Recurrence of CCHS-associated PHOX2B Poly-Alanine expansion variant due to paternal mosaicism

BACKGROUND

Paired-like Homeobox 2B (PHOX2B) is considered the causative gene of Congenital Central Hypoventilation Syndrome (CCHS), a dominant genetic disorder characterized by impaired central respiratory control and subsequent hypoventilation during sleep.

METHODS

Herein, we present a family with recurrent severe CCHS. The potential causative genetic variant was confirmed through Whole-Exome Sequencing (WES), Sanger sequencing, and droplet digital PCR (ddPCR). Furthermore, prenatal diagnosis was performed on the proband's mother at 20 weeks of her fourth pregnancy upon request.

RESULTS

The proband and her brother were both carriers of the PHOX2B polyalanine expansion variant: c.744_758dupCGCGGCAGCGGCGGCGGCGGC. Sanger sequencing revealed that the proband's father had a small variant peak in the gene position, implying potential somatic mosaicism. In addition, ddPCR results showed that the proband's father had germline mosaicism, with a mosaicism proportion of 14.3%. Notably, the detect p.(Ala241[26]) variant was not detected in the fetus.

CONCLUSIONS

These findings have important implications for improving genetic counseling of CCHS families as they suggest that even parents without CCHS symptoms may have somatic chimerism, necessitating careful genetic counseling and consideration of prenatal testing for subsequent pregnancies.

A 38-Year-Old Woman With REM Predominant Central Sleep Apnea After Bulbar Infarction

CASE PRESENTATION

A 38-year-old previously healthy woman was referred to our sleep center for recurrent witnessed breathing arrest during sleep. She had been brought to the ED 3 months earlier because of sudden onset of dizziness with nausea and vomiting, numbness and weakness of the left limb, less clear speech, double vision, dysphagia, and choking cough while drinking water. Brain MRI showed an acute cerebral infarction in the left medulla oblongata (Fig 1). High-resolution MRI showed vertebral artery dissection (Fig 2). Antiplatelet aggregation, lipid reduction, plaque stabilization, and trophic nerve treatments were administered, and the left limb strength, speech, and swallowing function improved. She complained of poor sleep and difficulties with memory.

Effects of Adaptive Servo-Ventilation on Quality of Life: The READ-ASV Registry

Rationale: Adaptive servo-ventilation (ASV) effectively treats sleep-disordered breathing, including central sleep apnea (CSA) and coexisting obstructive sleep apnea (OSA).Objectives: The prospective, multicenter European READ-ASV (Registry on the Treatment of Central and Complex Sleep-Disordered Breathing with Adaptive Servo-Ventilation) registry investigated the effects of first-time ASV therapy on disease-specific quality of life (QoL).Methods: The registry enrolled adults with CSA with or without OSA who had ASV therapy prescribed between September 2017 and March 2021. The primary endpoint was change in disease-specific QoL (Functional Outcomes of Sleep Questionnaire [FOSQ]) score between baseline and 12-month follow-up. Sleepiness determined using the Epworth Sleepiness Scale (ESS) score was a key secondary outcome. For subgroup analysis, participants were classified as symptomatic (FOSQ score < 17.9 and/or ESS score > 10) or asymptomatic (FOSQ score ⩾ 17.9 and/or ESS score ⩽ 10).Results: A total of 801 individuals (age, 67 ± 12 yr; 14% female; body mass index, 31 ± 5 kg/m2; apnea-hypopnea index, 48 ± 22/h) were enrolled; analyses include those with paired baseline and follow-up data. After 12 ± 3 months on ASV, median (interquartile range) FOSQ score had increased significantly from baseline (+0.8 [-0.2 to 2.2]; P < 0.001; n = 499). This was due to a significantly increased FOSQ score in symptomatic participants (+1.69 [0.38 to 3.05]), with little change in asymptomatic individuals (+0.11 [-0.39 to 0.54]). The median ESS score also improved significantly from baseline during ASV (-2.0 [-5.0 to 0.0]; P < 0.001).Conclusions: ASV treatment of CSA with or without coexisting OSA was associated with improvements in disease-specific QoL and daytime sleepiness, especially in individuals with sleep-disordered breathing symptoms before therapy initiation. These improvements in patient-reported outcomes support the use of ASV in this population.

Congenital Central Hypoventilation Syndrome: The Singularity of A Successful Case

N/a.

Pediatric long-term noninvasive respiratory support in children with central nervous system disorders

RATIONALE

The use of long-term noninvasive respiratory support is increasing in children along with an extension of indications, in particular in children with central nervous system (CNS) disorders.

OBJECTIVE

The aim of this study was to describe the characteristics of children with CNS disorders treated with long-term noninvasive respiratory support in France.

METHODS

Data were collected from 27 French pediatric university centers through an anonymous questionnaire filled for every child treated with noninvasive ventilatory support ≥3 months on 1st June 2019.

MAIN RESULTS

The data of 182 patients (55% boys, median age: 10.2 [5.4;14.8] years old [range: 0.3-25]) were collected: 35 (19%) patients had nontumoral spinal cord injury, 22 (12%) CNS tumors, 63 (35%) multiple disabilities, 26 (14%) central alveolar hypoventilation and 36 (20%) other CNS disorders. Seventy five percent of the patients were treated with noninvasive ventilation (NIV) and 25% with continuous positive airway pressure (CPAP). The main investigations performed before CPAP/NIV initiation were nocturnal gas exchange recordings, alone or coupled with poly(somno)graphy (in 29% and 34% of the patients, respectively). CPAP/NIV was started in an acute setting in 10% of the patients. Median adherence was 8 [6;10] hours/night, with 12% of patients using treatment <4 h/day. Nasal mask was the most common interface (70%). Airway clearance techniques were used by 31% of patients.

CONCLUSION

CPAP/NIV may be a therapeutic option in children with CNS disorders. Future studies should assess treatment efficacy and patient reported outcome measures.

Polysomnographic findings in the ultra-rare McLeod syndrome: further documentation of sleep apnea as a possible feature

STUDY OBJECTIVES

McLeod syndrome is a very rare multisystemic neurodegenerative disease linked to mutations in the XK gene. It has cardiac, neurologic, and neuromuscular manifestations and shares similarities with Huntington's disease. The aim of this study was to evaluate sleep patterns of patients affected by McLeod syndrome.

METHODS

This retrospective case series of four males who underwent diagnostic polysomnography (mean age 53.8 ± 2.5 years) includes self-reported and objective evaluation of sleep using the Epworth Sleepiness Scale, genetic tests, documentation of clinical course and features, and laboratory-based full-night attended video-polysomnography.

RESULTS

In three out of four patients, an Epworth Sleepiness Scale score ≥ 7 was evident. The average apnea-hypopnea index was 45.0 ± 19.0, with predominantly obstructive phenotype in three patients and predominant central events (central sleep apnea syndrome) in one patient. A significantly increased periodic limb movement index during sleep was observed in all patients. All patients tolerated continuous positive airway pressure or pressure controlled therapy.

CONCLUSIONS

Polysomnography of all patients confirmed sleep apnea syndrome as a feature of McLeod syndrome. Three patients were diagnosed with obstructive sleep apnea and one with central sleep apnea syndrome. In addition, periodic limb movement index was increased in all patients.

CITATION

Dieter M, Kevin P, Tobias V, et al. Polysomnographic findings in the ultra-rare McLeod syndrome: further documentation of sleep apnea as a possible feature. J Clin Sleep Med. 2024;20(3):339-344.

Higher baseline heart rate variability in CCHS patients with progestin-associated recovery of hypercapnic ventilatory response

After a fortuitous observation of two cases of chemosensitivity recovery in women with congenital central hypoventilation syndrome (CCHS) who took desogestrel, we aimed to evaluate the ventilatory response to hypercapnia of five CCHS patients with or without treatment consisting of desogestrel (DESO) or levonorgestrel (LEVO). Only two patients became responsive to hypercapnia under treatment, according to their basal vagal heart rate variability. These results suggest that heart rate variability may be promising tool to discriminate patients susceptible to become responsive to hypercapnia under DESO-LEVO treatment.Clinical Trials Identifier NCT01243697.

An update on diagnosis and management of obstructive sleep apnoea in the first 2 years of life

The aim of this review is to summarise evidence that became available after publication of the 2017 European Respiratory Society statement on the diagnosis and management of obstructive sleep apnoea syndrome (OSAS) in 1- to 23-month-old children. The definition of OSAS in the first 2 years of life should probably differ from that applied in children older than 2 years. An obstructive apnoea-hypopnoea index >5 events·h-1 may be normal in neonates, as obstructive and central sleep apnoeas decline in frequency during infancy in otherwise healthy children and those with symptoms of upper airway obstruction. A combination of dynamic and fixed upper airway obstruction is commonly observed in this age group, and drug-induced sleep endoscopy may be useful in selecting the most appropriate surgical intervention. Adenotonsillectomy can improve nocturnal breathing in infants and young toddlers with OSAS, and isolated adenoidectomy can be efficacious particularly in children under 12 months of age. Laryngomalacia is a common cause of OSAS in young children and supraglottoplasty can provide improvement in children with moderate-to-severe upper airway obstruction. Children who are not candidates for surgery or have persistent OSAS post-operatively can be treated with positive airway pressure (PAP). High-flow nasal cannula may be offered to young children with persistent OSAS following surgery, as a bridge until definitive therapy or if they are PAP intolerant. In conclusion, management of OSAS in the first 2 years of life is unique and requires consideration of comorbidities and clinical presentation along with PSG results for treatment decisions, and a multidisciplinary approach to treatment with medical and otolaryngology teams.

Volume assured pressure support mode use for non-invasive ventilation in pediatrics

There has been increasing interest in utilizing volume assured pressure support (VAPS) modes of ventilation for children, which historically had only been favored in adult populations. In addition to patients with obesity hypoventilation syndrome, newer pediatric populations for which it has recently been prescribed include congenital central hypoventilation syndrome and children with neuromuscular disease such as Duchenne muscular dystrophy and spinal muscular atrophy. Given its expanding use in pediatrics, greater familiarity with VAPS is essential for pediatric pulmonologists and sleep physicians. This review article will highlight methods of initiation for this mode, specific ventilator settings, discussion of suitable pediatric patient populations, ventilator titrations via formal polysomnograms and detailed ventilator data downloads specific interpretation. Finally, common challenges to be aware of and how to troubleshoot relevant machine alarms will be reviewed.

Association of hypoxic burden metrics with cardiovascular outcomes in heart failure and sleep-disordered breathing

AIMS

Heart failure (HF) and sleep-disordered breathing (SDB) frequently coexist. We aimed to compare the prognostic value of different nocturnal hypoxic burden metrics in hospitalized HF patients.

METHODS AND RESULTS

HF patients underwent polygraphy screening for SDB in this prospective cohort. Hypoxic burden metrics assessed using pulse oximetry included time < 90% oxygen saturation (T90), proportion of total recording time < 90% oxygen saturation (TRT90), oxygen desaturation index (ODI), and mean oxygen saturation (meanSO2 ). The prespecified endpoints were the composite of cardiovascular death or admission for worsening HF. This study included 764 hospitalized HF patients, 16.5% and 36.6% of whom had obstructive and central sleep apnoea, respectively. With a median follow-up time of 2.2 years, endpoint events occurred in 410 (53.7%) patients. In univariate and multivariate analyses, T90, TRT90, and meanSO2 were substantially associated with the composite outcome, whereas ODI was not. After multivariate Cox model adjustment, patients with 5.0 ≤ T90 ≤ 52.0 min [hazard ratio (HR) 1.32, 95% confidence interval (CI): 1.02-1.71, P = 0.034] or T90 > 52.0 min (HR 1.56, 95% CI: 1.21-2.02, P = 0.001) had a greater risk of the composite outcome than those with T90 < 5.0 min. The TRT90 and T90 results were similar. Compared with meanSO2  > 95%, meanSO2  < 93% (HR 1.47, 95% CI: 1.16-1.88, P = 0.002) was correlated with adverse outcomes.

CONCLUSIONS

The hypoxic burden metrics T90, TRT90, and meanSO2 , but not ODI, were independent predictors of cardiovascular death or readmission for worsening HF. Indicators of duration and severity, not just the frequency of nocturnal hypoxaemia, should be valued and considered for intervention to improve outcomes in HF patients.

Catathrenia in severe obstructive sleep apnea: A novel entity never described before

STUDY OBJECTIVES

Catathrenia, derived from the Greek κατά (kata) meaning below and θρηνώ (threnia) to lament, is characterized by expiratory groaning episodes during sleep. In a case series of nine patients with severe obstructive sleep apnea, we observed a peculiar groaning entity that has not been described before.

METHODS

We described and illustrated the cases with polysomnographic tracings and additional audio recordings.

RESULTS

All patients were men, obese (body mass index 39 ± 6 kg/m2) with an apnea-hypopnea index ranging from 47 to 125/h. In addition, we identified groaning events that were consistently preceded by a cortical arousal associated with a "rescue" respiration after an obstructive hypopnea or apnea. These events exhibited characteristics of "mixed apnea's", but the "central apnea-like part" was a prolonged expiratory groaning phase, with immediately after the terminal expiratory snort appearance of an obstructive apnea. In case the duration of this expiration was at least 10 s we calculated these events separately and the index was 8.4 ± 7.7/h. More rarely (index 0.6 ± 0.5/h) a "central apnea mimicking event" with groaning not followed by an obstruction, was observed. We also observed groaning episodes during expiration with a shorter duration (less than 10 s), not calculated separately. Positive airway pressure, which was well tolerated, eliminated these events.

CONCLUSIONS

This novel catathrenia entity preceded by a cortical arousal and "rescue" respiration in response to obstructive events is intriguing. Possible explanations for these observations are further discussed in this article.

The lesion site of organophosphorus-induced central apnea and the effects of antidotes

Organophosphorus poisoning kills individuals by causing central apnea; however, the underlying cause of death remains unclear. Following findings that the pre-Bötzinger complex impairment alone does not account for central apnea, we analyzed the effect of paraoxon on the brainstem-spinal cord preparation, spanning the lower medulla oblongata to phrenic nucleus. Respiratory bursts were recorded by connecting electrodes to the ventral 4th cervical nerve root of excised brainstem-spinal cord preparations obtained from 6-day-old Sprague-Dawley rats. We observed changes in respiratory bursts when paraoxon, neostigmine, atropine, and 2-pyridine aldoxime methiodide were administered via bath application. The percentage of burst extinction in the paraoxon-poisoning group was 50% compared with 0% and 18.2% in the atropine and 2-pyridine aldoxime methiodide treatment groups, respectively. Both treatments notably mitigated the paraoxon-induced reduction in respiratory bursts. In the neostigmine group, similar to paraoxon, bursts stopped in 66.7% of cases but were fully reversed by atropine. This indicates that the primary cause of central apnea is muscarinic receptor-mediated in response to acetylcholine excess. Paraoxon-induced central apnea is hypothesized to result from neural abnormalities within the inferior medulla oblongata to the phrenic nucleus, excluding pre-Bötzinger complex. These antidotes antagonize central apnea, suggesting that they may be beneficial therapeutic agents.

Central sleep apnea treated by a constant low-dose CO2 supplied by a novel device

CO2 inhalation has been previously reported as a treatment for central sleep apnea both when associated with heart failure or where the cause is unknown. Here, we evaluated a novel CO2 supply system using a novel open mask capable of comfortably delivering a constantly inspired fraction of CO2 ([Formula: see text]) during sleep. We recruited 18 patients with central sleep apnea (13 patients with cardiac disease, and 5 patients idiopathic) diagnosed by diaphragm electromyogram (EMG) recordings made during overnight full polysomnography (PSG) (night 1). In each case, the optimal [Formula: see text] was determined by an overnight manual titration with PSG (night 2). Titration commenced at 1% CO2 and increased by 0.2% increments until central sleep apnea (CSA) disappeared. Patients were then treated on the third night (night 3) with the lowest therapeutically effective concentration of CO2 derived from night 2. Comparing night 1 and night 3, both apnea-hypopnea index (AHI; 31 ± 14 vs. 6 ± 3 events/h, P < 0.01) and arousal index (22 ± 8 vs. 15 ± 8 events/h, P < 0.01) were significantly improved during CO2 treatment. Sleep efficiency improved from 71 ± 18 to 80 ± 11%, P < 0.05, and sleep latency was shorter (23 ± 18 vs. 10 ± 10 min, P < 0.01). Heart rate was not different between night 1 and night 3. Our data confirm the feasibility of our CO2 delivery system and indicate that individually titrated CO2 supplementation with a novel device including a special open mask can reduce sleep disordered breathing severity and improve sleep quality. Randomized controlled studies should now be undertaken to assess therapeutic benefit for patients with CSA.NEW & NOTEWORTHY A novel device using a special mask was developed and proved that CO2 therapy using the device could eliminate central sleep apnea (CSA) events and improve sleep quality including reducing arousal index in patients with heart failure. The device would become a useful clinical treatment for heart failure patients with CSA.

Clinical and financial impact of sleep disordered breathing on heart failure admissions

BACKGROUND

The impact of sleep disordered breathing (SDB) on heart failure (HF) is increasingly recognized. However, limited data exist in support of quantification of the clinical and financial impact of SDB on HF hospitalizations.

METHODS

A sleep-heart registry included all patients who underwent inpatient sleep testing during hospitalization for HF at a single cardiac center. Readmission data and actual costs of readmissions were obtained from the institutional honest broker. Patients were classified based on the inpatient sleep study as having no SDB, obstructive sleep apnea (OSA), or central sleep apnea (CSA). Cumulative cardiac readmission rates and costs through 3 and 6 months post-discharge were calculated. Unadjusted and adjusted (age, sex, body mass index, and left ventricular ejection fraction) modeling of cost was performed.

RESULTS

The cohort consisted of 1547 patients, 393 (25%) had no SDB, 438 (28%) had CSA, and 716 (46%) had OSA. Within 6 months of discharge, 195 CSA patients (45%), 264 OSA patients (37%), and 109 no SDB patients (28%) required cardiovascular readmissions. Similarly, 3- and 6-month mortality rates were higher in both SDB groups than those with no SDB. Both unadjusted and adjusted readmission costs were higher in the OSA and CSA groups compared to no SDB group at 3 and 6 months post-discharge with the CSA and OSA group costs nearly double (~ $16,000) the no SDB group (~ $9000) through 6 months.

INTERPRETATION

Previously undiagnosed OSA and CSA are common in patients hospitalized with HF and are associated with increased readmissions rate and mortality.

Evaluation of polysomnography findings in children with genetic skeletal disorders

Children with genetic skeletal disorders have variable conditions that can lead to sleep-disordered breathing, and polysomnography is the gold standard for diagnosing this condition. We aimed to review polysomnography findings, to assess the severity of sleep apnea, and to investigate the clinical variables predictive of sleep-disordered breathing in these patients. We retrospectively collected the medical records of patients with genetic skeletal disorders who underwent polysomnography for 5 years. Twenty-seven children with various genetic skeletal disorders, including achondroplasia (14), Crouzon syndrome (3), acromesomelic dysplasia Maroteaux type (3), Apert syndrome (2), osteopetrosis (1), Jeune dysplasia (1), Desbuquois dysplasia (1), acrodysostosis (1), and spondyloepiphyseal dysplasia (1) were enrolled. The median age at the first polysomnography was 58 (1st-3rd quartile: 31-113) months. The overall sleep-disordered breathing results were: 19 (70.3%) had obstructive sleep apneas (OSA) (4 mild, 6 moderate, 9 severe), 2 (7.4%) had central apneas, 4 (14.8%) had nocturnal hypoventilation. There was a significant correlation between non-ambulatory status with both total AHI and OSA (p < 0.001, rho: -0.66/p = 0.04, rho: 0.38, respectively). Nine patients received positive airway pressure titration, and the oAHI values of all returned to the normal range. These patients were started with positive airway pressure treatment. Our cohort showed that the majority of the patients with skeletal dysplasia had sleep apnea syndrome characterised mainly by OSA, highlighting the importance of polysomnography screening for sleep disorders. Positive airway pressure therapy represents an effective treatment for sleep-disordered breathing in those patients.

Longitudinal Assessment of Sleep Apnea in the Year After Stroke in a Population-Based Study

BACKGROUND

The aim of this study was to characterize change in sleep-disordered breathing severity in the year following stroke, overall, and by ethnicity, within the population-based Brain Attack Surveillance in Corpus Christi Project.

METHODS

First-ever ischemic strokes (n=414) were ascertained by active and passive surveillance and validated by stroke-trained physicians. Patients with stroke were invited to participate in portable sleep apnea testing (ApneaLink Plus) at baseline and 3, 6, and 12 months poststroke. Sleep-disordered breathing severity was assessed by the respiratory event index (apneas and hypopneas/hour of recording). The component obstructive apnea index and central apnea index were also assessed. Time and ethnicity effects on outcomes, as well as ethnic differences in time effects, were analyzed using generalized estimating equations with multivariable adjustment for confounding factors.

RESULTS

Mean age (n=414) was 63.9 years (SD=10.9); 68.4% were Mexican American. Baseline mean respiratory event index, obstructive apnea index, and central apnea index were 21.3 (SD=16.6), 8.6 (SD=11.5), and 1.5 (SD=3.2), respectively. There was no time effect on respiratory event index (P=0.35) but obstructive apnea index increased over time (P<0.01). Averaged over follow-up, respiratory event index and obstructive apnea index were significantly higher in Mexican American than non-Hispanic White persons. No ethnic difference in the time effect was found for either outcome. For central apnea index, there was an ethnicity-time interaction (P=0.01) such that central apnea index increased in non-Hispanic White but did not change in Mexican American persons.

CONCLUSIONS

Sleep-disordered breathing severity was significant and stable for most individuals in the year after stroke. These results do not confirm previous reports of diminishing sleep-disordered breathing severity over time after stroke and would support early assessment and treatment where indicated.

Sleep and respiratory abnormalities in adults with developmental and epileptic encephalopathies using polysomnography and video-EEG monitoring

This study evaluated sleep and respiratory abnormalities, and their relationship with seizures, in adults with developmental and epileptic encephalopathies (DEEs). We studied consecutive adults with DEEs undergoing inpatient video-EEG monitoring and concurrent polysomnography between December 2011 and July 2022. Thirteen patients with DEEs were included (median age: 31 years, range: 20-50; 69.2% female): Lennox-Gastaut syndrome (n = 6), Lennox-Gastaut syndrome-like phenotype (n = 2), Landau-Kleffner syndrome (n = 1), epilepsy with myoclonic-atonic seizures (n = 1), and unclassified DEEs (n = 3). Sleep architecture was often fragmented by epileptiform discharges and seizures resulting in arousals (median arousal index: 29.0 per h, range: 5.1-65.3). Moderate-to-severe obstructive sleep apnea (OSA) was observed in seven patients (53.8%). Three patients (23.1%) had tonic seizures that frequently occurred with central apnea; one met criteria for mild central sleep apnea. Of the patients with tonic seizures, two had other identifiable seizure manifestations, but in one patient, central apnea was commonly the only discernable seizure manifestation. Polysomnography during video-EEG is an effective diagnostic tool in detecting sleep and seizure-related respiratory abnormalities. Clinically significant OSA may increase the risk of comorbid cardiovascular disease and premature mortality. Treatment of epilepsy may improve sleep quality, and conversely, improved sleep, may decrease seizure burden.

[Central apneas and cardiovascular diseases]

Central apneas (CA) and periodic breathing (PB) are the most common related breathing disorders in heart failure, being observed in up to 50% of patients. Once considered only a sleep-related phenomenon, actually CA/PB occur across the whole 24 h period and their presence in the awake patient even in the upright position and during physical effort has been associated with a worse clinical profile and a greater mortality. Chemoreflex activation, circulatory time delay and altered plant gain are the pathophysiological determinants. While the use of guideline-recommended medical and device treatment represents the first step in the management of CA in heart failure patients, no specific therapy has been demonstrated to reduce CA-related impact on mortality. In particular, the use of non-invasive ventilation has yielded contradictory results in the context of large-scale randomized clinical trials. The design and testing of therapies targeting the pathophysiological triggers of CA, such as chemoreflex sensitivity, may prove valuable in the next future.

Ventilatory and Orthostatic Challenges Reveal Biomarkers for Neurocognition in Children and Young Adults With Congenital Central Hypoventilation Syndrome

BACKGROUND

Children and young adults with congenital central hypoventilation syndrome (CCHS) are at risk of cognitive deficits. They experience autonomic dysfunction and chemoreceptor insensitivity measured during ventilatory and orthostatic challenges, but relationships between these features are undefined.

RESEARCH QUESTION

Can a biomarker be identified from physiologic responses to ventilatory and orthostatic challenges that is related to neurocognitive outcomes in CCHS?

STUDY DESIGN AND METHODS

This retrospective study included 25 children and young adults with CCHS tested over an inpatient stay. Relationships between physiologic measurements during hypercarbic and hypoxic ventilatory challenges, hypoxic ventilatory challenges, and orthostatic challenges and neurocognitive outcomes (by Wechsler intelligence indexes) were examined. Independent variable inclusion was determined by significant associations in Pearson's analyses. Multivariate linear regressions were used to assess relationships between measured physiologic responses to challenges and neurocognitive scores.

RESULTS

Significant relationships were identified between areas of fluid intelligence and measures of oxygen saturation (SpO2) and heart rate (HR) during challenges. Specifically, perceptual reasoning was related to HR (adjusted regression [β] coefficient, -0.68; 95% CI, 1.24 to -0.12; P = .02) during orthostasis. Working memory was related to change in HR (β, -1.33; 95% CI, -2.61 to -0.05; P = .042) during the hypoxic ventilatory challenge. Processing speed was related to HR (β, -1.19; 95% CI, -1.93 to -0.46; P = .003) during orthostasis, to baseline SpO2 (hypercarbic and hypoxic β, 8.57 [95% CI, 1.63-15.51]; hypoxic β, 8.37 [95% CI, 3.65-13.11]; P = .002 for both) during the ventilatory challenges, and to intrachallenge SpO2 (β, 5.89; 95% CI, 0.71-11.07; P = .028) during the hypoxic ventilatory challenge.

INTERPRETATION

In children and young adults with CCHS, SpO2 and HR-or change in HR-at rest and as a response to hypoxia and orthostasis are related to cognitive outcomes in domains of known risk, particularly fluid reasoning. These findings can guide additional research on the usefulness of these as biomarkers in understanding the impact of daily physical stressors on neurodevelopment in this high-risk group.

Images: Caffeine therapy for central sleep apnea, hypoxemia, and hypoventilation in a term neonate

The evaluation of higher-risk infants with brief resolved unexplained events and term infants with central sleep apnea can be clinically challenging due to the multitude of potential etiologies. We report a 7-day-old term neonate hospitalized for evaluation of brief resolved unexplained events with oxygen desaturations during sleep. Polysomnography showed central sleep apnea, hypoxemia, hypoventilation, periodic breathing, and mild obstructive sleep apnea. Following initial evaluations and while awaiting genetic testing, primary central sleep apnea of infancy was suspected and caffeine was initiated. Three days after initiating caffeine, polysomnography showed resolution of hypoxemia, hypoventilation, obstructive sleep apnea, and periodic breathing and improved central sleep apnea. The central apnea-hypopnea index reduced from 58 to 6.8 events/h. Although caffeine is utilized in apnea of prematurity, there is limited literature regarding caffeine in term infants with apnea. Our case demonstrates that in term infants with primary central sleep apnea of infancy, immature regulation of respiration may persist and a trial of caffeine could be considered.

CITATION

Shah AS, Leu RM, Shah SP, Martinez F, Kasi AS. Caffeine therapy for central sleep apnea, hypoxemia, and hypoventilation in a term neonate. J Clin Sleep Med. 2023;19(5):1005-1008.

Mortality Patterns Associated with Central Sleep Apnea among Veterans: A Large, Retrospective, Longitudinal Report

Rationale: Central sleep apnea (CSA) is associated with high mortality. Current knowledge stems from studies with limited sample size (fewer than 100 subjects) and in homogeneous populations such as heart failure (HF). Objectives: To address this knowledge gap, we compared the mortality pattern and time to death between the CSA and obstructive sleep apnea (OSA) patients in the large Veterans Health Administration patient population using the big data analytic approach. Methods: This is a retrospective study using national Veterans Health Administration electronic medical records from October 1, 1999, through September 30, 2020. We grouped the patients with underlying sleep disorders into CSA and OSA, using the International Classification of Diseases, Ninth and Tenth Revision codes. We applied Cox regression analysis to compare the mortality rate and hazard ratio (HR) among the two groups and adjusted HR by gender, race, body mass index (BMI), age, and Charlson Comorbidity Index. In CSA groups, a machine-learning algorithm was used to determine the most important predictor of time to death. Further subgroup analysis was also performed in patients that had comorbid HF. Results: Evaluation of patients resulted in 2,961 grouped as CSA and 1,487,353 grouped as OSA. Patients with CSA were older (61.8 ± 15.6 yr) than those with OSA (56.7 ± 13.9 yr). A higher proportion of patients with CSA (25.1%) died during the study period compared with the OSA cohort (14.9%). The adjusted HR was 1.53 (95% confidence interval [CI], 1.43-4.65). Presence of HF history of cerebrovascular disease, hemiplegia, and having a BMI less than 18.5 were among the highest predictors of mortality in CSA. The subgroup analysis revealed that the presence of HF was associated with increased mortality both in CSA (HR, 7.4; 95% CI, 6.67-8.21) and OSA (HR, 4.3; 95% CI, 4.26-4.34) groups. Conclusions: Clinically diagnosed CSA was associated with a shorter time to death from the index diagnostic date. Almost one-fifth of patients with CSA died within 5 years of diagnosis. The presence of HF, history of cerebrovascular disease and hemiplegia, male sex, and being underweight were among the highest predictors of mortality in CSA. CSA was associated with higher mortality than OSA, independent of associated comorbidity.

Central sleep apnea and daytime sleepiness in Niemann-Pick type C disease: a report of 2 cases

Niemann-Pick disease type C (NPC) is an autosomal recessive hereditary disease in which sphingomyelin and cholesterol are deposited in various organs of the body. The clinical manifestations of NPC include neurologic symptoms and cataplexy; other symptoms related to sleep have seldom been reported. One previous study described various sleep disorders including chronic insomnia, obstructive sleep apnea, restless legs syndrome, and rapid eye movement sleep behavior disorder, thus suggesting that sleep disorders in patients with NPC are more prevalent than previously thought and warrant close attention. Here, we describe sleep disorders in 2 patients with NPC and discuss the clinical characteristics and, for the first time, discuss potential pathogenic mechanisms underlying sleep disorders in such patients.

CITATION

Zhang Y, Cheng Y, Li N, et al. Central sleep apnea and daytime sleepiness in Niemann-Pick type C disease: a report of 2 cases. J Clin Sleep Med. 2023;19(2):409-414.

Noninvasive Ventilation Automated Technologies: A Bench Evaluation of Device Responses to Sleep-Related Respiratory Events

BACKGROUND

Noninvasive ventilation (NIV) is the reference standard treatment for most situations of chronic respiratory failure. NIV settings must be titrated to both preserve upper-airway patency and control hypoventilation. Automatic adjustment of pressure support (PS) and expiratory positive airway pressure (EPAP) may facilitate the initiation and follow-up of domiciliary NIV. However, whether the automatic-adjustment algorithms embedded into current devices accurately detect, respond to, and score common sleep-related respiratory events remains unclear.

METHODS

A bench was set up to simulate central hypopnea (CH), central apnea (CA), obstructive hypopnea (OH), and obstructive apnea (OA). Four home ventilators were evaluated, with their dedicated modes for automatic PS and EPAP adjustment.

RESULTS

All 4 devices increased PS during CH, CA, and OH. However, PS adjustment varied widely in magnitude, with tidal volumes within 100 ± 20% of the target being provided by only 3 devices for CH, one for CA, and one for OH. Two devices increased EPAP for OH and 3 for OA, including one that also increased EPAP for CA. Only 2 devices scored residual hypopnea after simulated CA, and only one scored a residual event after OH. One device scored no event.

CONCLUSIONS

Current NIV devices differed markedly in their responses to, and reporting of, standardized sleep-related respiratory events. Further improvements in embedded NIV algorithms are needed to allow more widespread out-of-laboratory initiation and follow-up of NIV.

ERS technical standards for using type III devices (limited channel studies) in the diagnosis of sleep disordered breathing in adults and children

For more than three decades, type III devices have been used in the diagnosis of sleep disordered breathing in supervised as well as unsupervised settings. They have satisfactory positive and negative predictive values for detecting obstructive and central sleep apnoea in populations with moderately high pre-test probability of symptoms associated with these events. However, standardisation of commercially available type III devices has never been undertaken and the technical specifications can vary widely. None have been subjected to the same rigorous processes as most other diagnostic modalities in the medical field. Although type III devices do not include acquisition of electroencephalographic signals overnight, the minimum number of physical sensors required to allow for respiratory event scoring using standards outlined by the American Academy of Sleep Medicine remains debatable. This technical standard summarises data on type III studies published since 2007 from multiple perspectives in both adult and paediatric sleep practice. Most importantly, it aims to provide a framework for considering current type III device limitations in the diagnosis of sleep disordered breathing while raising research- and practice-related questions aimed at improving our use of these devices in the present and future.

Impact of transcatheter edge-to-edge mitral valve repair on central sleep apnoea

Aims

Sleep-disordered breathing (SDB) and its subtype central sleep apnoea (CSA) are highly prevalent in patients with heart failure and associated with worse prognosis. Whereas pharmacological therapy of heart failure has been shown to ameliorate CSA, results from previous studies on the effect of mitral regurgitation therapy on SDB are contradicting. The aim of this study was to assess the impact of transcatheter edge-to-edge mitral valve repair (TEER) on prevalence and severity of CSA.

Methods and results

We enrolled 47 patients undergoing TEER for symptomatic mitral regurgitation in a prospective study. Secondary mitral regurgitation and left ventricular ejection fraction < 50% were present in 79% and 68% of patients, respectively. Respiratory polygraphy was performed before TEER in a compensated condition and four weeks after the procedure. 34 patients completed the follow-up. At baseline, 19 (56%) patients showed moderate-to-severe SDB, of whom 13 (68%) were classified as CSA. Both apnoea-hypopnoea index and percentage of recorded time spent in Cheyne-Stokes respiration strongly decreased from baseline to follow-up (median [IQR] 16 [7–30] vs. 7 [4–15] /h, p = 0.007; 6 [0–34] vs. 0 [0–8] %, p = 0.008). Median relative reduction of central apnoea index was 75% (p = 0.023), while obstructive apnoea index did not change significantly. Increase in stroke volume after TEER and high systolic pulmonary artery pressure at baseline predicted a > 50% reduction of both Apnoea-hypopnoea index and Cheyne-Stokes respiration.

Conclusion

TEER is associated with a significant short-term reduction of CSA and Cheyne-Stokes respiration in high-risk patients, strengthening its value as an effective treatment option for advanced heart failure.

Graphical abstract

Non-polyalanine repeat mutation in PHOX2B is detected in autopsy cases of sudden unexpected infant death

Background

Congenital central hypoventilation syndrome (CCHS), which is caused by PHOX2B with phenotypic variations, has a point of controversy: CCHS is putatively involved in autopsy cases of sudden unexpected infant death (SUID) including sudden infant death syndrome.

Objective

The relation of CCHS to SUID cases was investigated by extensive genotyping of PHOX2B.

Methods

We analyzed 93 DNA samples of less than one-year-old SUID cases that were autopsied in our department. Unrelated adult volunteers (n = 942) were used as the control.

Results

No polyalanine tract expansion was detected in the SUID cases. The allelic frequencies of repeat contractions and SNP (rs28647582) in intron 2 were not significantly different from that in those control group. Further extensive sequencing revealed a non-polyalanine repeat mutation (NPARM) of c.905A>C in a sudden death case of a one-month-old male infant. This missense mutation (p.Asn302Thr), registered as rs779068107, was annotated to ‘Affected status is unknown’, but it might be associated with the sudden death.

Conclusion

NPARM was more plausibly related to sudden unexpected death than expansions because of severe clinical complications. This finding indicates possible CCHS involvement in forensic autopsy cases without ante-mortem diagnosis.

Central Apneas Due to the CLIFAHDD Syndrome Successfully Treated with Pyridostigmine

NALCN mutations lead to complex neurodevelopmental syndromes, including infantile hypotonia with psychomotor retardation and characteristic facies (IHPRF) and congenital contractures of limbs and face, hypotonia, and developmental delay (CLIFAHDD), which are recessively and dominantly inherited, respectively. We present a patient in whom congenital myasthenic syndrome (CMS) was suspected due to the occurrence of hypotonia and apnea episodes requiring resuscitation. For this reason, treatment with pyridostigmine was introduced. After starting the treatment, a significant improvement was observed in reducing the apnea episodes and slight psychomotor progress. In the course of further diagnostics, CMS was excluded, and CLIFAHDD syndrome was confirmed. Thus, we try to explain a possible mechanism of clinical improvement after the introduction of treatment with pyridostigmine in a patient with a mutation in the NALCN gene.

Developmental disorders affecting the respiratory system: CCHS and ROHHAD

Rapid-onset Obesity with Hypothalamic dysfunction, Hypoventilation, and Autonomic Dysregulation (ROHHAD) and Congenital Central Hypoventilation Syndrome (CCHS) are ultra-rare distinct clinical disorders with overlapping symptoms including altered respiratory control and autonomic regulation. Although both disorders have been considered for decades to be on the same spectrum with necessity of artificial ventilation as life-support, recent acquisition of specific knowledge concerning the genetic basis of CCHS coupled with an elusive etiology for ROHHAD have definitely established that the two disorders are different. CCHS is an autosomal dominant neurocristopathy characterized by alveolar hypoventilation resulting in hypoxemia/hypercarbia and features of autonomic nervous system dysregulation (ANSD), with presentation typically in the newborn period. It is caused by paired-like homeobox 2B (PHOX2B) variants, with known genotype-phenotype correlation but pathogenic mechanism(s) are yet unknown. ROHHAD is characterized by rapid weight gain, followed by hypothalamic dysfunction, then hypoventilation followed by ANSD, in seemingly normal children ages 1.5-7 years. Postmortem neuroanatomical studies, thorough clinical characterization, pathophysiological assessment, and extensive genetic inquiry have failed to identify a cause attributable to a traditional genetic basis, somatic mosaicism, epigenetic mechanism, environmental trigger, or other. To find the key to the ROHHAD pathogenesis and to improve its clinical management, in the present chapter, we have carefully compared CCHS and ROHHAD.

Central respiratory chemoreception

Brain PCO2 is sensed primarily via changes in [H+]. Small pH changes are detected in the medulla oblongata and trigger breathing adjustments that help maintain arterial PCO2 constant. Larger perturbations of brain CO2/H+, possibly also sensed elsewhere in the CNS, elicit arousal, dyspnea, and stress, and cause additional breathing modifications. The retrotrapezoid nucleus (RTN), a rostral medullary cluster of glutamatergic neurons identified by coexpression of Phoxb and Nmb transcripts, is the lynchpin of the central respiratory chemoreflex. RTN regulates breathing frequency, inspiratory amplitude, and active expiration. It is exquisitely responsive to acidosis in vivo and maintains breathing autorhythmicity during quiet waking, slow-wave sleep, and anesthesia. The RTN response to [H+] is partly an intrinsic neuronal property mediated by proton sensors TASK-2 and GPR4 and partly a paracrine effect mediated by astrocytes and the vasculature. The RTN also receives myriad excitatory or inhibitory synaptic inputs including from [H+]-responsive neurons (e.g., serotonergic). RTN is silenced by moderate hypoxia. RTN inactivity (periodic or sustained) contributes to periodic breathing and, likely, to central sleep apnea. RTN development relies on transcription factors Egr2, Phox2b, Lbx1, and Atoh1. PHOX2B mutations cause congenital central hypoventilation syndrome; they impair RTN development and consequently the central respiratory chemoreflex.

Central sleep apnea

Central apnea syndrome is a disorder with protean manifestations and concomitant conditions. It can occur as a distinct clinical entity or as part of another clinical syndrome. The pathogenesis of central sleep apnea (CSA) varies depending on the clinical condition. Sleep-related withdrawal of the ventilatory drive to breathe is the common denominator among all cases of central apnea, whereas hypocapnia is the final common pathway leading to apnea in the majority of central apnea. Medical conditions most closely associated with CSA include heart failure, stroke, spinal cord injury, and opioid use, among others. Nocturnal polysomnography is the standard diagnostic method, including measurement of sleep and respiration. The latter includes detection of flow, measurement of oxyhemoglobin saturation and detection of respiratory effort. Management strategy incorporates clinical presentation, associated conditions, and the polysomnographic findings in an individualized manner. The pathophysiologic heterogeneity may explain the protean clinical manifestations and the lack of a single effective therapy for all patients. While research has enhanced our understanding of the pathogenesis of central apnea, treatment options are extrapolated from treatment of obstructive sleep apnea. Co-morbid conditions and concomitant obstructive sleep apnea influence therapeutic approach significantly. Therapeutic options include positive pressure therapy, pharmacologic therapy, and supplemental Oxygen. Continuous positive airway pressure (CPAP) is the initial standard of care, although the utility of other modes of positive pressure therapy, as well as pharmacotherapy and device-based therapies, are currently being investigated.

Sleep and breathing disorders in heart failure

Sleep disorders are prevalent in heart failure and include insomnia, poor sleep architecture, periodic limb movements and periodic breathing, and encompass both obstructive (OSA) and central sleep apnea (CSA). Polysomnographic studies show excess light sleep and poor sleep efficiency particularly in those with heart failure. Multiple studies of consecutive patients with heart failure show that about 50% of patients suffer from either OSA or CSA. While asleep, acute pathological consequences of apneas and hypopneas include altered blood gases, sleep fragmentation, and large negative swings in intrathoracic pressure. These pathological consequences are qualitatively similar in both types of sleep apnea, though worse in OSA than CSA. Sleep apnea results in oxidative stress, inflammation, and endothelial dysfunction, best documented in OSA. Multiple studies show that both OSA and CSA are associated with excess hospital readmissions and premature mortality. However, no randomized controlled trial (RCT) has been reported for OSA, but sensitivity analysis of two randomized controlled trials has concluded that use of positive airway pressure devices is associated with excess mortality in patients with heart failure and CSA. Phrenic nerve stimulation has shown improvement in sleep apnea events and daytime sleepiness; however, no randomized controlled trials have demonstrated improvement in survival in patients with heart failure. The correct identification and treatment of heart failure patients with sleep and breathing disorders could affect the long-term outcomes of these patients.

Transvenous Phrenic Nerve Stimulation for Central Sleep Apnea: Clinical and Billing Review

Central sleep apnea (CSA) frequently coexists with heart failure and atrial fibrillation and contributes to cardiovascular disease progression and mortality. A transvenous phrenic nerve stimulation (TPNS) system has been approved for the first time by the Food and Drug Administration for the treatment of CSA. This system, remedē® ZOLL Medical, Inc. is implanted during a minimally invasive outpatient procedure, and has shown a favorable safety and efficacy profile. Currently, patients' access to this therapy remains limited by the small number of specialized centers in the US and the absence of a standard coverage process by insurers. While a period of evaluation by insurers is expected for new therapies in their early stages, the impact on patients is particularly severe given the already limited treatment options for CSA. Implantation and management of this novel therapy requires the establishment of a specialized multidisciplinary program as part of a Sleep Medicine practice and support from health care systems and hospitals. Several centers in the US have been successful in building sustainable TPNS program offering this novel therapy to their patients by navigating the current reimbursement environment. In this article, we will review the background and efficacy data of TPNS and briefly address relevant aspects of the clinical activities involved in a TPNS program. The article will present the status of coverage and reimbursement for this novel therapy. We will also discuss the current approach to obtaining reimbursement from third party payors during this transitional period of evaluation by Medicare and other insurers.

Optimized Detection of Central Apneas Preceding Late-Onset Sepsis in Premature Infants

In neonatal intensive care units, respiratory traces of premature infants developing late onset sepsis (LOS) may also show episodes of apneas. However, since clinical patient monitors often underdetect apneas, clinical experts are required to investigate patients' traces looking for these events. In this work we present a method to optimize an existing algorithm for central apnea (CA) detection and how we used it together with human annotations to investigate the occurrence of CAs preceding LOS.The algorithm was optimized by using a previously-annotated dataset consisting of 90 hours, extracted from 10 premature infants. This allowed to double precision (19.7% vs 9.3%, median values per patient) without affecting recall (90.5% vs 94.5%) compared to the original algorithm. This choice caused the missed identification of just 1 additional CA (4 vs 3) in the whole dataset. The optimized algorithm was then used to annotate a second dataset consisting of 480 hours, extracted from 10 premature infants diagnosed with LOS. Annotations were corrected by two clinical experts.A significantly higher number of CA annotations was found in the 6 hours prior to sepsis onset (p-value < 0.05). The use of the optimized algorithm followed by human annotations proved to be a suitable, time-efficient method to annotate CAs before sepsis in premature infants, enabling future use in large datasets.

Research Priorities for Patients with Heart Failure and Central Sleep Apnea. An Official American Thoracic Society Research Statement

Background: Central sleep apnea (CSA) is common among patients with heart failure and has been strongly linked to adverse outcomes. However, progress toward improving outcomes for such patients has been limited. The purpose of this official statement from the American Thoracic Society is to identify key areas to prioritize for future research regarding CSA in heart failure.

Methods: An international multidisciplinary group with expertise in sleep medicine, pulmonary medicine, heart failure, clinical research, and health outcomes was convened. The group met at the American Thoracic Society 2019 International Conference to determine research priority areas. A statement summarizing the findings of the group was subsequently authored using input from all members.

Results: The workgroup identified 11 specific research priorities in several key areas: 1) control of breathing and pathophysiology leading to CSA, 2) variability across individuals and over time, 3) techniques to examine CSA pathogenesis and outcomes, 4) impact of device and pharmacological treatment, and 5) implementing CSA treatment for all individuals

Conclusions: Advancing care for patients with CSA in the context of heart failure will require progress in the arenas of translational (basic through clinical), epidemiological, and patient-centered outcome research. Given the increasing prevalence of heart failure and its associated substantial burden to individuals, society, and the healthcare system, targeted research to improve knowledge of CSA pathogenesis and treatment is a priority.

Prevalence of sleep-disordered breathing in opioid users with chronic pain: a systematic review and meta-analysis

STUDY OBJECTIVES

Opioids have been reported to increase the risk for sleep-disordered breathing (SDB) in patients with noncancer chronic pain on opioid therapy. This study aims to determine the pooled prevalence of SDB in opioid users with chronic pain and compare it with patients with pain:no opioids and no pain:no opioids.

METHODS

A literature search of PubMed, Medline, Embase, and Cochrane Central Register of Controlled Trials was conducted. We included all observational studies that reported the prevalence of SDB in patients with chronic pain on long-term opioid therapy (≥3 months). The primary outcome was the pooled prevalence of SDB in opioid users with chronic pain (pain:opioids group) and a comparison with pain:no opioids and no pain:no opioids groups. The meta-analysis was performed using a random-effects model.

RESULTS

After screening 1,404 studies, 9 studies with 3,791 patients were included in the meta-analysis (pain:opioids group, n = 3181 [84%]; pain:no opioids group, n = 359 [9.4%]; no pain:no opioids group, n = 251 [6.6%]). The pooled prevalence of SDB in the pain:opioids, pain:no opioids, and no pain:no opioids groups were 91%, 83%, and 72% in sleep clinics and 63%, 10%, and 75% in pain clinics, respectively. Furthermore, in the pain: opioids group, central sleep apnea prevalence in sleep and pain clinics was 33% and 20%, respectively.

CONCLUSIONS

The pooled prevalence of SDB in patients with chronic pain on opioid therapy is not significantly different compared with pain:no opioids and no pain:no opioids groups and varies considerably depending on the site of patient recruitment (ie, sleep vs pain clinics). The prevalence of central sleep apnea is high in sleep and pain clinics in the pain:opioids group. Clinical Trial Registration: Registry: PROSPERO: International prospective register of systematic reviews; Name: Prevalence of sleep disordered breathing, hypoxemia and hypercapnia in patients on oral opioid therapy for chronic pain management; URL: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42018103298; Identifier: CRD42018103298.

Ld-EEG Effective Brain Connectivity in Patients With Cheyne-Stokes Respiration

The characterization of brain cortical activity in heart-failure patients affected by Cheyne-Stokes Respiration might provide relevant information about the mechanism underlying this pathology. Central autonomic network is gaining increasing attention for its role in the regulation of breathing and cardiac functions. In this scenario, evaluating changes in cortical connectivity associated with Cheyne-Stokes Respiration may be of interest in the study of specific brain-activity related to such disease. Nonetheless, the inter subject variability, the temporal dynamics of Central-Apnea/Hyperpnea cycles and the limitations of clinical setups lead to different methodological challenges. To this aim, we present a framework for the assessment of cortico-cortical interactions from Electroencephalographic signals acquired using low-density caps and block-design paradigms, arising from endogenous triggers. The framework combines ICA-decomposition, unsupervised clustering, MVAR modelling and a permutation-bootstrap strategy for evaluating significant connectivity differences between conditions. A common network, lateralized towards the left hemisphere, was depicted across 8 patients exhibiting Cheyne-Stokes Respiration patterns during acquisitions. Significant differences in connectivity at the group level were observed based on patients' ventilatory condition. Interactions were significantly higher during hyperpnea periods with respect to central apneas and occurred mainly in the delta band. Opposite-sign differences were observed for higher frequencies (i.e. beta, low-gamma).

Central Sleep Apnea Alters Neuronal Excitability and Increases the Randomness in Sleep-Wake Transitions

OBJECTIVE

While most studies on Central Sleep Apnea (CSA) have focused on breathing and metabolic disorders, the neuronal dysfunction that causes CSA remains largely unknown. Here, we investigate the underlying neuronal mechanism of CSA by studying the sleep-wake dynamics as derived from hypnograms.

METHODS

We analyze sleep data of seven groups of subjects: healthy adults (n = 48), adults with obstructive sleep apnea (OSA) (n = 29), adults with CSA (n = 25), healthy children (n = 40), children with OSA (n = 18), children with CSA (n = 73) and CSA children treated with CPAP (n = 10). We calculate sleep-wake parameters based on the probability distributions of wake-bout durations and sleep-bout durations. We compare these parameters with results obtained from a neuronal model that simulates the interplay between sleep- and wake-promoting neurons.

RESULTS

We find that sleep arousals of CSA patients show a characteristic time scale (i.e., exponential distribution) in contrast to the scale-invariant (i.e., power-law) distribution that has been reported for arousals in healthy sleep. Furthermore, we show that this change in arousal statistics is caused by triggering more arousals of similar durations, which through our model can be related to a higher excitability threshold in sleep-promoting neurons in CSA patients.

CONCLUSIONS

We propose a neuronal mechanism to shed light on CSA pathophysiology and a method to discriminate between CSA and OSA. We show that higher neuronal excitability thresholds can lead to complex reorganization of sleep-wake dynamics.

SIGNIFICANCE

The derived sleep parameters enable a more specific evaluation of CSA severity and can be used for CSA diagnosis and monitor CSA treatment.

Breathing detection from tracheal sounds in both temporal and frequency domains in the context of phrenic nerve stimulation

Electrical stimulation of the phrenic nerves via implanted devices allows to counteract some disadvantages of mechanical ventilation in patients with high tetraplegia or Ondine's syndrome. Existing devices do not allow to monitor breathing or to adapt the electroventilation to patients' actual needs. A reliable breathing monitor with an inbuilt alarm function would improve patient safety. In our study, a real-time acoustic breathing detection method is proposed as a possible solution to improve implanted phrenic stimulation. A new algorithm to process tracheal sounds has been developed. It combines breathing detection in both temporal and frequency domains. The algorithm has been applied on recordings from 18 healthy participants. The obtained average sensitivity, specificity and accuracy of the detection are: 99.31%, 96.84% and 98.02%, respectively. These preliminary results show a first positive proof of the interest of such an approach. Additional experiments are needed, including longer recordings from individuals with tetraplegia or Ondine Syndrome in various environments to go further in the validation.

Effects of optimized heart failure medication on central sleep apnea with Cheyne-Stokes respiration pattern in chronic heart failure with reduced left-ventricular ejection fraction

Central Sleep Apnea with Cheyne Stokes Respiration (CSA-CSR) is often diagnosed in patients with chronic heart failure (CHF). CSA-CSR displays a periodic breathing pattern with a typical waxing and waning breathing with central sleep apnea phases in between. Optimization of heart failure medication with Angiotensin receptor neprilysin inhibition (ARNi) can effect phenotypic traits of CSA-CSR indicating improvements of both, hemodynamic parameters and central chemosensitivity.

Monitoring of nocturnal central sleep apnea in Heart failure patients using noncontact respiratory differences

Monitoring of respiration patterns allows the early detection of various breathing disorders and may better identify those at risk for adverse acute outcomes in a variety of clinical settings. In this paper, we report on the use of SleepMinder (SM), a bedside non-contact Doppler-based biomotion recording sensor, to monitor remotely the nocturnal respiration patterns of 50 patients with systolic Heart failure (HF) while undergoing a lab based Polysomnography (PSG) test. A new respiration rate (RR) monitoring algorithm was developed based on the collected overnight radar signals. Two schemes of RR scoring were utilized: respiratory rate count (RRC) and instantaneous respiratory rates (IRR). Analysis of SM vs. PSG revealed that the mean/median IRR scored by SM is highly correlated with that scored on the nasal flow/effort signals from the corresponding PSG studies on all patients, with a significant correlation coefficient of 0.98 (average absolute difference of 0.31 breaths/min), and 0.97 (p<;0.01, average absolute difference of 0.38 breaths/min) for the median and mean of RR respectively. Our experimental results also show that the difference between the RR estimations from IRR and RRC schemes can be utilized to identify central sleep apnea (CSA)/Cheyne-Stokes respiration (CSR) sections without additional apnea detection modules. As a result, with a sensitivity and specificity of 71% and 88% respectively, and an accuracy of 86%, our CSA/CSR screener, plugged with our RR estimation, can play an important role in the remote management of HF patients.

Focus on Functional Delayed Central Sleep Apnea Following Cervical Laminectomy. An Example of Respiratory Dysfunction in Restorative Neurosurgical Procedures

In sleep-related breathing disorders, sleep apnea is a clinical symptom that can be categorized as obstructive sleep apnea (OSA) or mixed apnea by analysis using polysomnography. The occurrence of delayed central sleep apnea (CSA) is an extremely rare complication of cervical laminectomy for spondylotic myelopathy. So far only three studies concerning such an event have been reported in the literature. Naim-ur-Rahman, in 1994, reported a case of postoperative CSA following C3-C6 laminectomy, and Visocchi and colleagues, in 2014, in two studies, stressed the lack of association with any other neurological sign of spinal cord damage. No definitive mechanism has been recognized so far for delayed CSA after cervical laminectomy. A transient dysfunction of the reticulo-spinal fibers directed to the nucleus of the phrenic nerve can be speculated, although neither emi-diaphragm paralysis, nor any prominent nocturnal sleep-related disorders are associated with this delayed CSA.

Heart failure - what's new and what's changed?

Physicians responsible for the care of patients with heart failure due to left ventricular systolic dysfunction have access to a broad range of evidence-based treatments that prolong life and reduce symptoms. In spite of the significant progress made over the last four decades, there is an ongoing need for novel therapies to treat a condition that is associated with stubbornly high morbidity and mortality. In this article, we discuss the findings of SERVE-HF, a randomised controlled trial of adaptive servo-ventilation in patients with left ventricular systolic dysfunction, as well as EMPA-REG, a study of the effects of a novel diabetic agent that may be of greater interest to heart failure specialists than diabetologists. We also examine further analyses of the groundbreaking PARADIGM-HF trial, which attempt to answer some of the unresolved questions from the original study of the first combined angiotensin-receptor blocker and neprilysin inhibitor, sacubitril valsartan. The recently published National Institute for Health and Care Excellence guidelines for the management of acute heart failure and plans to introduce best practice tariffs bring into focus the need for well-organised, multidisciplinary care. We discuss the challenges involved in developing and delivering a specialist service that meets the needs of a growing population of patients living with heart failure.