Nasopharyngeal microbiota in children is associated with severe asthma exacerbations.

BACKGROUND: The respiratory microbiome has been associated with the etiology and disease course of asthma. OBJECTIVE: We sought to assess the nasopharyngeal microbiota in children with a severe asthma exacerbation and their associations with medication, air quality, and viral infection. METHODS: A cross-sectional study was performed among children aged 2 to 18 years admitted to the medium care unit (MCU; n = 84) or intensive care unit (ICU; n = 78) with an asthma exacerbation. For case-control analyses, we matched all cases aged 2 to 6 years (n = 87) to controls in a 1:2 ratio. Controls were participants of either a prospective case-control study or a longitudinal birth cohort (n = 182). The nasopharyngeal microbiota was characterized by 16S-rRNA-gene sequencing. RESULTS: Cases showed higher Shannon diversity index (ICU and MCU combined; P = .002) and a distinct microbial community composition when compared with controls (permutational multivariate ANOVA R2 = 1.9%; P < .001). We observed significantly higher abundance of Staphylococcus and "oral" taxa, including Neisseria, Veillonella, and Streptococcus spp. and a lower abundance of Dolosigranulum pigrum, Corynebacterium, and Moraxella spp. (MaAsLin2; q < 0.25) in cases versus controls. Furthermore, Neisseria abundance was associated with more severe disease (ICU vs MCU MaAslin2, P = .03; q = 0.30). Neisseria spp. abundance was also related with fine particulate matter exposure, whereas Haemophilus and Streptococcus abundances were related with recent inhaled corticosteroid use. We observed no correlations with viral infection. CONCLUSIONS: Our results demonstrate that children admitted with asthma exacerbations harbor a microbiome characterized by overgrowth of Staphylococcus and "oral" microbes and an underrepresentation of beneficial niche-appropriate commensals. Several of these associations may be explained by (environmental or medical) exposures, although cause-consequence relationships remain unclear and require further investigations.

Efficacy of a loading dose of IV salbutamol in children with severe acute asthma admitted to a PICU: a randomized controlled trial.

The optimal dose regimen for intravenous (IV) treatment in children with severe acute asthma (SAA) is still a matter of debate. We assessed the efficacy of adding a salbutamol loading dose to continuous infusion with salbutamol in children admitted to a pediatric intensive care unit (PICU) with SAA. This multicentre, placebo-controlled randomized trial in the PICUs of four tertiary care children's hospitals included children (2-18 years) with SAA admitted between 2017 and 2019. Children were randomized to receive either a loading dose IV salbutamol (15 mcg/kg, max. 750 mcg) or normal saline while on continuous salbutamol infusion. The primary outcome was the asthma score (Qureshi) 1 h after the intervention. Analysis of covariance models was used to evaluate sensitivity to change in asthma scores. Serum concentrations of salbutamol were obtained. Fifty-eight children were included (29 in the intervention group). Median baseline asthma score was 12 (IQR 10-13) in the intervention group and 11 (9-12) in the control group (p = 0.032). The asthma score 1 h after the intervention did not differ significantly between the groups (p = 0.508, ß-coefficient = 0.283). The median increase in salbutamol plasma levels 10 min after the intervention was 13 µg/L (IQR 5-24) in the intervention group and 4 µg/L (IQR 0-7) in the control group (p = 0.001). Side effects were comparable between both groups. CONCLUSION: We found no clinical benefit of adding a loading dose IV salbutamol to continuous infusion of salbutamol, in children admitted to the PICU with SAA. Clinically significant side effects from the loading dose were not encountered. WHAT IS KNOWN: • Pediatric asthma guidelines struggle with an evidence-based approach for the treatment of SAA beyond the initial steps of oxygen suppletion, repetitive administration of inhaled ß2-agonists, and systemic steroids. • During an SAA episode, effective delivery of inhaled drugs is unpredictable due to severe airway obstruction. WHAT IS NEW: • This study found no beneficial effect of an additional loading dose IV salbutamol in children admitted to the PICU. • This study found no clinically significant side effects from the loading dose.

It Is Not Just the FEV1 That Matters, but the Personal Goals We Reach Along the Way: Qualitative, Multicenter, Prospective, Observational Study.

BACKGROUND: The COVID-19 pandemic has boosted the use of forced expiratory volume in 1 second (FEV1) telemonitoring in pediatric asthma, but a consensus on its most efficient and effective implementation is still lacking. To find answers, it is important to study how such an intervention is perceived, experienced, and used by both patients and health care professionals (HCPs). OBJECTIVE: The aim of this study was to provide perspectives on how FEV1 home monitoring should be used in pediatric asthma. METHODS: This is a qualitative, multicenter, prospective, observational study which included patients with asthma aged 6-16 and HCPs. Primary outcomes were results of 2 surveys that were sent to all participants at study start and after 3-4 months. Secondary outcomes consisted of FEV1 device usage during 4 months after receiving the FEV1 device. RESULTS: A total of 39 participants (26 patients and 13 HCPs) were included in this study. Survey response rates were 97% (38/39) at the start and 87% (34/39) at the end of the study. Both patients and HCPs were receptive toward online FEV1 home monitoring and found it contributive to asthma control, self-management, and disease perception. The main concerns were about reliability of the FEV1 device and validity of home-performed lung function maneuvers. FEV1 devices were used with a median frequency of 7.5 (IQR 3.3-25.5) during the 4-month study period. CONCLUSIONS: Patients and HCPs are receptive toward online FEV1 home monitoring. Frequency of measurements varied largely among individuals, yet perceived benefits remained similar. This emphasizes that online FEV1 home monitoring strategies should be used as a means to reach individual goals, rather than being a goal on their own.

A virtual asthma clinic for children: fewer routine outpatient visits, same asthma control.

eHealth is an appealing medium to improve healthcare and its value (in addition to standard care) has been assessed in previous studies. We aimed to assess whether an eHealth intervention could improve asthma control while reducing 50% of routine outpatient visits.In a multicentre, randomised controlled trial with a 16-month follow-up, asthmatic children (6-16 years) treated in eight Dutch hospitals were randomised to usual care (4-monthly outpatient visits) and online care using a virtual asthma clinic (VAC) (8-monthly outpatient visits with monthly web-based monitoring). Outcome measures were the number of symptom-free days in the last 4 weeks of the study, asthma control, forced expiratory volume in 1 s, exhaled nitric oxide fraction, asthma exacerbations, unscheduled outpatient visits, hospital admissions, daily dose of inhaled corticosteroids and courses of systemic corticosteroids.We included 210 children. After follow-up, symptom-free days differed statistically between the usual care and VAC groups (difference of 1.23 days, 95% CI 0.42-2.04; p=0.003) in favour of the VAC. In terms of asthma control, the Childhood Asthma Control Test improved more in the VAC group (difference of 1.17 points, 95% CI 0.09-2.25; p=0.03). No differences were found for other outcome measures.Routine outpatient visits can partly be replaced by monitoring asthmatic children via eHealth.

The effect of 3% and 6% hypertonic saline in viral bronchiolitis: a randomised controlled trial.

Bronchiolitis is a common disorder in young children that often results in hospitalisation. Except for a possible effect of nebulised hypertonic saline (sodium chloride), no evidence-based therapy is available. This study investigated the efficacy of nebulised 3% and 6% hypertonic saline compared with 0.9% hypertonic saline in children hospitalised with viral bronchiolitis. In this multicentre, double-blind, randomised, controlled trial, children hospitalised with acute viral bronchiolitis were randomised to receive either nebulised 3%, 6% hypertonic saline or 0.9% normal saline during their entire hospital stay. Salbutamol was added to counteract possible bronchial constriction. The primary endpoint was the length of hospital stay. Secondary outcomes were need for supplemental oxygen and tube feeding. From the 292 children included in the study (median age 3.4 months), 247 completed the study. The median length of hospital stay did not differ between the groups: 69 h (interquartile range 57), 70 h (IQR 69) and 53 h (IQR 52), for 3% (n=84) and 6% (n=83) hypertonic saline and 0.9% (n=80) normal saline, respectively, (p=0.29). The need for supplemental oxygen or tube feeding did not differ significantly. Adverse effects were similar in the three groups. Nebulisation with hypertonic saline (3% or 6% sodium chloride) although safe, did not reduce the length of stay in hospital, duration of supplemental oxygen or tube feeding in children hospitalised with moderate-to-severe viral bronchiolitis.

Oxygen saturation targets for children with respiratory distress: a systematic review.

Background: In children with respiratory distress, supplemental oxygen is indicated at peripheral oxygen saturation (SpO2) thresholds of 90-94%. However, these thresholds are poorly studied. We conducted a systematic review to summarise the existing evidence for SpO2 thresholds in children with respiratory distress. Methods: Electronic databases and registries were searched for original articles published from 1 January 2010 to 7 January 2022 comparing two or more SpO2 thresholds in children with respiratory distress. Primary outcomes were safety, including mortality, neurocognitive outcomes and readmissions, and effectiveness, including admission rate and length of hospital stay. Methodological appraisal was performed using the Cochrane Risk of Bias 2 (RoB-2) or Risk of Bias in Non-Randomized Studies - of Interventions (ROBINS-I) tools. Results were narratively synthesised. Results: We retrieved 3384 results; seven studies were included. Lower thresholds ranged from 80% to 92% and were compared with higher thresholds ranging from 92% to 94%. Studies were highly heterogeneous in setting, design, population and outcomes. Risk of bias varied from low to high. Lower SpO2 thresholds had equivalent mortality, neurocognitive outcomes and readmissions or re-attendance to healthcare to higher thresholds. Lower SpO2 thresholds showed a significant decrease in admission rates by up to 40% and shortened hospitalisation duration by 10-18 h. Conclusions: The current SpO2 thresholds of 90-94% in children with respiratory distress may be too high, which could lead to unnecessary hospitalisations and prolonged hospitalisation duration. SpO2 thresholds as low as 88% are potentially safe in children with respiratory distress and may reduce hospitalisation rates and length of stay. However, high-quality evidence is needed to support this.

Risk factors for pediatric intensive care admission in children with acute asthma.

INTRODUCTION: Severe acute asthma in children is associated with substantial morbidity and may require pediatric ICU (PICU) admission. The aim of the study was to determine risk factors for PICU admission. METHODS: The study used a retrospective multicenter case-control design. The cases included children admitted to the PICU because of severe acute asthma and a history of out-patient treatment by pediatricians or pediatric pulmonologists. Controls were children with asthma without a PICU admission for severe acute asthma. The children were matched for sex, age, hospital, and time elapsed since the diagnosis of asthma. Fourteen possible risk factors were analyzed. RESULTS: Sixty-six cases were matched to 164 controls. In univariate analysis, all but one of the analyzed variables were significantly associated with PICU-hospitalization. After multivariate conditional logistic regression analysis, 4 risk factors remained significant. These included active or passive smoking, allergies, earlier hospitalization for asthma, and non-sanitized home. CONCLUSIONS: Physicians and parents should be aware of these risk factors, and efforts should be made to counteract them.

Paediatric asthma: everything that seemed to be certain no longer is.

'Paediatric asthma: everything that seemed to be certain no longer is', holds the promise of leaving you with more questions than answers at the end of this review of paediatric asthma 2008-2009. This has often been true for asthma research, in particular over the past few years. Research with direct consequences for a clinician managing children with wheezing or asthma is discussed such as limitations in the characterisation of asthma phenotypes and the influence of early viral infections on asthma and the development of atopic sensitisation. It appears that wheezing in preschool children with specific viral pathogens confers differential rates of asthma risk. Viruses and day-care shift respiratory morbidity to an early age when it is more troublesome than at a later age but are not protective for sensitisation or asthma. What needs to be further explored is the relationship between viruses and recurrent wheeze or asthma in studies with stringently defined phenotypes including personal atopic status, timing of infection, and severity of infection. A modification of preschool wheeze phenotypes or replacement by other phenotypes that have been defined with the application of different methods is needed. Oral corticosteroids should not be prescribed in preschool children with acute mild to moderate viral wheeze, unless a severe outcome is anticipated or if the child has a classic atopic phenotype. Despite initial high expectations, FeNO was proven not to be beneficial for routine monitoring of asthma treatment.

Quality of life and psychosocial outcomes in children with severe acute asthma and their parents.

OBJECTIVES: To prospectively evaluate quality of life (QoL) and psychosocial outcomes in children with severe acute asthma (SAA) after pediatric intensive care (PICU) admission compared to children with SAA who were admitted to a general ward (GW). In addition, we assessed post-traumatic stress (PTS) and asthma-related QoL in the parents. METHODS: A preplanned follow-up of 3-9 months of our nationwide prospective multicenter study, in which children with SAA admitted to a Dutch PICU (n=110) or GW (n=111) were enrolled between 2016-2018. Asthma-related QoL, PTS symptoms, emotional and behavioral problems, and social impact in children and/or parents were assessed with validated web-based questionnaires. RESULTS: We included 100 children after PICU and 103 after GW admission, with a response rate of 50% for the questionnaires. Median time to follow-up was 5 months (range 1-12 months). Time to reach full schooldays after admission was significantly longer in the PICU group (mean of 10 vs 4 days, p=0.001). Parents in the PICU group reported more PTS symptoms (intrusion p=0.01, avoidance p=0.01, arousal p=0.02) compared to the GW group. CONCLUSION: No significant differences were found between PICU and GW children on self-reported outcome domains, except for the time to reach full schooldays. PICU parents reported PTS symptoms more often than the GW group. Therefore, monitoring asthma symptoms and psychosocial screening of children and parents after PICU admission should both be part of standard care after SAA. This should identify those who are at risk for developing PTSD, in order to timely provide appropriate interventions. This article is protected by copyright. All rights reserved.

Population Pharmacokinetics of Intravenous Salbutamol in Children with Refractory Status Asthmaticus.

BACKGROUND: Intravenous salbutamol is used to treat children with refractory status asthmaticus, however insufficient pharmacokinetic data are available to guide initial and subsequent dosing recommendations for its intravenous use. The pharmacologic activity of salbutamol resides predominantly in the (R)-enantiomer, with little or no activity and even concerns of adverse reactions attributed to the (S)-enantiomer. OBJECTIVE: Our aim was to develop a population pharmacokinetic model to characterize the pharmacokinetic profile for intravenous salbutamol in children with status asthmaticus admitted to the pediatric intensive care unit (PICU), and to use this model to study the effect of different dosing schemes with and without a loading dose. METHODS: From 19 children (median age 4.9 years [range 9 months-15.3 years], median weight 18 kg [range 7.8-70 kg]) treated with continuous intravenous salbutamol at the PICU, plasma samples for R- and S-salbutamol concentrations (111 samples), as well as asthma scores, were collected prospectively at the same time points. Possible adverse reactions and patients' clinical data (age, sex, weight, drug doses, liver and kidney function) were recorded. With these data, a population pharmacokinetic model was developed using NONMEM 7.2. After validation, the model was used for simulations to evaluate the effect of different dosing regimens with or without a loading dose. RESULTS: A two-compartment model with separate clearance for R- and S-salbutamol (16.3 L/h and 8.8 L/h, respectively) best described the data. Weight was found to be a significant covariate for clearance and volume of distribution. No other covariates were identified. Simulations showed that a loading dose can result in higher R-salbutamol concentrations in the early phase after the start of infusion therapy, preventing accumulation of S-salbutamol. CONCLUSIONS: The pharmacokinetic model of intravenous R- and S-salbutamol described the data well and showed that a loading dose should be considered in children. This model can be used to evaluate the pharmacokinetic-pharmacodynamic relationship of intravenous salbutamol in children, and, as a next step, the effectiveness and tolerability of intravenous salbutamol in children with severe asthma.

Risk factors for intensive care admission in children with severe acute asthma in the Netherlands: a prospective multicentre study.

RATIONALE: Severe acute asthma (SAA) can be fatal, but is often preventable. We previously observed in a retrospective cohort study, a three-fold increase in SAA paediatric intensive care (PICU) admissions between 2003 and 2013 in the Netherlands, with a significant increase during those years of numbers of children without treatment of inhaled corticosteroids (ICS). OBJECTIVES: To determine whether steroid-naïve children are at higher risk of PICU admission among those hospitalised for SAA. Furthermore, we included the secondary risk factors tobacco smoke exposure, allergic sensitisation, previous admissions and viral infections. METHODS: A prospective, nationwide multicentre study of children with SAA (2-18 years) admitted to all Dutch PICUs and four general wards between 2016 and 2018. Potential risk factors for PICU admission were assessed using logistic regression analyses. MEASUREMENTS AND MAIN RESULTS: 110 PICU and 111 general ward patients were included. The proportion of steroid-naïve children did not differ significantly between PICU and ward patients. PICU children were significantly older and more exposed to tobacco smoke, with symptoms >1 week prior to admission. Viral susceptibility was not a significant risk factor for PICU admission. CONCLUSIONS: Children with SAA admitted to a PICU were comparable to those admitted to a general ward with respect to ICS treatment prior to admission. Preventable risk factors for PICU admission were >7 days of symptoms without adjustment of therapy and exposure to tobacco smoke. Physicians who treat children with asthma must be aware of these risk factors.

A Loading Dose of IV Salbutamol in an Adolescent with Severe Acute Asthma and Cardiac Arrest.

Severe acute asthma (SAA) can lead to respiratory failure and can be fatal. For rational use of intravenous (IV) bronchodilators, evidence regarding the pharmacokinetics and pharmacodynamics is lacking in children. The use of a loading dose IV salbutamol is not mentioned in any international guideline, and its use varies greatly between PICUs worldwide. We describe a 17-year-old Caucasian female with SAA resulting in an out-of-hospital cardiac arrest. After basic life support and return of spontaneous circulation, the ambulance administered oxygen, inhaled salbutamol, IV magnesium sulphate, and systemic corticosteroids. Despite of this, she was still in severe respiratory distress. Therefore, a loading dose of IV salbutamol was administered, after which an immediate improvement was observed. Having a loading dose of IV salbutamol available for emergency medical services use for SAA in children with life-threatening SAA in the out-of-hospital setting is important to consider. Further study on the dose and the effect of a loading dose IV salbutamol in children with SAA is necessary.

Episodic viral wheeze and multiple-trigger wheeze in preschool children are neither distinct nor constant patterns. A prospective multicenter cohort study in secondary care.

OBJECTIVES: To evaluate whether episodic viral wheeze (EVW) and multiple-trigger wheeze (MTW) are clinically distinguishable and stable preschool wheezing phenotypes. METHODS: Children of age 1 to 4 year with recurrent, pediatrician-confirmed wheeze were recruited from secondary care; 189 were included. Respiratory and viral upper respiratory tract infection (URTI) symptoms were recorded weekly by parents in an electronic diary during 12 months. Every 3 months, diary-based symptoms were classified as EVW or MTW and compared to phenotypes assigned by pediatricians based on clinical history. We collected nasal samples for respiratory virus PCR during URTI, respiratory symptoms and in absence of symptoms. RESULTS: Of 660 3-month periods, the diary-based phenotype was EVW in 11%, MTW in 54% and 35% were free from respiratory episodes. Pediatrician-based classification showed 59% EVW and 26% MTW. The Kappa measure of agreement between diary-based and pediatrician-assigned phenotypes was very low (0.12, 95%CI, 0.07-0.17). Phenotypic instability was observed in 32% of cases. PCR was positive in 71% during URTI symptoms, 66% during respiratory symptoms and 38% in the absence of symptoms. CONCLUSION: This study shows that EVW and MTW are variable over time within patients. Pediatrician classification of these phenotypes based on clinical history does not correspond to prospectively recorded symptom patterns. The applicability of these phenotypes as a basis for therapeutic decisions and prognosis should be questioned.

Children with severe acute asthma admitted to Dutch PICUs: A changing landscape.

The number of children requiring pediatric intensive care unit (PICU) admission for severe acute asthma (SAA) around the world has increased. OBJECTIVES: We investigated whether this trend in SAA PICU admissions is present in the Netherlands. METHODS: A multicenter retrospective cohort study across all tertiary care PICUs in the Netherlands. Inclusion criteria were children (2-18 years) hospitalized for SAA between 2003 and 2013. Data included demographic data, asthma diagnosis, treatment, and mortality. RESULTS: In the 11-year study period 590 children (660 admissions) were admitted to a PICU with a threefold increase in the number of admissions per year over time. The severity of SAA seemed unchanged, based on the first blood gas, length of stay and mortality rate (0.6%). More children received highflow nasal cannula (P < 0.001) and fewer children needed invasive ventilation (P < 0.001). In 58% of the patients the maximal intravenous (IV) salbutamol infusion rate during PICU admission was 1 mcg/kg/min. However, the number of patients treated with IV salbutamol in the referring hospitals increased significantly over time (P = 0.005). The proportion of steroid-naïve patients increased from 35% to 54% (P = 0.004), with a significant increase in both age groups (2-4 years [P = 0.026] and 5-17 years [P = 0.036]). CONCLUSIONS: The number of children requiring PICU admission for SAA in the Netherlands has increased. We speculate that this threefold increase is explained by an increasing number of steroid-naïve children, in conjunction with a lowered threshold for PICU admission, possibly caused by earlier use of salbutamol IV in the referring hospitals.

Differential inhibition of 17alpha-hydroxylase and 17,20-lyase activities by three novel missense CYP17 mutations identified in patients with P450c17 deficiency.

The microsomal enzyme cytochrome P450c17 is an important regulator of steroidogenesis. The enzyme has two functions: 17alpha-hydroxylase and 17,20-lyase activities. These functions determine the ability of adrenal glands and gonads to synthesize 17alpha-hydroxylated glucocorticoids (17alpha-hydroxylase activity) and/or sex steroids (17,20-lyase activity). Both enzyme functions depend on correct steroid binding, but it was recently shown that isolated lyase deficiency can also be caused by mutations located in the redox partner interaction domain. In this article we present the clinical history and molecular analysis of two patients with combined 17alpha-hydroxylase/17,20-lyase deficiency and four patients with isolated 17,20-lyase deficiency. In these six patients, four missense CYP17 mutations were identified. Two mutations were located in the steroid-binding domain (F114V and D116V), and the other two mutations were found in the redox partner interaction domain (R347C and R347H). We investigated the activity of these mutated proteins by transfection experiments in COS-1 cells using pregnenolone, progesterone, or their hydroxylated products as a substrate and measuring 17alpha-hydroxylase- and 17,20-lyase-dependent metabolites in the medium. The mutations in the steroid-binding domain (F114V and D116V) of P450c17 caused combined, complete (F114V), or partial (D116V) 17alpha-hydroxylase and 17,20-lyase deficiencies, whereas mutations in the redox partner interaction domain (R347C and R347H) displayed less severe 17alpha-hydroxylase deficiency, but complete 17,20-lyase deficiency. These findings are consistent with the clinical data and support the observation that the redox partner interaction domain is essential for normal 17,20-lyase function of P450c17.

Asthma therapy for children under 5 years of age.

PURPOSE OF REVIEW: The evidence for effectiveness of currently used asthma medication for wheeze in young children is reviewed. RECENT FINDINGS: The management of the infant and preschool child with wheezing is complicated by the uncertainty with respect to the aetiology. Difficulties in defining phenotypes and objective outcome parameters combined with the transient nature of symptoms which often resolve spontaneously have confounded many therapeutic studies. Recent studies on the effect of pharmacotherapy in wheezing infants have tried to define a more homogeneous phenotype as well as make a selection of patients that are likely to respond to the studied drug. In addition, these studies have used lung function parameters and nitric oxide as one of the outcome measurements. Studies on the nature of inflammation and the development of airway remodelling in infants and young children are done to further define phenotypes. SUMMARY: Currently, there are no evidence-based guidelines and not even consensus statements on the right approach in pharmacological treatment of wheezing in infants and preschool children. The main issue still is the difficulty in coming to a correct diagnosis. Further studies are needed on the nature and the diagnostics of phenotypes and on the effect of early intervention.