Sleep-Disordered Breathing in Neuromuscular Disease: Diagnostic and Therapeutic Challenges

Definition of diaphragmatic sleep disordered breathing and clinical meaning in Duchenne muscular dystrophy

BACKGROUND

Diaphragmatic sleep disordered breathing (dSDB) has been recently identified as sleep dysfunction secondary to diaphragmatic weakness in Duchenne muscular dystrophy (DMD). However, scoring criteria for the identification of dSDB are missing.This study aimed to define and validate dSDB scoring criteria and to evaluate whether dSDB severity correlates with respiratory progression in DMD.

METHODS

Scoring criteria for diaphragmatic apnoea (dA) and hypopnoeas (dH) have been defined by the authors considering the pattern observed on cardiorespiratory polygraphy (CR) and the dSDB pathophysiology.10 sleep professionals (physiologists, consultants) blinded to each other were involved in a two-round Delphi survey to rate each item of the proposed dSDB criteria (Likert scale 1-5) and to recognise dSDB among other SDB. The scorers' accuracy was tested against the authors' panel.Finally, CR previously conducted in DMD in clinical setting were rescored and diaphragmatic Apnoea-Hypopnoea Index (dAHI) was derived. Pulmonary function (forced vital capacity per cent of predicted, FVC%pred), overnight oxygen saturation (SpO2) and transcutaneous carbon dioxide (tcCO2) were correlated with dAHI.

RESULTS

After the second round of Delphi, raters deemed each item of dA and dH criteria as relevant as 4 or 5. The agreement with the panel in recognising dSDB was 81%, kappa 0.71, sensitivity 77% and specificity 85%.32 CRs from DMD patients were reviewed. dSDB was previously scored as obstructive. The dAHI negatively correlated with FVC%pred (r=-0.4; p<0.05). The total number of dA correlated with mean overnight tcCO2 (r 0.4; p<0.05).

CONCLUSIONS

dSDB is a newly defined sleep disorder that correlates with DMD progression. A prospective study to evaluate dSDB as a respiratory measure for DMD in clinical and research settings is planned.

Sleep and sleep-related breathing disorders in patients with spinal muscular atrophy: a changing perspective from novel treatments?

Spinal Muscular Atrophy (SMA) is an inherited neuromuscular disorder characterized by progressive muscle weakness and atrophy, resulting from the degeneration of motor neurons in the spinal cord. A critical aspect of SMA is its impact on respiratory function. As the disease progresses, respiratory muscles, in particular intercostal muscles, become increasingly affected, leading to breathing difficulties and respiratory failure. Without intervention, many children with SMA type 1 die from respiratory failure before their second year of life. While assisted ventilation has improved survival, it often results in ventilator dependence. The development of new SMN-augmenting therapies has renewed optimism, but their long-term impact on respiratory function is uncertain, and non-invasive respiratory support remains an important part of SMA management. Despite the importance of respiratory support in SMA, knowledge regarding sleep disorders in this population is limited. This review aims to synthesize existing literature on sleep and sleep-related breathing disorders in patients with SMA, with a focus on SMA type 1. We summarize evidence of sleep-disordered breathing and respiratory failure in SMA, as well as outcomes and survival benefits associated with non-invasive or invasive ventilation with or without pharmacological therapies. We also discuss current knowledge regarding the effects of novel disease-modifying therapies for SMA on respiratory function and sleep. In conclusion, optimal care for children with SMA requires a multidisciplinary approach that includes neurology and respiratory specialists. This review highlights the importance of monitoring sleep and respiratory function in SMA, as well as the potential benefits and challenges associated with assisted ventilation combined with new therapies.

Home Noninvasive Ventilation in COPD

Evidence is increasing that long-term noninvasive ventilation (LTNIV) can improve outcomes in individuals with severe, hypercapnic COPD. Although the evidence remains unclear in some aspects, LTNIV seems to be able to improve patient-related and physiologic outcomes like dyspnea, FEV1 and partial pressure of carbon dioxide (Pco2) and also to reduce rehospitalizations and mortality. Efficacy generally is associated with reduction in Pco2. To achieve this, an adequate interface (mask) is essential, as are appropriate ventilation settings that target the specific respiratory physiologic features of COPD. This will ensure comfort, synchrony, and adherence that will result in physiologic improvements. This article briefly reviews the newest evidence and current guidelines on LTNIV in severe COPD. It describes an actual patient who benefitted from the therapy. Finally, it provides strategies for initiating and optimizing this LTNIV in COPD, discussing high-pressure noninvasive ventilation, optimization of triggering, and control of inspiratory time. As demand increases, clinicians will need to be familiar with this therapy to reap its benefits, because inadequately adjusted LTNIV will not be tolerated or effective.

Perioperative Management in Neuromuscular Diseases: A Narrative Review

Patients with neuromuscular diseases are particularly vulnerable in the perioperative period to the development of pulmonary and cardiac complications, or medication side effects. These risks could include hypoventilation, aspiration pneumonia, exacerbation of underlying cardiomyopathy, arrhythmias, adrenal insufficiency, prolonged neuromuscular blockade, issues related to thermoregulation, rhabdomyolysis, malignant hyperthermia, or prolonged mechanical ventilation. Interventions at each of the perioperative stages can be implemented to mitigate these risks. A careful pre-operative evaluation may help identify risk factors so that appropriate interventions are initiated, including cardiology consultation, pulmonary function tests, initiation of noninvasive ventilation, or implementation of preventive measures. Important intraoperative issues include positioning, airway and anesthetic management, and adequate ventilation. The postoperative period may require correction of electrolyte abnormalities, control of secretions with medications, manual or mechanical cough assistance, avoiding the risk of reintubation, judicious pain control, and appropriate medication management. The aim of this review is to increase awareness of the particular surgical challenges in this vulnerable population, and guide the clinician on the various evaluations and interventions that may result in a favorable surgical outcome.

Spectrum of sleep-disordered breathing and quality of sleep in adolescent and adult patients with spinal muscular atrophy

Sleep-disordered breathing is common among children with spinal muscular atrophy, but has been hardly studied among adult subjects. Little is known about sleep quality in spinal muscular atrophy. The aims of this study were to evaluate occurrence and characteristics of sleep-disordered breathing and subjective sleep quality among adolescent and adult patients with spinal muscular atrophy type 2 or 3. Twenty patients aged 33.9 ± 15.2 years were studied. They underwent nocturnal cardiorespiratory monitoring, lung and muscular function evaluation, and were administered the Pittsburgh Sleep Quality Index questionnaire. Nineteen patients showed sleep-disordered breathing, with obstructive events in seven subjects and non-obstructive events in the remaining 12. In the latter group, 10 patients showed pseudo-obstructive hypopneas. Patients with non-obstructive sleep-disordered breathing were younger (p = 0.042), had a lower body mass index (p = 0.0001), were more often affected by spinal muscular atrophy type 2 (p = 0.001), and showed worse impairment of respiratory function than patients with obstructive sleep-disordered breathing. Ten patients were classified as poor sleepers and 10 patients good sleepers. In the whole sample, sniff nasal inspiratory pressure proved to be the only independent predictor of sleep quality (p = 0.009). In conclusion, sleep-disordered breathing is common even among adult patients with spinal muscular atrophy type 2 and 3, and may show either obstructive or different types on non-obstructive features. A worse respiratory muscle function is associated to non-obstructive sleep-disordered breathing and poorer sleep quality. Sleep quality should receive greater attention especially in patients with spinal muscular atrophy type 2, who have a poorer respiratory muscle function, as it could affect their quality of life.

Sleep disordered breathing assessment in patient with slowly progressive neuromuscular disease

BACKGROUND

Sleep-disordered breathing (SDB) is common in patients with neuromuscular diseases (NMD). Focusing on hypercapnia may lead to the neglect of other SDB such as obstructive and/or central sleep apnea syndrome (SAS). Our objectives were to assess the risk of inappropriate SDB management according to different screening strategies and to evaluate the prevalence and determinants of isolated and overlapping sleep apnea in patients with slowly progressive NMD.

METHODS

This monocentric, cross-sectional, retrospective study analyzed medical records of adult NMD patients referred to a sleep department. Diagnostic strategies, including respiratory polygraphy (RP), nocturnal transcutaneous capnography (tcCO2), and blood gases (BG), were assessed for their performance in diagnosing SDB. Demographics and pulmonary function test results were compared between patients with or without SDB to identify predictors.

RESULTS

Among the 149 patients who underwent a full diagnostic panel (RP + tcCO2 + BG), 109 were diagnosed with SDB. Of these, 33% had isolated SAS, and central apneas were predominant. Using single diagnostic strategies would lead to inappropriate SDB management in two thirds of patients. A combination of 2 diagnostic tools resulted respectively in 21.1, 22.9 and 42.2 % of inappropriate SDB management for RP + tcCO2, RP + BG and tcCO2 + BG.

CONCLUSION

The significant prevalence of sleep apnea syndrome in patients with slowly progressive NMD highlights the need for increased awareness among clinicians. Improved diagnostics involve a systematic approach addressing both sleep apnea and diurnal and nocturnal alveolar hypoventilation to avoid inappropriate management and limit the consequences of SDB.

Insomnia and sleep-disordered breathing in FKRP-related limb-girdle muscular dystrophy R9. The Norwegian LGMDR9 cohort study (2020)

Limb-girdle muscular dystrophy R9 (LGMDR9) is a progressive and disabling genetic muscle disease. Sleep is relevant in the patient care as it impacts on health, functioning, and well-being. LGMDR9 may potentially affect sleep by physical or emotional symptoms, myalgia, or sleep-disordered breathing (SDB) through cardiorespiratory involvement. The objective was to investigate the occurrence of insomnia and unrecognized or untreated SDB in LGMDR9, associated factors, and relationships with fatigue and health-related quality of life (HRQoL). All 90 adults in a Norwegian LGMDR9 cohort received questionnaires on sleep, fatigue, and HRQoL. Forty-nine of them underwent clinical assessments and 26 without mask-based therapy for respiration disorders additionally underwent polysomnography (PSG) and capnometry. Among 77 questionnaire respondents, 31% received mask-based therapy. The prevalence of insomnia was 32% of both those with and without such therapy but was significantly increased in fatigued respondents (54% vs 21%). Insomnia levels correlated inversely with mental HRQoL. Among 26 PSG candidates, an apnea-hypopnea index (AHI) ≥ 5/h was observed in 16/26 subjects (≥ 15/h in 8/26) with median 6.8 obstructive apneas and 0.2 central apneas per hour of sleep. The AHI was related to advancing age and an ejection fraction < 50%. Sleep-related hypoventilation was detected in one subject. Fatigue severity did not correlate with motor function or nocturnal metrics of respiration or sleep but with Maximal Inspiratory Pressure (r = - 0.46). The results indicate that insomnia and SDB are underrecognized comorbidities in LGMDR9 and associated with HRQoL impairment and heart failure, respectively. We propose an increased attention to insomnia and SDB in the interdisciplinary care of LGMDR9. Insomnia and pulmonary function should be examined in fatigued patients.

A Case of Nemaline Myopathy With Sleep-Related Hypoventilation Diagnosed Using Polysomnography During Daytime Napping

This is the case of a 49-year-old woman who was admitted to the hospital for a close examination of pulmonary hypertension; however, the next morning, she developed carbon dioxide (CO2) narcosis and was started on artificial ventilation. As pulmonary arterial hypertension was ruled out, the patient was extubated, and 24-hour transcutaneous partial pressure of carbon dioxide (PCO2)(transcutaneous carbon dioxide (TcPCO2)) monitoring was performed to diagnose sleep-related hypoventilation. Polysomnography (PSG) during daytime napping revealed markedly decreased chest motion and a "pseudo-central event," which was neither central nor obstructive hypopnea. Based on the PSG results and physical examination findings, a neuromuscular disorder was suspected, and a muscle biopsy was performed to diagnose nemaline myopathy. Neuromuscular diseases are widely recognized for their association with sleep-disordered breathing; thus, sleep-related hypoventilation should also be considered. Monitoring of TcPCO2 and PSG are useful tools in identifying the cause of hypoventilation; however, overnight PSG may cause CO2 narcosis in some diseases. In such cases, PSG may be beneficial during daytime napping.

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.

Validation of a portable monitor compared with polysomnography for screening of obstructive sleep apnea in polio survivors

Subjective

Sleep-disordered breathing (SDB) is highly prevalent in polio survivors. Obstructive sleep apnea (OSA) is the most frequent type. Full polysomnography (PSG) is recommended for OSA diagnosis in patients with comorbidities by current practice guidelines, but it is not always accessible. The purpose of this study was to evaluate whether type 3 portable monitor (PM) or type 4 PM might be a viable alternative to PSG for the diagnosis of OSA in postpolio subjects.

Methods

A total of 48 community-living polio survivors (39 men and 9 women) with an average age of 54.4 ± 5.3 years referred for the evaluation of OSA and who volunteered to participate were recruited. First, they completed the Epworth Sleepiness Scale (ESS) questionnaire and underwent pulmonary function testing and blood gas tests the day before PSG night. Then, they underwent an overnight in-laboratory PSG with a type 3 PM and type 4 PM recording simultaneously.

Results

The AHI from PSG, respiratory event index (REI) from type 3 PM, and ODI₃ from type 4 PM was 30.27 ± 22.51/h vs. 25.18 ± 19.11/h vs. 18.28 ± 15.13/h, respectively (P < 0.001). For AHI ≥ 5/h, the sensitivity and specificity of REI were 95.45 and 50%, respectively. For AHI ≥ 15/h, the sensitivity and specificity of REI were 87.88% and 93.33%, respectively. The Bland-Altman analysis of REI on PM vs. AHI on PSG showed a mean difference of -5.09 (95% confidence interval [CI]: -7.10, -3.08; P < 0.001) with limits of agreement ranging from -18.67 to 8.49 events/h. ROC curve analysis for patients with REI ≥ 15/h showed an area under the curve (AUC) of 0.97. For AHI ≥ 5/h, the sensitivity and specificity of ODI₃ from type 4 PM were 86.36 and 75%, respectively. For patients with AHI ≥ 15/h, the sensitivity was 66.67%, and the specificity was 100%.

Conclusion

Type 3 PM and Type 4 PM could be alternative ways to screen OSA for polio survivors, especially for moderate to severe OSA.

Epidemiology and natural history in 101 subjects with FKRP-related limb-girdle muscular dystrophy R9. The Norwegian LGMDR9 cohort study (2020)

We aimed to investigate the epidemiology and natural history of FKRP-related limb-girdle muscular dystrophy R9 (LGMDR9) in Norway. We identified 153 genetically confirmed subjects making the overall prevalence 2.84/100,000, the highest reported figure worldwide. Of the 153 subjects, 134 (88 %) were homozygous for FKRP c.826C>A giving a carrier frequency for this variant of 1/101 in Norway. Clinical questionnaires and patient notes from 101 subjects, including 88 c.826C>A homozygotes, were reviewed, and 43/101 subjects examined clinically. Age of onset in c.826C>A homozygotes demonstrated a bimodal distribution. Female subjects showed an increased cumulative probability of wheelchair dependency and need for ventilatory support. Across the cohort, the need for ventilatory support preceded wheelchair dependency in one third of the cases, usually due to sleep apnea. In c.826C>A homozygotes, occurrence of cardiomyopathy correlated positively with male gender but not with age or disease stage. This study highlights novel gender differences in both loss of ambulation, need for ventilatory support and the development of cardiomyopathy. Our results confirm the need for vigilance in order to detect respiratory insufficiency and cardiac involvement, but indicate that these events affect males and females differently.

Chronic Neuromuscular Respiratory Failure and Home Assisted Ventilation

Chronic respiratory failure is a common, important complication of many types of neuromuscular and chest wall disorders. While the pathophysiology of each disease may be different, these disorders can variably affect all muscles involved in breathing, including inspiratory, expiratory, and bulbar muscles, ultimately leading to chronic respiratory failure and hypoventilation. The use of home assisted ventilation through noninvasive interfaces aims to improve the symptoms of hypoventilation, improve sleep quality, and, when possible, improve mortality. An increasing variety of interfaces has allowed for improved comfort and compliance. In a minority of scenarios, noninvasive ventilation is either not appropriate or no longer effective due to disease progression, and a transition to tracheal ventilation should be considered.

Impact of hypoxia on male reproductive functions

Male reproductive functions, which include testicular steroidogenesis, spermatogenesis, and sexual/erectile functions are key in male fertility, but may be adversely altered by several factors, including hypoxia. This review demonstrates the impact of hypoxia on male reproductive functions. Acute exposure to hypoxia promotes testosterone production via stimulation of autophagy and upregulation of steroidogenic enzymes and voltage-gated L-type calcium channel, nonetheless, chronic exposure to hypoxia impairs steroidogenesis via suppression of the hypothalamic-pituitary-testicular axis. Also, hypoxia distorts spermatogenesis and reduces sperm count, motility, and normal forms via upregulation of VEGF and oxidative stress-sensitive signaling. Furthermore, hypoxia induces sexual and erectile dysfunction via a testosterone-dependent downregulation of NO/cGMP signaling and upregulation of PGE1/TGFβ1-driven penile endothelial dysfunction. Notably, hypoxia programs male sexual function and spermatogenesis/sperm quality via feminization and demasculinization of males and oxidative stress-mediated alteration in sperm DNA methylation. Since oxidative stress plays a central role in hypoxia-induced male reproductive dysfunction, studies exploring the effects of antioxidants and upregulation of transcription of antioxidants on hypoxia-induced male reproductive dysfunction are recommended.

Respiratory Function and Sleep Disordered Breathing in Pediatric Duchenne Muscular Dystrophy

BACKGROUND

The decline of respiratory function in Duchenne muscular dystrophy (DMD) is associated with sleep disordered breathing (SDB) and alteration of nocturnal gas exchange, first manifesting as nocturnal hypoventilation (NH). However, the correlation between pulmonary function measured by spirometry (PFT) and the onset of SDB with or without NH is unclear.

AIM

To identify the prevalence and features of SDB and to investigate the relationship between lung function determined by forced vital capacity (FVC) and sleep abnormalities in a large paediatric DMD population.

METHODS

Retrospective, single-center cohort study. FVC% predicted (FVC%) was calculated using predicted equations from the Global Lung Function Initiative. NH was defined by transcutaneous (tc) CO2 >50 mmHg for >25% of total sleep time (TST); borderline NH by a mean tcCO2 between 45-50mmHg or tcCO2>50mmHg for ≤25% of TST; Clinically meaningful obstructive sleep apnea (OSA) by obstructive Apnea-Hypopnea Index >5. The sensitivity, specificity, positive and negative predictive value of FVC<50% to indicate presence of nocturnal hypoventilation were calculated.

RESULTS

134 patients underwent 284 sleep studies and 1222 PFT. Mean (SD) age at first and last sleep study was 12.9 (2.7) and 14.3 (2.6) years. Borderline NH (n=31) was detected in both ambulant and early-non ambulant subjects, while 100% of NH cases (n=14) were non-ambulant. NH was detected in 4/14 patients despite an FVC>50%. Seventeen/26 patients with OSA presented with concomitant NH or borderline NH. FVC<50% was associated with NH indicating a sensitivity and specificity of 73% and 86%, respectively. Positive and negative predictive value were 32% and 97% respectively. PFT showed a non-linear, sudden FVC% decline in 18% of cases.

CONCLUSIONS

FVC% <50 was associated with NH in close to a third of patients. CO2 elevation can be associated with obstructive/pseudo-obstructive events and was also observed in early non-ambulant cases or in the presence of FVC>50%. These results are relevant for the clinical management of SDB.

The level of carbon dioxide is the determinant of successful noninvasive ventilation pressure titration in patients with nonhypercapnic primary central sleep apnea: a case report

Primary central sleep apnea is classified as nonhypercapnic central sleep apnea. High loop gain, lower CO₂ reserves, and other reasons can lead to hypocapnia in patients who develop intermittent hyperventilation during sleep. Therefore, it is necessary to monitor nocturnal CO₂ level for these patients. We report a female patient diagnosed with nonhypercapnic primary central sleep apnea who complained of snoring, apnea, and excessive daytime sleepiness. With the monitoring of transcutaneous partial pressure of CO₂, manual noninvasive ventilation pressure titration was performed with continuous positive airway pressure, bilevel positive airway pressure in a spontaneous-timed mode, and adaptive servo-ventilation mode for 3 nights, respectively. Only adaptive servo-ventilation mode could stabilize the transcutaneous partial pressure of CO₂ above the apneic threshold (approximately 40 mm Hg) with successfully eliminating central apnea events. It is concluded that the level of CO₂ is the determinant of successful noninvasive ventilation pressure titration in patients with nonhypercapnic central sleep apnea.

CITATION

Han X, Zhao D, Wang J, Wang Y, Dong L, Chen B-y. The level of carbon dioxide is the determinant of successful noninvasive ventilation pressure titration in patients with nonhypercapnic primary central sleep apnea: a case report. J Clin Sleep Med. 2022;18(1):319-324.

The effect of exercise on balance in patients with stroke, Parkinson, and multiple sclerosis: a systematic review and meta-analysis of clinical trials

BACKGROUND

Stroke, Parkinson, and multiple sclerosis are a range of diseases affecting the nervous system and show balance impairments due to damage of the balance control system. Many early articles have been published on the effect of exercise on balance in patients suffering from neuromuscular diseases. However, a comprehensive study showing a clear result of these three diseases was not found. Hence, the purpose of the present meta-analysis and systematic review is to determine the effect of exercise on balance in people with stroke, Parkinson, and multiple sclerosis.

METHODS

According to the PRISMA 2009 multi-step instructions, keywords related to the purpose of the research were browsed in the MeSH browser databases; IranDoc, MagIran, IranMedex, SID, ScienceDirect, Web of Science (WoS), ProQuest, Medline (PubMed), Scopus, and Google Scholar were searched to extract articles published in Persian and English language. The search process for retrieving the articles in the sources mentioned from January 01, 2000, to December 30, 2020, was done. The heterogeneity index of the studies was determined using the I² test. Given the heterogeneity, the random-effects model was used to combine the articles and the results.

RESULTS

Initially, 7067 articles were found, but after removing duplicate and irrelevant articles, 96 clinical trials with a sample size of the intervention group of 1760 people were included in the study. As a result of the articles' composition, the mean balance score index after exercise in the intervention group showed a significant increase of 0.67 ± 0.12 of the unit (P˂0.01). The highest rate of increase in the balance score after the intervention was reported in patients with myelomeningocele with 1.66 ± 0.3 unit (P˂0.01).

CONCLUSION

Considering the positive effect of using exercise on increasing the balance in patients with stroke, Parkinson, and multiple sclerosis, it is recommended that health care providers implement a regular exercise program to improve the condition of these patients.

Validation of home portable monitoring for the diagnosis of sleep-disordered breathing in adolescents and adults with neuromuscular disorders

STUDY OBJECTIVES

Sleep-disordered breathing (SDB) is common in patients with neuromuscular disorders (NMD), developing before chronic hypercapnia appears. Polysomnography (PSG) is the diagnostic gold standard but is often impractical and poorly accessible for individuals with NMD. We sought to determine the diagnostic accuracy, feasibility, and patient preference of home sleep apnea testing (HSAT) compared with PSG for the detection of SDB in NMD.

METHODS

Participants with NMD at risk for SDB aged ≥ 13 years underwent HSAT followed by overnight PSG with concomitant laboratory sleep apnea testing (same device as HSAT). Sensitivity and specificity were calculated for standard apnea-hypopnea index cutoffs for mild (≥ 5 events/h), moderate (≥ 15 events/h), and severe SDB (≥ 30 events/h) and for an oxygen desaturation index ≥ 5 events/h. Receiver operating characteristic curves were built. A questionnaire assessed patient preference.

RESULTS

Of 38 participants, 73% had moderate to severe SDB and 79% had technically acceptable HSAT. For an apnea-hypopnea index ≥ 15 events/h, HSAT sensitivity and specificity were 50% and 88%, respectively. For an oxygen desaturation index ≥ 5 events/h, HSAT sensitivity and specificity were 95% and 78%, respectively. The area under the receiver operating characteristic curve for an apnea-hypopnea index ≥ 15 events/h was 0.88 (95% confidence interval, 0.69-1.00) for HSAT. The HSAT underestimated the apnea-hypopnea index from PSG (bias, -10.7 ± 15.9 events/h). HSAT was preferred to PSG by 61% of participants.

CONCLUSIONS

HSAT is feasible, preferred by patients, and reliable for detecting SDB in most patients, although it cannot definitively rule out SDB. Therefore, HSAT is a viable diagnostic approach for SDB in NMD when PSG is not feasible, recognizing that it does not accurately distinguish between upper-airway obstruction and hypoventilation. Additional work is needed to further optimize home sleep testing in NMD.

CITATION

Westenberg JN, Petrof BJ, Noel F, et al. Validation of home portable monitoring for the diagnosis of sleep-disordered breathing in adolescents and adults with neuromuscular disorders. J Clin Sleep Med. 2021;17(8):1579-1590.

Sleep disordered breathing: Assessment and therapy in the age of emerging neuromuscular therapies

The term neuromuscular disease (NMD) encompasses a large variety of disorders that result in abnormal muscle function. Although it may be conventional to relate the use of this term to the most common muscular diseases (Duchenne muscular dystrophy [DMD], spinal muscular atrophy [SMA], and amyotrophic lateral sclerosis, etc), it is important to extend the term to pathologies manifested by severe neurologic (brain and spinal cord) malformations and injuries. In many of these scenarios, there are common mechanisms that contribute to sleep disordered breathing (SDB) and respiratory insufficiency although comorbidities may be somewhat different. Advances in the understanding of these diseases and their natural history, and increasing availability of mechanical ventilation to these patients have improved survival. The development of novel genetic and molecular therapies (as in the cases of DMD, SMA, and X-linked myotubular myopathy) provides an opportunity to use SDB as a reasonable outcome measure while also allowing the use of polysomnography as a validation tool in the assessments of effectiveness of therapies. We seek to provide an understanding of SDB in NMDs, and in the same light, would like to begin the conversation of thinking about weaning respiratory support when possible.

[Clinical features of sleep-disordered breathing in children with neuromuscular disease]

OBJECTIVE

To study the clinical features of sleep-disordered breathing (SDB) in children with neuromuscular disease (NMD).

METHODS

A retrospective analysis was performed on the medical data of 18 children who were diagnosed with NMD and underwent polysomnography (PSG) (NMD group). Eleven children without NMD who had abnormal sleeping habit and normal sleep structure on PSG were enrolled as the control group. The two groups were compared in terms of the daily and nocturnal symptoms of SDB, incidence rate of obstructive sleep apnea (OSA), pulmonary function, end-tidal partial pressure of carbon dioxide (PetCO₂), features of sleep structure, and sleep respiratory events.

RESULTS

In the NMD group, 16 children (89%) had related daily and nocturnal symptoms of SDB, and the youngest age was 1 year at the onset of such symptoms. Compared with the control group, the NMD group had significant reductions in total sleep time and sleep efficiency (P < 0.05), a significant reduction in the proportion of rapid eye movement (REM) sleep (P < 0.05), significant increases in obstructive apnea and hypopnea events (P < 0.05) and oxygen reduction events during REM sleep (P < 0.05), and a significant reduction in blood oxygen saturation during REM sleep (P < 0.05). In the NMD group, 17 children (94%) were diagnosed with OSA, and all children had normal lung function and PetCO₂.

CONCLUSIONS

There is a high proportion of children with SDB among the children with NMD, and SDB can be observed in the early stage of NMD, which results in the damage of sleep structure and the reduction in sleep efficiency. Respiratory events are mainly obstructive events, and oxygen reduction events are mainly observed during REM sleep.

Expiratory obstruction in patients with Duchenne muscular dystrophy under non-invasive ventilation: A step-by-step analysis of a new obstructive pattern

PURPOSE

Non-invasive ventilation (NIV) is the reference standard for managing chronic hypoventilation in patients with Duchenne muscular dystrophy (DMD). In these patients, upper airway obstruction under NIV may compromise efficacy and adherence. We aim to describe a novel pattern of expiratory obstructive events occurring during nocturnal barometric NIV.

METHODS

We retrospectively included all patients with DMD who underwent full-night polygraphy during NIV as part of their usual follow-up between May 2018 and July 2019.

RESULTS

We provide a step-by-step description of this previously undescribed pattern of obstruction. Expiratory obstructions lead to end-inspiratory breath-holding and impossibility to take another inspiratory breath with a barometric mode until expiration occurs. These events were observed in 4 (36%) of 11 DMD patients under barometric NIV.

CONCLUSION

Expiratory obstructions may be common in DMD patients receiving NIV and should be sought out routinely. This previously undescribed variant of obstructive event must be identified.

The adult multidisciplinary respiratory neuromuscular clinic

Many neuromuscular disorders (NMD) are complicated by respiratory failure. These patients are best managed in a multidisciplinary outpatient clinic to provide timely access to the various disciplines they require. The key mainstay of treatment of respiratory failure in patients with NMD is noninvasive ventilation, supported by secretion clearance, speech and language therapy, optimisation of nutrition and the maintenance of mobility. Patients with specific conditions may also require cardiology, neurology, orthopaedics, urology and psychological services. The respiratory NMD multidisciplinary team should also provide access to palliative care, and caregiver health and wellbeing should also be reviewed at clinical reviews. The future of care for the respiratory NMD patient will increasingly involve home services and telehealth and the clinic should be equipped and resourced to deliver these. Although not all health systems will be able to provide all elements of the multidisciplinary team discussed here, this review provides the “ideal” recipe for the adult multidisciplinary team and the evidence base underpinning this from which a clinic can be developed.

Care for neuromuscular-related respiratory failure is complex and is best delivered in a multidisciplinary context. The future will increasingly involve home services and telehealth, and their burden needs to be considered when establishing this service.https://bit.ly/33fNsMT

The effects of non-invasive mechanical ventilation on cardiac autonomic dysfunction in spinal muscular atrophy

In patients with spinal muscular atrophy (SMA), obstructive sleep apnea syndrome (OSAS) constitutes an important cause of cardiovascular morbidity and mortality. We investigated heart rate variability (HRV) to evaluate the effects of non-invasive mechanical ventilation on cardiac autonomic dysfunction in patients with SMA and OSAS. Six patients with SMA (type 1 and 2) and six age- and sex-matched healthy children were consecutively enrolled. A whole-night diagnostic polysomnography was performed, and SMA patients with OSAS were given non-invasive mechanical ventilation therapy. HRV analysis was performed on the basis of whole-night electrocardiography recordings via a computer-base program. Apnea-hypopnea index (AHI) was 9.2 ± 6.2/hr in SMA patients, while it was 0.4 ± 0.5/hr in controls (p = 0.036). All SMA patients had OSAS, while none of the controls had OSAS (p = 0.012). Mean percentage of successive R wave of QRS complex (R-R) intervals>50 ms was significantly lower in SMA patients than those in controls (p = 0.031). Significant correlations were found between AHI and high-frequency power, low/high-frequency ratio in wakefulness and in sleep (p<0.05). Repeated HRV analysis in SMA patients following OSAS therapy showed significant reductions in average R-R duration (p = 0.028) and percentage of successive R-R intervals>50 ms (p = 0.043). Our study demonstrates the beneficial effects of non-invasive mechanical ventilation on cardiac autonomic dysfunction in SMA patients with OSAS.

COVID-19 and pregnancy: A review of clinical characteristics, obstetric outcomes and vertical transmission

Background

Since its emergence in December 2019, COVID‐19 has spread to over 210 countries, with an estimated mortality rate of 3–4%. Little is understood about its effects during pregnancy.

Aims

To describe the current understanding of COVID‐19 illness in pregnant women, to describe obstetric outcomes and to identify gaps in the existing knowledge.

Methods

Medline Ovid, EMBASE, World Health Organization COVID‐19 research database and Cochrane COVID‐19 in pregnancy spreadsheet were accessed on 18/4, 18/5 and 23/5 2020. Articles were screened via Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines. The following were excluded: reviews, opinion pieces, guidelines, articles pertaining solely to other viruses, single case reports.

Results

Sixty articles were included in this review. Some pregnant participants may have been included in multiple publications, as admission dates overlap for reports from the same hospital. However, a total of 1287 confirmed SARS‐CoV‐2 positive pregnant cases are reported. Where universal testing was undertaken, asymptomatic infection occurred in 43.5–92% of cases. In the cohort studies, severe and critical COVID‐19 illness rates approximated those of the non‐pregnant population. Eight maternal deaths, six neonatal deaths, seven stillbirths and five miscarriages were reported. Nineteen neonates were SARS‐CoV‐2 positive, confirmed by reverse transcription polymerase chain reaction of nasopharyngeal swabs. [Correction added on 2 September 2020, after first online publication: the number of neonates indicated in the preceding sentence has been corrected from ‘Thirteen’ to ‘Nineteen’.]

Conclusions

Where universal screening was conducted, SARS‐CoV‐2 infection in pregnancy was often asymptomatic. Severe and critical disease rates approximate those in the general population. Vertical transmission is possible; however, it is unclear whether SARS‐CoV‐2 positive neonates were infected in utero, intrapartum or postpartum. Future work should assess risks of congenital syndromes and adverse perinatal outcomes where infection occurs in early and mid‐pregnancy.

Obstructive sleep apnea in developmental age. A narrative review

Sleep is a physiological function that undergoes, at different stages of life, to considerable variations in neurophysiological and behavioral functions. The developmental age is a period characterized by a continuous process of physical and neuropsychological changes and synaptic remodeling processes that are the neurophysiological basis of brain plasticity, typical of this developmental phase, occurring mainly during sleep. In the description of obstructive sleep apnea (OSA) in children, two main points should be highlighted: its variability in different age groups, and its specificity compared with OSA in adults. The definition and criteria used for the diagnosis of OSA in adults are not applicable to OSA in developmental age. Although the adenotonsillar hypertrophy is the most common risk factor for pediatric OSA, obesity is becoming an increasingly prevalent risk factor, mostly in early childhood (6-9 years) and adolescence. OSA has been shown to affect cognitive function in children and adults. However, OSA impact on cognitive function in children is more severe since acting on the plastic brain structures can change the neuro-psychic development, learning skills, and social interactions. There is a clear difference in the definition of pathology between developmental age and adulthood according to the instrumental parameters: an AHI ≥ 5, which represents, in the pediatric age, the cut-off for a therapeutic pathway necessary to avoid a long-term effect on the child, instead, it represents in adulthood, the lower limit value for the definition of disease. This is a narrative review concerning obstructive sleep apnea in developmental age.Conclusions: OSA is a common disorder in children and those at risk must be identified, studied, and treated promptly because untreated OSA can be responsible for cardiovascular, metabolic, and neurocognitive morbidities and may induce, sometimes, non-reversible deficits given his insistence on a period of physical and neuro-psychic development.What is Known:•This is a review concerning Obstructive Sleep Apnea in developmental age•Clinical manifestation, diagnostic and therapeutic criteria of sleep apnea in developmental ageWhat is New:•This is a "narrative" review•This narrative review describes sleep apnea comparing and analyzing the different ages of life.

Beatmung bei neuromuskulären Erkrankungen

Neuromuskuläre Erkrankungen betreffen das erste und zweite Motoneuron, die peripheren Nerven, die neuromuskulären Übertragung und die Muskelzelle. Es handelt sich um eine heterogene Gruppe von erblichen, degenerativen und autoimmunen Erkrankungen. Eine korrekte diagnostische Einordnung ist erforderlich, da zentralnervöse, kardiale, endokrine und weitere Begleitsymptome vorliegen können und für einige Erkrankungen bereits medikamentöse Therapien zur Verfügung stehen. Neuromuskuläre Erkrankungen haben eine große Bedeutung in der neuromuskulären Beatmungsmedizin. Die respiratorische Symptomatik resultiert in der Regel aus Paresen der am Atmen, Schlucken oder Husten beteiligten Muskulatur mit konsekutiver ventilatorischer Insuffienz, Dysphagie bis hin zur Speichelaspiration und Sekretretention. Mittels eines strukturierte Sekretmanagements und einer effektive nichtinvasive oder invasive Beatmungstherapie können neuromuskuläre Patienten viele Jahre mit guter Lebensqualität überleben. Themen dieses Kapitels sind ein Überblick über die neuromuskulären Erkrankungen, die Indikationen und Strategien der nichtinvasiven und der invasiven Beatmung und eine ausführliche Darstellung beatmungsmedizinisch besonders relevanter neuromuskulärer Erkrankungen wie der amyotrophe Lateralsklerose, des Guillain-Barré-Syndroms, der Myasthenia gravis und der Critical-Illness-Polyneuropathie/-Myopathie.

Sleep-Disordered Breathing in Neuromuscular and Chest Wall Diseases

Neuromuscular and chest wall diseases include a diverse group of conditions that share common risk factors for sleep-disordered breathing, including respiratory muscle weakness and/or thoracic restriction. Sleep-disordered breathing results from both the effects of normal sleep on ventilation and the additional challenges imposed by the underlying disorders. Patterns of sleep- disordered breathing vary with the specific diagnosis and stage of disease. Sleep hypoventilation precedes diurnal respiratory failure and may be difficult to recognize clinically because symptoms are nonspecific. Polysomnography has a role in both the diagnosis of sleep-disordered breathing and in the titration of effective noninvasive positive-pressure ventilation.

The role of sleep diagnostics and non-invasive ventilation in children with spinal muscular atrophy

Spinal muscular atrophy (SMA) is a degenerative motor neurone disorder causing progressive muscular weakness. Without assisted ventilation or novel therapies, most children with SMA type 1 die before the second year of life due to respiratory failure as the respiratory muscles and bulbar function are severely affected. Active respiratory treatment (mechanically assisted cough, invasive or non-invasive ventilation) has improved survival significantly in recent decades, but often at the cost of becoming ventilator dependent. The advent of a new oligonucleotide based therapy (Nusinersen) has created new optimism for improving motor function. However, the long-term effect on respiratory function is unclear and non-invasive respiratory support will remain an important part of medical management in patients with SMA. This review summarises the existing knowledge about sleep-disordered breathing and respiratory failure in patients with SMA, especially type 1, as well as the evidence of improved outcome and survival in patients treated with non-invasive or invasive ventilation. Practical considerations and ethical concerns are delineated with discussion on how these may be affected by the advent of new therapies such as Nusinersen.

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.

Hydrogen Sulfide Alleviates Lipopolysaccharide-Induced Diaphragm Dysfunction in Rats by Reducing Apoptosis and Inflammation through ROS/MAPK and TLR4/NF-κB Signaling Pathways

Diaphragm dysfunction is an important clinical problem worldwide. Hydrogen sulfide (H₂S) is involved in many physiological and pathological processes in mammals. However, the effect and mechanism of H₂S in diaphragm dysfunction have not been fully elucidated. In this study, we detected that the level of H₂S was decreased in lipopolysaccharide- (LPS-) treated L6 cells. Treatment with H₂S increased the proliferation and viability of LPS-treated L6 cells. We found that H₂S decreased reactive oxygen species- (ROS-) induced apoptosis through the mitogen-activated protein kinase (MAPK) signaling pathway in LPS-treated L6 cells. Administration of H₂S alleviated LPS-induced inflammation by mediating the toll-like receptor-4 (TLR-4)/nuclear factor-kappa B (NF-κB) signaling pathway in L6 cells. Furthermore, H₂S improved diaphragmatic function and structure through the reduction of inflammation and apoptosis in the diaphragm of septic rats. In conclusion, these findings indicate that H₂S ameliorates LPS-induced diaphragm dysfunction in rats by reducing apoptosis and inflammation through ROS/MAPK and TLR4/NF-κB signaling pathways. Novel slow-releasing H₂S donors can be designed and applied for the treatment of diaphragm dysfunction.

Sleep disordered breathing in motor neurone disease

Motor neurone disease (MND) is a neurodegenerative disease defined by axonal loss and gliosis of upper and lower motor neurones in the motor cortex, lower brainstem nuclei and ventral horn of the spinal cord. MND is currently incurable and has a poor prognosis, with death typically occurring 3 to 5 years after disease onset. The disease is characterised by rapidly progressive weakness leading to paralysis, fasciculations, bulbar symptoms (including dysarthria and dysphagia) and respiratory compromise. Respiratory complications arise as a result of weakness of upper airway (pharyngeal and laryngeal) muscles and respiratory muscles (diaphragm, intercostal and accessory muscles) leading to respiratory failure. Due to early involvement of respiratory muscles in MND, sleep disordered breathing (SDB) occurs at a higher frequency than compared to the general population. SDB usually precedes daytime respiratory symptoms and chronic respiratory failure. It significantly impacts upon patients' quality of life and survival and its presence may predict prognosis. Managing SDB in MND with non-invasive ventilation (NIV) improves quality of life and survival. Early identification and management of SDB in MND patients is therefore crucial. This update will review assessments of respiratory muscle function, types of SDB and the effects of NIV in patients with MND.