Assessment of Peak Inspiratory Flow in Young Infants with Acute Viral Bronchiolitis: Physiological Basis for Initial Flow Setting in Patients Supported with High-Flow Nasal Cannula.

OBJECTIVE: To assess the inspiratory demand in young infants with acute viral bronchiolitis to provide a physiological basis for initial flow setting for patients supported with high flow nasal cannula. STUDY DESIGN: Prospective study in 44 infants up to 6 months old with acute viral bronchiolitis, admitted to a pediatric intensive care unit from November 2017 to March 2019. Airflow measurements were performed using spirometry. The primary endpoint was the inspiratory demand as measured by peak tidal inspiratory flow (PTIF). The secondary endpoints were the relationships determined between PTIF, patient weight, and disease severity. RESULTS: Median (Q25-Q75) age and weight of the patients were 37 (20-67) days and 4.3 (3.5-5.0) kg, respectively. Mean PTIF was 7.45 (95% CI 6.51-8.39, min-max: 2.40-16.00) L/minute. PTIF indexed to weight was 1.68 (95% CI 1.51-1.85, min-max: 0.67-3.00) L/kg/minute. PTIF was <2.5 L/kg/minute in 89% (95% CI 75-96) of infants. PTIF was correlated with weight (ρ= 0 .55, P < .001) but not with markers of disease severity, including modified Woods clinical asthma score, Silverman-Andersen score, respiratory rate, fraction of inspired oxygen, and PCO2. CONCLUSIONS: High flow nasal cannula therapy is used commonly to support infants with acute viral bronchiolitis. The efficiency of the device is optimal if the flow setting matches the patient's inspiratory demand. According to our results, a flow rate of <2.5 L/kg/minute would be appropriate in most situations.

A 14-year Prospective Study of Human Coronavirus Infections in Hospitalized Children: Comparison With Other Respiratory Viruses.

BACKGROUND: Human coronaviruses (HCoVs) have been recognized as causative agents of respiratory tract infections.Our aim was to describe HCoV infections in hospitalized children in a prospective surveillance study for 14 years and compare them with other respiratory viruses. METHODS: As a part of an ongoing prospective study to identify the etiology of viral respiratory infections in Spain, we performed the analysis of HCoV infections in children hospitalized in a secondary hospital in Madrid, between October 2005 and June 2018. Clinical data of HCoV patients were compared with those infected by rhinovirus, respiratory syncytial virus and influenza. RESULTS: The study population consisted of 5131 hospitalizations for respiratory causes in children. A total of 3901 cases (75.9%) had a positive viral identification and 205 cases (4.1%) were positive for HCoV. Only 41 cases (20%) of HCoV infection were detected as single infections. Episodes of recurrent wheezing were the most common diagnosis, and 112 children (54%) had hypoxia. Clinical data in HCoV cases were similar to those associated with rhinovirus; however, patients with HCoV were younger. Other viruses were associated with hypoxia more frequently than cases with HCoV; high fever was more common in influenza infections and bronchiolitis in respiratory syncytial virus group. Although a slight peak of circulation appears mostly in winter, HCoV has been detected throughout the year as well. CONCLUSIONS: HCoV infections represent a small fraction of respiratory infections that require hospitalization in children and their characteristics do not differ greatly from other respiratory viral infections.

Sex differences in blood pro-oxidant status and platelet activation in children admitted with respiratory syncytial virus bronchiolitis: a pilot study.

BACKGROUND: Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis in the pediatric population worldwide and an important cause of death in developing countries. It has been demonstrated that the balance between oxidant and antioxidant systems is disrupted in children with bronchiolitis and that oxidative stress contributes to the pathogenesis of this disease. Platelets play an important role in antimicrobial host defenses and contribute to pulmonary vascular repair being either targets or source of reactive oxidizing species. The main purpose of this study was to assessing sex differences in clinical characteristics and platelets activation during RSV bronchiolitis in infancy. METHODS: In this retrospective study a total of 203 patients (112 boys and 91 girls) with bronchiolitis, aged 12 months or less, admitted to the Bambino Gesù Pediatric Hospital of Rome (Italy) in the period from January to December 2017, were enrolled. Moreover, in a select group of patients (15 boys and 12 girls) with diagnosis of moderate bronchiolitis from RSV, a pilot study on oxidative stress and platelet characteristics was carried out by electron paramagnetic resonance and flow cytometry respectively. Age-matched healthy control subjects (10 boys and 10 girls) were chosen as controls. Data were analyzed using Student' T test, Chi Squared test and one-way ANOVA test. RESULTS: This study highlights the influence of sex in the clinical course of bronchiolitis. In particular we found: i) a higher incidence of bronchiolitis in boys than in girls (55% vs 45%); ii) higher C reactive protein values in girls than boys (1.11 mg/dL vs 0.92 mg/dL respectively; p < 0.05); iii) a different degree of thrombocytosis during hospitalization (mild in the girls and severe in the boys). Moreover, in selected patients we found that compared to girls with bronchiolitis, boys showed: i) higher percentage of activated platelets (8% vs 2% respectively; p < 0.05) and iii) higher number of platelets forming homotypic aggregates (2.36% vs 0.84% respectively, p < 0.05). CONCLUSION: The present study affirm that the bronchiolitis is an infection in which sex seems to act as a modulating factor only in the clinical course, influencing also the choice of the therapy should be made.

Clinical factors associated with intubation in the high flow nasal cannula era.

BACKGROUND: Bronchiolitis is the most common cause for hospitalization in infants. While the use of high flow nasal cannula (HFNC) has increased, it has not uniformly reduced intubation rates. OBJECTIVE: We identified factors associated with respiratory failure in children with bronchiolitis on HFNC. METHODS: We conducted a retrospective study of previously healthy children <24 months of age with bronchiolitis, who were treated with HFNC in two pediatric emergency departments from 1/2014-1/2018. The primary outcome was the identification of demographic and clinical factors that are associated with intubation after an antecedent trial of HFNC. A multivariable logistic regression model was constructed to identify predictors of respiratory failure. RESULTS: Of 2657 children on HFNC, the median age was 7 months, while the median age of the intubated cohort was 3 months. Ten percent (271) progressed to mechanical ventilation within 48 h of PED presentation. Of the 301 patients that needed escalation to CPAP and/or BiPAP, 91 required intubation. Factors associated with intubation were young age and a high respiratory tool score; factors associated with no progression to intubation were a reduction in tachycardia after initiation of HFNC and presentation after day 5 of illness. A secondary analysis also revealed decreased rate of intubation with the use of bronchodilators. We identified demographic, clinical, and therapeutic factors that are associated with requiring intubation. CONCLUSION: Given the high burden of bronchiolitis in pediatric emergency departments, these factors can be considered upon presentation of children with bronchiolitis to selectively identify children at higher risk for respiratory failure.

The impact of viral bronchiolitis phenotyping: Is it time to consider phenotype-specific responses to individualize pharmacological management?

Although recent guidelines recommend a minimalist approach to bronchiolitis, there are several issues with this posture. First, there are concerns about the definition of the disease, the quality of the guidelines, the method of administration of bronchodilators, and the availability of tools to evaluate the response to therapies. Second, for decades it has been assumed that all cases of viral bronchiolitis are the same, but recent evidence has shown that this is not the case. Distinct bronchiolitis phenotypes have been described, with heterogeneity in clinical presentation, molecular immune signatures and clinically relevant outcomes such as respiratory failure and recurrent wheezing. New research is critically needed to refine viral bronchiolitis phenotyping at the molecular and clinical levels as well as to define phenotype-specific responses to different therapeutic options.

Does nebulized hypertonic saline shorten hospitalization in young children with acute viral wheezing?

BACKGROUND: Although previous studies have shown benefits of nebulized hypertonic saline (HS) for improving airway clearance and shortening hospitalization in infants with bronchiolitis, prospective blinded studies in preschool children with acute viral wheezing are limited. OBJECTIVES: To determine nebulized 3% HS efficacy in young children admitted with acute viral wheezing. METHODS: This double-blind, randomized controlled trial was conducted in children aged 6 months to 5 years admitted with acute viral wheezing from July 1st to December 31st 2016. Patients were randomized to receive inhalation of 2.5 mg salbutamol dissolved in either 3% HS or normal saline (NS). Clinical data, asthma clinical severity score, and length of hospital stay (LOS) were recorded. RESULTS: A total of 47 patients were enrolled (22 in HS and 25 in NS) without significant differences in demographic data and baseline clinical scores. Median LOS and median time of oxygen therapy were significantly shorter in HS than NS group: 48 versus 72 h, P = 0.021 and 36 versus 72 h, P = 0.025, respectively. HS patients had significantly improved asthma clinical severity scores, respiratory rates and oxygen saturation at 12 h compared to NS group (P-value 0.042, 0.032, and 0.043). There were no adverse events. CONCLUSION: In children under 5 years admitted with acute viral wheezing, nebulized hypertonic saline/salbutamol significantly shortened hospital stay length, time of oxygen therapy, and improved asthma clinical severity score faster than normal saline/salbutamol.

Etiology and clinical features of viral bronchiolitis in infancy.

BACKGROUND: Bronchiolitis is a common lower respiratory tract infection in infancy. The aim of this review is to present the clinical profile of viral bronchiolitis, the different culprit viruses and the disease severity in relation to the viral etiology. DATA SOURCES: Databases including PubMed and Google Scholar were searched for articles about the clinical features of bronchiolitis and its viral etiology. The most relevant articles to the scope of this review were analyzed. RESULTS: Currently there are two main definitions for bronchiolitis which are not identical, the European definition and the American one. The most common viral pathogen that causes bronchiolitis is respiratory syncytial virus which was identified in 1955; now many other viruses have been implicated in the etiology of bronchiolitis such as rhinovirus, adenovirus, metapneumovirus, and bocavirus. Several studies have attempted to investigate the correlation of bronchiolitis severity with the type of detected virus or viruses. However, the results were not consitent. CONCLUSIONS: For the time being, the diagnosis of bronchiolitis remains clinical. The isolation of the responsible respiratory pathogens does not seem to confer to the prognosis of the disease severity.

Lack of association between viral load and severity of acute bronchiolitis in infants.

OBJECTIVE:: To investigate the correlation between respiratory syncytial viral load and length of hospitalization in infants with acute wheezing episodes. METHODS:: This was a two-year, cross-sectional study of infants ≤ 12 months of age with bronchiolitis at the time of admission to a tertiary hospital. For the identification of respiratory viruses, nasopharyngeal secretions were collected. Samples were analyzed (throughout the study period) by direct immunofluorescence and (in the second year of the study) by quantitative real-time PCR. We screened for three human viruses: rhinovirus, respiratory syncytial virus, and metapneumovirus. RESULTS:: Of 110 samples evaluated by direct immunofluorescence, 56 (50.9%) were positive for a single virus, and 16 (14.5%) were positive for two or more viruses. Among those 72 samples, the most prevalent virus was respiratory syncytial virus, followed by influenza. Of 56 samples evaluated by quantitative real-time PCR, 24 (42.8%) were positive for a single virus, and 1 (1.7%) was positive for two viruses. Among those 25 samples, the most prevalent virus was again respiratory syncytial virus, followed by human rhinovirus. Coinfection did not influence the length of the hospital stay or other outcome s. In addition, there was no association between respiratory syncytial virus load and the length of hospitalization. CONCLUSIONS:: Neither coinfection nor respiratory syncytial viral load appears to influence the outcomes of acute bronchiolitis in infants. OBJETIVO:: Investigar a correlação entre a carga viral do vírus sincicial respiratório e o tempo de internação hospitalar em lactentes com episódios de sibilância aguda. MÉTODOS:: Este foi um estudo transversal de dois anos envolvendo lactentes de até 12 meses de idade com bronquiolite no momento da internação em um hospital terciário. Para a identificação dos vírus respiratórios foram coletadas secreções nasofaríngeas. As amostras foram analisadas (por todo o período do estudo) por imunofluorescência direta e (no segundo ano do estudo) por PCR quantitativa em tempo real para três vírus humanos (rinovírus, vírus sincicial respiratório e metapneumovírus). RESULTADOS:: Das 110 amostras avaliadas por imunofluorescência direta, 56 (50,9%) foram positivas para um único vírus, e 16 (14,5%) foram positivas para dois ou mais vírus. Nessas 72 amostras, o vírus mais prevalente foi o vírus sincicial respiratório, seguido por influenza. Das 56 amostras avaliadas por PCR quantitativa em tempo real, 24 (42,8%) foram positivas para um único vírus, e 1 (1,7%) foi positiva para dois vírus. Nessas 25 amostras, o vírus mais prevalente foi o vírus sincicial respiratório, seguido por rinovírus humano. A coinfecção não influenciou o tempo de internação ou outros desfechos. Além disso, não houve associação entre a carga viral de vírus sincicial respiratório e o tempo de internação. CONCLUSÕES:: A coinfecção e a carga viral do vírus sincicial respiratório não parecem influenciar os desfechos em lactentes com bronquiolite aguda.

Rhinopharyngeal Retrograde Clearance Induces Less Respiratory Effort and Fewer Adverse Effects in Comparison With Nasopharyngeal Aspiration in Infants With Acute Viral Bronchiolitis.

BACKGROUND: Acute viral bronchiolitis is an inflammatory disease of the lower respiratory tract. This study aimed to compare the immediate effects of retrograde rhinopharyngeal clearance with nasopharyngeal aspiration in children admitted with acute viral bronchiolitis. METHODS: This was a randomized controlled clinical trial with children admitted for acute viral bronchiolitis up to 12 months old. Subjects were divided into a nasopharyngeal aspiration group and a clearance group, submitted to retrograde rhinopharyngeal clearance with physiological solution (0.9%) instillation. In both groups, there were 3 evaluations on the same day (data collections 1, 2, and 3), including cardiorespiratory parameters, clinical score of respiratory dysfunction, and adverse effects. RESULTS: One hundred children were included, with no statistical differences between groups regarding the characteristics of the sample. There was a significant reduction (P < .05) in heart rate in data collections 1 and 2 after 10 and 30 min. The number of episodes of nasal bleeding (28 vs 1) and vomiting (11 vs 7) was higher in the aspiration group compared with the clearance group. Children classified as moderate showed a significant reduction of retractions (100% vs 84.6%) and nasal bleeding (44.8% vs 0%). An increase of 6.7 and 19.5% in wheezing and retractions, respectively, was shown for the aspiration group, whereas the clearance group showed only 4.6% for both parameters. CONCLUSIONS: The use of retrograde rhinopharyngeal clearance in the management of infants with acute viral bronchiolitis can be an alternative for the clearance of the upper airways, since it showed immediate positive effects on the occurrence of complications and signs of respiratory effort compared with nasopharyngeal aspiration. Children classified with a moderate clinical score appear to benefit the most. (ClinicalTrials.gov registration NCT02460614.).

Lack of association between viral load and severity of acute bronchiolitis in infants / Falta de associação entre carga viral e gravidade da bronquiolite aguda em lactentes

ABSTRACT Objective: To investigate the correlation between respiratory syncytial viral load and length of hospitalization in infants with acute wheezing episodes. Methods: This was a two-year, cross-sectional study of infants ≤ 12 months of age with bronchiolitis at the time of admission to a tertiary hospital. For the identification of respiratory viruses, nasopharyngeal secretions were collected. Samples were analyzed (throughout the study period) by direct immunofluorescence and (in the second year of the study) by quantitative real-time PCR. We screened for three human viruses: rhinovirus, respiratory syncytial virus, and metapneumovirus. Results: Of 110 samples evaluated by direct immunofluorescence, 56 (50.9%) were positive for a single virus, and 16 (14.5%) were positive for two or more viruses. Among those 72 samples, the most prevalent virus was respiratory syncytial virus, followed by influenza. Of 56 samples evaluated by quantitative real-time PCR, 24 (42.8%) were positive for a single virus, and 1 (1.7%) was positive for two viruses. Among those 25 samples, the most prevalent virus was again respiratory syncytial virus, followed by human rhinovirus. Coinfection did not influence the length of the hospital stay or other outcome s. In addition, there was no association between respiratory syncytial virus load and the length of hospitalization. Conclusions: Neither coinfection nor respiratory syncytial viral load appears to influence the outcomes of acute bronchiolitis in infants.

RESUMO Objetivo: Investigar a correlação entre a carga viral do vírus sincicial respiratório e o tempo de internação hospitalar em lactentes com episódios de sibilância aguda. Métodos: Este foi um estudo transversal de dois anos envolvendo lactentes de até 12 meses de idade com bronquiolite no momento da internação em um hospital terciário. Para a identificação dos vírus respiratórios foram coletadas secreções nasofaríngeas. As amostras foram analisadas (por todo o período do estudo) por imunofluorescência direta e (no segundo ano do estudo) por PCR quantitativa em tempo real para três vírus humanos (rinovírus, vírus sincicial respiratório e metapneumovírus). Resultados: Das 110 amostras avaliadas por imunofluorescência direta, 56 (50,9%) foram positivas para um único vírus, e 16 (14,5%) foram positivas para dois ou mais vírus. Nessas 72 amostras, o vírus mais prevalente foi o vírus sincicial respiratório, seguido por influenza. Das 56 amostras avaliadas por PCR quantitativa em tempo real, 24 (42,8%) foram positivas para um único vírus, e 1 (1,7%) foi positiva para dois vírus. Nessas 25 amostras, o vírus mais prevalente foi o vírus sincicial respiratório, seguido por rinovírus humano. A coinfecção não influenciou o tempo de internação ou outros desfechos. Além disso, não houve associação entre a carga viral de vírus sincicial respiratório e o tempo de internação. Conclusões: A coinfecção e a carga viral do vírus sincicial respiratório não parecem influenciar os desfechos em lactentes com bronquiolite aguda.

Actualización en el tratamiento de bronquiolitis aguda: menos es más / Update in the treatment of acute bronchiolitis: less is more

Viral bronchiolitis is a major worldwide cause of morbidity and mortality in children under two years old. Evidence-based management guidelines suggest that there is no effective treatment for bronchiolitis and that supportive care - hydration and oxygenation - remains the cornerstone of clinical management. In this review we describe the current guidelines of treatment with emphasis in the limitation of unnecessary testing and intervention. Also, we discuss the future directions in the research of new therapies for bronchiolitis.

La bronquiolitis viral es una causa importante de morbilidad y mortalidad en niños de menos de dos años de edad en todo el mundo. Las guías clínicas basadas en la evidencia sugieren que no existe un tratamiento efectivo para la bronquiolitis y que la hidratación y una adecuada oxigenación, siguen siendo la base del manejo clínico. En esta revisión, se describen las actuales guías de tratamiento haciendo énfasis en limitar los exámenes e intervenciones innecesarias. También discutimos la investigación en nuevas terapias para la bronquiolitis.

The bronchiolitis season is upon us--recommendations for the management and prevention of acute viral bronchiolitis.

Despite being so common, bronchiolitis remains poorly diagnosed and managed. This article is intended as an update on issues pertaining to this condition.

Vitamin D Levels Are Unrelated to the Severity of Respiratory Syncytial Virus Bronchiolitis Among Hospitalized Infants.

BACKGROUND: Vitamin D deficiency at birth has been reported as a risk factor for respiratory syncytial virus (RSV) lower respiratory tract infection during the first year of life. Limited data are available on whether an infant's vitamin D status is associated with the severity of acute RSV bronchiolitis. METHODS: Infants < 1 year of age and hospitalized with their first episode of RSV bronchiolitis were enrolled into the RSV Bronchiolitis in Early Life II cohort. We investigated the relationships between vitamin D status at enrollment and the following indicators of bronchiolitis severity: duration of hospitalization, lowest oxygen saturation measured during hospitalization, and bronchiolitis severity score. RESULTS: Among the 145 enrolled infants, the median (quartile 1 [Q1], Q3) serum 25-OH-VitD level was 36.8 (29.8, 42.3) ng/mL, with 14 infants (9.7%) having deficient serum vitamin D levels (25-OH-VitD <20 ng/mL). Vitamin D-deficient infants were younger than infants with 25-OH-VitD ≥ 20 ng/mL (2.8 vs 4.5 months, respectively; P = .04) and were less likely to consume infant's formula (42.9% vs 87.0%, respectively; P < .01). The following indicators of acute bronchiolitis severity did not differ between infants who were vitamin D-deficient and nondeficient: duration of hospitalization (P = .53), lowest oxygen saturation (P = .45), and bronchiolitis severity score (P = .97), even after adjusting for age, and for infant's formula consumption. CONCLUSIONS: Among this cohort of infants that were hospitalized for RSV bronchiolitis, vitamin D status at the time of bronchiolitis was not associated with indicators of acute bronchiolitis severity.

Nasopharyngeal bacterial burden and antibiotics: Influence on inflammatory markers and disease severity in infants with respiratory syncytial virus bronchiolitis.

OBJECTIVES: Animal studies suggest that RSV increases nasopharyngeal (NP) bacterial colonization facilitating bacterial infections. We investigated the influence of antibiotic treatment and colonization with potentially pathogenic bacteria on inflammatory markers and disease severity in RSV-infected in infants. METHODS: Healthy young infants hospitalized with RSV bronchiolitis (n = 136) and age-matched healthy controls (n = 23) were enrolled and NP samples cultured for potentially pathogenic bacteria including: Gram-positive bacteria (GPB): Staphylococcus aureus, Streptococcus pneumoniae, ß-hemolytic Streptococcus; and Gram-negative bacteria (GNB): Moraxella catarrhalis and Haemophilus influenzae. Clinical parameters and plasma IL-8, IL-6 and TNF-α concentrations were compared according to the bacterial class and antibiotic treatment. RESULTS: Antibiotic treatment decreased by 10-fold NP bacterial recovery. Eighty-one percent of RSV infants who did not receive antibiotics before sample collection were colonized with pathogenic bacteria. Overall, GNB were identified in 21% of patients versus 4% of controls who were mostly colonized with GPB. Additionally, in RSV patients NP white blood cell counts (p = 0.026), and blood neutrophils (p = 0.02) were higher in those colonized with potentially pathogenic bacteria versus respiratory flora. RSV patients colonized with GNB had higher plasma IL-8 (p = 0.01) and IL-6 (p < 0.01) concentrations than controls, and required longer duration of oxygen (p = 0.049). CONCLUSIONS: Infants with RSV bronchiolitis colonized with potentially pathogenic bacteria had increased numbers of mucosal and systemic inflammatory cells. Specifically, colonization with GNB was associated with higher concentrations of proinflammatory cytokines and a trend towards increased disease severity.

Viral Load in Infants Hospitalized for Respiratory Syncytial Virus Bronchiolitis Correlates with Recurrent Wheezing at Thirty-Six-Month Follow-Up.

The relationship between viral infection, host immune response in infants with respiratory syncytial virus (RSV) bronchiolitis and subsequent wheezing is discussed. We measured RSV-RNA load and interferon-λ1-3 expression in the nasopharyngeal washings from 68 infants hospitalized for RSV bronchiolitis, and wheezing was assessed 36 months after the first episode of bronchiolitis. Higher RSV-RNA load and higher interferon-λ2/3 levels were found in children with recurrent wheezing at 36-month follow-up.

Computerized Assessment of Wheezing in Children With Respiratory Syncytial Virus Bronchiolitis Before and After Hypertonic Saline Nebulization.

BACKGROUND: Studies suggest an effect of nebulized hypertonic saline solution on air-flow limitation in subjects with respiratory syncytial virus (RSV) bronchiolitis, but results are based on subjective scores of clinical severity and are not clear. In this observational study, we used a noninvasive computerized tool to quantify wheezing before and after nebulization with hypertonic saline in children admitted for RSV infection. METHODS: Twenty-seven children (≤ 24 months old) admitted to the pediatric ward of the Medical Center Leeuwarden with polymerase chain reaction-confirmed RSV bronchiolitis were included. Subjects were simultaneously assessed both clinically and by computerized acoustic monitoring before and 15 min after treatment with nebulized hypertonic saline solution. RESULTS: Clinical assessment, defined by the Respiratory Distress Assessment Instrument score, did not change after nebulization (n = 27, 5.0 vs 4.7, P = .17). Computerized acoustic monitoring showed no improvement in wheezing (n = 27, 3.4% vs 2.0%, P = .05) or inspiration/expiration ratio (0.85 vs 0.85, P = .93) after nebulization. CONCLUSIONS: Hypertonic saline nebulization does not improve air flow, as assessed by both clinical and computerized acoustic scores, in children admitted for RSV.

Infants with viral bronchiolitis demonstrate two distinct patterns of nocturnal oxyhaemoglobin desaturation.

AIM: This study aimed to demonstrate that viral bronchiolitis is associated with intermittent oxygen saturation of haemoglobin (SpO2 ) drops (≥3%) and low basal SpO2 between episodes of haemoglobin desaturation. METHODS: Infants with bronchiolitis underwent pulse oximetry during the first night following hospital admission and a subgroup of them underwent repeat oximetry before hospital discharge. Oximetry was also performed in infants with partial upper airway obstruction (UAO) and without lung disease and in control participants without UAO or lung disease. RESULTS: We enrolled 53 infants: 21 with bronchiolitis, 11 with UAO and 21 healthy controls. Participants with bronchiolitis had lower basal SpO2 (median 93.7% [10th-90th percentiles: 91.1-96.8]) than the subjects with UAO (96.9% [95.3-98.1]; p < 0.01) or the controls (98.7% [96.9-99.3]; p < 0.01). The bronchiolitis group was not different from the UAO group regarding the desaturation index (23.3 episodes/hour [10.3-46.6] and 15.5 episodes/hour [5.4-36.4], respectively; p = 0.08), but differed significantly from the controls (3.1 episodes/hour [0.3-5.5]; p < 0.01). The basal SpO2 and desaturation index improved in 10 subjects with bronchiolitis who had follow-up oximetry before discharge, but these indices remained abnormal when compared to values in the control group. CONCLUSION: Bronchiolitis was characterised by low nocturnal basal SpO2 and intermittent SpO2 drops.

Lung function by impulse oscillometry at age 5-7 years after bronchiolitis at age 0-6 months.

BACKGROUND: Viral bronchiolitis in infancy has been associated with increased bronchial reactivity and reduced lung function in later childhood and even in adulthood. However, lung function at preschool age is less studied, mainly due to technical difficulties. The purpose of the study was to evaluate lung function and bronchial reactivity at preschool age in children who were hospitalized for bronchiolitis in early infancy. SUBJECTS AND METHODS: Airway resistance and reactance, and bronchial reactivity to exercise were studied with impulse oscillometry (IOS) at the mean age of 6.3 years in 103 children hospitalized for bronchiolitis at less than 6 months of age. RESULTS: In baseline lung-function measurement, resistance (n = 8; 7.8%) or reactance (19; 18.4%) at 5 Hz were pathological in 20% of children compared to Finnish population-based height-adjusted reference values. Increased bronchial reactivity by exercise challenge (5; 4.9%) or bronchodilatation (11; 10.7%) tests was present in 16%. Irreversible changes were revealed in only one case. CONCLUSIONS: Though reduced lung function and increased airway reactivity were rather common, evidence for persistent lung function reduction was rare, less than 1%, at preschool age in children hospitalized for bronchiolitis caused mainly by respiratory syncytial virus at age less than 6 months.

Rhinovirus infection in children hospitalized with acute bronchiolitis and its impact on subsequent wheezing or asthma: a comparison of etiologies.

BACKGROUD: Children who suffer a viral lower respiratory infection early in life are prone to subsequent wheezing and asthma: RSV and rhinovirus are thought to be the primary causative pathogens. Epidemiologic and long-term data on these pathogens in Thailand are limited. OBJECTIVES: To detect the causative pathogens in children hospitalized with a first episode of acute wheezing and to compare the respective impact on the recurrence of wheezing and development of asthma. METHOD: We conducted a 5-year cohort study of children under 2 hospitalized with acute bronchiolitis at two tertiary hospitals. Nasopharyngeal secretions were collected at admission to determine the causative pathogens by RT-PCR. RESULTS: 145/170 samples (85%) were positive for pathogens. RSV, rhinovirus, influenza, bacteria and hMPV was found in 64.7%, 18.2%, 17.6%, 12.9% and 3.5% of children respectively. The majority (94/152; 62%) of participants reported having recurrent wheezing within the first year of follow-up (mean duration 5.5 ± 7.2 months). Only 16% still had wheezing episodes after 5 years. Asthma was diagnosed in 41 children (45%), most of whom were treated with inhaled corticosteroid. There were no statistically significant differences among the various etiologies. CONCLUSION: Rhinovirus ranked second after RSV as the cause of hospitalizations of children with acute bronchiolitis. More than half of these children had recurrent wheezing which mostly disappeared before the age of 6. Nearly half were subsequently diagnosed with asthma at the 5th year of follow-up. The specific pathogens did not account for a statistically significant difference in subsequent wheezing or asthma development.