Prospective multicenter bronchiolitis study: predicting intensive care unit admissions

Infants under 6 months with bronchiolitis are most likely to need major medical interventions in the 5 days after onset

AIM

This study examined the need for, and timing of, major medical interventions (MMIs) in infants under 6 months of age with bronchiolitis.

METHODS

We reviewed the medical records of 353 children who visited our emergency department with bronchiolitis. MMI was defined as the need for any of the following interventions during admission: supplementary oxygen, intravenous fluids, intravenous antibiotics or admission to the intensive care unit.

RESULTS

Altogether 19% of the 353 patients required a MMI and 3% had apnoea. The patients with apnoea were all under 2 months of age, and 90% had a respiratory syncytial virus (RSV) infection and 40% had been born prematurely. The risk of needing a MMI continued for up to 5 days after disease onset. A positive RSV test predicted a MMI with an odds ratio (OR) of 11.5 (95% CI 2.6-50.5), and a fever of over 38°C predicted a MMI with an OR of 3.5 (95% CI 1.4-8.8). Each 1% increase in the initial oxygen saturation value was associated with a decreased risk of MMI (OR 0.7, 95% CI 0.6-0.8).

CONCLUSION

Infants under 6 months of age with bronchiolitis were most likely to need MMIs in the first 5 days after disease onset.

Nasopharyngeal gene expression, a novel approach to study the course of respiratory syncytial virus infection

Respiratory syncytial virus (RSV) causes mild infections in the vast majority of children. However, in some cases, it causes severe disease, such as bronchiolitis and pneumonia. Development of severe RSV infection is determined by the host response. Therefore, the main aim of this study was to identify biomarkers associated with severe RSV infection. To identify biomarkers, nasopharyngeal gene expression was profiled by microarray studies, resulting in the selection of five genes: ubiquitin D, tetraspanin 8, mucin 13, β-microseminoprotein and chemokine ligand 7. These genes were validated by real-time quantitative PCR in an independent validation cohort, which confirmed significant differences in gene expression between mildly and severely infected and between recovery and acute patients. Nasopharyngeal aspirate samples are regularly taken when a viral respiratory tract infection is suspected. In this article, we describe a method to discriminate between mild and severe RSV infection based on differential host gene expression. The combination of pathogen detection and host gene expression analysis in nasopharyngeal aspirates will significantly improve the diagnosis and prognosis of respiratory tract infections.

Factors associated with disease severity in children with bronchiolitis

OBJECTIVE

Bronchiolitis is one of the top causes of hospitalization of infants in the United States. Several clinical factors have been associated with hospitalization; however, few studies have examined factors related to severe disease. Our goal was to describe the clinical characteristics and hospital course of children admitted with bronchiolitis and to identify factors related to intensive care unit (ICU) admission in this population.

METHODS

We conducted a retrospective review of all children less than 2 years of age admitted to a children's hospital with bronchiolitis between July 2008 and July 2011. Demographic and clinical data were collected including information regarding hospital course, treatments received and respiratory pathogens.

RESULTS

During the study period, 734 children were admitted to the hospital with bronchiolitis, 22% of whom were admitted to the ICU and 10% of whom were intubated and mechanically ventilated. Admission to the ICU was associated with younger age [110 (45-210) days versus 69 (35-149) days, p < 0.001] and history of premature birth (OR 1.7, 95% CI 1.1-2.4, p = 0.01), but not with race or ethnicity. The use of respiratory treatments was common in the children admitted to the ICU but was not associated with shortened durations of hospitalization. In addition, neither prematurity nor young age were associated with either increased duration of hospitalization or with increased likelihood of mechanical ventilation.

CONCLUSIONS

During acute bronchiolitis infections, younger children and those with a history of prematurity were more likely to be admitted to the ICU with severe disease.

Racial/ethnic differences in the presentation and management of severe bronchiolitis

BACKGROUND AND OBJECTIVE

Bronchiolitis is the leading cause of hospitalization for US infants and is associated with increased risk of childhood asthma. Although studies have shown differences in the presentation and management of asthma across race/ethnicity, it is unclear if such differences are present for bronchiolitis. We examined if racial/ethnic differences exist in the presentation and management of severe bronchiolitis.

METHODS

We performed a 16-center, prospective cohort study from 2007 to 2010. Children <2 years old hospitalized with a diagnosis of bronchiolitis were included. A structured interview, chart review, and 1-week phone follow-up were completed. Multivariable logistic regression was used to examine the independent association between race/ethnicity and diagnostic imaging, treatment (eg, albuterol, corticosteroids, and continuous positive airway pressure/intubation), management (eg, intensive care unit admission and length of stay), discharge on inhaled corticosteroids, and bronchiolitis relapse.

RESULTS

Among 2130 patients, 818 (38%) were non-Hispanic white (NHW), 511 (24%) were non-Hispanic black (NHB), and 801 (38%) were Hispanic. Compared with all groups, NHB children were most likely to receive albuterol before admission (odds ratio [OR]: 1.58; 95% confidence interval [CI]: 1.20-2.07) and least likely to receive chest x-rays during hospitalization (OR: 0.66; 95% CI: 0.49-0.90). Hispanic children were most likely to be discharged on inhaled corticosteroids (OR: 1.92; 95% CI: 1.19-3.10).

CONCLUSION

We observed differences between NHW and minority children regarding preadmission albuterol use, inpatient diagnostic imaging, and prescription of inhaled corticosteroids at discharge, practices that deviate from the American Academy of Pediatrics guidelines. The causes of these differences require further study, but they support implementation of care pathways for severe bronchiolitis.

A systematic review of predictive modeling for bronchiolitis

PURPOSE

Bronchiolitis is the most common cause of illness leading to hospitalization in young children. At present, many bronchiolitis management decisions are made subjectively, leading to significant practice variation among hospitals and physicians caring for children with bronchiolitis. To standardize care for bronchiolitis, researchers have proposed various models to predict the disease course to help determine a proper management plan. This paper reviews the existing state of the art of predictive modeling for bronchiolitis. Predictive modeling for respiratory syncytial virus (RSV) infection is covered whenever appropriate, as RSV accounts for about 70% of bronchiolitis cases.

METHODS

A systematic review was conducted through a PubMed search up to April 25, 2014. The literature on predictive modeling for bronchiolitis was retrieved using a comprehensive search query, which was developed through an iterative process. Search results were limited to human subjects, the English language, and children (birth to 18 years).

RESULTS

The literature search returned 2312 references in total. After manual review, 168 of these references were determined to be relevant and are discussed in this paper. We identify several limitations and open problems in predictive modeling for bronchiolitis, and provide some preliminary thoughts on how to address them, with the hope to stimulate future research in this domain.

CONCLUSIONS

Many problems remain open in predictive modeling for bronchiolitis. Future studies will need to address them to achieve optimal predictive models.

Epidemiological and genetic characteristics associated with the severity of acute viral bronchiolitis by respiratory syncytial virus

OBJECTIVE

to assess the epidemiological and genetic factors associated with severity of acute viral bronchiolitis (AVB) by respiratory syncytial virus (RSV).

DATA SOURCE

the key words "bronchiolitis", "risk factor", "genetics" and "respiratory syncytial virus", and all combinations among them were used to perform a search in the PubMed, SciELO, and Lilacs databases, of articles published after the year 2000 that included individuals younger than 2 years of age.

DATA SYNTHESIS

a total of 1,259 articles were found, and their respective summaries were read. Of these, 81 were selected, which assessed risk factors for the severity of AVB, and were read in full; the 60 most relevant studies were included. The epidemiologic factors associated with AVB severity by RSV were prematurity, passive smoking, young age, lack of breastfeeding, chronic lung disease, congenital heart disease, male gender, ethnicity, viral coinfection, low weight at admission, maternal smoking during pregnancy, atopic dermatitis, mechanical ventilation in the neonatal period, maternal history of atopy and/or asthma during pregnancy, season of birth, low socioeconomic status, Down syndrome, environmental pollution, living at an altitude > 2,500 meters above sea level, and cesarean section birth. Conversely, some children with severe AVB did not present any of these risk factors. In this regard, recent studies have verified the influence of genetic factors on the severity of AVB by RSV. Polymorphisms of the TLRs, RANTES, JUN, IFNA5, NOS2, CX3CR1, ILs, and VDR genes have been shown to be associated with more severe evolution of AVB by RSV.

CONCLUSION

the severity of AVB by RSV is a phenomenon that depends on the varying degrees of interaction among epidemiological, environmental, and genetic variables.

Glucocorticoids for acute viral bronchiolitis in infants and young children

BACKGROUND

Previous systematic reviews have not shown clear benefit of glucocorticoids for acute viral bronchiolitis, but their use remains considerable. Recent large trials add substantially to current evidence and suggest novel glucocorticoid-including treatment approaches.

OBJECTIVES

To review the efficacy and safety of systemic and inhaled glucocorticoids in children with acute viral bronchiolitis.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2012, Issue 12), MEDLINE (1950 to January week 2, 2013), EMBASE (1980 to January 2013), LILACS (1982 to January 2013), Scopus® (1823 to January 2013) and IRAN MedEx (1998 to November 2009).

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing short-term systemic or inhaled glucocorticoids versus placebo or another intervention in children under 24 months with acute bronchiolitis (first episode with wheezing). Our primary outcomes were: admissions by days 1 and 7 for outpatient studies; and length of stay (LOS) for inpatient studies. Secondary outcomes included clinical severity parameters, healthcare use, pulmonary function, symptoms, quality of life and harms.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data on study and participant characteristics, interventions and outcomes. We assessed risk of bias and graded strength of evidence. We meta-analysed inpatient and outpatient results separately using random-effects models. We pre-specified subgroup analyses, including the combined use of bronchodilators used in a protocol.

MAIN RESULTS

We included 17 trials (2596 participants); three had low overall risk of bias. Baseline severity, glucocorticoid schemes, comparators and outcomes were heterogeneous. Glucocorticoids did not significantly reduce outpatient admissions by days 1 and 7 when compared to placebo (pooled risk ratios (RRs) 0.92; 95% confidence interval (CI) 0.78 to 1.08 and 0.86; 95% CI 0.7 to 1.06, respectively). There was no benefit in LOS for inpatients (mean difference -0.18 days; 95% CI -0.39 to 0.04). Unadjusted results from a large factorial low risk of bias RCT found combined high-dose systemic dexamethasone and inhaled epinephrine reduced admissions by day 7 (baseline risk of admission 26%; RR 0.65; 95% CI 0.44 to 0.95; number needed to treat 11; 95% CI 7 to 76), with no differences in short-term adverse effects. No other comparisons showed relevant differences in primary outcomes.

AUTHORS' CONCLUSIONS

Current evidence does not support a clinically relevant effect of systemic or inhaled glucocorticoids on admissions or length of hospitalisation. Combined dexamethasone and epinephrine may reduce outpatient admissions, but results are exploratory and safety data limited. Future research should further assess the efficacy, harms and applicability of combined therapy.

Morbidity and outcome of severe respiratory syncytial virus infection

BACKGROUND

Respiratory syncytial virus (RSV) is the main cause of severe acute respiratory infection (SARI) in infants and young children. This study aimed to identify risk factors for intensive care unit (ICU) admission, prolonged length of stay (PLOS), and mortality in patients hospitalized with SARI caused by RSV.

METHODS

This prospective cohort study included children hospitalized with SARI (according to the World Health Organization definition) and whose laboratory results proved RSV infection during the period from February 2010 to May 2011.

RESULTS

Out of 240 enrolled patients, 24 patients (10%) were admitted to the ICU, 57 patients (24.3%) had a PLOS of >9 days and 12 patients (5%) died. The presence of cyanosis (P = 0.000; OR, 351.7) and lung consolidation (P = 0.006, OR, 9.3) were independent risk factors associated with ICU admission. The need for ICU admission (P = 0.000; OR, 6.1) and lung consolidation (P = 0.008, OR, 2.46) were independent risk factors associated with PLOS. The presence of an underlying congenital heart disease (P = 0.03, OR, 18.3), thrombocytopenia (P = 0.04, OR, 32.86) and mechanical ventilation (P = 0.000; OR, 449.4) were the only independent risk factors associated with mortality in our study.

CONCLUSIONS

Early recognition of risk factors for complicated RSV disease on admission prompts early interventions and early ICU admissions for these children.

A comparative study of respiratory syncytial virus (RSV) prophylaxis in premature infants within the Canadian Registry of Palivizumab (CARESS)

We examined the dosing regimens, compliance, and outcomes of premature infants who received palivizumab within the Canadian Registry of Palivizumab (CARESS). Infants receiving ≥1 dose of palivizumab during the 2006-2011 respiratory syncytial virus (RSV) seasons were recruited across 30 sites. Respiratory illness events were captured monthly. Infants ≤32 completed weeks gestational age (GA) (Group 1) were compared to 33-35 completed weeks GA infants (Group 2) following prophylaxis. In total, 6,654 patients were analyzed (Group 1, n = 5,183; Group 2, n = 1,471). The mean GA was 29.9 ± 2.9 versus 34.2 ± 2.2 weeks for Groups 1 and 2, respectively. Group differences were significant (all p-values <0.05) for the following: proportion of males, Caucasians, siblings, multiple births, maternal smoking, smoking during pregnancy, household smokers, >5 household individuals, birth weight, and enrolment age. Overall, infants received 92.6 % of expected injections. Group 1 received significantly more injections, but a greater proportion of Group 2 received injections within recommended intervals. The hospitalization rates were similar for Groups 1 and 2 for respiratory illness (4.7 % vs. 3.7 %, p = 0.1) and RSV (1.5 % vs. 1.4 %, p = 0.3). Neither the time to first respiratory illness [hazard ratio = 0.9, 95 % confidence interval (CI) 0.7-1.2, p = 0.5] nor to first RSV hospitalization (hazard ratio = 1.3, 95 % CI 0.8-2.2, p = 0.3) were different. Compliance with RSV prophylaxis is high. Despite the higher number of palivizumab doses in infants ≤32 completed weeks GA, the two groups' respiratory illness and RSV-positive hospitalization rates were similar.

Prospective multicenter study of children with bronchiolitis requiring mechanical ventilation

OBJECTIVE

To identify factors associated with continuous positive airway pressure (CPAP) and/or intubation for children with bronchiolitis.

METHODS

We performed a 16-center, prospective cohort study of hospitalized children aged <2 years with bronchiolitis. For 3 consecutive years from November 1 until March 31, beginning in 2007, researchers collected clinical data and a nasopharyngeal aspirate from study participants. We oversampled children from the ICU. Samples of nasopharyngeal aspirate were tested by polymerase chain reaction for 18 pathogens.

RESULTS

There were 161 children who required CPAP and/or intubation. The median age of the overall cohort was 4 months; 59% were male; 61% white, 24% black, and 36% Hispanic. In the multivariable model predicting CPAP/intubation, the significant factors were: age <2 months (odds ratio [OR] 4.3; 95% confidence interval [CI] 1.7-11.5), maternal smoking during pregnancy (OR 1.4; 95% CI 1.1-1.9), birth weight <5 pounds (OR 1.7; 95% CI 1.0-2.6), breathing difficulty began <1 day before admission (OR 1.6; 95% CI 1.2-2.1), presence of apnea (OR 4.8; 95% CI 2.5-8.5), inadequate oral intake (OR 2.5; 95% CI 1.3-4.3), severe retractions (OR 11.1; 95% CI 2.4-33.0), and room air oxygen saturation <85% (OR 3.3; 95% CI 2.0-4.8). The optimism-corrected c-statistic for the final model was 0.80.

CONCLUSIONS

In this multicenter study of children hospitalized with bronchiolitis, we identified several demographic, historical, and clinical factors that predicted the use of CPAP and/or intubation, including children born to mothers who smoked during pregnancy. We also identified a novel subgroup of children who required mechanical respiratory support <1 day after respiratory symptoms began.

Nasopharyngeal lactate dehydrogenase concentrations predict bronchiolitis severity in a prospective multicenter emergency department study

We reexamined the finding of an inverse relationship between values of nasopharyngeal lactate dehydrogenase, a marker of the innate immune response, and bronchiolitis severity. In a prospective, multicenter study of 258 children, we found in a multivariable model that higher nasopharyngeal lactate dehydrogenase values in young children with bronchiolitis were independently associated with a decreased risk of hospitalization.

Clinical predictors of nasal continuous positive airway pressure requirement in acute bronchiolitis

INTRODUCTION

There is growing use of nasal continuous positive airway pressure ventilation (nCPAP) for infants with bronchiolitis, based on clinical assessment of severity. Despite this there have been no studies which identify clinical predictors for the requirement of nCPAP.

OBJECTIVE

To identify clinical factors in infants with acute bronchiolitis in the emergency department (ED), which might predict a requirement for nCPAP following admission.

MATERIALS AND METHODS

Retrospective review of pediatric ED case notes was conducted on bronchiolitis admissions to one dedicated Paediatric ED over a 12-month period. Potential predictors were identified through literature review. Data extraction of predictors was carried out and recorded for each case. Logistic regression was conducted for each variable to identify statistically significant predictors of nCPAP requirement.

RESULTS

Twenty-eight (17%) of the 163 admitted infants received nCPAP. The strongest predictors of nCPAP requirement in were as follows: oxygen requirement within the ED (P < 0.001), lower oxygen saturation (P < 0.001), younger age at presentation (P = 0.002), higher respiratory rate (P = 0.002), higher heart rate (P = 0.003), lower Glasgow Coma Scale score (0.006), and younger gestational age (P = 0.024).

CONCLUSION

We have identified clinical variables that were predictive of nCPAP requirement in infants admitted to our unit with bronchiolitis, oxygen requirement in the ED being the strongest single predictor. This is the first such study in the UK, and we hope it may be a starting point for further work that may provide an evidence base to aid clinicians in predicting the use of nCPAP in infants with bronchiolitis.

Incidence and predisposing factors for severe disease in previously healthy term infants experiencing their first episode of bronchiolitis

AIM

To determine the incidence and predisposing factors for severe bronchiolitis in previously healthy term infants <12 months of age experiencing their first episode of bronchiolitis.

METHODS

Epidemiological, clinical and virological data were prospectively collected. Severity was assessed by the need for ventilatory support.

RESULTS

Of the 310 infants enrolled, 16 (5.1%) presented with severe bronchiolitis requiring ventilatory support (11 since admission). Compared with infants with less severe bronchiolitis, infants with severe disease presented with lower birth weight, gestational age, postnatal weight and postnatal age, and were more likely to be born by cesarian section. C-reactive protein positive results (>0.8 mg/dL) and pulmonary consolidation on chest X-ray were more common among infants with severe disease. Severity was independently associated with younger age on admission <30 days, respiratory syncytial virus (RSV) infection and lymphocyte counts < 3200/μL. No significant differences were found between epidemiologic variables.

CONCLUSIONS

Severe bronchiolitis is uncommon in previously healthy term infants <12 months of age and when present develops soon after disease onset. Severity is predicted by young age and RSV carriage, whereas epidemiologic variables seem less likely to intervene.

Central apnoeas in infants with bronchiolitis admitted to the paediatric intensive care unit

AIM

To further characterize apnoea(s) complicating bronchiolitis because of respiratory syncytial virus (RSV), to describe the incidence of this complication and identify possible risk factors for apnoea(s) and its development.

METHODS

The files of infants admitted to the paediatric intensive care unit (PICU) for RSV bronchiolitis during three bronchiolitis seasons (2004-2007) were reviewed for demographic, clinical and laboratory parameters. Parameters were compared between patients with and without apnoeas.

RESULTS

Seventy-nine patients met the study criteria: 43 were admitted to the PICU for central apnoeas and the remainder for respiratory distress or failure. The percentage of infants admitted for apnoea increased during the study period (28.6 to 77.1%, p = 0.004). The overall prevalence of apnoea in this population was 4.3%. Possible risk factors for apnoea(s) were younger age (1.3 vs. 4.3 months, p = 0.002), lower admission weight (3.3 vs. 5 kg, p < 0.001), lower gestational age (35.8 vs. 37.8 weeks, p = 0.01), admission from the emergency room (50% vs. 9.1%, p < 0.001) and lack of hyperthermia (p < 0.001). Respiratory acidosis was found to be a protective factor on logistic regression analysis.

CONCLUSION

The prevalence of apnoea in infants admitted to the PICU for RSV bronchiolitis in our centre may be increasing. Preterm, younger infants with no fever are at relatively high risk of apnoea at presentation, while older infants with fever are at lower risk.

Prospective multicenter study of bronchiolitis: predictors of an unscheduled visit after discharge from the emergency department

OBJECTIVES

There is little evidence about which children with bronchiolitis will have worsened disease after discharge from the emergency department (ED). The objective of this study was to determine predictors of post-ED unscheduled visits.

METHODS

The authors conducted a prospective cohort study of patients discharged from 2004 to 2006 at 30 EDs in 15 U.S. states. Inclusion criteria were diagnosis of bronchiolitis, age <2 years, and discharge home; the exclusion criterion was previous enrollment. Unscheduled visits were defined as urgent visits to an ED/clinic for worsened bronchiolitis within 2 weeks.

RESULTS

Of 722 patients eligible for the current analysis, 717 (99%) had unscheduled visit data, of whom 121 (17%; 95% confidence interval [CI] = 14% to 20%) had unscheduled visits. Unscheduled visits were more likely for children age <2 months (11% vs. 6%; p = 0.04), males (70% vs. 57%; p = 0.007), and those with history of hospitalization (27% vs. 18%; p = 0.01). The two groups were similar in other demographic and clinical factors (all p > 0.10). Using multivariable logistic regression, independent predictors of unscheduled visits were age <2 months, male, and history of hospitalization.

CONCLUSIONS

In this study of children age younger than 2 years with bronchiolitis, one of six children had unscheduled visits within 2 weeks of ED discharge. The three predictors of unscheduled visits were age under 2 months, male sex, and previous hospitalization.

Predictors of respiratory failure among previously healthy children with respiratory syncytial virus infection

BACKGROUND

Respiratory syncytial virus (RSV)-related disease is the leading cause of hospitalization among infants, with approximately 7% to 21% of these patients developing acute respiratory failure.

OBJECTIVE

The aim of this study was to identify clinical variables at initial presentation in the emergency department (ED) that may predict the subsequent need for mechanical ventilation among previously healthy, RSV-infected children who require pediatric intensive care unit (PICU) hospitalization.

STUDY DESIGN

This is a retrospective study of 67 previously healthy, RSV-infected patients admitted from January 1997 to March 2000 to the PICU. The primary outcome for this study was the need for mechanical ventilation. The relationship between clinical variables at initial ED presentation and the need for mechanical ventilation were explored using univariate and multiple logistic regression analysis.

RESULTS

On multivariate analysis, the presence of lethargy (odds ratio [OR], 12.2; P = .005), grunting (OR, 9.3; P = .01), and a Paco(2) 65 mm Hg or greater (OR, 11.8; P = .013) were clinical factors at initial presentation in the ED associated with the subsequent need for mechanical ventilation among the study cohort. A developmental model that included lethargy, grunting, and a Paco(2) of 65 mm Hg or greater performed well as a prediction model. The developmental model had a sensitivity of 71%, specificity of 96%, a positive predictive value of 86%, and a negative predictive value of 91%.

CONCLUSIONS

The presence of lethargy, grunting, and a Paco(2) of 65 mm Hg or greater at initial presentation in the ED were predictive for the subsequent need for mechanical ventilation in previously healthy, RSV-infected children admitted to the PICU.