significant independent predictors of respiratory decompensation were age ≤3 months (odds ratio [OR]: 3.25; 95% confidence interval [CI]: 2.09-5.07), age 3 to 6 months (OR: 1.76; 95% CI: 1.04-3.0), black race (OR: 1.94; 95% CI: 1.27-2.95), emergency department hypoxemia (OR: 2.34; 95% CI: 1.30-4.21), and retractions or accessory muscle use (OR: 2.26; 95% CI: 1.48-3.46). Children with 0 of 4 predictors were found to have a low risk of decompensation (3%).

CONCLUSIONS

Young age, black race, emergency department hypoxemia, and retractions or accessory muscle use were associated with respiratory decompensation in children with bronchiolitis. These factors should be considered at presentation, as they identify children who require a higher level of respiratory monitoring and support and others who may not benefit.

Antibiotics for persistent cough or wheeze following acute bronchiolitis in children

BACKGROUND

Bronchiolitis is a common acute respiratory condition with high prevalence worldwide. This clinically diagnosed syndrome is manifested by tachypnoea (rapid breathing), with crackles or wheeze in young children. In the acute phase of bronchiolitis (≤ 14 days), antibiotics are not routinely prescribed unless the illness is severe or a secondary bacterial infection is suspected. Although bronchiolitis is usually self-limiting, some young children continue to have protracted symptoms (e.g. cough and wheezing) beyond the acute phase and often re-present to secondary care.

OBJECTIVES

To compare the effectiveness of antibiotics versus controls (placebo or no treatment) for reducing or treating persistent respiratory symptoms following acute bronchiolitis within six months of acute illness.

SEARCH METHODS

We searched the following databases: the Cochrane Airways Group Register of Trials, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid), Embase (Ovid), the World Health Organization (WHO) trial portal, the Australian and New Zealand Clinical Trials Registry, and ClinicalTrials.gov, up to 26 August 2016.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing antibiotics versus controls (placebo or no treatment) given in the post-acute phase of bronchiolitis (> 14 days) for children younger than two years with a diagnosis of bronchiolitis.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies against predefined criteria, and selected, extracted, and assessed data for inclusion. We contacted trial authors for further information.

MAIN RESULTS

In this review update, we added one study with 219 children. A total of two RCTs with 249 children (n = 240 completed) were eligible for inclusion in this review. Both studies contributed to our primary and secondary outcomes, but we assessed the quality of evidence for our three primary outcomes as low, owing to the small numbers of studies and participants; and high attrition in one of the studies. Data show no significant differences between treatment groups for our primary outcomes: proportion of children (n = 249) who had persistent symptoms at follow-up (odds ratio (OR) 0.69, 95% confidence interval (CI) 0.37 to 1.28; fixed-effect model); and number of children (n = 240) rehospitalised with respiratory illness within six months (OR 0.54, 95% CI 0.05 to 6.21; random-effects model). We were unable to analyse exacerbation rate because studies used different methods to report this information. Data showed no significant differences between treatment groups for our secondary outcome: proportion of children (n = 240) with wheeze at six months (OR 0.47, 95% CI 0.06 to 3.95; random-effects model). One study reported bacterial resistance, but only at 48 hours (thus with limited applicability for this review). Another study reported adverse events from which all children recovered and remained in the study.

AUTHORS' CONCLUSIONS

Current evidence is insufficient to inform whether antibiotics should be used to treat or prevent persistent respiratory symptoms in the post-acute bronchiolitis phase. Future RCTs are needed to evaluate the efficacy of antibiotics for reducing persistent respiratory symptoms. This is particularly important in populations with high acute and post-acute bronchiolitis morbidity (e.g. indigenous populations in Australia, New Zealand, and the USA).