Predictors of sleep hypoxemia in children with cystic fibrosis

Pulmonary Vascular Dysfunctions in Cystic Fibrosis

Cystic fibrosis (CF) is an inherited disorder caused by a deleterious mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Given that the CFTR protein is a chloride channel expressed on a variety of cells throughout the human body, mutations in this gene impact several organs, particularly the lungs. For this very reason, research regarding CF disease and CFTR function has historically focused on the lung airway epithelium. Nevertheless, it was discovered more than two decades ago that CFTR is also expressed and functional on endothelial cells. Despite the great strides that have been made in understanding the role of CFTR in the airway epithelium, the role of CFTR in the endothelium remains unclear. Considering that the airway epithelium and endothelium work in tandem to allow gas exchange, it becomes very crucial to understand how a defective CFTR protein can impact the pulmonary vasculature and overall lung function. Fortunately, more recent research has been dedicated to elucidating the role of CFTR in the endothelium. As a result, several vascular dysfunctions associated with CF disease have come to light. Here, we summarize the current knowledge on pulmonary vascular dysfunctions in CF and discuss applicable therapies.

Effects of Obstructive Sleep Apnea on Airway Immunity and Susceptibility to Respiratory Infections

Obstructive sleep apnea is a prevalent sleep disorder characterized by recurrent episodes of partial or complete upper airway collapse during sleep, leading to disrupted breathing patterns and intermittent hypoxia. OSA results in systemic inflammation but also directly affects the upper and lower airways leading to upregulation of inflammatory pathways and alterations of the local microbiome. These changes result in increased susceptibility to respiratory infections such as influenza, COVID-19, and bacterial pneumonia. This relationship is more complex and bidirectional in individuals with chronic lung disease such as chronic obstructive lung disease, interstitial lung disease and bronchiectasis.

Obstructive sleep apnea in children with cystic fibrosis on highly effective modulator therapy

INTRODUCTION

Obstructive sleep apnea (OSA) is common in children with cystic fibrosis (CF). Highly effective modulator therapies (HEMT) have led to improved sinopulmonary disease, but whether this translates to a lower frequency of OSA is unknown.

METHODS

We conducted a single center retrospective review of polysomnographic (PSG) data from 2012 to 2023 in patients aged 0-18 years with CF to assess frequency of OSA. Participants were classified based on HEMT status. Logistic regression was used to quantify the association between HEMT and OSA with p < .05 considered significant.

RESULTS

Forty-nine children underwent PSG during the study period. Ten percent were of non-White race and 24% were of Hispanic ethnicity. Twenty-one children (43%) were on HEMT. These children were older than those not on modulators (11.6 vs. 6.4 years; p = .0001) but no different with respect to gender, race, nutritional status, or lung function. Twenty-eight (57%) children had OSA. Odds of having OSA were higher in the HEMT group (odds ratio [OR] = 4.3; 95% confidence interval [CI]: 1.2-14.9; p = .02). Tonsillar hypertrophy was associated with an increased odds of having OSA independent of modulator status (OR: 6.6; 95% CI: 1.2-37.9; p = .03).

CONCLUSIONS

OSA is frequently diagnosed in the post-HEMT era in this large, racially diverse group of children with CF. Children on HEMT were older and more likely to have OSA as compared to those not on modulators but similar in nutritional status, lung function, and presence of upper airway pathology. Prospective studies are needed to further clarify the relationship between HEMT and OSA in children with CF.

Sleep Respiratory Disorders in Children and Adolescents with Cystic Fibrosis and Primary Ciliary Dyskinesia

Cystic fibrosis (CF) and primary ciliary dyskinesia (PCD) are genetic respiratory diseases featured by chronic upper and lower airway inflammation and infection, mainly due to impaired mucociliary clearance due to genetic mutations. Sleep is crucial to healthy children's normal physical and psychological development and has an important value in chronic respiratory diseases. Impaired sleep quality, such as sleep deprivation or insufficient sleep during the night, and sleep respiratory disorders (SRDs) are common in 5% to 30% of the general population. Sleep disruption leads to attention deficits, daytime sleepiness, fatigue and mood disorders and correlates to a worsened quality of life. Furthermore, sleep respiratory disorders (SRSs) are under-recognized comorbidities in CF and PCD patients. SRSs include a spectrum of symptoms ranging from primary snoring through upper airway resistance to obstructive sleep apnea (OSA), nocturnal hypoventilation and hypoxemia occurring in people with moderate to severe lung disease and damaging the disease-related outcomes and quality of life. Effective screening during sleep with polysomnography is very important for the timely initiation of efficacious treatments and to prevent worsened respiratory, metabolic and cardiovascular outcomes. However, the impact of SRDs on health and quality of life is still underinvestigated.

Cystic fibrosis year in review 2019: Section 2 pulmonary disease and infections

During the year 2019, research and case reports or series in the field of cystic fibrosis (CF) were in abundance. To adequately address the large body of CF research published during 2019, the CF year in review will be divided into three sections. This report is the second section, focusing specifically on new research related to pulmonary disease and infections. Additional sections will concentrate on CF transmembrane conductance regulator modulators and the multisystem effects of CF. It is an exciting time to be providing care for patients and their families with CF with all the exciting new discoveries that will be shared in these reviews.

Obstructive sleep apnea and nocturnal hypoxemia in adult patients with cystic fibrosis

Background

Obstructive sleep apnea (OSA), nocturnal hypoxemia and excessive daytime sleepiness (EDS) are common comorbidities in people with cystic fibrosis (pwCF). Most of the data showing this originates from children and adolescents. The aim of this study was to collect data on sleep parameters, EDS and pulmonary function from a large cohort of adult pwCF.

Methods

Full overnight polysomnography (PSG) was performed. EDS was determined using the Epworth Sleepiness Scale (ESS). Demographic and clinical data (body mass index [BMI], pulmonary function, capillary blood gases) were collected.

Results

A total of 52 adult pwCF were included (mean age 30.7 ± 8.0 years, mean percent predicted forced expiratory volume in 1 s [ppFEV1] of 52.1 ± 14.8). Overall AHI was in the normal range (4.5 ± 4.0/h); 21/52 pwCF (40%) had an apnea-hypopnea index > 5/h. Nocturnal hypoxemia was found in 25% of participants and this was associated with ppFEV1 (p = 0.014), awake oxygen saturation (SpO2; p = 0.021) and awake partial pressure of oxygen (pO2; p = 0.003); there were no significant differences in age, lung function and BMI were found for pwCF with versus without OSA (all p > 0.05). Eight pwCF (15%) had an ESS score > 10 (indicating EDS). OSA was best predicted by awake pO2 (area under the curve [AUC] 0.66, p = 0.048), while nocturnal hypoxemia was best predicted by ppFEV1 (AUC 0.74, p = 0.009), awake pO2 (AUC 0.76, p = 0.006) and awake SpO2 (AUC 0.71; p = 0.025).

Conclusion

OSA, nocturnal hypoxemia and EDS were common in adult pwCF, but no strong predictors were identified. Therefore, we suggest regular PSG and ESS scoring in adult pwCF, regardless of disease severity.

Sleep in children with cystic fibrosis: More under the covers

Cystic fibrosis (CF) is a chronic multisystem disease with manifestations from birth. It involves the entire respiratory system, with increased cough, and recurrent pulmonary infections, and it also leads to intestinal malabsorption, all of which can have an impact on sleep. In this review, we summarize the available literature on the various sleep disturbances in children with CF. Sleep quality and sleep efficiency are often impaired in children with CF. They may be accompanied by symptoms associated with sleep-disordered breathing (SDB), and objective findings, such as nocturnal hypoxemia. Importantly, a strong association has been shown between SDB and the severity of lung disease, and some studies have reported a similar association for sleep quality. Further research is needed to better characterize the association of sleep disturbances with respiratory outcomes and the impact of treatment of sleep disorders on pulmonary status in children with CF.

Effect of Triple Combination CFTR Modulator Therapy on Sleep in Adult Patients with Cystic Fibrosis

<b><i>Background:</i></b> Sleep-disordered breathing (SDB) and disturbed sleep are common, often underrecognized, comorbidities in people with cystic fibrosis (pwCF). <b><i>Objectives:</i></b> We studied the effect of CFTR triple combination therapy elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) on sleep in pwCF. <b><i>Method:</i></b> This was a prospective, observational sleep study in clinically stable adult pwCF. All participants underwent overnight polysomnography (PSG), before (T0) and after (T1) initiation of CFTR modulator therapy with ELX/TEZ/IVA. In addition, pulmonary function tests, calculation of BMI, and sweat chloride testing were performed. <b><i>Results:</i></b> Twenty-nine pwCF (mean age 32 ± 8 years; 15 female) participated in the study. Mean time between T0 and T1 was 194 ± 21 days. Total sleep time (TST) was 298 ± 40 min, with decreased sleep efficiency (SE) (76 ± 109) and increased sleep latency (SL) (73 ± 38 min). Sleep stages for NREM (N1–3) and REM sleep were within the normal range. Nocturnal respiratory events mainly occur during REM sleep (T0: AHI REM 8.3 ± 9.0/h; ODI REM 9.4 ± 10.6/h), whereas the overall AHI was normal (3.6 ± 3.7/h). After initiation of ELX/TEZ/IVA, we saw significant improvements in ppFEV1 (<i>p</i> &#x3c; 0.001) and BMI (<i>p</i> &#x3c; 0.001) and a reduction in sweat chloride levels (<i>p</i> &#x3c; 0.001). In parallel, there was a reduction in AHI (<i>p</i> = 0.003), ODI (<i>p</i> = 0.001), and nocturnal respiratory rate (<i>p</i> &#x3c; 0.001), both in total, REM and NREM sleep. Neither TST, SL, SE, nor sleep architecture was influenced (all <i>p</i> &#x3e; 0.05). <b><i>Conclusions:</i></b> Initiation of ELX/TEZ/IVA resulted in significant improvements in SDB in adult pwCF.

Obstructive sleep apnea in children and adolescents with cystic fibrosis and preserved lung function or mild impairment: a systematic review and meta-analysis of prevalence

OBJECTIVE/BACKGROUND

Sleep disorders in cystic fibrosis may be present before daytime clinical manifestations, regardless of lung function impairment, affecting quality of life and disease progression. This study investigated the prevalence of obstructive sleep apnea in children and adolescents with cystic fibrosis and preserved lung function or mild impairment, and evaluated its association with clinical variables.

METHODS

A systematic review with meta-analysis of prevalence was conducted, including observational studies with polysomnographies in patients with cystic fibrosis who presented mean lung function values > 60% predicted. The methodological quality of the studies was analyzed, and a meta-analysis was performed to assess the prevalence of obstructive sleep apnea.

RESULTS

Of the 2318 studies identified, 7 were included in the systematic review and 6 in the meta-analysis of prevalence. The confounding factors and strategies identified were the items with greatest weakness in the methodological quality assessment. Most studies were cross-sectional, and sample size ranged from 9 to 67 individuals. The most frequent criterion for defining obstructive sleep apnea was apnea-hypopnea index (AHI) > 1 per hour. The prevalence found ranged from 32.3 to 100% and the pooled prevalence was 65% (I² = 53.4%), considering AHI>1, and 52% (I² = 89.4%) for AHI>2 per hour. It was not possible to verify the association between obstructive sleep apnea and clinical variables.

CONCLUSIONS

A high prevalence of obstructive sleep apnea in children and adolescents with cystic fibrosis was found, regardless of age and lung function impairment, reinforcing the importance of investigating sleep-disordered breathing during clinical visits even when lung function is not yet compromised.

Association between habitual physical activity (HPA) and sleep quality in patients with cystic fibrosis

PURPOSE

Sleep disturbances and poor sleep quality are known to be present in patients with CF. Regular physical activity plays an important role in the treatment of CF patients due to its positive influence on progression of disease and quality of life. The aim of this work is to create a home-based sleep and activity profile and to investigate the influence of habitual physical activity (HPA) on sleep quality in children, adolescents, and adults with CF.

METHODS

A total of 109 CF patients (64 male, mean age 22.7 ± 12.0 years; mean ppFEV1 63.0 ± 26.7) were equipped with an actigraph for a home-based collection of data on sleep and activity over 4 weeks.

RESULTS

Age, FEV1, and BMI affect sleep and activity in CF patients. Especially younger age and higher FEV1 show a great influence on certain aspects of sleep (SE, TST, TIB, WASO, # of awakenings) and activity and its different intensities. General HPA does not affect sleep, but there is a strong correlation between times spent in vigorous to very vigorous intensities and better sleep quality.

CONCLUSION

Besides younger age and higher FEV1, daily activity in higher intensities influences sleeping behavior of CF patients in a positive way. Patients with poor sleep quality and sleep disturbances possibly benefit from an intensification of physical activity in the home environment. TRAIL REGISTRATION: number: 14-6117-BO (University Duisburg-Essen) and NCT03518697 (clinical trials).

Sleep-disordered breathing in cystic fibrosis

Sleep-disordered breathing (SBD) is an under recognized comorbidity in the cystic fibrosis (CF) population across the lifespan. Nocturnal hypoxemia, obstructive sleep apnea, and nocturnal hypoventilation are respiratory abnormalities that occur commonly during sleep in patients with lung disease, and have deleterious consequences to the quality of life in people with CF. Effective screening for these abnormalities is needed to allow for timely initiation of treatment, which has been reported to be efficacious. Lack of treatment leads to worsened pulmonary, cardiovascular, and metabolic outcomes in patients. In this review, we give an overview of SBD for the CF clinician, including prevalence, treatment, and suggestions for future research. We strongly encourage the CF community to incorporate evaluation for SBD in CF clinical care so that outcomes for the subset of the CF patients with comorbid SBD improve.

Sleep-disordered breathing and markers of morbidity in children and adolescents with cystic fibrosis

BACKGROUND

Studies have shown that sleep disorders occur in cystic fibrosis (CF) patients and may be present before daytime clinical manifestations.

OBJECTIVES

To evaluate the presence of sleep disorders among children and adolescents with CF, attempting to identify associations with pulmonary function, nutritional status, days in hospital, and days taking antibiotics.

METHODS

Individuals with a diagnosis of CF aged between 6 and 18 years were included. Information on sociodemographic, clinical profile, history of hospitalizations, and use of antibiotics in the last year were collected. Spirometry, bioimpedance, and polysomnography were performed. The presence of nocturnal hypoxemia and obstructive sleep apnea syndrome (OSAS) were evaluated and participants divided according to their presence.

RESULTS

Thirty-one patients were included. The prevalence of OSAS was 32.3% and nocturnal hypoxemia was 29.0%. Average nocturnal peripheral oxyhemoglobin saturation (SpO₂ ) correlated (P < .001) with forced vital capacity (r = .55) and forced expiratory volume in the first second (r = .62). The higher the percentage of total sleep time (TST) with SpO₂ less than 90%, the lower the pulmonary function. Individuals with OSAS and nocturnal hypoxemia had lower spirometric values compared to patients without these disorders, but the nocturnal hypoxemia group also had lower Shwachman-Kulczycki score, longer hospitalization time and antibiotic use. TST with SpO₂ less than 90% was associated with length of hospitalization (r²  = .53).

CONCLUSION

Children and adolescents with CF have sleep disorders, including OSAS (32.3%) and nocturnal hypoxemia (29%). Individuals with nocturnal hypoxemia presented lower lung function, worse clinical score, and higher morbidity. TST with SpO₂ less than 90% was associated with length of hospitalization.

Pediatric pulmonology year in review 2019: Sleep medicine

Pediatric Pulmonology publishes original research, review articles as well as case reports on a wide variety of pediatric respiratory disorders. In this article, we summarize the past year's publications in sleep medicine and we review selected literature from other journals within this field. Articles highlighted are topics on risk factors of sleep-disordered breathing, diagnosis, and treatment of obstructive sleep apnea as well as the utility of polysomnography in various complex conditions.

Attenuation of intermittent hypoxia-induced apoptosis and fibrosis in pulmonary tissues via suppression of ER stress activation

Background

Obstructive sleep apnea (OSA) is associated with pulmonary fibrosis and endothelial apoptosis in pulmonary tissues. Chronic intermittent hypoxia (IH) is considered to be the primary player in OSA, but the mechanisms underlying its effect on pulmonary tissues are unknown. Endoplasmic reticulum (ER) stress induced by IH treatment plays an important role in accelerating the process of fibrosis and induction of apoptosis.

Methods

Mice were placed in IH chambers for 4 weeks with an oscillating oxygen (O₂) concentration between 5 and 21%, cycling every 90s for 8 h daily. Mice were randomly divided into four groups: control group (normal oxygen), tauroursodeoxycholic acid (TUDCA) group (normal oxygen intraperitoneally injected with TUDCA), IH group and IH + TUDCA group. After 4 weeks, the proteins in three branch signaling pathways of ER stress, including protein kinase RNA (PKR)-like/Pancreatic ER kinase (PERK), activating transcription factor 6 (ATF-6) and inositol-requiring enzyme 1 (IRE-1), were evaluated. The cleaved caspase-3, caspase-12 and TUNNEL staining was assessed. Furthermore, the expression of transforming growth factor-β1 (TGF-β1) and thrombospondin-1(TSP-1), two extracellular matrix proteins that play critical role in fibrosis, were examined. Finally, Masson’s trichrome staining was performed to detect the expression of collagen.

Results

After 4 weeks of IH treatment, the expressions of two ER stress markers, glucose regulated protein-78 (Grp78) and transcription factor C/EBP homologous protein (CHOP) were increased which was prevented by administration of the ER stress attenuator, TUDCA. The expressions of PERK, but not those of ATF-6 and IRE-1, were increased. The effects of IH were accompanied by an increased number of apoptotic cells and increased expressions of cleaved caspase-3 and caspase-12 in pulmonary tissues. In addition, histological examination suggested the presence of fibrosis after chronic IH treatment, indicated by increased expression of collagen, which was associated with the up-regulation of TGF-β1 and TSP-1 that are known to promote fibrosis. Similarly, TUDCA could reduce the extent of fibrotic area and the expression levels of these proteins.

Conclusions

It reveals the roles of ER stress, especially the PERK pathway, in IH induced apoptosis and fibrosis in pulmonary tissues that might underlie the pulmonary complications observed in OSA.

Sleep disorders in cystic fibrosis: A systematic review and meta-analysis

Cystic fibrosis (CF) is a genetic disorder that leads to airway mucus accumulation, chronic inflammation, and recurrent respiratory infections - all likely impacting sleep. However, controlled studies of sleep in CF patients are limited, and have shown mixed results. We reviewed all publications on CF and sleep indexed in PubMed, CINAHL, and Scopus through April 2019. In the meta-analysis, we calculated pooled weighted mean differences for sleep quality, sleepiness, oximetry, and polysomnographic (PSG) parameters, using fixed or random-effects models as appropriate. A total of 87 manuscripts were reviewed. Compared to controls, children with CF had lower nighttime oxygen saturation nadirs, decreased sleep efficiency and a higher respiratory event index, with no differences in the percentage of REM sleep. Adults with CF had lower oxygen saturation nadirs, with a trend towards reduced sleep efficiency and no differences in REM sleep. In addition, patients with CF cough more during sleep and experience painful events that interfere with sleep. Actigraphy and questionnaires suggest disturbed sleep and daytime sleepiness. Noninvasive ventilation appears to improve gas exchange and symptoms. We conclude that when sleep is evaluated objectively or subjectively in patients with CF, perturbations are common, emphasizing the importance of their identification and treatment and inclusion as part of routine care. Additional research, with larger sample sizes and standardized outcomes, are necessary.