Association Between Hyponatremia and Higher Bronchiolitis Severity Among Children in the ICU With Bronchiolitis

Monocyte and neutrophil to lymphocyte ratios in hospitalized children with RSV bronchiolitis

OBJECTIVE

Acute bronchiolitis is the most common cause of hospitalization in young children. Data on monocyte-to-lymphocyte-ratio (MLR) and neutrophil-to-lymphocyte-ratio (NLR) as biomarkers are limited. We aim to evaluate these ratios in children hospitalized with respiratory syncytial virus (RSV) bronchiolitis and their value as biomarkers for severe clinical outcomes.

STUDY DESIGN

A single-center retrospective cohort study of children aged <2 years hospitalized due to RSV bronchiolitis, between January 2018 and March 2022, with a complete blood count upon admission. We divided the cohort into quartiles based on MLR and NLR values. We examined associations between quartiles and four clinical severity outcomes.

RESULTS

A total of 2038 children (median age: 4.4 months, IQR: 1.9-9.8) were included in the study. The median MLR and NLR values for quartiles 1-4 were 0.14, 0.22, 0.30, 0.47, and 0.37, 0.70, 1.16, 2.29, respectively. Children with higher MLR had higher hospitalization rates to the pediatric intensive care unit (PICU) (Q1 2.4%, Q4 9.4%, p < .001), extended hospital stays (Q1 19.4%, Q4 32%, p < .001), and lower minimal oxygen saturation (Q1 90%, Q4 87%, p < .001). Cut-off values of 0.34 for MLR and 0.67 for NLR optimally identified PICU admissions. In a model accounting for age and sex, the fourth MLR quartile had an RR of 3.4 (95% CI: 1.76-7.22) and successfully predicted PICU admissions (area under the curve = 0.73; 95% CI: 0.681-0.789).

CONCLUSIONS

MLR and NLR are potential biomarkers for identifying children with RSV bronchiolitis at a higher risk for severe outcomes, specifically PICU admission.

Children born preterm admitted to paediatric intensive care for bronchiolitis: a systematic review and meta-analysis

BACKGROUND

To undertake a systematic review of studies describing the proportion of children admitted to a paediatric intensive care unit (PICU) for respiratory syncytial virus (RSV) and/or bronchiolitis who were born preterm, and compare their outcomes in PICU with children born at term.

METHODS

We searched Medline, Embase and Scopus. Citations and references of included articles were searched. We included studies published from the year 2000 onwards, from high-income countries, that examined children 0-18 years of age, admitted to PICU from the year 2000 onwards for RSV and/or bronchiolitis. The primary outcome was the percentage of PICU admissions born preterm, and secondary outcomes were observed relative risks of invasive mechanical ventilation and mortality within PICU. We used the Joanna Briggs Institute Checklist for Analytical Cross-Sectional Studies to assess risk of bias.

RESULTS

We included 31 studies, from 16 countries, including a total of 18,331 children. Following meta-analysis, the pooled estimate for percentage of PICU admissions for RSV/bronchiolitis who were born preterm was 31% (95% confidence interval: 27% to 35%). Children born preterm had a greater risk of requiring invasive ventilation compared to children born at term (relative risk 1.57, 95% confidence interval 1.25 to 1.97, I2 = 38%). However, we did not observe a significant increase in the relative risk for mortality within PICU for preterm-born children (relative risk 1.10, 95% confidence interval: 0.70 to 1.72, I2 = 0%), although the mortality rate was low across both groups. The majority of studies (n = 26, 84%) were at high risk of bias.

CONCLUSIONS

Among PICU admissions for bronchiolitis, preterm-born children are over-represented compared with the preterm birth rate (preterm birth rate 4.4% to 14.4% across countries included in review). Preterm-born children are at higher risk of mechanical ventilation compared to those born at term.

Incidence and Risk Factors for Hyponatremia in Hospitalized Children with Lower Respiratory Tract Infections

Lower respiratory tract infection (LRTI) is an important cause of hospitalization in pediatric population. Hyponatremia is frequently present in children hospitalized with pneumonia and bronchiolitis and is associated with poorer outcomes. We conducted a study to identify the risk factors for hyponatremia in hospitalized children with LRTI and to evaluate the relationship between serum sodium levels and severity of respiratory distress. A total of 147 patients between 2 months and 12 years of age, admitted with the diagnosis of LRTI at the Mahatma Gandhi Mission Hospital and Medical College, a tertiary hospital in Navi Mumbai, Maharashtra, India, between December 2017 and November 2019, were studied prospectively. Patients with any other comorbidities were excluded. The severity of respiratory distress at presentation was graded using the Clinical Respiratory score (CRS). Serum electrolytes were sent within 1 hour of hospital admission. Median age of enrolled patients was 14 months. Overall, 23 (16%) children had mild respiratory distress, 97 (66%) had moderate respiratory distress, and 26 (18%) had severe distress. The incidence of hyponatremia in children admitted with LRTI was 66% and majority of them (70%) had mild hyponatremia. The incidence, as well as severity of hyponatremia differed significantly with etiology (p < 0.05). An inverse correlation was found between serum sodium levels and CRS at presentation (r = − 0.26, p = 0.001). In multivariate analyses, parenchymal disease was an independent risk factor for development of hyponatremia (adjusted odds ratio [aOR] = 5.64 (2.52–12.59), p < 0.001). Incidence and severity of hyponatremia in children with LRTI increased with severity of respiratory distress and presence of parenchymal disease.

The incidence, hospitalisations and deaths in acutely ill children with dysnatraemias

Aim

The aim was to evaluate the incidence, hospitalisations and deaths in acutely ill children with dysnatraemias.

Methods

This was a register‐based cohort study of 46 518 acutely ill children aged <16 years who visited a paediatric emergency department. Risk factors were assessed using two nested case–control studies.

Results

Moderate to severe hypernatraemia occurred in 92 children (0.20%; 95% confidence interval [CI]: 0.16%–0.24%) and moderate to severe hyponatraemia in 131 children (0.28%; 95% CI: 0.24%–0.33%). Underlying medical conditions increased the risk of both moderate to severe hypernatraemia (odds ratio [OR]: 17; 95% 5.5–51) and moderate to severe hyponatraemia (OR: 3.5; 95% CI: 2.0–5.9). The use of a feeding tube (OR: 14; 95% CI: 3.2–66) and intellectual disability (OR: 7.3; 95% CI: 3.0–18) was associated with moderate to severe hypernatraemia. The risk of death was associated with moderate to severe hypernatraemia (OR: 19; 95% CI: 2.0–2564) and moderate to severe hyponatraemia (OR: 33; 95% CI: 3.7–4311).

Conclusions

Severe dysnatraemias were more prevalent in acutely ill children with underlying medical conditions and were markedly associated with the risk for death.

Postoperative dysnatremia in infants after open-heart surgery occurs frequently and is associated with prolonged intensive care length of stay

BACKGROUND

Dysnatremia after surgery for congenital heart disease (CHD) is well known and has been associated with prolonged pediatric intensive care unit length of stay (PICU-LOS). Fluctuations in plasma sodium levels occur perioperatively. The primary aim of the study was to evaluate the occurrence of dysnatremia during the first 48 h after surgery and whether it was associated with PICU-LOS. The secondary aim was to evaluate if the degree of sodium fluctuations was associated with PICU-LOS.

METHODS

A retrospective observational, single-center study including infants undergoing surgery for CHD. The highest and lowest plasma sodium value was registered for the prespecified time periods. PICU-LOS was analyzed in relation to the occurrence of dysnatremia and the degree of plasma sodium fluctuations. The occurrence of dysnatremia was evaluated in relation to surgical procedure and fluid administration.

RESULTS

Two hundred and thirty infants who underwent 249 surgical procedures were included. Dysnatremia developed in more than 60% within 48 h after surgery. Infants with normonatremia had a 40%-50% shorter PICU-LOS among children in RACHS-1 category 3-6, compared with infants developing either hypo- or hyper-/hyponatremia within 48 h after surgery (p = .006). Infants who had a decline of plasma sodium >11 mmol/L had almost double the PICU-LOS compared to those with a decline of <8 mmol/L.

CONCLUSION

Dysnatremias were common after surgery for CHD and associated with prolonged PICU-LOS. The degree of decline in plasma sodium was significantly associated with PICU-LOS. Fluid administration both in terms of volume and components (blood products and crystalloids) as well as diuresis were related to the occurrence of dysnatremias.

The Differences Between RSV and no RSV Acute Bronchiolitis in Hospitalized Infants: A Cross-Sectional Study

To identify the differences between the RSV and non-RSV bronchiolitis in hospitalized infants in a Greek tertiary pediatric unit and the possible risk factors related to severe forms of the illness. We performed a retrospective cross-sectional data analysis by reviewing medical records of patients that were hospitalized for acute bronchiolitis from 2012 to 2019. The patients with RSV bronchiolitis were found to require antibiotic treatment, IV fluids, adrenaline, and hypertonic saline inhalations more frequently than the non-RSV patients. They also required prolonged hospitalization, especially those that were admitted to PICU, and received oxygen therapy for longer periods. We searched risk factors for severe forms of the disease according to the need for admission to PICU, the supplemental oxygen and the extended length of hospital stay, concurrently. The patients with RSV bronchiolitis developed more severe illness in comparison with patients with bronchiolitis due to other respiratory viruses.

Hyponatremia at the onset of necrotizing enterocolitis is associated with intestinal surgery and higher mortality

It has previously been shown that hyponatremia reflects the severity of inflammation in pediatric gastrointestinal diseases. Interpretation of electrolyte disorders is a common, but not well studied challenge in neonatology, especially in the context of early detection of necrotizing enterocolitis and bowel necrosis. The aim of this study was to assess if hyponatremia, or a decrease in plasma sodium level, at the onset of necrotizing enterocolitis (NEC) is associated with intestinal ischemia/necrosis requiring bowel resection and/or NEC-related deaths. This was a retrospective cohort study including patients with verified NEC (Bell's stage ≥ 2) during the period 2009-2014. Data on plasma sodium 1-3 days before and at the onset of NEC were collected. The exposure was hyponatremia, defined as plasma sodium < 135 mmol/L and a decrease in plasma sodium. Primary outcome was severe NEC, defined as need for intestinal resection due to intestinal ischemia/necrosis and/or NEC-related death within 2 weeks of the onset of NEC. Generalized linear models were applied to analyze the primary outcome and presented as odds ratio. A total of 88 patients with verified NEC were included. Fifty-four (60%) of them had severe NEC. Hyponatremia and a decrease in plasma sodium at onset of NEC were associated with increased odds of severe NEC (OR crude 3.91, 95% CI (1.52-10.04) and 1.19, 95% CI (1.07-1.33), respectively). Also, a sub-analysis, excluding infants with pneumoperitoneum during the NEC episode, showed an increased odds ratio for severe NEC in infants with hyponatremia (OR 23.0, 95% CI (2.78-190.08)).

CONCLUSIONS

The findings of hyponatremia and/or a sudden decrease in plasma sodium at the onset of NEC are associated with intestinal surgery or death within 2 weeks.

WHAT IS KNOWN

• Clinical deterioration, despite optimal medical treatment, is a relative indication for surgery in infants with necrotizing enterocolitis. • Hyponatremia is a common condition in preterm infants from the second week of life.

WHAT IS NEW

• Hyponatremia and a decrease in plasma sodium level at the onset of necrotizing enterocolitis are positively associated with need of surgery or death within 2 weeks. • In infants with necrotizing enterocolitis, without pneumoperitoneum, where clinical deterioration despite optimal medical treatment is the only indication for surgery, hyponatremia, or a decrease in plasma sodium level can predict the severity of the disease.

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.

Respiratory Syncytial Virus-Associated Neurologic Complications in Children: A Systematic Review and Aggregated Case Series

OBJECTIVES

To describe the features and frequency of respiratory syncytial virus (RSV)-associated severe acute neurologic disease in children.

STUDY DESIGN

We performed a systematic review of the literature to identify reports of severe acute neurologic complications associated with acute RSV infection in children aged <15 years (PROSPERO Registration CRD42019125722). Main outcomes included neurologic, clinical, and demographic features of cases and the frequency of disease. We aggregated available case data from the published literature and from the Australian Acute Childhood Encephalitis (ACE) study.

RESULTS

We identified 87 unique studies from 26 countries describing a spectrum of RSV-associated severe acute neurologic syndromes including proven encephalitis, acute encephalopathy, complex seizures, hyponatremic seizures, and immune-mediated disorders. The frequency of RSV infection in acute childhood encephalitis/encephalopathy was 1.2%-6.5%. We aggregated data from 155 individual cases with RSV-associated severe acute neurologic complications; median age was 11.0 months (IQR 2.0-21.5), most were previously healthy (71/104, 68%). Seizure was the most frequently reported neurologic feature (127/150, 85%). RSV was detected in the central nervous system of 12 cases. Most children recovered (81/122, 66%); however, some reports described partial recovery (33/122, 27%) and death (8/122, 7%).

CONCLUSIONS

RSV-associated neurologic complications have been widely reported, but there is substantial heterogeneity in the design and quality of existing studies. The findings from our study have implications for the investigation, management, and prevention of RSV-associated neurologic complications. Further, this systematic review can inform the design of future studies aiming to quantify the burden of childhood RSV-associated neurologic disease.

Nutritional management of young infants presenting with acute bronchiolitis in Belgium, France and Switzerland: survey of current practices and documentary search of national guidelines worldwide

Feeding difficulties are common in young infants presenting with acute bronchiolitis, but limited data is available to guide clinicians adapting nutritional management. We aimed to assess paediatricians' nutritional practices among Western Europe French speaking countries. A survey was disseminated to describe advice given to parents for at home nutritional support, in hospital nutritional management, and preferred methods for enteral nutrition and for intravenous fluid management. A documentary search of international guidelines was concomitantly conducted. Ninety-three (66%) contacted physicians responded. Feeding difficulties were a common indication for infants' admission. Written protocols were rarely available. Enteral nutrition was favoured most of the time when oral nutrition was insufficient and might be withheld in case of severe dyspnoea to decrease respiratory workload. Half of physicians were aware of hyponatremia risk and pathophysiology, and isotonic intravenous solutions were used in less than 15% of centres. International guideline search (23 countries) showed a lack of detailed nutritional management recommendations in most of them.Conclusion: practices were inconsistent among physicians. Guidelines detailed nutritional management poorly. Awareness of hyponatremia risk in relation to intravenous hypotonic fluids and of the safety of enteral hydration and nutrition is insufficient. New guidelines including detailed nutritional management recommendations are urgently needed. What is Known? • Infants presenting with acute bronchiolitis face feeding difficulties. • Underfeeding may promote undernutrition, and intravenous hydration with hypotonic fluids may induce hyponatremia. What is New? • Physicians' nutritional practices are inconsistent and awareness of hyponatremia risk and pathophysiology is insufficient among physicians. • Awareness of hyponatremia risk and pathophysiology is insufficient among physicians. • The reasons for enteral nutrition withholding in bronchiolitis infants are not evidence based, and national guidelines of acute bronchiolitis across the world are elusive regarding nutritional management. • National guidelines of acute bronchiolitis across the world are elusive regarding nutritional management.

Outcomes of Children With Critical Bronchiolitis Meeting at Risk for Pediatric Acute Respiratory Distress Syndrome Criteria

OBJECTIVES

New definitions of pediatric acute respiratory distress syndrome include criteria to identify a subset of children "at risk for pediatric acute respiratory distress syndrome." We hypothesized that, among PICU patients with bronchiolitis not immediately requiring invasive mechanical ventilation, those meeting at risk for pediatric acute respiratory distress syndrome criteria would have worse clinical outcomes, including higher rates of pediatric acute respiratory distress syndrome development.

DESIGN

Single-center, retrospective chart review.

SETTING

Mixed medical-surgical PICU within a tertiary academic children's hospital.

PATIENTS

Children 24 months old or younger admitted to the PICU with a primary diagnosis of bronchiolitis from September 2013 to April 2014. Children intubated before PICU arrival were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Collected data included demographics, respiratory support, oxygen saturation, and chest radiograph interpretation by staff radiologist. Oxygen flow (calculated as FIO2 × flow rate [L/min]) was calculated when oxygen saturation was 88-97%. The median age of 115 subjects was 5 months (2-11 mo). Median PICU length of stay was 2.8 days (1.5-4.8 d), and median hospital length of stay was 5 days (3-10 d). The criteria for at risk for pediatric acute respiratory distress syndrome was met in 47 of 115 subjects (40.9%). Children who were at risk for pediatric acute respiratory distress syndrome were more likely to develop pediatric acute respiratory distress syndrome (15/47 [31.9%] vs 1/68 [1.5%]; p < 0.001), had longer PICU length of stay (4.6 d [2.8-10.2 d] vs 1.9 d [1.0-3.1 d]; p < 0.001) and hospital length of stay (8 d [5-16 d] vs 4 d [2-6 d]; p < 0.001), and increased need for invasive mechanical ventilation (16/47 [34.0%] vs 2/68 [2.9%]; p < 0.001), compared with those children who did not meet at risk for pediatric acute respiratory distress syndrome criteria.

CONCLUSIONS

Our data suggest that the recent definition of at risk for pediatric acute respiratory distress syndrome can successfully identify children with critical bronchiolitis who have relatively unfavorable clinical courses.

Hyponatremia in infants with new onset moderate-severe bronchiolitis: A cross-sectional study

BACKGROUND

The reported cumulative prevalence of hyponatremia (sodium <135 mmol/L) in bronchiolitis is 28%. However, sodium level was never measured by direct potentiometry, the method recommended by the International Federation of Clinical Chemistry and Laboratory Medicine. Aim of this study was to assess the prevalence of hyponatremia, measured by direct potentiometry, in infants with moderate-severe bronchiolitis.

METHODS

A prospective cross-sectional study was conducted in infants ≥1month and ≤24months of age with bronchiolitis.

RESULTS

160 consecutive infants were enrolled. Hyponatremia was observed in 91 (57%) patients and occurred more commonly in infants ≤6 months than in older infant (P < 0.005).

CONCLUSION

The first study on sodium level measured by the direct potentiometry in infants with bronchiolitis points out that the prevalence of hyponatremia is two-fold higher than so far reported.

Hyponatremia and Hypotonic Intravenous Fluids Are Associated With Unfavorable Outcomes of Bronchiolitis Admissions

OBJECTIVES

Hyponatremia has been associated with unfavorable outcomes when present at admission in children with bronchiolitis. Delayed hyponatremia may be a modifiable risk factor for severe disease that is influenced by intravenous fluid (IVF) tonicity. We hypothesized that both hyponatremia and prescription of severely hypotonic IVF are associated with unfavorable outcomes, and that prescription of severely hypotonic IVF is associated with subsequent hyponatremia.

METHODS

Data were retrospectively extracted for 1557 pediatric inpatients with bronchiolitis. Any day on which a subject was prescribed IVF with sodium <70 mEq/L was termed "IVF <70." All other days on which IVF was prescribed were termed "IVF ≥70." Any blood sodium ≤135 mEq/L defined hyponatremia for that day. All other days with sodium available were labeled normonatremia. Variables were compared with Spearman correlation, Wilcoxon rank test, or χ². Significant results had P < .05.

RESULTS

Blood sodium levels correlated negatively with hospital length of stay (r = -0.477, P < .0001). On each of the first 4 days of hospitalization, significantly increased hospital length of stay was observed in patients with hyponatremia (n = 134 [25.7% of subjects with available sodium data]) versus patients with normonatremia (n = 387 [74.3%]), and in patients prescribed IVF <70 (n = 348 [46.3% of subjects prescribed IVF]) versus patients prescribed IVF ≥70 (n = 403 [53.7%]). Patients prescribed IVF <70 had increased rates of hyponatremia on the subsequent day versus patients prescribed IVF ≥70 (50.0% vs 26.9%, P < .001).

CONCLUSIONS

In children hospitalized with bronchiolitis, hyponatremia may be a modifiable risk factor for severe disease that may be mitigated by avoiding use of severely hypotonic IVF.

Association of nasopharyngeal microbiota profiles with bronchiolitis severity in infants hospitalised for bronchiolitis

Little is known about the relationship between the specific airway microbiota composition and severity of bronchiolitis. We aimed to identify nasopharyngeal microbiota profiles and link these profiles to acute severity in infants hospitalised for bronchiolitis.We conducted a multicentre prospective cohort study of 1005 infants (age <1 year) hospitalised for bronchiolitis over three winters, 2011-2014. By applying a 16S rRNA gene sequence and clustering approach to the nasopharyngeal aspirates collected within 24 h of hospitalisation, we determined nasopharyngeal microbiota profiles and their association with bronchiolitis severity. The primary outcome was intensive care use, i.e. admission to an intensive care unit or use of mechanical ventilation.We identified four nasopharyngeal microbiota profiles: three profiles were dominated by one of Haemophilus, Moraxella or Streptococcus, while the fourth profile had the highest bacterial richness. The rate of intensive care use was highest in infants with a Haemophilus-dominant profile and lowest in those with a Moraxella-dominant profile (20.2% versus 12.3%; unadjusted OR 1.81, 95% CI 1.07-3.11, p=0.03). After adjusting for 11 patient-level confounders, the rate remained significantly higher in infants with Haemophilus-dominant profiles (OR 1.98, 95% CI 1.08-3.62, p=0.03). These findings were externally validated in a separate cohort of 307 children hospitalised for bronchiolitis.