Acute viral bronchiolitis: Physician perspectives on definition and clinically important outcomes

Parenteral versus enteral fluid therapy for children hospitalised with bronchiolitis

BACKGROUND

The main focus of treatment for children hospitalised with bronchiolitis is supportive, including oxygen supplementation, respiratory support, and fluid therapy. Up to half of infants hospitalised with bronchiolitis require non-oral fluid therapy due to dehydration or concerns related to the safety of oral feeding. The two main modalities used for non-oral fluid therapy are parenteral (intravenous (IV)) and enteral tube (nasogastric (NG) or orogastric (OG)). However, it is not known which mode is optimal in young children.

OBJECTIVES

To systematically review randomised clinical trials (RCTs) of the effectiveness and safety of parenteral and enteral tube fluid therapy for children under two years of age hospitalised with bronchiolitis.

SEARCH METHODS

We conducted a search of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, Web of Science, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform on 8 March 2021. We handsearched conference proceedings, conducted forward and backward searching of citation lists of relevant articles, and contacted experts.

SELECTION CRITERIA

We included RCTs and quasi-RCTs of children aged up to two years admitted to hospital with a clinical diagnosis of bronchiolitis who required fluid therapy. The trials compared enteral tube fluid therapy with parenteral fluid therapy. The primary outcome was difference in length of hospital stay in hours after each non-oral fluid therapy modality. As actual time of discharge can be impacted by various factors, we also assessed theoretical length of stay (i.e. time when a patient is safe for discharge). We assessed several secondary outcomes.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.  MAIN RESULTS: The searches yielded 615 unique records, of which four articles underwent full-text screening. We included two trials (810 children). Oakley 2013 was an open, non-blinded RCT of infants aged two to 12 months admitted to hospitals in Australia and New Zealand with a clinical diagnosis of bronchiolitis during three bronchiolitis seasons. The trial enrolled 759 children, of which 381 were randomised to NG tube therapy and 378 to IV therapy. Risk of bias was low in most domains. Kugelman 2013 was an open, non-blinded RCT that enrolled infants aged less than six months with a clinical diagnosis of "moderate bronchiolitis" at a single hospital in Israel. The study enrolled 51 infants, of which 31 were assigned to NG or OG tube therapy and 20 to IV therapy. Risk of bias was unclear in most domains. The application of enteral tube fluid therapy compared to IV fluid therapy probably makes little to no difference for actual length of hospital stay (mean difference (MD) 6.8 hours, 95% confidence interval (CI) -4.7 to 18.4 hours; 2 studies, 810 children, moderate certainty evidence). There was also little to no difference for theoretical length of stay (MD 4.4 hours, 95% CI -3.6 to 12.4 hours; 2 studies, 810 children, moderate certainty evidence). For the secondary outcomes, enteral tube fluid therapy probably makes little to no difference for time to resume full oral feeding compared to IV fluid therapy (MD 2.8 hours, 95% CI -3.6 to 9.2 hours; 2 studies, 810 children, moderate certainty evidence). The use of enteral tube for fluid therapy probably results in a large increase in the success of insertion of fluid modality at first attempt (risk ratio (RR) 1.52, 95% CI 1.36 to 1.69; 1 study, 617 children, moderate certainty evidence), and probably largely reduces the chances of change in fluid therapy modality (RR 0.52, 95% CI 0.38 to 0.71; 1 study, 759 children, moderate certainty evidence) compared to IV fluid.  Oakley 2013 reported 47 local complication events after discharge in the IV fluid group compared to 30 events in the NG tube group. They also evaluated parental satisfaction, which was high with both modalities. Enteral tube fluid therapy makes little to no difference to the duration of oxygen supplementation (MD 2.2 hours, 95% CI -5.0 to 9.5 hours; 2 studies, 810 children, moderate certainty evidence). Compared with the IV fluid therapy group, there was a 17% relative reduction in the number of intensive care unit admissions (RR 0.83, 95% CI 0.47 to 1.46; 1 study, 759 children, moderate certainty evidence) and a 19% relative reduction in number of readmissions to hospital (RR 0.81, 95% CI 0.33 to 2.04; 1 study, 678 children, moderate certainty evidence) in the enteral tube fluid therapy group. Adverse events were uncommon in both trials, with likely little to no differences between groups.

AUTHORS' CONCLUSIONS

Based on two RCTs, enteral tube feeding likely results in little to no difference in length of hospital stay compared with the IV fluid group. However, enteral tube fluid therapy likely results in a large increase in the success of insertion of fluid modality at first attempt, and a large reduction in change in modality of fluid therapy. It also probably reduces local complications compared to the IV fluid group. Despite bronchiolitis being one of the most prevalent childhood conditions, we identified only two studies with under 1000 participants in total, which highlights the need for multicentre trials. Future studies should explore type of fluid administered, parent-reported outcomes and preferences, and the role of shared decision-making.

Immune biomarkers predicting bronchiolitis disease severity: A systematic review

Bronchiolitis is one of the leading causes of hospitalisation in infancy, with highly variable clinical presentations ranging from mild disease safely managed at home to severe disease requiring invasive respiratory support. Identifying immune biomarkers that can predict and stratify this variable disease severity has important implications for clinical prognostication/disposition. A systematic literature search of the databases Embase, PubMed, ScienceDirect, Web of Science, and Wiley Online Library was performed. English language studies that assessed the association between an immune biomarker and bronchiolitis disease severity among children aged less than 24 months were included. 252 distinct biomarkers were identified across 90 studies. A substantial degree of heterogeneity was observed in the bronchiolitis definitions, measures of disease severity, and study designs. 99 biomarkers showed some significant association with disease severity, but only 18 were significant in multiple studies. However, all of these candidate biomarkers had comparable studies that reported conflicting results. Conclusion: The heterogeneity among included studies and the lack of a consistently significant biomarker highlight the need for consensus on bronchiolitis definitions and severity measures, as well as further studies assessing their clinical utility both in isolation and in combination.

Asthma diagnosis in infants and preschool children: a systematic review of clinical guidelines

BACKGROUND AND AIM

The definition and diagnosis of asthma are the subject of controversy that is particularly intense in the case of individuals in the first years of life, due to reasons such as the difficulty of performing objective pulmonary function tests or the high frequency with which the symptoms subside in the course of childhood. Since there is no consensus regarding the diagnosis of asthma in preschool children, a systematic review has been carried out.

MATERIALS AND METHODS

A systematic search was made of the clinical guidelines published in the last 10 years and containing information referred to the concept or diagnosis of asthma in childhood - including the first years of life (infants and preschool children). A series of key questions were established, and each selected guide was analyzed in search of answers to those questions. The review protocol was registered in the international prospective register of systematic reviews (PROSPERO), with registration number CRD42017074872.

RESULTS

Twenty-one clinical guidelines were selected: 10 general guides (children and adults), eight pediatric guides and three guides focusing on preschool children. The immense majority accepted that asthma can be diagnosed from the first years of life, without requiring pulmonary function tests or other complementary techniques. The response to treatment and the exclusion of other alternative diagnoses are key elements for establishing the diagnosis. Only one of the guides denied the possibility of diagnosing asthma in preschool children.

CONCLUSIONS

There is generalized although not unanimous agreement that asthma can be diagnosed in preschool children.

[Criteria heterogeneity in the diagnosis of acute bronchiolitis in Spain]

INTRODUCTION

Acute viral bronchiolitis (AB) is one of the most common respiratory diseases in infants. However, diagnostic criteria for AB are heterogeneous and not very well known.

OBJECTIVE

To identify the diagnostic criteria for AB used by experts and clinical paediatricians in Spain.

METHODS

Delphi study with Spanish AB experts, looking for the points of agreement about AB diagnosis. A subsequent cross-sectional study was conducted by means of an on-line questionnaire addressed to all Spanish paediatricians, reached through electronic mail messages sent by nine paediatric scientific societies. Descriptive and factorial analyses were carried out, looking for any association of diagnostic criteria with demographic or geographic variables, or with paediatric subspecialty.

RESULTS

Agreement was reached by 40 experts in many issues (first episode of respiratory distress and high respiratory frequency, diagnosis in any season of the year, and usefulness of virus identification in making diagnosis), but opposite views were maintained on key characteristics such as the maximum age for diagnosis. The on-line questionnaire was completed by 1297 paediatricians. Their diagnostic criteria were heterogeneous and strongly associated with their paediatric sub-specialty. Their agreement with the Spanish expert consensus and with international standards was very poor.

CONCLUSIONS

Diagnostic criteria for AB in Spain are heterogeneous. These differences could cause variability in clinical practice with AB patients.

Criteria heterogeneity in the diagnosis of acute bronchiolitis in Spain

INTRODUCTION

Acute viral bronchiolitis (AB) is one of the most common respiratory diseases in infants. However, diagnostic criteria for AB are heterogeneous and not very well known.

OBJECTIVE

To identify the diagnostic criteria for AB used by experts and clinical paediatricians in Spain.

METHODS

Delphi study with Spanish AB experts, looking for the points of agreement about AB diagnosis. A subsequent cross-sectional study was conducted by means of an online questionnaire addressed to all Spanish paediatricians, reached through electronic mail messages sent by nine paediatric scientific societies. Descriptive and factorial analyses were carried out, looking for any association of diagnostic criteria with demographic or geographic variables, or with paediatric subspecialty.

RESULTS

Agreement was reached by 40 experts in many issues (first episode of respiratory distress and high respiratory frequency, diagnosis in any season of the year, and usefulness of virus identification in making diagnosis), but opposite views were maintained on key characteristics such as the maximum age for diagnosis. The online questionnaire was completed by 1297 paediatricians. Their diagnostic criteria were heterogeneous and strongly associated with their paediatric sub-specialty. Their agreement with the Spanish expert consensus and with international standards was very poor.

CONCLUSIONS

Diagnostic criteria for AB in Spain are heterogeneous. These differences could cause variability in clinical practice with AB patients.

Non-invasive ventilation for the management of children with bronchiolitis (NOVEMBR): a feasibility study and core outcome set development protocol

BACKGROUND

Bronchiolitis is an acute lower respiratory infection which predominantly affects young children. Treatment for bronchiolitis is limited to supportive therapy. Nasal oxygen therapy is part of routine care, and delivery now incorporates varying levels of non-invasive continuous positive airway pressure and/or high-flow nasal cannula oxygen therapy. Despite wide clinical use, there remains a lack of evidence on the comparative effectiveness and safety of these interventions. Furthermore, research in this field is hampered by the use of multiple outcome measures in current clinical trials.

METHODS/DESIGN

This mixed methods study includes a systematic review of outcome measures, telephone interviews with parents, focus group workshops and a Delphi survey with healthcare professionals and parents. These methods will be used to identify and prioritise outcomes for inclusion in a core outcome set and to explore issues pertinent to the design of a future randomised controlled trial comparing different modes of oxygen therapy for bronchiolitis. UK hospitals will also be contacted and asked to complete a survey to provide an overview of current practice to enable assessment of capability and capacity to run a future clinical trial.

DISCUSSION

This study will facilitate the design of a future clinical trial of non-invasive ventilation in children with bronchiolitis which is acceptable to important stakeholders. Furthermore, core outcome set development will improve standardisation, measurement and reporting of clinically important outcomes in bronchiolitis.

TRIAL REGISTRATION

ISRCTN Registry, ISRCTN75766048. Registered on 18 December 2017. This study was retrospectively registered in the ISRCTN Registry and on the Core Outcome Measures in Effectiveness Trials (COMET) Initiative database (15 September 2017).

Bronchiolitis clinics and medical treatment

Bronchiolitis is the most common acute lower respiratory tract infection in infants and the first cause of hospitalization in this age group. Despite it has been studied for over 70 years, its management remains controversial and nowadays the treatment is only supportive. Pediatricians should be well acquainted with the clinical course of the disease. In particular, they should know that the severity of respiratory symptoms peaks between days 3-7 of the disease and dehydration is a key sign to consider for the management. In this review, we will discuss the most controversial points in the management of bronchiolitis according to six evidence-based guidelines, six clinical practice guidelines and five consensus-based reviews.

Clinical definition of respiratory viral infections in young children and potential bronchiolitis misclassification

Viral respiratory infections are often grouped as a single respiratory syndrome named 'viral bronchiolitis', independently of the viral etiology or individual risk factors. Clinical trials and guidelines have used a more stringent definition of viral bronchiolitis, including only the first episode of wheezing in children less than 12 months of age without concomitant respiratory comorbidities. There is increasing evidence suggesting that this definition is not being followed by pediatric care providers, but it is unclear to what extent viral respiratory infections are currently misclassified as viral bronchiolitis using standard definitions. We conducted a retrospective analysis of hospitalized young children (≤3 years) due to viral respiratory infections. Bronchiolitis was defined as the first wheezing episode less than 12 months of age. Demographic variables and comorbidities were obtained by electronic medical record review. The study comprised a total of 513 hospitalizations (n=453). Viral bronchiolitis was diagnosed in 144 admissions (28.1%). Notably, we identified that the majority of children diagnosed with bronchiolitis (63%) were misclassified as they had prior episodes of wheezing. Many children with bronchiolitis misclassification had significant comorbidities, including prematurity (51%), neuromuscular conditions (9.8%), and congenital heart disease (9.8%). Misclassification of bronchiolitis is a common problem that may lead to inappropriate management of viral respiratory infections in young children. A comprehensive approach that takes into consideration viral etiology and individual risk factors may lead to a more accurate clinical assessment of this condition and would potentially prevent bronchiolitis misclassification.

Respiratory mechanics in infants with severe bronchiolitis on controlled mechanical ventilation

Background

Analysis of respiratory mechanics during mechanical ventilation (MV) is able to estimate resistive, elastic and inertial components of the working pressure of the respiratory system. Our aim was to discriminate the components of the working pressure of the respiratory system in infants on MV with severe bronchiolitis admitted to two PICU’s.

Methods

Infants younger than 1 year old with acute respiratory failure caused by severe bronchiolitis underwent neuromuscular blockade, tracheal intubation and volume controlled MV. Shortly after intubation studies of pulmonary mechanics were performed using inspiratory and expiratory breath hold. The maximum inspiratory and expiratory flow (QI and QE) as well as peak inspiratory (PIP), plateau (PPL) and total expiratory pressures (tPEEP) were measured. Inspiratory and expiratory resistances (RawI and RawE) and Time Constants (K_TI and K_TE) were calculated.

Results

We included 16 patients, of median age 2.5 (1–5.8) months. Bronchiolitis due to respiratory syncytial virus was the main etiology (93.8%) and 31.3% had comorbidities. Measured respiratory pressures were PIP 29 (26–31), PPL 24 (20–26), tPEEP 9 [8–11] cmH2O. Elastic component of the working pressure was significantly higher than resistive and both higher than threshold (tPEEP – PEEP) (P < 0.01). QI was significantly lower than QE [5 (4.27–6.75) v/s 16.5 (12–23.8) L/min. RawI and RawE were 38.8 (32–53) and 40.5 (22–55) cmH2O/L/s; K_TI and K_TE [0.18 (0.12–0.30) v/s 0.18 (0.13–0.22) s], and K_TI:K_TE ratio was 1:1.04 (1:0.59–1.42).

Conclusions

Analysis of respiratory mechanics of infants with severe bronchiolitis receiving MV shows that the elastic component of the working pressure of the respiratory system is the most important. The elastic and resistive components in conjunction with flow profile are characteristic of restrictive diseases. A better understanding of lung mechanics in this group of patients may lead to change the traditional ventilatory approach to severe bronchiolitis.

Electronic supplementary material

The online version of this article (10.1186/s12890-017-0475-6) contains supplementary material, which is available to authorized users.

Pediatric pulmonology year in review 2016: Part 2

Pediatric Pulmonology continues to publish research and clinical topics related to the entire range of children's respiratory disorders. As we have done annually in recent years, we here summarize some of the past year's publications in our major topic areas, as well as selected literature in these areas from other core journals relevant to our discipline. This review (Part 2) covers selected articles on neonatology, asthma, physiology and lung function testing, and infectious diseases.

The heterogeneity of viral bronchiolitis: A lack of universal consensus definitions

Viral bronchiolitis is one of the most common hospital presentations in infancy and as such represents a major healthcare burden worldwide. However despite this, there are currently no effective targeted therapies nor can those infants at highest risk for developing severe disease or subsequent respiratory morbidity be predicted on initial hospital presentation. Current definitions of bronchiolitis in the published literature vary significantly in terms of the age range at presentation, specific clinical symptoms, causative virus, and the inclusion or exclusion of infants with previous presentations and/or various comorbidities. In this review, we highlight how this heterogeneity among definitions contributes to a lack of clarity on this condition and its likely multiple endotypes. We argue that without a new universal consensus definition or sets of definitions, progress into bronchiolitis will continue to be stalled.