Nocturnal hypoxia and sleep disturbances in cystic fibrosis

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.

Telemedicine and remote monitoring in cystic fibrosis

PURPOSE OF REVIEW

Guidelines for cystic fibrosis (CF) care recommend multidisciplinary teams see patients at least quarterly with frequent measurement of spirometry and collection of respiratory cultures. This can be burdensome for people with CF, particularly if they live far from a specialized care center. This has led to an interest in telehealth coupled with remote monitoring. We review the recent literature on these topics for people with CF.

RECENT FINDINGS

The COVID-19 pandemic accelerated a move toward remote delivery of CF care and multiple recent publications have reported on the feasibility of telehealth, remote spirometry, remote collection of respiratory cultures, adherence monitoring, cough assessment, symptom monitoring and activity tracking. Useful data can be obtained and both clinicians and patients have favorable opinions about remote delivery of healthcare, though the impact on clinical outcomes is not yet known.

SUMMARY

Telehealth and remote monitoring for people with CF is feasible and has grown in use, though it is too early to know how prominently these approaches will fit into routine care for CF.

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.

Risk factors for obstructive sleep apnea in cystic fibrosis

INTRODUCTION

Despite emerging data that suggest a high frequency and severity of obstructive sleep apnea (OSA) among patients with cystic fibrosis (CF), few of them are referred for polysomnography. Little is known about which patients with CF are at increased risk for OSA and which sleep symptoms merit investigation.

METHODS

A single-center retrospective analysis of clinical and polysomnographic data from 2009, January 1 to October 31, 2020 in referred children and adults with CF.

RESULTS

Among 74 patients (42 children, 32 adults) with CF, 39 (53%) had OSA. No age or sex differences emerged in OSA frequency. Mean apnea-hypopnea index (AHI) was higher among overweight/obese adults (n = 16) as compared with adults of normal weight or underweight (11.4 vs. 6.2; p = 0.005). Adults with (n = 10) versus without a crowded oropharynx had 13.0 times greater odds of OSA (95% confidence interval (CI): 1.4, 121.4; p = 0.02). Children with (n = 24) versus without tonsillar hypertrophy had a higher risk for OSA (OR = 5.2; 95% CI: 1.4, 19.8; p = 0.02), as did children with (n = 10) versus without symptomatic chronic sinusitis (OR = 5.8; 95% CI: 1.1, 32.1; p = 0.04). Neither snoring, excessive daytime sleepiness, nor lung disease severity were associated with OSA.

CONCLUSION

Key risk factors for OSA may differ between children and adults with CF: upper airway pathology appears important in children and overweight/obesity or a crowded oropharynx in adults. Given the lack of sensitivity of snoring, daytime sleepiness, and lung disease severity, detection of OSA may require a low threshold for polysomnographic assessment in this vulnerable population.

Actigraphic and patient and family reported sleep outcomes in children and youth with cystic fibrosis: A systematic review

BACKGROUND

Sleep concerns are commonly reported by children and youth with cystic fibrosis (CF). Understanding normative sleep in the home environment and as reported from the perspective of patients and parents is a first step in responding to an important clinical concern and developing a sleep intervention strategy. This systematic review aimed to describe actigraphic and self/parent reported measures of sleep quantity; quality; and determine factors associated with poor sleep quantity and/or quality in children and youth (0-25yrs.) with CF.

METHODS

Five online databases; Medline, Embase, CINAHL, PsycInfo, and CENTRAL were searched for relevant articles from inception-February 2020. Studies reporting primary data, using either qualitative/quantitative methods or both were eligible for inclusion. Eligible full text articles were independently screened by two reviewers. Data from included studies were independently extracted and synthesized by one reviewer and accuracy verified independently by a second reviewer.

RESULTS

This review found 31 articles that met inclusion criteria. Analysis found evidence demonstrating that actigraphic SE was lower, actigraphic nighttime awakenings were greater, and self/parent-reported measures of sleep quality were poorer in children and youth with CF. Study findings related to actigraphic TST, WASO, and self/parent-reported sleep duration were mixed. Thirteen factors demonstrated an association with poor quality sleep.

CONCLUSIONS

In children and youth with CF, evidence exists of objectively measured sleep disturbance and poor self/parent reported sleep quality. Further longitudinal and comparative research studies are warranted to better understand sleep disturbance in this population. Clinically, sleep assessment should be an integral part of routine CF care.

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 screening for cystic fibrosis patients: A survey of cystic fibrosis programs

OBJECTIVE

The prevalence of sleep disorders in patients with cystic fibrosis (CF) is unknown, and no standardized screening or treatment guidelines exist to address sleep disorders in CF. The objective of this study is to characterize current sleep screening practices in adult, pediatric, combined, and affiliate CF programs.

METHODS

A survey was developed in Research Electronic Data Capture and distributed to program directors of accredited CF programs in the United States.

RESULTS

Eighty-eight program directors responded (36% adult, 43% pediatric, 16% combined, 3% affiliate, and 1% unidentified). Of the respondents, 68% were part of an academic institution, 24% were associated with an academic institution, and 8% were part of a community or private program. Program sizes ranged from less than 50 to more than 500 patients. Routine or informal sleep screening was not performed in 44% of adults, 29% of pediatricians, and 35% of combined and affiliate programs. Most programs (>80%) have access to otolaryngology and sleep medicine although not all of these programs refer patients for evaluation of sleep disorders. Most program directors (77%) perceive sleep disorders as a problem in CF and would recommend routine sleep screening. Possible barriers to sleep screening included clinic flow, screening fatigue, and lack of recommendations for sleep screening.

CONCLUSIONS

Formal sleep screening is inconsistent among CF care centers although most survey respondents would recommend the inclusion of screening in routine CF care. Future work is needed to further evaluate the impact of sleep disorders in CF and determine best practices for standardization of sleep screening and treatment.

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.

Sleep-disordered breathing in cystic fibrosis

INTRODUCTION

Cystic fibrosis (CF) is a life-shortening, genetic disease that affects approximately 30,000 Americans. Although patients frequently report snoring, mouth breathing, and insomnia, the extent to which sleep-disordered breathing (SDB) may underlie these complaints remains unknown.

METHODS

Single-center retrospective review of polysomnography results from referred patients with and without CF individually-matched (1:2) for age, gender, race, and body mass index (BMI).

RESULTS

Mean ages were 8.0 ± 5.2 (sd) and 35.9 ± 12.9 years, among 29 children and 23 adults with CF respectively. The CF and non-CF groups were well-matched in age and BMI. Subjects with vs. without CF had three times greater odds of moderate-severe SDB (apnea-hypopnea index (AHI) ≥ 5 in children, ≥ 15 in adults) (p = 0.01). Nocturnal oxygen saturation nadir (Minimum SpO₂) was lower among CF vs. non-CF groups (p = 0.002). For every 1-unit increase in AHI, the decline in Minimum SpO₂ was larger for subjects with vs. without CF (p = 0.05). In subjects with CF, forced expiratory volume in 1 s percent predicted (FEV1 PPD) was associated with Minimum SpO₂ (Pearson r = 0.68, p < 0.0001) but not AHI (r = -0.19, p = 0.27). For every 1-unit increase in AHI, magnitude of decline in Minimum SpO₂ was larger for those with low vs. normal FEV1 PPD (p = 0.01).

CONCLUSION

Severity of SDB may be worse among referred patients with vs. without CF. The SDB may modify the relationship between CF lung disease and nocturnal hypoxemia. Markers of lung disease severity including lung function do not predict SDB severity, suggesting the need for routine polysomnography to screen for this sleep disorder.

Lung clearance index evaluation in detecting nocturnal hypoxemia in cystic fibrosis patients: Toward a new diagnostic tool

BACKGROUND

Nocturnal hypoxemia adversely affects outcomes in patients with cystic fibrosis (CF). Although an early detection of this abnormality may be desirable, still its predictability remains uncertain. The Lung Clearance Index (LCI) is a measure of lung ventilation distribution obtained from a multiple-breath washout technique (MBW), recently implemented in patients with CF. This study aimed to establish whether the LCI predicts nocturnal hypoxemia in patients with stable CF, with mild to moderate disease, and normal diurnal gas exchange.

METHODS

31 stable patients (15 males, mean age 17.4 ± 5.2 years) with mild to moderate CF, normoxic when awake, were enrolled. In all patients we performed nocturnal cardio-respiratory polygraphy, lung function measurement, and MBW test to derive LCI values.

RESULTS

LCI was abnormal in most of the patients and inversely correlated with mean nocturnal SpO₂ (r = -0.880 p < 0.01). A receiver operating characteristic (ROC) analysis, performed to assess whether LCI predicted nocturnal hypoxemia, revealed a high predictive accuracy of LCI for nocturnal desaturation (AUC = 0.96; Youden index = 0.79). Forced expiratory volume in 1 s (FEV₁) was predictive only in patients with more severe airway obstruction, with a moderate degree of accuracy (AUC 0.71).

CONCLUSIONS

The LCI showed a high effectiveness in predicting nocturnal hypoxemia in stable patients with CF, particularly when compared with a traditional parameter of lung function such as FEV₁.

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.

Home Oxygen Therapy for Children. An Official American Thoracic Society Clinical Practice Guideline

Background: Home oxygen therapy is often required in children with chronic respiratory conditions. This document provides an evidence-based clinical practice guideline on the implementation, monitoring, and discontinuation of home oxygen therapy for the pediatric population.

Methods: A multidisciplinary panel identified pertinent questions regarding home oxygen therapy in children, conducted systematic reviews of the relevant literature, and applied the Grading of Recommendations, Assessment, Development, and Evaluation approach to rate the quality of evidence and strength of clinical recommendations.

Results: After considering the panel’s confidence in the estimated effects, the balance of desirable (benefits) and undesirable (harms and burdens) consequences of treatment, patient values and preferences, cost, and feasibility, recommendations were developed for or against home oxygen therapy specific to pediatric lung and pulmonary vascular diseases.

Conclusions: Although home oxygen therapy is commonly required in the care of children, there is a striking lack of empirical evidence regarding implementation, monitoring, and discontinuation of supplemental oxygen therapy. The panel formulated and provided the rationale for clinical recommendations for home oxygen therapy based on scant empirical evidence, expert opinion, and clinical experience to aid clinicians in the management of these complex pediatric patients and identified important areas for future research.

Predictors of sleep hypoxemia in children with cystic fibrosis

OBJECTIVES

To identify the determinants of nocturnal hypoxemia in children with CF using clinical parameters, polysomnography (PSG), and lung function.

HYPOTHESIS

Sleep hypoxemia in children with CF is predicted by both apnea hypopnea index (AHI) and percent predicted forced expiratory volume in one second (pFEV1).

DESIGN

Retrospective case series.

METHODS

Children aged 5-18 years were included based on (i) a diagnosis of CF; and (ii) availability of concurrent PSG and pFEV1 data. The impact of (i) demographic and clinical parameters; and (ii) PSG and pFEV1, on the total sleep time spent with arterial oxygen saturation below 90% (TSpO₂  < 90) was measured using regression analysis. P-value <0.05 was considered significant.

RESULTS

The mean age was 11.6 years (95% confidence interval: 9.5, 13.1). Twenty of 35 (57%) were boys and the mean body mass index percentile was 42.1 (31.5, 52.6). The most common ethnicity was white (66%). OSA was diagnosed in 50%. Neither demographic predictors nor clinical variables predicted the severity of hypoxemia (R²  = 0.23, P = 0.09). While pFEV1 and PSG variables accounted for significant proportion of the overall variance in TSpO₂  < 90 (R²  = 0.53, P < 0.001), pFEV1 was identified as the single best predictor of sleep hypoxemia. A pFEV1 cut-off of 53% indicated a sensitivity of 0.80 and a specificity of 0.87 in predicting sleep hypoxemia.

CONCLUSIONS

pFEV1 is the best predictor of sleep hypoxemia in children with CF and referred for PSG. No demographic or clinical predictors of hypoxemia were identified in this population.

Sleep-disordered breathing in cystic fibrosis pediatric subjects

Objectives

To describe the frequency of sleep-disordered breathing (SDB) in pediatric cystic fibrosis (CF) and to study associations between polysomnographic respiratory parameters and available clinical information.

Methods

This was a retrospective, cross-sectional study. The sample data were obtained from information recorded on patient charts in 2015 and 2016. The study included all individuals with CF aged from 2 to 20 years for whom records were available for polysomnography performed within the previous two years.

Results

Sixteen individuals with CF (mean age 11 ± 5.6 years old) were included. Polysomnographic respiratory parameter abnormalities were defined as an apnea-hypopnea index (AHI) exceeding one event per hour of sleep or an oxyhemoglobin saturation (SpO₂) nadir below 90%; observed in 10 subjects (62.5%). Forced expiratory volume in first second (FEV₁) was correlated (r=0.602, p=0.023) with mean sleep SpO₂. FEV₁ was also negatively correlated with sleep peak end-tidal carbon dioxide (EtpCO₂) (r=-0.645, p=0.024). Additionally, chronic airway colonization by Pseudomonas aeruginosa was associated with mean EtpCO₂ in non-REM sleep (p=0.024).

Discussion

SDB was frequently observed in this sample of children with CF. There was an association between CF respiratory disease progression markers and sleep breathing parameters in children. Sleep studies appear to be an important tool for assessment of the respiratory status of these individuals with CF, although further studies are needed, especially with carbon dioxide sleep analysis.

Growth and protease secretion of Scedosporium aurantiacum under conditions of hypoxia

One of the micro-environmental stresses that fungal pathogens, such as Scedosporium aurantiacum, colonising human lungs encounter in vivo is hypoxia, or deficiency of oxygen. In this work, we studied the impacts of a hypoxic micro-environment (oxygen levels ≤1%) on the growth of a clinical S. aurantiacum isolate (WM 06.482; CBS 136046) and an environmental strain (S. aurantiacum WM 10.136; CBS 136049) on mucin-containing synthetic cystic fibrosis sputum medium. Additionally, profiles of secreted proteases were compared between the two isolates and protease activity was assessed using class-specific substrates and inhibitors. Overall, both isolates grew slower and produced less biomass under hypoxia compared to normoxic conditions. The pH of the medium decreased to 4.0 over the cultivation time, indicating that S. aurantiacum released acidic compounds into the medium. Accordingly, secreted proteases of the two isolates were dominated by acidic proteases, including aspartic and cysteine proteases, with optimal protease activity at pH 4.0 and 6.0 respectively. The clinical isolate produced higher aspartic and cysteine protease activities. Conversely, all serine proteases, including elastase-like, trypsin-like, chymotrypsin-like and subtilisin-like proteases had higher activities in the environmental isolate. Sequence similarities to 13 secreted proteases were identified by mass spectrometry (MS) by searching against other fungal proteases in the NCBI database. Results from MS analysis were consistent with those from activity assays. The clinical highly-virulent, and environmental low-virulence S. aurantiacum isolates responded differently to hypoxia in terms of the type of proteases secreted, which may reflect their different virulence properties.

Sleep disturbances and their impact in pediatric cystic fibrosis

Cystic fibrosis is a chronic, life-shortening illness that affects multiple systems and results in frequent respiratory infections, chronic cough, fat malabsorption and malnutrition. Poor sleep is often reported by patients with cystic fibrosis. Although objective data to explain these complaints have been limited, they do show poor sleep efficiency and frequent arousals. Abnormalities in gas exchange are also observed during sleep in patients with cystic fibrosis. The potential impact of these abnormalities in sleep on health and quality of life remains largely unstudied. This review summarizes what is known about sleep in children with cystic fibrosis, and implications for clinical practice. This report also highlights new evidence on the impact of sleep problems on disease-specific outcomes such as lung function, and identifies areas that need further exploration.

How Well Do Children with Cystic Fibrosis Sleep? An Actigraphic and Questionnaire-Based Study

OBJECTIVE

To measure sleep patterns and quality, objectively and subjectively, in clinically stable children with cystic fibrosis (CF) and healthy control children, and to examine the relationship between sleep quality and disease severity.

STUDY DESIGN

Clinically stable children with CF and healthy control children (7-18 years of age) were recruited. Sleep patterns and quality were measured at home with actigraphy (14 days). Overnight peripheral capillary oxygen saturation was measured via the use of pulse oximetry. Daytime sleepiness was evaluated by the Pediatric Daytime Sleepiness Scale (PDSS) and subjective sleep quality by the Sleep Disturbance Scale for Children and Obstructive Sleep Apnea-18.

RESULTS

A total of 87 children with CF and 55 control children were recruited with no differences in age or sex. Children with CF had significantly lower total sleep time and sleep efficiency than control children due to frequent awakenings and more wake after sleep onset. In children with CF, forced expiratory volume in 1 second and overnight peripheral capillary oxygen saturation nadir correlated positively with total sleep time and sleep efficiency and negatively with frequency of awakenings and wake after sleep onset. Patients with CF had significantly greater Sleep Disturbance Scale for Children (45 vs 35; P < .001), Obstructive Sleep Apnea-18 (35 vs 24; P < .001), and PDSS scores (14 vs 11; P < .001). There was a negative correlation between PDSS and forced expiratory volume in 1 second (r = -0.23; P < .05).

CONCLUSIONS

Even in periods of clinical stability, children with CF get less sleep than their peers due to more time in wakefulness during the night rather than less time spent in bed. Objective measures of sleep disturbance and subjective daytime sleepiness were related to disease severity. In contrast, parents of children with CF report high levels of sleep disturbance unrelated to disease severity.

Respiratory sleep disturbance in children and adolescents with cystic fibrosis

Sleep disturbance has been described in cystic fibrosis (CF) patients as relevant to clinical and lung function predictive factors helping to improve the diagnosis and early intervention. Related paediatric studies are scarce.

OBJECTIVE

To describe respiratory sleep disturbance (RSD) and its association with spirometric indices in a population of CF children. A second aim was to determine if spirometric indices and wake-time SpO2 are predictors of sleep disturbance.

METHODS

A cross-sectional study involving 33CF paediatric patients. All participants underwent in-lab polysomnography (PSG), pulse oximetry and spirometry. A standardized sleep questionnaire was completed for each patient. Two subgroups were considered: I - Normal (FEV1>-1.64 z-score); II - Obstructed (FEV1≤-1.64 z-score).

RESULTS

Participant's median age was 12 (6-18) years, 16 (48.5%) were male. Twenty-nine patients (87.9%) presented sleep complaints. Sleep efficiency was reduced; sleep latency and waking after sleep onset (WASO) increased. N1 increased, N2, N3, REM and awakenings were normal. The apnoea-hypopnoea index was 0.6/h (sd 0.9); respiratory disturbance index (RDI) was 6.6/h (sd 5.2). Mean awaking (97% (sd 1.1)) and sleep SpO2 (95% (sd 2.7)) were normal; mean nocturnal oximetry desaturation index was 2.36/h; minimal nocturnal SpO2 was 89% (sd 4.1). We found associations between mean nocturnal SPO2 and mean values of FEV1 (r=0.528; p=0.002) and FEF25-75 (r=0.426; p=0.013). There were significant differences in nocturnal SpO2 between normal and obstructed patients (p<0.000). PSG data correlated with the questionnaire answers for night awakenings and WASO (p=0.985) and difficult breathing during sleep and RDI (p=0.722). This study points to most CF children having sleep complaints, and highlights the correlation between subjective assessment of sleep and PSG and spirometric results. Awake-time SpO2 and spirometric values are possible risk predictors for nocturnal desaturation.

Clinical Practice Guidelines From the Cystic Fibrosis Foundation for Preschoolers With Cystic Fibrosis

Cystic fibrosis (CF) clinical care guidelines exist for the care of infants up to age 2 years and for individuals ≥6 years of age. An important gap exists for preschool children between the ages of 2 and 5 years. This period marks a time of growth and development that is critical to achieve optimal nutritional status and maintain lung health. Given that disease often progresses in a clinically silent manner, objective and sensitive tools that detect and track early disease are important in this age group. Several challenges exist that may impede the delivery of care for these children, including adherence to therapies. A multidisciplinary committee was convened by the CF Foundation to develop comprehensive evidence-based and consensus recommendations for the care of preschool children, ages 2 to 5 years, with CF. This document includes recommendations in the following areas: routine surveillance for pulmonary disease, therapeutics, and nutritional and gastrointestinal care.

Nocturnal hypoxemia in children and adolescents with cystic fibrosis

OBJECTIVE:

To determine the prevalence of nocturnal hypoxemia and its association with pulmonary function, nutritional status, sleep macrostructure, and obstructive respiratory events during sleep in a population of clinically stable children and adolescents with cystic fibrosis (CF).

METHODS:

This was a cross-sectional study involving 67 children and adolescents with CF between 2 and 14 years of age. All of the participants underwent polysomnography, and SpO₂ was measured by pulse oximetry. We also evaluated the Shwachman-Kulczycki (S-K) scores, spirometry findings, and nutritional status of the patients.

RESULTS:

The study involved 67 patients. The mean age of the patients was 8 years. The S-K scores differed significantly between the patients with and without nocturnal hypoxemia, which was defined as an SpO₂ < 90% for more than 5% of the total sleep time (73.75 ± 6.29 vs. 86.38 ± 8.70; p < 0.01). Nocturnal hypoxemia correlated with the severity of lung disease, FEV₁ (r_s = −0.42; p = 0.01), FVC (r_s = −0.46; p = 0.01), microarousal index (r_s = 0.32; p = 0.01), and apnea-hypopnea index (r_s = 0.56; p = 0.01).

CONCLUSIONS:

In this sample of patients with CF and mild-to-moderate lung disease, nocturnal oxygenation correlated with the S-K score, spirometry variables, sleep macrostructure variables, and the apnea-hypopnea index.

Regulation of airway nucleotides in chronic lung diseases

The physiological relevance of the purinergic signaling network for airway defenses is emerging through cumulating reports of abnormal ATP and adenosine (ADO) levels in the airway secretions of patients with asthma, chronic pulmonary obstructive diseases, cystic fibrosis and idiopathic pulmonary fibrosis. The consequences for airway defenses range from abnormal clearance responses to the destruction of lung tissue by excessive inflammation. This chapter reviews the challenges of assessing airway purines in human subjects, and identifies the general trend in aberrant airway composition. Most diseases are associated with an accumulation of ATP and/or ADO in bronchoalveolar lavage, sputum or exhaled breadth condensate. Intriguing is the case of cystic fibrosis patients, which do not accumulate airway ADO, but its precursor, AMP. This observation launched the investigation of ectonucleotidases as target proteins for the correction of airway purine levels in chronic respiratory diseases. This chapter exposes the extensive rearrangement of the enzymatic network taking place in diseased airways, and identifies signaling pathways likely involved in the aberrant regulation of the airway purines.

Recommendations for long-term home oxygen therapy in children and adolescents

OBJECTIVE

To advise pediatricians, neonatologists, pulmonologists, pediatric pulmonologists, and other professionals in the area on the main indications and characteristics of long-term home oxygen therapy in children and adolescents.

DATA SOURCE

A literature search was carried out in the MEDLINE/PubMed database (1990 to 2011). Additionally, references from selected studies were included. As consistent scientific evidence does not exist for many aspects, some of the recommendations were based on clinical experience.

DATA SYNTHESIS

Long-term home oxygen therapy has been a growing practice in pediatric patients and is indicated in bronchopulmonary dysplasia, cystic fibrosis, bronchiolitis obliterans, interstitial lung diseases, and pulmonary hypertension, among others. The benefits are: decrease in hospitalizations, optimization of physical growth and neurological development, improvement of exercise tolerance and quality of sleep, and prevention of pulmonary hypertension/cor pulmonale. The levels of oxygen saturation indicative for oxygen therapy differ from those established for adults with chronic obstructive pulmonary disease, and vary according to age and disease. Pulse oximetry is used to evaluate oxygen saturation; arterial blood gas is unnecessary. There are three available sources of oxygen: gas cylinders, liquid oxygen, and oxygen concentrators. The flows used are usually smaller, as are the number of hours/day needed when compared to the use in adults. Some diseases show improvement and oxygen therapy discontinuation is possible.

CONCLUSIONS

Long-term home oxygen therapy is increasingly common in pediatrics and has many indications. There are relevant particularities when compared to its use in adults, regarding indications, directions for use, and monitoring.

Nocturnal oxygen saturation in children with stable cystic fibrosis

BACKGROUND

Hypoxemia during sleep is a common finding in Cystic Fibrosis (CF) patients with more advanced lung disease. Nocturnal hypoxemia is associated with frequent awakenings and poor sleep quality. For children with CF, data of nocturnal oxygen saturation are sparse.

OBJECTIVE

To assess the oxygen saturation profile during sleep in 25 clinically stable children with CF lung disease and to correlate these data with spirometry, cough frequency, sleep quality, and CT-scan scores.

METHOD

During two nights cough was recorded with a digital audio recorder in 25 clinically stable CF patients. In addition oxygen saturation was measured. The day following the recording spirometry was carried out. CT scores were obtained from the most recent routine CT scan.

RESULTS

Twenty-two patients were included in the study. Mean age (range) was 13 (6-18) years. Spirometry was FVC% 84 (range 52-114), FEV(1) % 77 (range 43-115), and FEF(75) % 50 (range 12-112). The mean SO(2) was 95.6% for the first and 96.2% for the second night. Mean SO(2) between the two nights correlated strongly (r(s) = 0.84, P < 0.001). Positive correlation was observed between mean SO(2) of the two nights (mean × SO(2)) and FVC, FEV(1) and FEF(75). Correlations were found between mean × SO(2) and the total CT score (r(s) = -0.45, P = 0.05) and the bronchiectasis subscore (r(s) = -0.48, P = 0.03).

CONCLUSION

Nocturnal oxygen saturation in children with stable CF is lower than that in healthy children, and is correlated with lung function parameters and CT scores. Monitoring oxygen saturation during one night is sufficient to get a representative recording.

Sleep Patterns in Children with Cystic Fibrosis

This study examined sleep patterns and the association between sleep and perceived health for children with and without CF. Ninety families (45 CF) completed questionnaires about the child's sleep and health. Significant group differences were found for sleep patterns (bedtime, wake time, total sleep time), symptoms of sleep disordered breathing, and sleep disturbances. Poorer perceived health was associated with sleep disturbances among children with CF, but not for children without CF. This study highlights the importance of including sleep in the evaluation of children with CF, as both medical and behavioral interventions can improve the sleep of children with CF.

Sleep problems in children and adolescents with common medical conditions

Untreated sleep disturbances and sleep disorders pose significant adverse daytime consequences and place children at considerable risk for poor health outcomes. Sleep disturbances occur at a greater frequency in children with acute and chronic medical conditions compared with otherwise healthy peers. Sleep disturbances in medically ill children can be associated with sleep disorders, comorbid with acute and chronic conditions, or secondary to underlying disease-related mechanisms, treatment regimens, or hospitalization. Clinical management should include a multidisciplinary approach with particular emphasis on routine, regular sleep assessments and prevention of daytime consequences, and promotion of healthy sleep habits and health outcomes.