Deep inspiration (DI) dilates normal airway precontracted with methacholine. The fact that this effect is diminished or absent in asthma could be explained by the presence of bronchial inflammation. ...The hypothesis was tested that DI induces more relaxation in methacholine induced bronchoconstriction-solely determined by the smooth muscle contraction-than in exercise induced bronchoconstriction, which is contributed to by both smooth muscle contraction and airway wall inflammation. The respiratory conductance (Grs) response to DI was monitored in asthmatic children presenting a moderately positive airway response to challenge by methacholine (
= 36) or exercise (
= 37), and expressed as the post- to pre-DI Grs ratio (Grs
). Both groups showed similar change in FEV
after challenge and performed a DI of similar amplitude. Grs
however was significantly larger in methacholine than in exercise induced bronchoconstriction (
< 0.02). The bronchodilatory effect of DI is thus less during exercise- than methacholine-induced bronchoconstriction. The observation is consistent with airway wall inflammation-that characterizes exercise induced bronchoconstriction-rendering the airways less responsive to DI. More generally, it is surmised that less relief of bronchoconstriction by DI is to be expected during indirect than direct airway challenge. The current suggestion that airway smooth muscle constriction and airway wall inflammation may result in opposing effects on the bronchomotor action of DI opens important perspective to the routine testing of asthmatic children. New crossover research protocols comparing the mechanical consequences of the DI maneuver are warranted during direct and indirect bronchial challenges.
While the early introduction of food allergens in the infant diet has been shown to be effective at preventing the development of food allergy (FA), its implementation in real life has been ...associated with various challenges. Interventions aimed at correcting skin barrier dysfunction have been explored in recent decades as a distinct or complementary mean to prevent allergic sensitization through the skin and subsequent development of FA. Studies assessing the application of emollient from birth have yielded conflicting results, and meta‐analyses have demonstrated either no effect or only a slight positive effect on FA prevention. However, a careful review of the clinical trials reveals that different emollients were used, which may have explained some of the discrepancies between study results. Emollient application protocols also varied widely between studies. While firm conclusions cannot be drawn with regard to their overall efficacy at preventing FA, the available data provide valuable insight into the characteristics that could be associated with a more effective intervention. Namely, successful trials tended to use emollients with an acidic pH of 5.5, applied over the entire body, and combined with topical corticosteroids in affected areas. Consensus on the optimal strategy to restore skin barrier function could help improve the homogeneity and clinical relevance of future trials on this topic. In the meantime, clinicians should avoid products associated with worse outcomes.
Cough is typically associated with physical activity in children with asthma, but the characteristics of the relationship between cough and exercise has not been established under physiological ...conditions. The aim of the study was to describe the effect of exercise on the reflex cough response elicited by a single breath of capsaicin in non-asthmatic children. A group of non-asthmatic adults was studied as reference. Thirty children and 29 adults were recruited. The cough reflex sensitivity to capsaicin was first determined to establish the dose that provokes 5 cough efforts (C5). The number of coughs elicited by C5 (NC5) was then compared at baseline and during a standardized submaximal treadmill exercise. Data are expressed as median (interquartile range). Children and adults showed a significant decrease in NC5 (respectively from 5.0 (4.0-6.0) to 2.5 (2.0-4.0),
< 0.0005 and from 6.0 (5.0-7.0) to 2.0 (0.0-3.0,
< 0.0005). During exercise, NC5 was observed to decrease in all adult subjects, but in only 24/30 children (80%,
= 0.02). A trend for a higher incidence of personal and familial atopy was observed in children that lacked cough down-regulation during exercise compared with other children. It is concluded that the cough reflex response to capsaicin is down regulated by exercise in both children and adults. The effect however is less consistently observed in the former. The difference may reflect maturation of descending inhibitory pathways of the cough reflex, but may also be associated to atopy. The data stress the importance of assessing the time relationship of cough and exercise in questionnaire studies of asthma.
Objectives
Few data on alveolar hypoventilation in Prader‐Willi syndrome (PWS) are available and the respiratory follow‐up of these patients is not standardized. The objectives of this study were to ...evaluate the prevalence of alveolar hypoventilation in children with PWS and identify potential risk factors.
Study Design
This retrospective study included children with PWS recorded by polysomnography (PSG) with transcutaneous carbon dioxide pressure (PtcCO2) or end‐tidal CO2 (ETCO2) measurements, between 2007 and 2021, in a tertiary hospital center. The primary outcome was the presence of alveolar hypoventilation defined as partial pressure of carbon dioxide (pCO2) ≥ 50 mmHg during ≥2% of total sleep time (TST) or more than five consecutive minutes.
Results
Among the 57 included children (38 boys, median age 4.8 years, range 0.1–15.6, 60% treated with growth hormone GH, 37% obese), 19 (33%) had moderate‐to‐severe obstructive sleep apnea syndrome (defined as obstructive apnea‐hypopnea index ≥5/h) and 20 (35%) had hypoventilation. The median (range) pCO2 max was 49 mmHg (38–69). Among the children with hypoventilation, 25% were asymptomatic. Median age and GH treatment were significantly higher in children with hypoventilation compared to those without. There was no significant difference in terms of sex, BMI, obstructive or central apnea‐hypopnea index between both groups.
Conclusion
The frequency of alveolar hypoventilation in children and adolescents with PWS is of concern and may increase with age and GH treatment. A regular screening by oximetry‐capnography appears to be indicated whatever the sex, BMI, and rate of obstructive or central apneas.
Cough and expiration reflex are major lower airway defense mechanisms that have not been studied throughout development in relation with the feeding behavior.
To describe airway defense reflexes ...evoked by mechanical stimulation of the trachea in developing rabbit pups.
Sixty one pups were allocated to 3 groups according to their feeding behavior: suckling (
= 22), weanling (
= 21) and weaning (
= 18) group. The incidence and sensitivity of defense reflexes triggered by mechanical tracheal stimulation were studied in anesthetized and tracheotomized animals. Data are expressed as median (25th to 75th percentile).
The overall incidence of defensive responses (cough and/or expiration reflex) was found to be significantly higher in suckling 100% (50-100%);
= 0.01 and weanling 75% (40-100%);
= 0.05 animals when compared to weaning ones 37.5% (0-75%). However, cough motor pattern accounted for only 29% (0-62%) of all defensive responses in suckling rabbits and its frequency was significantly lower in this group when compared with weanling 100%(50-100%);
= 0.006 or weaning group 62%(50-100%),
= 0.05. In other word the expiration reflex was the dominant response in suckling animals.
Incidence and motor pattern of defensive responses were found to be linked to the pup feeding behavior and the expiration reflex was the major response triggered in suckling pups. The results suggest that this reflex is especially fitted to occur during the coordinated swallowing - breathing fast activities of sucking.
Due to a limited number of pediatric sleep centers, the aim was to test the feasibility of ambulatory polysomnography (PSG-home) in a group of French children suspected of OSA.
Children undergoing ...one-night PSG-home, with the device installed at the pediatric sleep physician's office, were prospectively included. General failure was considered when PSG-home recording captured < 5 h of artifact-free sleep or when ≥ 1 channel (nasal flow, thoraco-abdominal belts, oximetry) presented artifacts > 75% of the recording time. No-OSA was defined as an obstructive apnea-hypopnia index (OAHI) < 1 event/h and respiratory-related arousals index (RAI) < 1 event/h. OSA was defined as upper airways resistance syndrome (UARS) with OAHI < 1 event/h with RAI ≥ 1 event/h, or mild OSA (OAHI ≥ 1 event/h-5 events/h), moderate OSA (OAHI ≥ 5 events/h-10 events/h), or severe OSA (OAHI ≥ 10 events/h). Parents completed a severity hierarchy score questionnaire, Conners Parent Rating Scale, and an adapted Epworth Sleepiness Scale.
Fifty-seven children aged 3 through 16 years were included. PSG-home was technically acceptable in 46 (81%). Failure due to nasal cannula was observed in 11% (n = 6), oximetry in 7% (n = 4), and both in 2% (n = 1) of cases. No difference in feasibility was found according to age, sex, OSA severity, or comorbidities. There were 14 (25%) children categorized as no-OSA, 43 (75%) as OSA, 4 (7%) as UARS, 26 (46%) as mild, 6 (10%) as moderate, and 7 (12%) as severe OSA. Neither questionnaires nor clinical and physical examination predicted OSA diagnosis.
When equipment is installed at the professional's office and a parent monitors the child, PSG-home is feasible and technically acceptable in children aged 3 through 16 years old. The short delay and feasibility provided by PSG-home could improve the management of children suspected of OSA.
Ambulatory exams were preferred in children during the COVID-19 pandemic. Polysomnography (PSG), the gold standard for obstructive sleep apnea (OSA) diagnosis, requires several leads and sensors to ...be attached to the child's body. Children are more comfortable with respiratory polygraphic (RP) recording, which needs fewer sensors.
To compare respiratory parameters obtained by home RP with those obtained by home PSG with the device installed at the child's home by a trained sleep nurse from a national health care provider.
Data from home PSGs performed in children aged 2–19 years were retrospectively included. The obstructive apnea-hypopnea index (OAHI) was computed in PSG and then in RP after removing the sleep signals. The two indexes were compared using non-parametric paired Wilcoxon rank test, Bland-Altman analysis and sensitivity–specificity analysis.
44 PSGs of 44 children were included with only 34 (77%) PSGs interpretable. Median (min-max) OAHI was significantly underestimated in RP than in PSG (2.2 (0–25) vs 4.0 (0.4–28), p < 0.0001), confirmed also by the Bland-Altman diagram, the magnitude of the difference being mean ± standard deviation −1.7 ± 1.7. The sensitivity and specificity of OAHI in RP to identify an OAHI ≥2/h in PSG was 0.91 for both.
Unattended ambulatory RP performed at child's house and installed under carefully controlled conditions is a useful exam for diagnosing OSA in children with or without comorbidities. However, RP must be installed in a supervised environment and interpreted with caution as it tends to underestimate OSA severity.
•During the COVID-19 epidemic, pediatricians favored ambulatory exams in children.•Respiratory polygraphy (RP) is preferable in children since it has less sensors than polysomnography.•RP must be interpreted with caution as it tends to underestimate the severity of obstructive sleep apnea.•Unattended ambulatory RP installed under controlled conditions is useful for diagnosing obstructive sleep apnea in children.
A child suspected of exercise-induced laryngeal obstruction and asthma is examined by laryngoscopy and respiratory resistance (Rrs) after exercise challenge. Immediately at exercise cessation, the ...visualized adduction of the larynx in inspiration is reflected in a paroxystic increase in Rrs. While normal breathing has apparently resumed later on during recovery from exercise, the pattern of Rrs in inspiration is observed to reoccur following a deep breath or swallowing. The procedure may thus help diagnosing the site of exercise-induced obstruction when laryngoscopy is not available and identify re-inducers of laryngeal dysfunction.
Obstructive sleep apnea syndrome (OSAS) treatment has been shown to improve cardiac behavioral and cognitive functions in typically developing children. Early OSAS diagnosis in children with Down ...syndrome (DS) would be important to prevent its complications, especially cognitive ones, but remains overlooked. The main objective of our study was to assess the cognitive function of children with DS, with and without OSAS. The second objective was to determine the impact of the therapeutic intervention on the cognitive function of children with OSAS. This study included 41 children with DS who underwent polysomnography for OSAS diagnosis and a cognitive evaluation. They were aged between 3.4 and 17.3 years and 24 (59%) were boys. Their median OAHI was 2.6 (0–31)/h of sleep, 30 (73%) were diagnosed with OSAS (15 had mild OSAS, and 15 had moderate/severe OSAS). Some scores of the Raven's colored progressive matrices were negatively correlated with the respiratory arousal index, OAHI tended to be positively correlated with Reiss behavioral problems. 24 (59%) patients received a treatment. Even if we were unable to demonstrate this formally due that only 16 children (39%) accepted a follow-up visit, some displayed improvement in their neuropsychological scores, especially those with moderate/severe OSAS after treatment. Children with DS have low intellectual abilities and more risk of developing OSAS compared to the general population, which may lead to further neurocognitive impairment. Early screening and management are important in this population to prevent any further neurocognitive delay in their development.
•Obstructive sleep apnea syndrome (OSAS) is associated with learning disabilities.•Children with Down syndrome (DS) and OSAS are more vulnerable to OSAS complications.•OSAS treatment may prevent further neurocognitive delay in their development.•Children with DS must be promptly screened and treated for OSAS.
Periodic breathing (PB) is considered physiological in the neonatal period and usually disappears in the first months of life. There are few data available on persistent PB after the neonatal period. ...The objective of this study was to characterize infants born at term with persistent PB after the age of 1 month through polysomnography (PSG) performed during symptoms.
This retrospective case series included infants born at term between 2012 and 2021, without an underlying disease, who presented with symptoms of persistent PB during a PSG. Persistent PB was defined as more than 1 % of total sleep time (TST) of PB after 1 month of life, and PB was defined as a succession of at least three episodes of central apnea lasting more than 3 s and separated by less than 20 s of normal breathing.
A total of 10 infants born at term were included. They underwent PSG for brief resolved unexplained events, desaturation, pauses in breathing, cyanosis, and/or signs of respiratory distress. The percentage of TST spent with PB was 18.1 % before 3 months of age (n = 7), and 4.7 % between 3 and 6 months of age (n = 10). During the first PSG, ≥3 % of desaturation events were observed in 77-100 % of the PB episodes. At the first PSG, nine of the 10 infants had an obstructive apnea-hypopnea index of >10/h and five of 10 infants had a central apnea index of >5/h. Gastroesophageal reflux (GER) was suspected in eight infants. All infants showed improvement in the initial symptoms during the first year of life.
This study presents cases of persistent and symptomatic PB after 1 month of life in infants born at term. The interesting finding was the presence of obstructive sleep apnea syndrome and/or central apnea syndrome in the majority of children, along with GER.
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