Analysis of mandibular jaw movements to assess ventilatory support management of children with obstructive sleep apnea syndrome treated with positive airway pressure therapies

BACKGROUND

The polysomnography (PSG) is the gold-standard for obstructive sleep apnea (OSA) syndrome diagnosis and assessment under positive airway pressure (PAP) therapies in children. Recently, an innovative digital medicine solution, including a mandibular jaw movement (MJM) sensor coupled with automated analysis, has been validated as an alternative to PSG for pediatric application.

OBJECTIVE

This study aimed to assess the reliability of MJM automated analysis for the assessment of residual apnea/hypopnea events during sleep in children with OSA treated with noninvasive ventilation (NIV) or continuous PAP (CPAP).

METHODS

In this open-label prospective non-randomized multicentric trial, we included children aged from 5 to 18 years with a diagnosis of severe OSA. The children underwent in-laboratory PSG with simultaneous MJM monitoring and at-home recording with MJM monitoring 3 months later. Agreement between PSG and MJM analysis in measuring the residual apnea-hypopnea index (AHI) was evaluated by the Bland-Altman method. The treatment effect on residual AHI was estimated for both PSG and MJM analysis.

RESULTS

Fifteen (60% males) children were included with a median age of 12 years [interquartile range 8-15]. Two (17%) were ventilated with NIV and 13 (83%) with CPAP. There was a good agreement between MJM-AHI and PSG-AHI with a median bias of -0.25 (95% CI: -3.40 to +2.04) events/h. The reduction in AHI under treatment was consistently significant across the three measurement methods: in-laboratory PSG and MJM recordings in the laboratory and at home.

CONCLUSION

Automated analysis of MJM is a highly reliable alternative method to assess residual events in a small population treated with PAP therapies.

ERS International Congress 2023: highlights from the Paediatrics Assembly

Respiratory health in children is essential for general wellbeing and healthy development in the short and long term. It is well known that many respiratory diseases in adulthood have their origins in early life, and therefore research on prevention of respiratory diseases and management of children with respiratory diseases will benefit patients during the full life course. Scientific and clinical advances in the field of respiratory health are moving at a fast pace. This article summarises some of the highlights in paediatric respiratory medicine presented at the hybrid European Respiratory Society (ERS) International Congress 2023 which took place in Milan (Italy). Selected sessions are summarised by Early Career Members of the Paediatrics Assembly (Assembly 7) under the supervision of senior ERS officers, and cover a wide range of research areas in children, including respiratory physiology and sleep, asthma and allergy, cystic fibrosis, respiratory infection and immunology, neonatology and intensive care, respiratory epidemiology and bronchology.

A BEAT-PCD consensus statement: a core outcome set for pulmonary disease interventions in primary ciliary dyskinesia

Background

Consistent use of reliable and clinically appropriate outcome measures is a priority for clinical trials, with clear definitions to allow comparability. We aimed to develop a core outcome set (COS) for pulmonary disease interventions in primary ciliary dyskinesia (PCD).

Methods

A multidisciplinary international PCD expert panel was set up. A list of outcomes was created based on published literature. Using a modified three-round e-Delphi technique, the panel was asked to decide on relevant end-points related to pulmonary disease interventions and how they should be reported. First, inclusion of an outcome in the COS was determined. Second, the minimum information that should be reported per outcome. The third round finalised statements. Consensus was defined as ≥80% agreement among experts.

Results

During the first round, experts reached consensus on four out of 24 outcomes to be included in the COS. Five additional outcomes were discussed in subsequent rounds for their use in different subsettings. Consensus on standardised methods of reporting for the COS was reached. Spirometry, health-related quality-of-life scores, microbiology and exacerbations were included in the final COS.

Conclusion

This expert consensus resulted in a COS for clinical trials on pulmonary health among people with PCD.

Bronchodilator response by interrupter technique to guide management of preschool wheeze

OBJECTIVE

We examined relationships between clinical features and pulmonary function before and after inhaled corticosteroid (ICS) treatment in wheezy preschool children, and specifically, whether measuring bronchodilator response (BDR) could predict benefit from ICS.

DESIGN

Clinical non-randomised intervention study SETTING: Secondary care.

PATIENTS

Preschool children (2 years to <6 years) with recurrent wheeze.

INTERVENTIONS

Inhaled beta-agonist, ICS.

OUTCOME MEASURES

We measured prebronchodilator and postbronchodilator interrupter resistance (Rint) and symptom scores at 0 (V1), 4 (V2) and 12 (V3) weeks. At V2, those with a predetermined symptom level commenced ICS. Modified Asthma Predictive Index (mAPI) and parental perception of response to bronchodilator were recorded. Response to ICS was defined as a reduction in daily symptom score of >0.26. Positive BDR was defined as fall in Rint of ≥0.26 kPa.s/L, ≥35% predicted or ≥1.25 Z Scores.

RESULTS

Out of 138 recruited children, 67 completed the full study. Mean (SD) prebronchodilator Rint at V2 was 1.22 (0.35) kPa.s/L, and fell after starting ICS (V3) to 1.09 (0.33) kPa.s/L (p<0.001), while mean (SD) daily symptom score fell from 0.56 (0.36) to 0.28 (0.36) after ICS (p<0.001). Positive Rint BDR before ICS (at V1 and/or V2), using all three threshold criteria, was significantly associated with response to ICS on symptom scores at V3 (p<0.05). mAPI was not significantly associated with response to ICS, and parents' perception of response to bronchodilator was not related to measured Rint BDR .

CONCLUSIONS

Rint BDR may be helpful in selecting which wheezy preschool children are likely to benefit from ICS.

Digital Action Plan (Web App) for Managing Asthma Exacerbations: Randomized Controlled Trial

BACKGROUND

A written action plan (WAP) for managing asthma exacerbations is recommended.

OBJECTIVE

We aimed to compare the effect on unscheduled medical contacts (UMCs) of a digital action plan (DAP) accessed via a smartphone web app combined with a WAP on paper versus that of the same WAP alone.

METHODS

This randomized, unblinded, multicenter (offline recruitment in private offices and public hospitals), and parallel-group trial included children (aged 6-12 years) or adults (aged 18-60 years) with asthma who had experienced at least 1 severe exacerbation in the previous year. They were randomized to a WAP or DAP+WAP group in a 1:1 ratio. The DAP (fully automated) provided treatment advice according to the severity and previous pharmacotherapy of the exacerbation. The DAP was an algorithm that recorded 3 to 9 clinical descriptors. In the app, the participant first assessed the severity of their current symptoms on a 10-point scale and then entered the symptom descriptors. Before the trial, the wordings and ordering of these descriptors were validated by 50 parents of children with asthma and 50 adults with asthma; the app was not modified during the trial. Participants were interviewed at 3, 6, 9, and 12 months to record exacerbations, UMCs, and WAP and DAP use, including the subjective evaluation (availability and usefulness) of the action plans, by a research nurse.

RESULTS

Overall, 280 participants were randomized, of whom 33 (11.8%) were excluded because of the absence of follow-up data after randomization, leaving 247 (88.2%) participants (children: n=93, 37.7%; adults: n=154, 62.3%). The WAP group had 49.8% (123/247) of participants (children: n=45, 36.6%; mean age 8.3, SD 2.0 years; adults: n=78, 63.4%; mean age 36.3, SD 12.7 years), and the DAP+WAP group had 50.2% (124/247) of participants (children: n=48, 38.7%; mean age 9.0, SD 1.9 years; adults: n=76, 61.3%; mean age 34.5, SD 11.3 years). Overall, the annual severe exacerbation rate was 0.53 and not different between the 2 groups of participants. The mean number of UMCs per year was 0.31 (SD 0.62) in the WAP group and 0.37 (SD 0.82) in the DAP+WAP group (mean difference 0.06, 95% CI -0.12 to 0.24; P=.82). Use per patient with at least 1 moderate or severe exacerbation was higher for the WAP (33/65, 51% vs 15/63, 24% for the DAP; P=.002). Thus, participants were more likely to use the WAP than the DAP despite the nonsignificant difference between the action plans in the subjective evaluation. Median symptom severity of the self-evaluated exacerbation was 4 out of 10 and not significantly different from the symptom severity assessed by the app.

CONCLUSIONS

The DAP was used less often than the WAP and did not decrease the number of UMCs compared with the WAP alone.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02869958; https://clinicaltrials.gov/ct2/show/NCT02869958.

Respiratory function and sleep in children with myotonic dystrophy type 1

Myotonic dystrophy type 1 (DM1) is a rare neuromuscular disease in children causing sleep and respiratory disorders that are poorly described in the literature compared to adult forms. This retrospective observational study was performed at the Armand Trousseau University Hospital, Assistance Publique-Hôpitaux de Paris (APHP), Paris, France. We retrospectively collected data from lung function tests, nocturnal gas exchange recordings, and polysomnography of 24 children with DM1. 39% of the children with DM1 reported respiratory symptoms indicative of sleep disordered breathing. Three patients (12%) presented with a restrictive respiratory pattern, 10 (42%) with a sleep apnoea syndrome, mainly of obstructive origin (2/10 with severe obstructive sleep apnea syndrome), and 11 (45%) with nocturnal alveolar hypoventilation. Non-invasive ventilation (NIV) was indicated in 9 (37.5%) children, although tolerance was poor. No significant deterioration in respiratory function or nocturnal gas exchange was observed during the NIV-free period. This study provides new and useful insights into DM1 disease evolution in children to better adapt for respiratory follow-up and management. This highlights the need for future research to better understand the origin of respiratory and sleep disorders in patients with DM1.

Nasal nitric oxide measurement in children for the diagnosis of primary ciliary dyskinesia: European Respiratory Society technical standard

Nasal nitric oxide (nNO) is extremely low in most people with primary ciliary dyskinesia (PCD) and its measurement is an important contributor to making the diagnosis. Existing guidelines and technical standards focus on nNO measurements in older, cooperative children using chemiluminescent analysers. However, measurements of nNO in pre-school children (2-5 years) may facilitate early diagnosis, and electrochemical rather than chemiluminescence analysers are widely used. Pre-schoolers often need different methods to be employed when measuring nNO. Hence a European Respiratory Society Task Force has developed this technical standard as the first step towards standardising sampling, analysis, and reporting of nNO measured as part of the diagnostic testing for PCD in all age groups including preschool-age children. Furthermore, we considered both chemiluminescence and electrochemical analysers that are in use worldwide. There was paucity of quality evidence for electrochemical analysers and sampling methods used in young children, and this manuscript proposes future research priorities to allow updates of this technical standard.

Longitudinal assessment of loss and gain of lung function in childhood asthma

OBJECTIVE

The Childhood Asthma Management Program revealed that 25.7% of children with mild to moderate asthma exhibit loss of lung function. The objective was to assess the trajectories of function by means of serial FEV₁ in asthmatic children participating in out-of-hospital follow-up.

METHODS

A total of 295 children (199 boys) who had undergone at least 10 spirometry tests from the age of 8 were selected from a single-center open cohort. The annualized rate of change (slope) for prebronchodilator FEV₁ (percent predicted) was estimated for each participant and three patterns were defined: significantly positive slope, significantly negative slope, and null slope (non-significant P-value; Pearson test). The standard deviation (SD) of each individual slope was recorded as a variability criterion of FEV₁.

RESULTS

The median (25^th; 75^th percentile) age at inclusion and the last visit was 8.5 (8.2; 9.3) and 15.4 (14.8, 16.0) years, respectively. Tracking of function (null slope) was observed in 68.8% of the children, while 27.8% showed a loss of function or reduced growth (negative slope) and 3.4% showed a gain in function (positive slope). The children characterized by loss of function depicted a better initial function and a lower FEV₁ variability during their follow-up than children with tracking or gain of lung function. At the last visit, these children were characterized by a lower lung function than children with tracking or gain of lung function.

CONCLUSION

Better initial FEV₁ value and less FEV₁ variability are associated with loss of lung function or reduced lung growth in asthmatic children.

Prediction of height using ulna length in African-Caribbean children

Standing height is an essential anthropometric measurement in pediatrics. In children unable to stand upright, measurement of ulna to predict standing height is recommended, but height prediction equations based on the ulna have not been established in children of African ancestry. We hypothesized that such equations would result in lower predicted height compared to using equations derived from non-African children. We measured prospectively standing height and both ulna in 358 African-Caribbean children without bone deformity or muscle disease, referred to two pulmonary function test laboratories. Interobserver variability was low for standing height (n = 54) and ulna measurement (n = 51) (mean biases [95%CI]: -0.02 [-0.99; 0.95] and 0.05 [-0.91; 1.01] cm, respectively), as well as inter-ulna variability (n = 352; mean bias 0.03 95%CI [-0.66; 0.73] cm). We used the mean value of 247 bilateral ulna measurements to calculate prediction equations using a generalized linear model including age, sex, ulna length, and geographic origin group, the latter showing no influence on the model. In the validation population of 107 children, the median difference [inter-quartile range] between standing height and ulna-predicted height was -0.4 [-2.7; 1.0] cm. Of 260 reliable baseline spirometry, there was a strong concordance between bronchial obstruction diagnosis established using standing height or ulna-predicted height (kappa coefficient: 0.85 [0.77; 0.94]) with only 11 (4.3%) children misclassified. The ulna predicted height calculated from African-Caribbean prediction equations resulted in a smaller height than the height calculated using equations derived from non-African children.

Nasal nitric oxide measurement variability to establish a standard for reliable results

Nasal nitric oxide (nNO) measurement is a first-line test used to increase the post-measurement probability of primary ciliary dyskinesia (PCD) in subjects with symptoms consistent with this diagnosis [1]. The accuracy of nNO measurement is essential since it will orientate the work-up towards tests that are usually highly specialised and sometimes invasive. Accuracy of biological measurements relies on the technical and on the biological variability. While the accuracy of NO analysers is known better for chemiluminescence devices (e.g. <1 ppb with 1% linearity from 0.1 to 5000 ppb for CLD 88 (Eco Medics, Duernten, Switzerland)) than for widely used electrochemical devices (e.g. ±5 ppb for values <50 ppb and 10% for values >50 ppb for Niox Vero (Circassia, Oxford, UK)) [2], little is known on the biological variability of nNO measurements, except for increased nNO output variability in adults with rhinitis compared with healthy subjects and the positive effect of training on the level of nNO taken during expiration against a resistance (nNO-ER) in children [3, 4].

A repeatability of 10% for NO measurements obtained with the velum closed in the same or both nostrils is relevant, while measurements taken during tidal breathing should aim for a repeatability of 20% and 30%, respectivelyhttps://bit.ly/3sMnug6

An international survey on nasal nitric oxide measurement practices for the diagnosis of primary ciliary dyskinesia

Nasal nitric oxide (nNO) measurements are routinely used in the assessment of patients suspected to have primary ciliary dyskinesia (PCD), but recommendations for performing such measurements have not focused on children and do not include all current practices. To guide the development of a European Respiratory Society-supported technical standard for nNO measurements in children, an international online survey was conducted to better understand current practices for measuring nNO among providers involved in PCD diagnostics.

Seventy-eight professionals responded, representing 65 centres across 18 countries, mainly located in Europe and North America. Nearly all centres measured nNO in children and more than half of them performed measurements before 5-years of age. The test was often postponed in children with signs of acute airway infection. In Europe, the electrochemical technique was more frequently used than chemiluminescence. A similar proportion of centres performed measurements during exhalation against a resistance (49/65) or during tidal breathing (50/65) with 15 centres using only exhalation against a resistance and 15 centres using only tidal breathing. The cut-off values used to discriminate PCD was consistent across centres using chemiluminescence analyzers and these centres reported results as an output (nL.min−1). However, cut-off values were highly variable across centres using electrochemical devices, and nNO concentrations were typically reported as ppb.

This survey represents the first to determine real-world use of nNO measurements worldwide and revealed remarkable variability in methodology, equipment, and interpretation. These findings will be useful to standardise methods and training.

Evaluation of obesity and asthma as risk factors for moderate to severe obstructive sleep apnea in children

STUDY OBJECTIVES

Asthma and obesity are risk factors for obstructive sleep apnea (OSA) in children but their link to OSA severity is uncertain. We aimed at determining whether asthma or obesity were associated with an increased risk of moderate/severe OSA.

METHODS

Children undergoing a one-night polysomnography for suspicion of OSA were retrospectively included. Univariate and multivariate analyses were conducted to assess the clinical and demographic characteristics linked to moderate/severe OSA (obstructive apnea-hypopnea index ≥ 5/h of sleep) with odds ratio (OR) and 95% confidence interval reported.

RESULTS

490 children (311 (64%) boys) were included with a median [25th; 75th percentile] age of 8.7 [5.4; 12.9] years, 164 (33%) non-asthmatics non-obese, 122 (25%) obese non-asthmatics, 125 (26%) asthmatics non-obese, 79 (16%) asthmatics and obese. Moderate/severe OSA was present in 157 (32%) children (75/157 (48%) obese and 52/157 (33%) asthmatics). Independent factors associated with increased or decreased risk of moderate/severe OSA were: obesity and male sex (OR 1.82 [1.16; 2.87], P = 0.01, and 1.55 [1.02; 2.36], P = 0.04, respectively), and current asthma, age >6 years or behavioral disorders (OR 0.45 [0.29; 0.70], P < 0.001; 0.44 [0.27; 0.73], P < 0.001; and 0.55 [0.33; 0.92], P = 0.02, respectively). Abnormal resistance of the respiratory system (measured in 241 children), but not abnormal spirometry (measured in 213 children), increased the risk of moderate/severe OSA (OR 2.95 [1.46-5.96], P = 0.003).

CONCLUSIONS

In our cohort enriched in obese and asthmatic children, obesity was associated with higher risk of moderate/severe OSA whereas current asthma was not.

Estimating pulmonary function after surgery for adolescent idiopathic scoliosis using biplanar radiographs of the chest with 3D reconstruction

AIMS

This study addressed two questions: first, does surgical correction of an idiopathic scoliosis increase the volume of the rib cage, and second, is it possible to evaluate the change in lung function after corrective surgery for adolescent idiopathic scoliosis (AIS) using biplanar radiographs of the ribcage with 3D reconstruction?

METHODS

A total of 45 patients with a thoracic AIS which needed surgical correction and fusion were included in a prospective study. All patients underwent pulmonary function testing (PFT) and low-dose biplanar radiographs both preoperatively and one year after surgery. The following measurements were recorded: forced vital capacity (FVC), slow vital capacity (SVC), and total lung capacity (TLC). Rib cage volume (RCV), maximum rib hump, main thoracic curve Cobb angle (MCCA), medial-lateral and anteroposterior diameter, and T4-T12 kyphosis were calculated from 3D reconstructions of the biplanar radiographs.

RESULTS

All spinal and thoracic measurements improved significantly after surgery (p < 0.001). RCV increased from 4.9 l (SD 1) preoperatively to 5.3 l (SD 0.9) (p < 0.001) while TLC increased from 4.1 l (SD 0.9) preoperatively to 4.3 l (SD 0.8) (p < 0.001). RCV was correlated with all functional indexes before and after correction of the deformity. Improvement in RCV was weakly correlated with correction of the mean thoracic Cobb angle (p = 0.006). The difference in TLC was significantly correlated with changes in RCV (p = 0.041). It was possible to predict postoperative TLC from the postoperative RCV.

CONCLUSION

3D rib cage assessment from biplanar radiographs could be a minimally invasive method of estimating pulmonary function before and after spinal fusion in patients with an AIS. The 3D RCV reflects virtual chest capacity and hence pulmonary function in this group of patients. Cite this article: Bone Joint J 2022;104-B(1):112-119.

International consensus on lung function testing during COVID-19 pandemic and beyond

COVID-19 has negatively affected the delivery of respiratory diagnostic services across the world due to the potential risk of disease transmission during lung function testing. Community prevalence, reoccurrence of COVID-19 surges, and the emergence of different variants of the SARS-CoV-2 virus have impeded attempts to restore services. Finding consensus on how to deliver safe lung function services for both patients attending and for staff performing the tests are of paramount importance.

This international statement presents the consensus opinion of 23 experts in the field of lung function and respiratory physiology balanced with evidence from the reviewed literature. It describes a robust roadmap for restoration and continuity of lung function testing services during the COVID-19 pandemic and beyond.

Important strategies presented in this consensus statement relate to the patient journey when attending for lung function tests. We discuss appointment preparation, operational and environmental issues, testing room requirements including mitigation strategies for transmission risk, requirement for improved ventilation, maintaining physical distance, and use of personal protection equipment. We also provide consensus opinion on precautions relating to specific tests, filters, management of special patient groups, and alternative options to testing in hospitals.

The pandemic has highlighted how vulnerable lung function services are and forces us to re-think how long term mitigation strategies can protect our services during this and any possible future pandemic. This statement aspires to address the safety concerns that exist and provide strategies to make lung function tests and the testing environment safer when tests are required.

Mediterranean diet and lung function, sensitization, and asthma at school age: The PARIS cohort

BACKGROUND

The Mediterranean diet (MD) has known health benefits, but its specific impact on allergy development is unclear. As part of the PARIS birth cohort follow-up, we aimed to investigate the adherence of 8-year-old children to the MD and its association with allergic/respiratory morbidity at school age.

METHODS

Diet was assessed using a food frequency questionnaire completed by the parents. Adherence to the MD was assessed based on two scores: the KIDMED index and the Mediterranean Diet Score (MDS). Current allergic diseases (asthma, rhinitis, eczema), lung function indices (FEV₁ and FVC), FeNO and specific IgE levels were determined during a health check-up at 8 years. Associations between levels of adherence to the MD and respiratory/allergic morbidity were studied using multivariable logistic and linear regression models adjusted for potential confounders.

RESULTS

A total of 975 children were included in the present study, 35.6% with low adherence to the MD, 55.7% with moderate adherence and 8.7% with high adherence according to the KIDMED index. High family socioeconomic status, any breastfeeding at 6 months and consumption of organic food were associated with higher adherence to the MD. Compared with low adherence, high adherence was associated with lower risk of asthma and sensitization at 8 years, as well as higher FEV₁ and FVC.

CONCLUSION

This study suggests a protective effect of high adherence to the MD on allergic and respiratory morbidity at school age. These results need to be confirmed by further longitudinal analyses. A healthy diet may prevent allergic and respiratory morbidity in school-aged children.

Breath-holding and tidal breathing nasal NO to screen children for Primary Ciliary Dyskinesia

Nasal nitric oxide (nNO) measurement is recommended to screen for Primary Ciliary Dyskinesia (PCD) in subjects with suggestive history and symptoms. Clinical use of alternative methods (i.e., breath-hold [BH], tidal breathing [TB]) in children unable to perform the gold standard slow Exhalation against a Resistance (ER) method has not been sufficiently evaluated. We extracted retrospectively (2013-2019) 454 files (374 subjects) containing nNO results. Median [IQR] age at inclusion was 7.0 [4.7-11.0] years, 105 (28.1%) children were younger than 5 years. ER or BH methods were more frequently mastered by children older than 5 years compared to younger children (69.4% and 52.7% vs. 21% and 5.6%, respectively; p < .0001), the latter succeeding only in TB measurement in 77.4% of cases. In 130 files with both ER and BH measurements (nNO-ER and nNO-BH), nNO-BH was 102 [96.2; 108.3]% that of nNO-ER. In 175 files including nNO-ER and nNO-TB measurements, nNO-TB was 64.4 [IQR: 53.7; 80.4]% that of nNO-ER with an excellent correlation between nNO values (r = .94 [95% CI 0.91; 0.95]; p < .0001) and discordance in the interpretation of nNO results in 16 (10.2%) cases. Final PCD diagnosis was similar in patients included before or after 5 years of age (confirmed 16 (15.2%) and 48 (17.8%); excluded 81 (77.1%) and 192 (71.4%), respectively; p = .32). In conclusion, reliable nNO-BH and nNO-ER results are interchangeable. Children tested with ER or with TB method have similar final PCD diagnosis. Alternative methods to measure nNO might be studied further for use in clinical practice.

Severe central apnea secondary to cerebellar dysplasia in a child: look past Joubert syndrome

NONE

We report the case of a female patient aged 12 years referred to our pediatric sleep unit with a history of central sleep apnea associated with transient episodes of tachypnea on polysomnography recordings. The patient was otherwise healthy, with no personal or family medical history, and had a normal physical and neuropsychological examination. Brain magnetic resonance imaging showed signs of cerebellar vermis dysplasia but without the classical features of the molar tooth sign. The rest of the workup (genetic tests, blood tests, cardiac investigations) was normal except for an increased peripheral chemosensitivity to carbon dioxide and oxygen. The patient was successfully treated with bilevel positive airway pressure. This case report highlights the importance of performing brain magnetic resonance imaging in patients with central sleep apnea to study the cerebellum, beyond the brainstem area. Cerebellar malformations can be found even in the absence of any other neurological condition.

Peripheral obstruction without airflow limitation is rare and not specific to asthma in children

Peripheral (or small) airway obstruction (PAO) is considered a marker of childhood asthma but the techniques able to directly measure it are rarely used in routine. Usual spirometry and plethysmography can detect a certain degree of PAO when reduced forced vital capacity (FVC) is associated to normal forced expiratory volume in 1 s (FEV₁ ) to FVC ratio, and normal total lung capacity (TLC). The frequency of this functional pattern has never been studied in different pediatric respiratory conditions. To assess the prevalence and outcome of PAO in children with different diseases or symptoms, we retrospectively extracted from our database all files of Caucasian subjects encompassing spirometry and plethysmography measurements. Spirometry patterns (normal, airflow limitation [AFL; low FEV₁ /FVC], low FVC [with normal FEV₁ /FVC]) and final functional patterns (normal, AFL, PAO, restrictive [low TLC], or mixed) were described. We included 4394 files recorded in 1794 children (median [IQR] age: 10.7 [9.2-12.9] years). At inclusion, 125 (7%) children had low FVC of which 56 (44.8%, and 3.1% [95% CI 2.3-3.9] of the whole population) had PAO. PAO prevalence increased with age (OR (95% CI) per 2-year-increase: 2.26 (1.59-3.23); p < .001), and was more frequent in chronic bronchial diseases other than asthma (1.6% vs. 8.0%). On repeated tests, PAO frequently normalized (26.1%) or persisted (43.5%), but it less often progressed into AFL (13%) or restrictive (13%) patterns. PAO is an infrequent nonspecific and persistent functional pattern. Its prevalence increases with age and in diagnosis of chronic respiratory diseases other than asthma.

Infant feeding clusters are associated with respiratory health and allergy at school age in the PARIS birth cohort

BACKGROUND

As infant feeding may influence allergy development, we aimed to identify groups of infants based on feeding practices and to examine their associations with respiratory health/allergy at 8 years in the PARIS birth cohort.

METHODS

Data on breastfeeding, consumption of infant formula (regular, pre-/probiotics, partially hydrolysed with hypoallergenic label [pHF-HA], extensively hydrolysed [eHF], soya) and solid food introduction were collected using repeated questionnaires at 1, 3, 6, 9 and 12 months. Infants with similar feeding practices over the first year of life were grouped using multidimensional longitudinal cluster analysis. Respiratory/allergic morbidity was studied at 8 years as symptoms, doctor's diagnoses (asthma, hay fever, eczema, food allergy), and measurement of lung function, FeNO and specific IgE. Associations between feeding-related clusters and respiratory/allergic morbidity were investigated using multivariable logistic and linear regression models adjusted for potential confounders including early respiratory/allergic outcomes and parental history of allergy.

RESULTS

Five clusters were identified among 3446 infants: Cluster 1 (45%) mainly fed with regular formula, Cluster 2 (27%) exclusively breastfed during the first 3 months, and three other clusters consuming different types of formula (pre-/probiotics for Cluster 3 [17%], pHF-HA for Cluster 4 [7%], eHF/soya for Cluster 5 [4%]). Compared to Cluster 1, children from Cluster 2 tended to have a lower risk of asthma and children from Cluster 4 had a significant lower lung function (FEV₁ , FVC), higher FeNO and higher risk of sensitization at 8 years.

CONCLUSION

Early pHF-HA use was negatively associated with objective measures of respiratory/allergic morbidity at school age, while children breastfed for at least 3 months seem protected against asthma at 8 years old.

Association between lung function of school age children and short-term exposure to air pollution and pollen: the PARIS cohort

BACKGROUND

Daily levels of ambient air pollution and pollen may affect lung function but have rarely been studied together. We investigated short-term exposure to pollen and air pollution in relation to lung function in school-age children from a French population-based birth cohort.

METHODS

This study included 1063 children from the PARIS (Pollution and Asthma Risk: an Infant Study) cohort whose lung function and FeNO measurements were performed at age 8 years old. Exposure data were collected up to 4 days before testing. We estimated daily total pollen concentration, daily allergenic risk indices for nine pollen taxa, as well as daily concentrations of three air pollutants (particulate matter less than 10 µm (PM₁₀), nitrogen dioxide (NO₂), ozone (O₃)). Children with similar pollen and air pollution exposure were grouped using multidimensional longitudinal cluster analysis. Associations between clusters of pollen and air pollution exposure and respiratory indices (FEV₁, FVC, FeNO) were studied using multivariable linear and logistic regression models adjusted for potential confounders.

RESULTS

Four clusters of exposure were identified: no pollen and low air pollution (Cluster 1), grass pollen (Cluster 2), PM₁₀ (Cluster 3) and birch/plane-tree pollen with high total pollen count (Cluster 4). Compared with children in Cluster 1, children in Cluster 2 had significantly lower FEV₁ and FVC levels, and children from Cluster 3 had higher FeNO levels. For FEV₁ and FVC, the associations appeared stronger in children with current asthma. Additional analysis suggested a joint effect of grass pollen and air pollution on lung function.

CONCLUSION

Daily ambient chemical and biological air quality could adversely influence lung function in children.

Improvement in Asthma Symptoms and Pulmonary Function in Children After SARS-CoV-2 Outbreak

Introduction: Little is known on the effect of SARS-CoV-2 circulation on asthma daily symptoms in children. We compared asthma exacerbations, asthma symptom control and lung function before and after SARS-CoV-2 outbreak in children. Methods: Retrospective study of children with persistent asthma referred for lung function testing. The second quarter of 2020 being a period with nearly no activity, we compared the activity between the first, third and fourth quarters of 2019 and 2020 (Q1-2019 vs. Q1-2020, Q3-2019 vs. Q3-2020 and Q4-2019 vs. Q4-2020). Results: We retrieved 1,871 files in 2019 and 1,548 in 2020. The whole population [2,165 (63.3%) boys] had a median [IQR] age of 9.7 [6.8;13.1] years. There was no difference in age, sex, and ethnicity between 2019 and 2020 populations. Asthma was better controlled during Q4-2020 compared to Q4-2019 (P = 0.042), and there was a lower proportion of children with at least one exacerbation in the previous 3 months after the reopening, compared to the same period in 2019 (P < 0.0001). Baseline FEV₁ (Z-score) recorded after the reopening was significantly higher (with less reversibility) compared to the same period before the epidemic (P < 0.0001). Baseline FEV₁/FVC (Z-score) was significantly higher during Q3-2020 compared to Q3-2019 (P = 0.026), with fewer children having a significant reversibility (P = 0.035). Discussion: We demonstrated a trend toward increased exacerbations just before the recognition of the epidemic, and fewer exacerbations, better asthma symptom control and improvement in the lung function of asthmatic children after the reopening.

Nocturnal hypoventilation in Down syndrome children with or without sleep apnea

BACKGROUND

There is a high prevalence of obstructive sleep apnea (OSA) in children with Down syndrome (DS), sometimes associated with alveolar hypoventilation.

OBJECTIVE

To compare transcutaneous partial pressure of carbon dioxide (PtcCO₂ ) and pulse oximetry (SpO₂ ) in children with DS and in control children with OSA.

PATIENTS AND METHODS

This retrospective case-control study involved children followed in Trousseau Hospital (Paris) Sleep Center. Polysomnography (PSG) recordings and clinical files of children with DS were reviewed to identify clinical signs of OSA and comorbidities associated with DS. Controls were children who presented with OSA of ENT origin without other comorbidities (exceptions: two overweight, one obese, and three with well-controlled asthma). DS subjects and controls were matched for age and apnea hypopnea index.

RESULTS

There were 28 children in each group. Mean PtcCO₂ during sleep was significantly higher in patients with DS compared to controls (44 mm Hg vs 42 mm Hg, P = .001). Five (21%) patients with DS met the American Academy of Sleep medicine criteria for hypoventilation, compared to one (4%) in the control group. The mean PtcO₂ during sleep was significantly lower in patients with DS (77 mm Hg vs 82 mm Hg, P = .003).

CONCLUSIONS

This is the first study to compare nocturnal gas exchange in children with DS to a control group of children with similar OSA. Our data demonstrate that children with DS have increased PtcCO₂ regardless of the presence of OSA and its severity. This may be due to respiratory muscle hypotonia and/or ventilatory control alteration in patients with DS.

TTC12 Loss-of-Function Mutations Cause Primary Ciliary Dyskinesia and Unveil Distinct Dynein Assembly Mechanisms in Motile Cilia Versus Flagella

Cilia and flagella are evolutionarily conserved organelles whose motility relies on the outer and inner dynein arm complexes (ODAs and IDAs). Defects in ODAs and IDAs result in primary ciliary dyskinesia (PCD), a disease characterized by recurrent airway infections and male infertility. PCD mutations in assembly factors have been shown to cause a combined ODA-IDA defect, affecting both cilia and flagella. We identified four loss-of-function mutations in TTC12, which encodes a cytoplasmic protein, in four independent families in which affected individuals displayed a peculiar PCD phenotype characterized by the absence of ODAs and IDAs in sperm flagella, contrasting with the absence of only IDAs in respiratory cilia. Analyses of both primary cells from individuals carrying TTC12 mutations and human differentiated airway cells invalidated for TTC12 by a CRISPR-Cas9 approach revealed an IDA defect restricted to a subset of single-headed IDAs that are different in flagella and cilia, whereas TTC12 depletion in the ciliate Paramecium tetraurelia recapitulated the sperm phenotype. Overall, our study, which identifies TTC12 as a gene involved in PCD, unveils distinct dynein assembly mechanisms in human motile cilia versus flagella.

Associations of black carbon with lung function and airway inflammation in schoolchildren

BACKGROUND

Few studies have investigated the 24-hour respiratory health effects of personal black carbon (BC) and ultrafine particles (UFP) exposure in schoolchildren. The objective of this study was to investigate these associations with the lung function in children 10-years old with and without persistent respiratory symptoms.

METHODS

We conducted a cross-sectional study in 305 children (147 and 158 with and without persistent respiratory symptoms, respectively) from three European birth-cohorts: PARIS (France) and INMA Sabadell and Valencia (Spain). Personal 24-hour measurements of exposure concentrations to BC and UFP were performed by portable devices, before lung function testing. Forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC) and the fraction of exhaled nitric oxide (FeNO) were determined.

RESULTS

There was no association of UFP with lung function parameters or FeNO whereas the increase in 24-hour BC exposure concentrations was related to a statistically significant decrease in lung function parameters only among children with persistent respiratory symptoms [-96.8 mL (95% Confidence Interval CI: -184.4 to -9.1 mL) in FVC, and -107.2 mL (95% CI: -177.5 to -36.9 mL) in FEV₁ for an inter-quartile range of 1160 ng/m³ exposure increase]. A significant positive association between BC and FeNO was observed only in children with persistent respiratory symptoms with current wheezing and/or medication to improve breathing [FeNO increases with +6.9 ppb (95% CI: 0.7 to 13.1 ppb) with an inter-quartile range BC exposure increase].

CONCLUSION

Children suffering from persistent respiratory symptoms appear to be more vulnerable to BC exposure.

Update of the European paediatric respiratory medicine syllabus

The 10-year-old European syllabus for paediatric respiratory medicine (PRM; also known as paediatric pulmonology) was updated by a consensus-based method using an expert task force for redrafting, and a subsequent Delphi process to achieve consensus. There was a high degree of consensus for the final syllabus, which has been streamlined and made more relevant to current practice. All modules are now mandatory apart from the undertaking of research projects, which is optional. Although there are still a number of countries in Europe which do not recognise PRM as a separate subspecialty, there are paediatric respiratory physicians practising in every country in Europe, and a current and harmonised European syllabus in the subspecialty remains important for defining the training and areas of practice of PRM practitioners.

The European syllabus for paediatric respiratory medicine has been updated by a task force in conjunction with the ERS Paediatric Assembly and designated national experts. It has several new modules, and only one optional module remains.http://bit.ly/2KB9wcy

Unsupervised trajectories of respiratory/allergic symptoms throughout childhood in the PARIS cohort

BACKGROUND

Natural course and co-occurrence of asthma, eczema, and allergic rhinitis through childhood are still not fully documented. We aim to identify and characterize profiles based on the time course, severity, and apparent triggers of respiratory/allergy symptoms in school-aged children.

METHODS

Data on occurrence, severity, and triggers of asthma, rhinitis, and dermatitis symptoms were collected annually during the follow-up of the PARIS birth cohort. Children with similar symptom trajectories until 8-9 years were grouped into profiles using multidimensional (all symptoms considered simultaneously) cluster analysis. Associations between profiles and different health outcomes were analyzed using logistic or linear regression models.

RESULTS

Six distinct symptomatic profiles were identified. A profile was defined by persistent dermatitis symptoms, associated with sensitization to food and aeroallergens. Two profiles were characterized by wheezing: one with early transient wheezing and the other with persistent wheezing related to doctor-diagnosed asthma, airway obstruction, and perennial aeroallergen sensitization. Three profiles were characterized by rhinitis symptoms: one non-allergic and two allergic, either with persistent rhinitis symptoms related to allergic multimorbidity and sensitization to perennial aeroallergens, or with late-onset symptoms, related to both pollen and perennial aeroallergens sensitization as well as low lung function.

CONCLUSION

This study brings further insights into the developmental profiles of respiratory/allergic outcomes from birth to school age. The identified profiles clearly differed regarding objective features such as diagnosed morbidity, sensitization, or lung function measurements, thus highlighting their biologic and clinical relevance. Allergic rhinitis profiles deserve particular attention, since they were likely to be involved in multimorbidity patterns.

Interrupter resistance to measure dose-response to salbutamol in wheezy preschool children

AIM

Using a non-invasive lung function technique (interrupter resistance, Rint), we aimed to determine whether a dose-response to salbutamol could be detected in wheezy preschool children and if so, which dose of salbutamol should be administered to routinely evaluate bronchial reversibility.

METHOD

Wheezy children (3 to <7 years) were enrolled in a prospective multicenter study. Rint was measured at baseline, and after random assignment to a first dose (100 or 200 μg) and a second dose (cumulative dose: 400, 600, or 800 μg) of salbutamol. Data were analyzed using mixed modeling approach with an inhibitory maximal effect (I_max ) model, to account for a sparse sampling design. Simulations were performed to predict the percentage of children with significant Rint reversibility at several doses.

RESULTS

Final results were available in 99 children out of 106 children included. The model adequately fitted the data, showing satisfactory goodness-of-fit plots and a low residual error of 8%. Children with uncontrolled symptoms had lower I_max (ie, showed less reversibility) compared to children with totally/partly controlled symptoms (0.23 vs. 0.31, P < 0.001). Dose to reach 50% of I_max (D₅₀ ) was 51 μg. According to simulations, 88.1% of children with significant reversibility at dose 800 μg would already show significant reversibility at 400 μg.

CONCLUSION

Interrupter resistance was able to measure a dose-response curve to salbutamol in wheezy preschool children, which was similar to that of older patients. Young children require a high dose of salbutamol to correctly assess airway bronchodilator response, especially these with poor symptom control.

[Guidelines for methacholine provocation testing]

Bronchial challenge with the direct bronchoconstrictor agent methacholine is commonly used for the diagnosis of asthma. The "Lung Function" thematic group of the French Pulmonology Society (SPLF) elaborated a series of guidelines for the performance and the interpretation of methacholine challenge testing, based on French clinical guideline methodology. Specifically, guidelines are provided with regard to the choice of judgment criteria, the management of deep inspirations, and the role of methacholine bronchial challenge in the care of asthma, exercise-induced asthma, and professional asthma.

Gas exchanges in children with cystic fibrosis or primary ciliary dyskinesia: A retrospective study

Primary ciliary dyskinesia (PCD) and cystic fibrosis (CF) both entail bronchiectasis and pulmonary impairment as measured using spirometry, during childhood. We aimed at looking whether blood gas exchanges progressed differently between CF and PCD children in a retrospective study of repeated measurements. Comparisons between groups (Wilcoxon-Mann-Whitney and Chi-squared tests) and a mixed linear model, adjusted for age, evaluated associations between diseases and PaO₂, PaCO_2, or PaO_2-PaCO₂ ratio. Among 42 PCD and 73 CF children, 62% and 59% had respectively bronchiectasis (P = 0.75). Spirometry and blood gases were similar at inclusion (PaO₂ median [IQR] PCD -1.80 [-3.40; -0.40]; CF -1.80 [-4.20; 0.60] z-scores; P = 0.72). PaO₂ and PaO₂-PaCO₂ ratio similarly and significantly decreased with age in both groups (P < 0.01) whereas PaCO₂ increased more in CF (P = 0.02) remaining within the range of normal (except for one child). To conclude, gas exchange characteristics, similarly initially impaired in PCD and CF children, tended to less deteriorate with time in PCD children who could benefit from an early diagnosis.

[Digital action plan for asthma exacerbations (PANAME)]

BACKGROUND

A written action plan (WAP) reduces emergency visits for asthma exacerbations. However, a WAP is underused and often focused on asthma control. The innovation is an AppWeb that includes an expert software aimed at diagnosing the level of severity of asthma exacerbations and delivering a personalized digital action plan (DAP) when patients are in urgent need of medical advice. Symptoms describing the level of severity of asthma exacerbations and the consequent treatments have been established by working groups of the French Respiratory Societies (SPLF and SP2A for adults and children, respectively). The main objective of the study is to evaluate the effect of the DAP on the frequency of urgent medical attendance. Secondary objectives are to evaluate adherence to the DAP compared to a WAP and the qualitative satisfaction of patients using the DAP.

METHODOLOGY

A randomized, prospective, comparative, multicenter study on two parallel groups, conducted in private practice and in hospitals. In both arms, asthmatic patients (240 children aged 6 to 12 years and 270 adults aged 18 to 50 years) with severe asthma exacerbation(s) during the previous year and an Internet connection via a smartphone or a tablet computer, will have at their disposal a WAP and one arm will have, in addition, the DAP. Included patients will be followed up every three months for one year.

EXPECTED RESULTS

A decrease in the number of urgent medical attendances and better adherence in the WAP+DAP group compared to the WAP group.

How can we optimise inhaled beta2 agonist dose as 'reliever' medicine for wheezy pre-school children? Study protocol for a randomised controlled trial

Background

Asthma is a common problem in children and, if inadequately controlled, may seriously diminish their quality of life. Inhaled short-acting beta2 agonists such as salbutamol are usually prescribed as ‘reliever’ medication to help control day-to-day symptoms such as wheeze. As with many medications currently prescribed for younger children (defined as those aged 2 years 6 months to 6 years 11 months), there has been no pre-licensing age-specific pharmacological testing; consequently, the doses currently prescribed (200–1000 μg) may be ineffective or likely to induce unnecessary side effects. We plan to use the interrupter technique to measure airway resistance in this age group, allowing us for the first time to correlate inhaled salbutamol dose with changes in clinical response. We will measure urinary salbutamol levels 30 min after dosing as an estimate of salbutamol doses in the lungs, and also look for genetic polymorphisms linked to poor responses to inhaled salbutamol.

Methods

This is a phase IV, randomised, controlled, observer-blinded, single-centre trial with four parallel groups (based on a sparse sampling approach) and a primary endpoint of the immediate bronchodilator response to salbutamol so that we can determine the most appropriate dose for an individual younger child. Simple randomisation will be used with a 1:1:1:1 allocation.

Discussion

The proposed research will exploit simple, non-invasive and inexpensive tests that can mostly be performed in an outpatient setting in order to help develop the evidence for the correct dose of salbutamol in younger children with recurrent wheeze who have been prescribed salbutamol by their doctor.

Trial registration

EudraCT2014-001978-33, ISRCTN15513131. Registered on 8 April 2015.

Sleep disordered breathing in patients with Prader-Willi syndrome: A multicenter study

OBJECTIVES

Sleep disordered breathing (SDB) is common in patients with Prader-Willi syndrome (PWS) and systematic screening is recommended, especially before growth hormone treatment. The aim of the study was to describe the baseline SDB and therapeutic interventions in a large cohort of patients.

STUDY DESIGN

Retrospective study.

SUBJECT SELECTION

Eighty-eight patients with PWS, median [interquartile range] age of 5.1 [1.0-14.5] years old (range 0.3-44.3), who were followed in three centers (France, Italy).

METHODOLOGY

Anthropometrics, polygraphy (PG), and gas exchange data were analyzed.

RESULTS

Median body mass index (BMI) was 20 [16-34] kg/m(2), BMI z-score for patients aged 2-20 years old was 2.1 [1.2-2.8] SD, mixed-obstructive apnea-hypopnea index (MOAHI) 1.8 [0.6-5.0] events/hr, and central apnea index (CAI) 0.1 [0.0-0.6] events/hr. Minimum pulse oximetry (SpO2) was 88 [84-91]%, percentage of time with SpO2 <90% 0.1 [0.0-1.0]%, and oxygen desaturation index 2 [1-4]/hr. An apnea-hypopnea index (AHI) ≥ 1.5 and ≥ 5 events/hr was observed in 53% of children and 41% of adults, respectively. No correlations were observed between MOAHI and anthropometrics data (age, BMI, BMI z-score), while MOAHI significantly correlated with SpO2 indexes. Age and BMI only weakly correlated with SpO2 indexes. Growth hormone could be initiated in 48 patients. Regarding post-PG therapy, 9 patients had upper airway surgery, and noninvasive CPAP/bilevel ventilation was started in 16 patients.

CONCLUSIONS

Patients with PWS exhibit a high prevalence of SDB. The lack of association between obesity and SDB leads to hypothesize that hypotonia and/or facial dysmorphic features may play a major role in the occurrence of SDB.

Technical and practical issues for tidal breathing measurements of nasal nitric oxide in children

To promote early screening of patients with suspected Primary Ciliary Dyskinesia (PCD), nasal nitric oxide (nNO) measurements during tidal breathing (TB) have been developed for children unable to ensure velum closure (VC) during breath hold or expiration against resistance. To investigate technical and practical issues related to TB-nNO methods in children referred for suspected or asserted PCD, we recorded, in a prospective multicenter study, TB-nNO (calculated as the mean of 5 peaks, 10 or 30 sec during tidal breathing) and VC-nNO when available. We studied 142 children (PCD diagnosis asserted in 47, excluded in 39). Nasal NO values were significantly different according to methods, VC-nNO being higher than TB-nNO (TB-nNO 5 peaks higher than mean of 10 or 30 sec). Specificity (90-94%) and sensitivity (86-97%) were similar between TB-nNO and VC-nNO methods. Age was more correlated with VC-nNO than with TB-nNO. TB-nNO could differ between the two nostrils by more than 10% (or 10 ppb when nNO absolute value lower 100 ppb) in 32-43% of the tested children, according to the different tidal breathing values, and was reproducible in the long term but influenced by ambient NO. Despite TB-nNO values being lower than VC-nNO, TB-nNO was found to be as discriminant for PCD, and probably more discriminant in children less than 8 years old, as the VC method. These results were obtained using the chemiluminescence technique which allows an easier assessment of relevant factors such as nasal permeability and ambient NO than the electrochemical technique.

[Underdiagnosed asthma in third-grade children]

Undiagnosed asthma has been poorly studied before adolescence since it can go unnoticed by parents and doctors. Moreover, it is unusual to look for undiagnosed asthma by directly questioning children on the presence of current respiratory symptoms. Epidemiologic studies show that more adolescents quote symptoms suggestive of asthma than the prevalence of doctor-diagnosed asthma, but respiratory symptoms compatible with asthma remain undetected by parents of younger children more frequently than doctors diagnose asthma in their children. We attempted to evaluate the relevance of a questionnaire used since 2011 by school doctors in Paris to detect asthma. In this questionnaire, the family history of atopy and asthma were completed by the parents when they met the school doctor (last year of preschool) and questions on current respiratory symptoms were answered by third-grade children seen alone by the school doctor. One hundred and thirty-one children out of 1135 children questioned had a positive questionnaire for suspected asthma. In three-quarters of the cases, questionnaires were positive based on the children's answers on their respiratory symptoms (without a positive answer on personal or family history being necessary). The outcome of 41 children screened by the questionnaire was known. Twenty (49%) children had received a final diagnosis of asthma, of whom 12 were put on asthma controllers. Among these 20 children, two children underwent lung function testing and two others underwent tests for allergy. In eight children, tests had been requested by the child's GP, but no final diagnosis was reported by the parents. None of the 13 children in whom asthma was ruled out had any test performed. It was concluded that it is possible to detect undiagnosed asthma in children as young as 8 years by directly asking them about their respiratory symptoms. The knowledge of personal and family history can improve screening for asthma in these children. A more thorough evaluation of all children with a positive questionnaire is necessary to better understand the properties of the questionnaire. Finally, the best way to implement this screening program remains to be established (school health, GPs).

Airway Remodeling in Preschool Children with Severe Recurrent Wheeze

RATIONALE

Airway wall structure in preschoolers with severe recurrent wheeze is poorly described.

OBJECTIVES

To describe airway wall structure and inflammation in preschoolers with severe recurrent wheeze.

METHODS

Flexible bronchoscopy was performed in two groups of preschoolers with severe recurrent wheeze: group 1, less than or equal to 36 months (n = 20); group 2, 36-59 months (n = 29). We assessed airway inflammation, reticular basement membrane (RBM) thickness, airway smooth muscle (ASM), mucus gland area, vascularity, and epithelial integrity. Comparisons were then made with biopsies from 21 previously described schoolchildren with severe asthma (group 3, 5-11.2 yr).

MEASUREMENTS AND MAIN RESULTS

RBM thickness was lower in group 1 than in group 2 (3.3 vs. 3.9 μm; P = 0.02), was correlated with age (P < 0.01; ρ = 0.62), and was higher in schoolchildren than in preschoolers (6.8 vs. 3.8 μm; P < 0.01). ASM area was lower in preschoolers than in schoolchildren (9.8% vs. 16.5%; P < 0.01). Vascularity was higher in group 1 than in group 2 (P = 0.02) and group 3 (P < 0.05). Mucus gland area was higher in preschoolers than in schoolchildren (16.4% vs. 4.6%; P < 0.01). Inflammatory cell counts in biopsies were not correlated with airway wall structure. ASM area was higher in preschoolers with atopy than without atopy (13.1% vs. 7.7%; P = 0.01). Airway morphometrics and inflammation were similar in viral and multiple-trigger wheezers.

CONCLUSIONS

In preschoolers with severe recurrent wheeze, markers of remodeling and inflammation are unrelated, and atopy is associated with ASM. In the absence of control subjects, we cannot determine whether differences observed in RBM thickness and vascularity result from disease or normal age-related development.

Interrupter resistance and oxygen saturation for methacholine challenge in young children

Inspiratory Rint better detects BHR than expiratory Rint and might better match PD20PtcO2 changes http://ow.ly/TrMvB.