Sleep, sleep disordered breathing, and nocturnal hypoventilation in children with neuromuscular diseases

The latest on positive airway pressure for pediatric obstructive sleep apnea

INTRODUCTION

Obstructive sleep apnea (OSA) is an important and evolving area in the pediatric population, with significant sequelae when not adequately managed. The use of positive airway pressure (PAP) therapy is expanding rapidly and is being prescribed to patients with persistent OSA post adenotonsillectomy as well as those children who are not surgical candidates including those with medical complexity.

AREAS DISCUSSED

This article provides a state-of-the-art review on the diagnosis of pediatric OSA and treatment with positive airway pressure (PAP). The initiation of PAP therapy, pediatric interface considerations, PAP mode selection, administration and potential complications of PAP therapy, factors influencing PAP adherence, the use of remote ventilation machine downloads, considerations surrounding follow-up of patients post PAP initiation and evaluation of weaning off PAP will be reviewed. The literature search was conducted via PubMed, Cochrane Library and Google Scholar databases through to March 2024.

EXPERT OPINION

Further research is required to address barriers to adherence. Further innovation of home monitoring devices for both the diagnosis and assessment of OSA is required, given the limited pediatric sleep medicine resources in several countries worldwide.

Paediatric sleep diagnostics in the 21st century: the era of "sleep-omics"?

Paediatric sleep diagnostics is performed using complex multichannel tests in specialised centres, limiting access and availability and resulting in delayed diagnosis and management. Such investigations are often challenging due to patient size (prematurity), tolerability, and compliance with "gold standard" equipment. Children with sensory/behavioural issues, at increased risk of sleep disordered breathing (SDB), often find standard diagnostic equipment difficult.SDB can have implications for a child both in terms of physical health and neurocognitive development. Potential sequelae of untreated SDB includes failure to thrive, cardiopulmonary disease, impaired learning and behavioural issues. Prompt and accurate diagnosis of SDB is important to facilitate early intervention and improve outcomes.The current gold-standard diagnostic test for SDB is polysomnography (PSG), which is expensive, requiring the interpretation of a highly specialised physiologist. PSG is not feasible in low-income countries or outwith specialist sleep centres. During the coronavirus disease 2019 pandemic, efforts were made to improve remote monitoring and diagnostics in paediatric sleep medicine, resulting in a paradigm shift in SDB technology with a focus on automated diagnosis harnessing artificial intelligence (AI). AI enables interrogation of large datasets, setting the scene for an era of "sleep-omics", characterising the endotypic and phenotypic bedrock of SDB by drawing on genetic, lifestyle and demographic information. The National Institute for Health and Care Excellence recently announced a programme for the development of automated home-testing devices for SDB. Scorer-independent scalable diagnostic approaches for paediatric SDB have potential to improve diagnostic accuracy, accessibility and patient tolerability; reduce health inequalities; and yield downstream economic and environmental benefits.

Can postural changes in spirometry in children with Duchenne muscular dystrophy predict sleep hypoventilation?

AIM

To explore the relationship between postural changes in lung function and polysomnography (PSG) in children with Duchenne muscular dystrophy (DMD).

METHODS

In this prospective cross-sectional study, children with DMD performed spirometry in sitting and supine positions. A control group of age and gender matched healthy children also underwent postural lung function testing. PSG was performed within six months of spirometry.

RESULTS

Seventeen children with DMD, aged 12.3 ± 3 years performed sitting spirometry. 14 (84%) performed acceptable spirometry in the supine position. Mean FEV1sit and FVCsit were 77% (SD ± 22) and 74% (SD ± 20.4) respectively, with mean% ΔFVC(sit-sup) 9% (SD ± 11) (range 2% to 20%), and was significantly greater than healthy controls 4% (n = 30, SD ± 3, P < 0.001). PSG data on the 14 DMD children with acceptable supine spirometry showed total AHI 6.9 ± 5.9/hour (0.3 to 29), obstructive AHI 5.2 ± 4.0/hour (0.2 to 10), and REM AHI 14.1 ± -5.3/hour (0.1 to 34.7). ΔFVC(sit-sup) had poor correlation with hypoventilation on polysomnography.

CONCLUSION

Children with DMD and mild restrictive lung disease showed greater postural changes in spirometry than healthy controls but lower supine spirometry was not predictive of sleep hypoventilation.

Sleep in pediatric neuromuscular disorders

Sleep disordered breathing (SDB) is prevalent among children with neuromuscular disorders (NMD). The combination of respiratory muscle weakness, altered drive, and chest wall distortion due to scoliosis make sleep a stressful state in this population. Symptomatology can range from absent to snoring, nocturnal awakenings, morning headaches, and excessive daytime sleepiness. Sequelae of untreated SDB includes cardiovascular effects, metabolic derangements, and neurocognitive concerns which can be compounded by those innate to the NMD. The clinician should have a low threshold for obtaining polysomnography and recognize the nuances of individual disorders due to disproportionately impacted muscle groups such as hypoventilation in ambulating patients from diaphragm weakness. Non-invasive or invasive ventilation are the mainstay of treatment. In this review we explore the diagnosis and treatment of SDB in children with various NMD.

Characteristics and feasibility of ambulatory respiratory assessment of paediatric neuromuscular disease: an observational retrospective study

PURPOSE

To investigate the characteristics of respiratory involvement in Chinese paediatric neuromuscular disease (NMD) at early stage and to explore convenient monitoring methods.

MATERIALS AND METHODS

Children with NMD (age < 18) diagnosed at a multidisciplinary joint NMD clinic at Peking University First Hospital from January 2016 to April 2021 were included. Overnight polysomnography (PSG) and pulmonary function test (PFT) data were analysed, and the characteristics of four groups: congenital muscular dystrophy (CMD), congenital myopathy, spinal muscular atrophy, and Duchenne muscular dystrophy (DMD) were compared.

RESULTS

A total of 83 children with NMD were referred for respiratory assessment, of who 80 children underwent PSG; 41 performed spirometry and 38, both. The duration of pulse oxygen saturation (SpO2) <90% over apnoea and hypopnoea index (AHI) was lowest in DMD and significantly different from CMD (p = 0.033). AHI was positively correlated with the oxygen desaturation index (ODI) (r = 0.929, p = 0.000). The peak expiratory flow (PEF) were positively correlated with forced vital capacity (FVC), both as actual values and percent pred, respectively (r = 0.820, 0.719, p = 0.000). ROC derived sensitivity and specificity of prediction of AHI > 15/h or duration of SpO2<90% ≥ 60 min from FVC <51% pred was 75.8% and 85.7%, respectively.

CONCLUSIONS

AHI and hypoxia burden were independent factors in children with NMD in PSG and attention needed to be paid in both. FVC might be a daytime predictor for significant sleep-disordered breathing or hypoxia. Nocturnal consecutive oximetry with diurnal peak flow measurement may be convenient and effective for home monitoring at early stage of respiratory involvement.

Sleep Disordered Breathing in Children with Neuromuscular Disease

Sleep disordered breathing (SDB) in children with neuromuscular disease (NMD) is more prevalent compared to the general population, and often manifests as sleep-related hypoventilation, sleep-related hypoxemia, obstructive sleep apnea, central sleep apnea, and/or disordered control of breathing. Other sleep problems include, sleep fragmentation, abnormal sleep architecture, and nocturnal seizures in certain neuromuscular diseases. The manifestation of sleep disordered breathing in children depends on the extent, type, and progression of neuromuscular weakness, and in some instances, may be the first sign of a neuromuscular weakness leading to diagnosis of an NMD. In-lab diagnostic polysomnography (PSG) remains the gold standard for the diagnosis of sleep disordered breathing in children, but poses several challenges, including access to many children with neuromuscular disease who are non-ambulatory. If SDB is untreated, it can result in significant morbidity and mortality. Hence, we aimed to perform a comprehensive review of the literature of SDB in children with NMD. This review includes pathophysiological changes during sleep, clinical evaluation, diagnosis, challenges in interpreting PSG data using American Academy of Sleep (AASM) diagnostic criteria, management of SDB, and suggests areas for future research.

Sleep in children from northeastern Brazil with congenital Zika syndrome: assessment using polysomnography

STUDY OBJECTIVES

We performed this study to describe the characteristics of sleep in children with congenital Zika syndrome through polysomnographic assessment.

METHODS

Polysomnography with neurological setup and capnography was performed. Respiratory events were scored according to American Academy of Sleep Medicine criteria. Children were classified based on neuroclinical examination as having corticospinal plus neuromuscular abnormalities or exclusively corticospinal abnormalities. Neuroradiological classification was based on imaging exams, with children classed as having supratentorial plus infratentorial abnormalities or exclusively supratentorial abnormalities.

RESULTS

Of 65 children diagnosed with congenital Zika syndrome, sleep apnea was present in 23 children (35.4%), desaturation in 26 (40%), and snoring in 13 (20%). The most prevalent apnea type was central in 15 children (65.2%), followed by obstructive apnea in 5 (21.7%) and mixed type in 3 (13%). The average of the lowest saturation recorded was slightly below normal (89.1 ± 4.9%) and the mean partial pressure of end-tidal carbon dioxide value was normal. Periodic leg movements were present in 48 of 65 children. Lower ferritin levels were observed in 84.6% of children. Palatine and pharyngeal tonsils (adenoids) were small in most children and not associated with the presence of obstructive apnea. Ventriculomegaly and subcortical and nucleus calcification were the most frequent neuroimaging findings. Supratentorial and infratentorial anomalies were present in 26.7% (16 of 60) and exclusively supratentorial changes in 73.3% (44 of 60). In the neuroclinical classification, isolated corticospinal changes were more frequent and the mean peak in capnography was lower in this group. There was no difference regarding the presence of apnea for children in the neuroclinical and neuroradiological classification groups.

CONCLUSIONS

Sleep disorders were frequent in children with congenital Zika syndrome, with central sleep apnea being the main finding.

CITATION

Brandão Marquis V, de Oliveira Melo A, Pradella-Hallinan M, et al. Sleep in children from northeastern Brazil with congenital Zika syndrome: assessment using polysomnography. J Clin Sleep Med. 2023;19(10):1759-1767.

Limitations of the apnea-hypopnea index in children and young adults with neuromuscular disorders

There are no validated criteria to initiate noninvasive ventilation (NIV) in children and young adults with neuromuscular disease (NMD). In order to analyze NIV initiation criteria, we reviewed the polysomnography (PSG) criteria that led to the initiation of NIV in 61 consecutive patients with NMD, median age 4.1 (0.8-21) years, who had a PSG during their routine care. NIV was initiated on abnormal PSG data (apnea-hypopnea index (AHI) > 10 events/h and/or a transcutaneous carbon dioxide pressure > 50 mmHg and/or a pulse oximetry 〈 90%, both during at least 2% sleep time or 〉 5 consecutive minutes) in 11 (18%) patients. Six of these 11 patients had an AHI ≤ 10 events/h and would not have been ventilated if only AHI was retained. However, one of these 6 patients had isolated nocturnal hypoxemia, 3 isolated nocturnal hypercapnia and 2 abnormal respiratory events. Six (10%) patients with a normal PSG were started on NIV on clinical criteria. Our results show the limitation of the AHI when taken as the unique PSG criterion for NIV initiation in young patients with NMD and underline the need to include also abnormalities of overnight gas exchange into the NIV decision-making process.

Sleep apnoea and hypoventilation in patients with five major types of muscular dystrophy

BACKGROUND

The characteristics of and relationship between sleep apnoea and hypoventilation in patients with muscular dystrophy (MD) remain to be fully understood.

METHODS

We analysed 104 in-laboratory sleep studies of 73 patients with MD with five common types (DMD-Duchenne, Becker MD, CMD-congenital, LGMD-limb-girdle and DM-myotonic dystrophy). We used generalised estimating equations to examine differences among these types for outcomes.

RESULTS

Patients in all five types had high risk of sleep apnoea with 53 of the 73 patients (73%) meeting the diagnostic criteria in at least one study. Patients with DM had higher risk of sleep apnoea compared with patients with LGMD (OR=5.15, 95% CI 1.47 to 18.0; p=0.003). Forty-three per cent of patients had hypoventilation with observed prevalence higher in CMD (67%), DMD (48%) and DM (44%). Hypoventilation and sleep apnoea were associated in those patients (unadjusted OR=2.75, 95% CI 1.15 to 6.60; p=0.03), but the association weakened after adjustment (OR=2.32, 95% CI 0.92 to 5.81; p=0.08). In-sleep average heart rate was about 10 beats/min higher in patients with CMD and DMD compared with patients with DM (p=0.0006 and p=0.02, respectively, adjusted for multiple testing).

CONCLUSION

Sleep-disordered breathing is common in patients with MD but each type has its unique features. Hypoventilation was only weakly associated with sleep apnoea; thus, high clinical suspicion is needed for diagnosing hypoventilation. Identifying the window when respiratory muscle weakness begins to cause hypoventilation is important for patients with MD; it enables early intervention with non-invasive ventilation-a therapy that should both lengthen the expected life of these patients and improve its quality.Cite Now.

Sleep Respiratory Disturbances in Girls with Rett Syndrome

Individuals with Rett Syndrome (RTT), a rare neurodevelopmental disorder, present disordered breathing during wakefulness. Whilst findings on breathing during sleep are contradictory, the relation between sleep breathing and their clinical features, genetic characteristics, age, and sleep phase is rarely investigated, which is the objective of this study. Overnight polysomnography (PSG) was performed. Sleep macrostructure parameters were compared between the RTT subjects with and without sleep-disordered breathing (SDB). The association between the apnea-hypopnea index (AHI) with age at PSG was tested. Particularly for RTT subjects with SDB, the respiratory indexes in REM and NREM sleep were compared. Stratified analyses per clinical characteristics, genetic characteristics, and clinical features' severity were performed. Non-parametric statistics were applied. A sample of 11 female RTT subjects, aged 8.69 ± 5.29 years with ten confirmed with MECP2 mutations, were studied. The average AHI was 3.94 ± 1.19/h TST, of which eight (72.73%) had obstructive sleep apnea, i.e., six in 1/h TST ≤ AHI ≤ 5/h TST, and two in AHI > 5/h TST. The mean SpO₂% was 81.00 ± 35.15%. The AHI was not significantly correlated with their age at PSG (r_s = -0.15, p = 0.67). Sleep macrostructure in SDB-absent and SDB-present groups was not different. Respiratory indexes in those with obstructive sleep apnea showed no difference between REM and NREM sleep nor any of the strata. In our clinical sample, more than half of the RTT subjects with MECP2 mutations had obstructive sleep apnea in both NREM and REM sleep which was unrelated to their clinical features. Our results also indicated hypoxemia throughout nocturnal sleep in RTT. To conclude, our results suggest that disordered breathing during sleep is prevalently present in RTT as an independent clinical feature.

Feasibility and efficacy of active remote monitoring of home ventilation in pediatrics

BACKGROUND

Non-invasive positive airway pressure (PAP) therapy is used to treat children with sleep-disordered breathing. Effective management requires good adherence. In response to the problem of reduced adherence over time, a pilot study using ventilators equipped with technology to remotely monitor home adherence was undertaken.

METHODS

From July 2019, children requiring PAP therapy consented for remote monitoring. Data collected included ventilator usage, apnea-hypopnea index (AHI), and mask leak. Parents were contacted on Days 14, 42, and 90 post-establishment. A proforma was used to assess parental understanding and ways to improve therapy adherence. A parental feedback questionnaire was completed on Day 90 of the study.

RESULTS

Median nightly PAP usage over 90-day post-establishment was 6.58 h (interquartile range: 2.47-8.62); 60% of patients met criteria for good adherence (>4 h for >70% of nights). There was a decrease in median nightly usage in Week 1 (6.92 h) versus Week 12 (6.15 h), p =  0.04. Mask leak was higher in Week 1 (17.7 L/min) versus Week 12 (14.7 L/min), p =  0.053. There was no significant difference in AHI between Week 1 (2.7/h) versus Week 12 (2.3/h), p =  0.75. 45% of questionnaire respondents felt active remote monitoring positively influenced PAP usage, whilst 84% reported overall satisfaction with PAP therapy.

CONCLUSIONS

Remote monitoring technology has the potential to guide adjustments in PAP therapy, monitor and improve adherence in children, and reduce the burden of hospital-based review. Preliminary work shows high approval from parents.

Respiratory concerns in children with medical complexity

Children with medical complexity (CMC) are a diverse group of children affected by a spectrum of chronic disorders and physiologic abnormalities. Due to their underlying disorders, they disproportionately experience respiratory comorbidities and complications. Respiratory-related complications that arise in this population often begin subtly and progress over time and can result in lung injury, respiratory insufficiency, and eventual chronic respiratory failure. CMC make up a substantial proportion of pediatric hospitalizations and healthcare expenditures, with respiratory-related illness being one of the leading causes of admission. It is, therefore, important for the practitioner caring for these children to have knowledge of the common respiratory concerns in this population as well as prevention and management strategies. This review will describe the most common respiratory concerns in CMC and will provide an overview of diagnosis and management.

Slow oscillation density and amplitude decrease across development in pediatric Duchenne and Becker muscular dystrophy

STUDY OBJECTIVES

From childhood through adolescence, brain rhythms during non-rapid eye movement (NREM) sleep show dramatic development that mirror underlying brain maturation. For example, the function and characteristics of slow oscillations (SOs, <1 Hz) in healthy children are linked to brain development, motor skill, and cognition. However, little is known of possible changes in pediatric populations with neurologic abnormalities.

METHODS

We measured slow oscillations in 28 Duchenne and Becker muscular dystrophy male patients from age 4 to 20 years old during overnight in-lab clinical sleep studies. We compared our pediatric patients by age to evaluate the developmental changes of SOs from childhood to early and late adolescence.

RESULTS

Consistent with the current neuro- and physically typical literature, we found greater slow oscillation density (count of SOs per minute of each sleep stage) in NREM N3 than N2, and significantly greater slow oscillation density in frontal compared to central and occipital regions. However, separating patients into age-defined groups (child, early adolescent, and late adolescent) revealed a significant age effect, with a specific decline in the rate and amplitude of SOs.

CONCLUSIONS

We found that with age, pediatric patients with Duchenne muscular dystrophy show a significant decline in slow oscillation density. Given the role that slow oscillations play in memory formation and retention, it is critical to developmentally characterize these brain rhythms in medically complex populations. Our work converges with previous pediatric sleep literature that promotes the use of sleep electroencephalographic markers as prognostic tools and identifies potential targets to promote our patients' quality of life.

Respiratory Complications of Pediatric Neuromuscular Diseases

Respiration is an event of oxygen consumption and carbon dioxide production. Respiratory failure is common in pediatric neuromuscular diseases and the main cause of morbidity and mortality. It is a consequence of lung failure, ventilatory pump failure, or their combination. Lung failure often is due to chronic aspiration either from above or from below. It may lead to end-stage lung disease. Ventilatory pump failure is caused by increased respiratory load and progressive respiratory muscles weakness. This article reviews the normal function of the respiratory pump, general pathophysiology issues, abnormalities in the more common neuromuscular conditions and noninvasive interventions.

Acute flaccid myelitis: cause, diagnosis, and management

Acute flaccid myelitis (AFM) is a disabling, polio-like illness mainly affecting children. Outbreaks of AFM have occurred across multiple global regions since 2012, and the disease appears to be caused by non-polio enterovirus infection, posing a major public health challenge. The clinical presentation of flaccid and often profound muscle weakness (which can invoke respiratory failure and other critical complications) can mimic several other acute neurological illnesses. There is no single sensitive and specific test for AFM, and the diagnosis relies on identification of several important clinical, neuroimaging, and cerebrospinal fluid characteristics. Following the acute phase of AFM, patients typically have substantial residual disability and unique long-term rehabilitation needs. In this Review we describe the epidemiology, clinical features, course, and outcomes of AFM to help to guide diagnosis, management, and rehabilitation. Future research directions include further studies evaluating host and pathogen factors, including investigations into genetic, viral, and immunological features of affected patients, host-virus interactions, and investigations of targeted therapeutic approaches to improve the long-term outcomes in this population.

Evaluation and Management of Children with Obstructive Sleep Apnea Syndrome

Obstructive sleep apnea syndrome (OSAS) is a common pediatric disorder characterized by recurrent events of partial or complete upper airway obstruction during sleep which result in abnormal ventilation and sleep pattern. OSAS in children is associated with neurobehavioral deficits and cardiovascular morbidity which highlights the need for prompt recognition, diagnosis, and treatment. The purpose of this state-of-the-art review is to provide an update on the evaluation and management of children with OSAS with emphasis on children with complex medical comorbidities and those with residual OSAS following first-line treatment. Proposed treatment strategies reflecting recommendations from a variety of professional societies are presented. All children should be screened for OSAS and those with typical symptoms (e.g., snoring, restless sleep, and daytime hyperactivity) or risk factors (e.g., neurologic, genetic, and craniofacial disorders) should undergo further evaluation including referral to a sleep specialist or pediatric otolaryngologist and overnight polysomnography, which provides a definitive diagnosis. A cardiology and/or endocrinology evaluation should be considered in high-risk children. For the majority of children, first-line treatment is tonsillectomy with or without adenoidectomy; however, some children exhibit multiple levels of airway obstruction and may require additional evaluation and management. Anti-inflammatory medications, weight loss, and oral appliances may be appropriate in select cases, particularly for mild OSAS. Following initial treatment, all children should be monitored for residual symptoms and polysomnography may be repeated to identify persistent disease, which can be managed with positive airway pressure ventilation and additional surgical approaches if required.

The Feasibility and Utility of Level III Portable Sleep Studies in the Pediatric Inpatient Setting

STUDY OBJECTIVES

Sleep-disordered breathing (SDB) may significantly impact the course of medical illness in hospitalized children. Polysomnography (PSG) is the gold standard for establishing diagnosis of SDB, but its availability is limited. The aim of this study was to explore the feasibility and utility of level III portable sleep studies in hospitalized children with SDB.

METHODS

A retrospective study was conducted at a tertiary hospital over the preceding 2 years in hospitalized children < 18 years who had undergone a level III sleep study using the Nox T3 system. The information obtained included demographic data, comorbidities, indication for admission and sleep study, time interval between the study ordered and done, adequacy of technical data from sleep study, study diagnosis, and subsequent management interventions for SDB.

RESULTS

A total of 51 hospitalized children had these studies; 32 were female and mean age was 4.3 years. Approximately 90% of children had significant comorbidities, including neurological and craniofacial abnormalities. The majority (80%) of studies were conducted within 24 hours of the time requested and 92.1% studies had technically adequate data for analysis. Thirty-nine (76.5%) children were identified with SDB; all but one patient underwent therapy for SDB during that same hospitalization, including supplemental oxygen (48.7%), positive airway pressure therapy (23%), surgical intervention (38.2%) or caffeine (10.2%). Twelve percent of children had more than one intervention done.

CONCLUSIONS

The level III portable sleep study is readily available, sufficient to diagnose SDB, and help to provide appropriate medical and/or surgical therapies in hospitalized children with complex medical conditions.

Myotonic dystrophy type 1: clinical manifestations in children and adolescents

OBJECTIVE

Myotonic dystrophy type 1 (DM1) is an autosomal-dominant neuromuscular disease with variable severity affecting all ages; however, current care guidelines are adult-focused. The objective of the present study was to profile DM1 in childhood and propose a framework to guide paediatric-focused management.

DESIGN, SETTING AND PATIENTS

40 children with DM1 (mean age 12.8 years; range 2-19) were studied retrospectively for a total of 513 follow-up years at Sydney Children's Hospital. 143 clinical parameters were recorded.

RESULTS

The clinical spectrum of disease in childhood differs from adults, with congenital myotonic dystrophy (CDM1) having more severe health issues than childhood-onset/juvenile patients (JDM1). Substantial difficulties with intellectual (CDM1 25/26 96.2%; JDM1 9/10, 90.0%), fine motor (CDM1 23/30, 76.6%; JDM1 6/10, 60.0%), gastrointestinal (CDM1 17/30, 70.0%; JDM1 3/10, 30.0%) and neuromuscular function (CDM1 30/30, 100.0%; JDM1 25/30, 83.3%) were evident.

CONCLUSION

The health consequences of DM1 in childhood are diverse, highlighting the need for paediatric multidisciplinary management approaches that encompass key areas of cognition, musculoskeletal, gastrointestinal, respiratory, cardiac and sleep issues.

Sleep-Disordered Breathing and Spinal Cord Injury: A State-of-the-Art Review

Individuals living with spinal cord injury or disease (SCI/D) are at increased risk for sleep-disordered breathing (SDB), with a prevalence that is three- to fourfold higher than the general population. The main features of SDB, including intermittent hypoxemia and sleep fragmentation, have been linked to adverse cardiovascular outcomes including nocturnal hypertension in patients with SCI/D. The relationship between SDB and SCI/D may be multifactorial in nature given that level and completeness of injury can affect central control of respiration and upper airway collapsibility differently, promoting central and/or obstructive types of SDB. Despite the strong association between SDB and SCI/D, access to diagnosis and management remains limited. This review explores the role of SCI/D in the pathogenesis of SDB, poor sleep quality, the barriers in diagnosing and managing SDB in SCI/D, and the alternative approaches and future directions in the treatment of SDB, such as novel pharmacologic and nonpharmacologic treatments.

Changing respiratory expectations with the new disease trajectory of nusinersen treated spinal muscular atrophy [SMA] type 1

Spinal muscular atrophy [SMA] is the most common genetic cause of childhood mortality, primarily from the most severe form SMA type 1. It is a severe, progressive motor neurone disease, affecting the lower brainstem nuclei and the spinal cord. There is a graded level of severity with SMA children from a practical viewpoint described as "Non-sitters", "Sitters" and less commonly, "Ambulant" correlating with SMA Type 0/Type 1, Type 2 and Type 3 respectively. Children with SMA Type 0 have a severe neonatal form whilst those with SMA Type 1 develop hypoventilation, pulmonary aspiration, recurrent lower respiratory tract infections, dysphagia and failure to thrive before usually succumbing to respiratory failure and death before the age of 2 years. The recent introduction of the antisense oligonucleotide nusinersen into clinical practice in certain countries, following limited trials of less than two years duration, has altered the treatment landscape and improved the outlook considerably for SMN1 related SMA. Approximately 70% of infants appear to have a clinically significant response to nusinersen with improved motor function. It appears the earlier the treatment is initiated the better the response. There are other rarer genetic forms of SMA that are not treated with nusinersen. Clinical expectations will change although it is unclear as yet what the extent of response will mean in terms of screening initiatives [e.g., newborn screening], "preventative strategies" to maintain respiratory wellbeing, timing of introduction of respiratory supports, and prolonged life expectancy for the subcategory of children with treated SMA type 1. This article provides a review of the strategies available for supporting children with respiratory complications of SMA, with a particular emphasis on SMA Type 1.

Identification of sleep hypoventilation in young individuals with Becker muscular dystrophy: A pilot study

AIM

To report on sleep hypercapnia in Becker muscular dystrophy (BMD) at earlier stages than ever recognized.

SUBJECTS AND METHODS

This retrospective study examined nocturnal hypercapnia in six young Becker muscular dystrophy (BMD) patients with deletions of one or more exons of DMD gene. Clinical information, consecutive data on forced vital capacity (FVC%), forced expiratory volume in one second (FEV1%), peak expiratory flow (PEF%), peak cough flow (PCF), average PCO₂ in all-night monitoring, and left ventricular ejection fraction (LVEF) were reviewed.

RESULTS

In five BMD patients, including three who were still ambulant, nocturnal average PCO₂ was elevated to >45 mmHg at 12-31 years of age. Noninvasive positive pressure ventilation was initiated in four patients. Gradual declines in FVC% and PEF% were evident in one BMD patient with exon 3-7 deletion, whereas these functions did not change in the remaining BMD patients. PCF, FEV1%, and LVEF were less informative for the assessment of respiratory function in this patient series.

CONCLUSION

Sleep hypercapnia was present in certain BMD patients, which was unexpected from the routine pulmonary function tests. Individualized assessment of nocturnal PCO₂, partly based on the deletion types, should be further explored in the clinical practice of BMD patients.

Breathing with neuromuscular disease: Does compensatory plasticity in the motor drive to breathe offer a potential therapeutic target in muscular dystrophy?

Duchenne muscular dystrophy is a fatal neuromuscular disease associated with respiratory-related morbidity and mortality. Herein, we review recent work by our group exploring deficits and compensation in the respiratory control network governing respiratory homeostasis in a pre-clinical model of DMD, the mdx mouse. Deficits at multiple sites of the network provide considerable challenges to respiratory control. However, our work has also revealed evidence of compensatory neuroplasticity in the motor drive to breathe enhancing diaphragm muscle activity during increased chemical drive. The finding may explain the preserved capacity for mdx mice to increase ventilation in response to chemoactivation. Given the profound dysfunction in the primary pump muscle of breathing, we argue that activation of accessory muscles of breathing may be especially important in mdx (and perhaps DMD). Notwithstanding the limitations resulting from respiratory muscle dysfunction, it may be possible to further leverage intrinsic physiological mechanisms serving to compensate for weak muscles in attempts to preserve or restore ventilatory capacity. We discuss current knowledge gaps and the need to better appreciate fundamental aspects of respiratory control in pre-clinical models so as to better inform intervention strategies in human DMD.

Can daytime measures of lung function predict respiratory failure in children with neuromuscular disease?

Neuromuscular disorders in children are a heterogeneous group of conditions with a variable age of presentation and overlapping clinical manifestations, many of which have progressive respiratory morbidity. Respiratory insufficiency occurs as a consequence of an imbalance between demands on the respiratory system and respiratory muscle capacity. Daytime measures of pulmonary function are used routinely in these children to assess respiratory status and monitor the consequences of the progression of muscle weakness. This review describes the current evidence for daytime pulmonary function tests and their ability to predict imminent respiratory morbidity.

Pulmonary Manifestations of Neuromuscular Diseases

Neuromuscular disorders comprise a phenotypically diverse group of inherited and acquired diseases; however, they share common pathophysiologic mechanisms which produce significant respiratory complications. Respiratory and bulbar muscle weakness gives rise to ineffective cough, swallowing dysfunction results in aspiration-related lung disease, and abnormal muscle tone produces chest wall deformities - all of which ultimately leads to repeated chest infections and chronic respiratory failure. In this article, the authors describe the respiratory manifestations of neuromuscular disease and their underlying pathophysiological mechanisms. This review also highlights the diagnostic and management tools recommended for acute and chronic care. Aggressive pulmonary management is the most impactful at reducing the overall morbidity and improving the quality of life of children with neuromuscular disorders, at least while definitive molecular and gene replacement therapies remain elusive.

The value of respiratory muscle testing in children with neuromuscular disease

Routine lung function and respiratory muscle testing are recommended in children with neuromuscular disease (NMD), but these tests are based on noninvasive volitional maneuvers, such as the measurement of lung volumes and maximal static pressures, that young children may not always be able to perform. The realization of simple natural maneuvers such as a sniff or a cough, and the measurement of esophageal and gastric pressures during spontaneous breathing can add valuable information about the strength and endurance of the respiratory muscles in young children. Monitoring respiratory muscles in children with NMD may improve understanding of the natural history of NMD and the evaluation of disease severity. It may assist and guide clinical management and it may help the identification and selection of optimal end points, as well as the most informative parameters and patients for clinical trials.

Long-term ventilation in children: ten years later

INTRODUCTION

Home mechanical ventilation (HMV) represents a treatment option for patients with chronic respiratory failure and has changed prognosis and survival of many disorders in children. The aim of this study was to characterize a group of children on long-term mechanical ventilation (LTMV) for a period longer than 10 years.

METHODS

A retrospective analysis was carried out including patients on LTMV for more than 10 years (LTMV-10) in a tertiary pediatric hospital.

STATISTICAL ANALYSIS

PASW Statistics 18(®).

RESULTS

Thirty-one children (61% female) belong to the LTMV-10 group. Median age at the beginning of ventilatory support was 3 years (birth to 13 years). Main indications for assisted ventilation were neuromuscular disease (n=12, 39%), metabolic disease (n=7, 23%) and central hypoventilation (n=6, 19%). Volume ventilation was used in 2 children, and positive pressure ventilation in the others, mainly bilevel positive airway pressure (n=25, 81%). Invasive ventilation via tracheostomy was used since the beginning in four cases, and subsequently in two other children. The mean time of ventilatory support was 146 months and the maximum was 219 months. Respiratory morbidity was the most frequent cause of hospitalization and the annual rate of such episodes was 0.17 per child. Global mortality rate was 19%.

CONCLUSIONS

HMV programs provide necessary and safe assistance for children with severe chronic respiratory failure. As shown in our series, it is possible to be kept on this respiratory support modality for long periods with good compliance and a small number of hospitalizations.

Sleep disordered breathing in children with mitochondrial disease

A retrospective chart review study was performed to determine the presence of sleep disordered breathing (SDB) in children with primary mitochondrial disease (MD). The symptoms, sleep-related breathing, and movement abnormalities are described for 18 subjects (ages 1.5 to 18 years, 61% male) with MD who underwent polysomnography in our pediatric sleep center from 2007 to 2012. Of the 18 subjects with MD, the common indications for polysomnography were excessive somnolence or fatigue (61%, N = 11), snoring (44%, N = 8), and sleep movement complaints (17%, N = 3). Polysomnographic measurements showed SDB in 56% (N = 10) (obstructive sleep apnea in 60% (N = 6), hypoxemia in 40% (N = 4), and sleep hypoventilation in 20% (N = 2)). There was a significant association between decreased muscle tone and SDB (P: 0.043) as well as obese and overweight status with SDB (P = 0.036). SDB is common in subjects with MD. Early detection of SDB, utilizing polysomnography, should be considered to assist in identification of MD patients who may benefit from sleep-related interventions.

[Obstructive sleep apnea-hypopnea syndrome in children: beyond adenotonsillar hypertrophy]

The prevalence of obstructive sleep apnea-hypopnea syndrome in the general childhood population is 1-2% and the most common cause is adenotonsillar hypertrophy. However, beyond adenotonsillar hypertrophy, there are other highly prevalent causes of this syndrome in children. The causes are often multifactorial and include muscular hypotonia, dentofacial abnormalities, soft tissue hypertrophy of the airway, and neurological disorders). Collaboration between different specialties involved in the care of these children is essential, given the wide variability of conditions and how frequently different factors are involved in their genesis, as well as the different treatments to be applied. We carried out a wide literature review of other causes of obstructive sleep apnea-hypopnea syndrome in children, beyond adenotonsillar hypertrophy. We organised the prevalence of this syndrome in each pathology and the reasons that cause it, as well as their interactions and management, in a consistent manner.

WITHDRAWN: Long-term ventilation in children: Ten years later

This article has been withdrawn for editorial reasons because the journal will be published only in English. In order to avoid duplicated records, this article can be found at http://dx.doi.org/10.1016/j.rppnen.2014.03.017. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Managing snoring and obstructive sleep apnoea in childhood

Snoring assessment and its differentiation from obstructive sleep apnoea are difficult based upon a parent history and physical examination of the size of the tonsils. Not only is the presence of obstructive sleep apnoea important to diagnose, but confirming its severity is the key determinant in prioritising treatment in a resource-limited setting. This review provides current knowledge on the utility of common diagnostic tests, results of treatment options available and implications of treatment and unrecognised or untreated obstructive sleep apnoea.

Nocturnal phenotypical features of obstructive sleep apnea (OSA) in asthmatic children

BACKGROUND

Asthma and obstructive sleep apnea (OSA) often coexists during childhood. To delineate this clinical association, we investigated the phenotypical features of OSA in asthmatic children. Specifically, we hypothesized that asthmatic children have a distinct OSA phenotype that involves a higher prevalence of Rapid-Eye-Movement (REM)-related breathing abnormalities relative to children with OSA alone.

METHODS

We conducted a retrospective cross-sectional analysis of 141 children aged 2-12 years with OSA diagnosed by polysomnography (PSG) in our sleep center. Outcomes included PSG parameters, maximal %SaO2 REM desaturations and prevalence of REM-related OSA. Multivariate linear regression model or logistic regression model was built to study the joint effect of asthma and OSA parameters with control for potential confounders (significance level P < 0.05).

RESULTS

Baseline respiratory parameters, obstructive apnea-hypopnea index (OAHI) severity, and oxygenation during NREM sleep were unaffected by the presence of asthma in children with OSA. In contrast, maximal %SaO2 REM desaturation, REM-OAHI and prevalence of REM-related OSA in children with moderate-severe OSA were significantly increased in asthmatic children with OSA compared to subjects with OSA alone. Multivariate analysis revealed that the association between asthma and REM-related OSA parameters is independent of asthma control, BMI, age, and gender. The presence of REM-related OSA in asthmatics was unaffected by rhinitis or atopic status.

CONCLUSION

These results demonstrate that asthma is associated with REM-related breathing abnormalities in children with moderate-severe OSA. The link between asthma and REM-related OSA is independent of asthma control and obesity. Further research is needed to delineate the REM-sleep biological mechanisms that modulate the phenotypical expression of OSA in asthmatic children.

Consensus statement on standard of care for congenital myopathies

Recent progress in scientific research has facilitated accurate genetic and neuropathological diagnosis of congenital myopathies. However, given their relatively low incidence, congenital myopathies remain unfamiliar to the majority of care providers, and the levels of patient care are extremely variable. This consensus statement aims to provide care guidelines for congenital myopathies. The International Standard of Care Committee for Congenital Myopathies worked through frequent e-mail correspondences, periodic conference calls, 2 rounds of online surveys, and a 3-day workshop to achieve a consensus for diagnostic and clinical care recommendations. The committee includes 59 members from 10 medical disciplines. They are organized into 5 working groups: genetics/diagnosis, neurology, pulmonology, gastroenterology/nutrition/speech/oral care, and orthopedics/rehabilitation. In each care area the authors summarize the committee's recommendations for symptom assessments and therapeutic interventions. It is the committee's goal that through these recommendations, patients with congenital myopathies will receive optimal care and improve their disease outcome.

Perioperative management of the paediatric patient with coexisting neuromuscular disease

Children with neuromuscular diseases present a wide range of clinical manifestations and clinical implications for the anaesthesiologist. Neuromuscular diseases in children affect muscle strength by either directly weakening the muscle fibrils or indirectly by a degenerative nerve supply and weak neuromuscular junction. Of the more than 200 neuromuscular disorders known, the vast majority are genetic in origin. This review focuses on four of the more common neuromuscular disorders with emphasis on their pathophysiology and clinical implications for anaesthesiologists: malignant hyperthermia, the muscular dystrophies (Duchenne's, Becker's, and Emery-Dreifuss), mitochondrial disorders, and cerebral palsy.