Assessment of hypoxia in children with cystic fibrosis

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.

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.

Serum Appetite-Regulating Hormone Levels in Cystic Fibrosis Patients: Influence of the Disease Severity and the Type of Bacterial Infection-A Pilot Study

Cystic fibrosis (CF) belongs to the most common inherited diseases. The severity of the disease and chronic bacterial infections are associated with a lower body index, undernutrition, higher number of pulmonary exacerbations, more hospital admissions, and increased mortality. The aim of our study was to determine the impact of the severity of the disease and the type of bacterial infection in 38 CF patients on the serum level of appetite-regulating hormones including leptin, ghrelin, neuropeptide Y, agouti-signaling protein, proopiomelanocortin, kisspeptin, putative protein Y, and α-melanocyte-stimulating hormone. The patients were divided according to the severity of the disease according to spirometry and the type of chronic bacterial infection. We found that leptin level was significantly higher in patients with severe CF than in patients with mild disease (20.02 ± 8.09 vs. 12.38 ± 6.03 ng/mL, p = 0.028). Furthermore, leptin level was elevated in patients with chronic infection with Pseudomonas aeruginosa compared to uninfected participants (15.74 ± 7.02 vs. 9.28 ± 1.72 ng/mL, p = 0.043). The severity of the disease and the type of bacterial infection did not affect the levels of other appetite-regulating hormones. Moreover, we found a positive correlation between pro-inflammatory interleukin-6 and leptin level (p = 0.0426, R = 0.333). Taken together, our results indicate that both the severity of the disease and the type of bacterial infection are associated with elevated leptin levels in CF patients. Future CF treatment strategies should consider possible disturbances in the hormones that regulate appetite and the factors that influence their levels.

Intermittent hypoxia-induced enhancement of sociability and working memory associates with CNTNAP2 upregulation

Introduction

Hypoxia is an environmental risk factor for many disorders throughout life. Perinatal hypoxia contributes to autism spectrum disorder (ASD), while hypoxic conditions in the elderly facilitate memory deficits. However, the effects of hypoxia on adolescence remains elusive. CNTNAP2 is a critical molecule in ASD pathogenesis with undefined mechanisms. We investigate hypoxia’s impact on adolescence and the underlying mechanism related to CNTNAP2.

Methods

Three-chamber social approach test, Y maze, Morris Water Maze and Open Field Test were applied to evaluate behavioral alterations. Immunoblotting, 5′- RACE and dual-luciferase reporter assay were performed to examine CNTNAP2 protein expression, transcription start site (TSS) of human CNTNAP2 gene and CNTNAP2 promoter activity, respectively.

Results

Intermittent hypoxia treatment improved social behaviors and working memory in adolescent mice. CNTNAP2 was increased in the brains of hypoxia-treated mice. The sequencing results identified the TSS at 518 bp upstream of the translation start site ATG. Hypoxia upregulated CNTNAP2 by interacting with functional hypoxia response elements in CNTNAP2 promoter.

Conclusion

Intermittent hypoxia enhanced sociability and working memory associated with CNTNAP2 upregulation. Our study provides novel insights into intermittent hypoxia’s impact on development and the interaction between genetic and environmental risk factors in ASD pathogenesis.

Effects of Elexacaftor/Tezacaftor/Ivacaftor on Cardiorespiratory Polygraphy Parameters and Respiratory Muscle Strength in Cystic Fibrosis Patients with Severe Lung Disease

BACKGROUND

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators represent targeted therapies directly acting on the CFTR channel. The triple therapy Elexacaftor/Tezacaftor/Ivacaftor (ELX/TEZ/IVA) has been demonstrated to improve lung function and quality of life in cystic fibrosis (CF) patients. However, the effects of ELX/TEZ/IVA on sleep-disordered breathing (SDB) and respiratory muscle strength are poorly studied. The aim of this study was to assess the effects of ELX/TEZ/IVA in patients with CF and severe lung disease on cardiorespiratory polygraphy parameters, maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) measures.

METHODS

patients with CF aged ≥ 12 who started treatment in a compassionate use program were retrospectively studied through the evaluation of nocturnal cardiorespiratory polygraphy parameters, MIP and MEP; and six-minute walk test (6MWT) at baseline and at months 3, 6, and 12 of treatment.

RESULTS

Nine patients (mean age 30.3 ± 6.5 years) with severe CF (mean baseline ppFEV1 34.6 ± 5.1%) were evaluated. A significant improvement in nocturnal oxygenation measured by mean SpO2 (92.4 vs. 96.4%, p < 0.05), time spent with SpO2 ≤ 90% (-12.6, -14.6, -15.2 min from baseline at months 3, 6, and 12, respectively, p < 0.05), and respiratory rate (RR) was shown, at month 12 and across the time points compared with baseline, as well as in respiratory muscle strength, although only the change in MEP was significant.

CONCLUSIONS

We provide further evidence on the efficacy of the CFTR modulators ELX/TEZ/IVA, adding information about their effect on the respiratory muscles' performance and cardiorespiratory polygraphy parameters in CF patients with severe lung disease.

Aerobic fitness is associated with extracellular DNA levels in the sputum of patients with cystic fibrosis

AIMS

Patients with cystic fibrosis (CF) develop with progressive loss of lung function and aerobic fitness. However, the precise mechanisms of exercise intolerance are still controversial and appear to be influenced by several factors. This study aimed to evaluate the association of aerobic fitness with free DNA levels in the sputum of patients with CF.

METHODS

This cross-sectional study included patients with CF older than 6 years, free from active exacerbations, but who were able to produce spontaneously expectorated sputum. Extracellular DNA in the sputum was quantified. Lung function (spirometry) and aerobic fitness (cardiopulmonary exercise testing [CPET]) were performed. In addition, demographic, anthropometric and clinical data were collected.

RESULTS

Sixteen patients with a mean age of 19.4 ± 6.9 years and mean forced expiratory volume in the first second (FEV₁ ) of 51.8 ± 28.1 (% of predicted) were included. Mean peak oxygen consumption (VO₂ peak) was 32.8 ± 5.2 mL• kg^-1 • min^-1 , oxygen saturation at the end of the test was 90.6% ± 6.3% and mean extracellular DNA levels was 305.3 ± 153.6 μg/mL. Individuals with a VO₂ peak ≤ 30 mL• kg^-1 • min^-1 (P = .03) and a SpO₂ ≤ 90% at the end of the test (P = .03) had a greater amount of extracellular DNA in the sputum. The proportion of patients with reduced VO₂ peak in the group of patients with the lowest concentration of DNA in the sputum (<243 μg/mL) was significantly lower (0% vs 100%; P = .04).

CONCLUSION

There is an association between the presence of free DNA in sputum and aerobic fitness in patients with CF.

Multidisciplinary approach to patients with manifestations and pulmonary complications of cystic fibrosis

Cystic fibrosis (CF) is a genetic disease, with autosomal recessive transmission, multisystemic, characterized by a remarkable clinical polymorphism and significant lethal prospective. Respiratory manifestations dominate the clinical picture, being present in all patients. The aim of the paper was to analyze the incidence of clinical manifestations, especially respiratory ones, as well as the contribution of interdisciplinary consultations to the positive diagnosis of CF, in a group of 16 patients who were hospitalized and treated in the II^nd Pediatric Clinic and II^nd Medical Clinic of the Emergency County Hospital, Craiova, Romania, in a period of 20 years. The 16 patients diagnosed with and treated of CF had all shown increased values of sweat chloride concentration of over 60 mmol/L. The main symptoms and clinical signs encountered in these patients were cough (75%), sputum (62.5%), dyspnea (50%), wheezing (50%), stature hypotrophy (100%), pallor (37.5%), cyanosis (25%). All 16 patients had an acute exacerbation of chronic pulmonary disease. Of the total hospitalizations, the death was recorded only in the case of one female patient. The association of some clinical aspects specific with a positive result of the sweat test or the presence of the two pathological alleles made room for determining a positive diagnosis. The multisystemic nature of this disease requires a multidisciplinary approach to these patients. Histopathologically, there was a correspondence between lung morphological lesions and the results of imaging investigations.

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.

Glued in lipids: Lipointoxication in cystic fibrosis

Cystic Fibrosis (CF) is an autosomal recessive disease caused by mutations in the CF transmembrane regulator (CFTR) gene, which encodes a chloride channel located at the apical surface of epithelial cells. Unsaturated Fatty Acid (UFA) deficiency has been a persistent observation in tissues from patients with CF. However, the impacts of such deficiencies on the etiology of the disease have been the object of intense debates. The aim of the present review is first to highlight the general consensus on fatty acid dysregulations that emerges from, sometimes apparently contradictory, studies. In a second step, a unifying mechanism for the potential impacts of these fatty acid dysregulations in CF cells, based on alterations of membrane biophysical properties (known as lipointoxication), is proposed. Finally, the contribution of lipointoxication to the progression of the CF disease and how it could affect the efficacy of current treatments is also discussed.

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.

Circulating biomarkers of antioxidant status and oxidative stress in people with cystic fibrosis: A systematic review and meta-analysis

Introduction

Oxidative stress may play an important role in the pathophysiology of cystic fibrosis (CF). This review aimed to quantify CF-related redox imbalances.

Methods

Systematic searches of the Medline, CINAHL, CENTRAL and PsycINFO databases were conducted. Mean content of blood biomarkers from people with clinically-stable CF and non-CF controls were used to calculate the standardized mean difference (SMD) and 95% confidence intervals (95% CI).

Results

Forty-nine studies were eligible for this review including a total of 1792 people with CF and 1675 controls. Meta-analysis revealed that protein carbonyls (SMD: 1.13, 95% CI: 0.48 to 1.77), total F₂-isoprostane 8-iso-prostaglandin F_2α (SMD: 0.64, 95% CI: 0.23 to 1.05) and malondialdehyde (SMD: 1.34, 95% CI: 0.30 to 2.39) were significantly higher, and vitamins A (SMD: −0.66, 95% CI -1.14 to −0.17) and E (SMD: −0.74, 95% CI: −1.28 to −0.20), β-carotene (SMD: −1.80, 95% CI: −2.92 to −0.67), lutein (SMD: −1.52, 95% CI: −1.83 to −1.20) and albumin (SMD: −0.98, 95% CI: −1.68 to −0.27) were significantly lower in the plasma or serum of people with CF versus controls.

Conclusions

This systematic review and meta-analysis found good evidence for reduced antioxidant capacity and elevated oxidative stress in people with clinically-stable CF.

•

Blood biomarkers of oxidative stress were elevated in stable CF vs non-CF controls.

•

Lipid peroxidation was positively correlated with age and immune cell count in CF.

•

Antioxidants vitamins A & E, β-carotene, lutein and albumin were lower in stable CF.

•

Antioxidants were positively correlated with body mass index and lung function in CF.

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.

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.

What keeps children with cystic fibrosis awake at night?

BACKGROUND

Sleep disturbance is common in children with cystic fibrosis (CF) however there are limited studies investigating the causes for poor sleep quality. In a cross sectional observational study we aimed to evaluate the clinical correlates of sleep disturbance in this population.

METHODS

Children with CF (7-18years) free from pulmonary exacerbation completed medical review, overnight oximetry, the OSA-18 and 14days of actigraphy recordings with a sleep diary.

RESULTS

In addition to FEV₁ <80% and low baseline SpO₂, CF-related diabetes, PEG feeding and co-morbid behaviour disorder were associated with lower objective sleep quantity. Paternal smoking and a family member with a mood disorder were also associated with sleep disturbance. The use of electronic devices before bedtime was associated with lower sleep quantity and quality. FEV₁, nocturnal cough, age and a behaviour disorder predicted sleep duration. FEV₁, nocturnal cough, SpO₂ nadir and asthma predicted sleep efficiency. Conversely, sleep efficiency independently predicted FEV₁.

CONCLUSIONS

Reduced sleep quality in children with CF is related to lung health and co-morbidities. However, family characteristics and poor sleep hygiene in the child were also associated with sleep disturbance. Optimal management of CF would seem to be the primary intervention to alleviate children's sleep disturbance, however our data raises additional targets for attempts to improve sleep.

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.

Hypoxia-induced collagen synthesis of human lung fibroblasts by activating the angiotensin system

The exact molecular mechanism that mediates hypoxia-induced pulmonary fibrosis needs to be further clarified. The aim of this study was to explore the effect and underlying mechanism of angiotensin II (Ang II) on collagen synthesis in hypoxic human lung fibroblast (HLF) cells. The HLF-1 cell line was used for in vitro studies. Angiotensinogen (AGT), angiotensin converting enzyme (ACE), angiotensin II type 1 receptor (AT1R) and angiotensin II type 2 receptor (AT2R) expression levels in human lung fibroblasts were analysed using real-time polymerase chain reaction (RT-PCR) after hypoxic treatment. Additionally, the collagen type I (Col-I), AT1R and nuclear factor κappaB (NF-κB) protein expression levels were detected using Western blot analysis, and NF-κB nuclear translocation was measured using immunofluorescence localization analysis. Ang II levels in HLF-1 cells were measured with an enzyme-linked immunosorbent assay (ELISA). We found that hypoxia increased Col-I mRNA and protein expression in HLF-1 cells, and this effect could be inhibited by an AT1R or AT2R inhibitor. The levels of NF-κB, RAS components and Ang II production in HLF-1 cells were significantly increased after the hypoxia exposure. Hypoxia or Ang II increased NF-κB-p50 protein expression in HLF-1 cells, and the special effect could be inhibited by telmisartan (TST), an AT1R inhibitor, and partially inhibited by PD123319, an AT2R inhibitor. Importantly, hypoxia-induced NF-κB nuclear translocation could be nearly completely inhibited by an AT1R or AT2R inhibitor. Furthermore pyrrolidine dithiocarbamate (PDTC), a NF-κB blocker, abolished the expression of hypoxia-induced AT1R and Col-I in HLF-1 cells. Our results indicate that Ang II-mediated NF-κB signalling via ATR is involved in hypoxia-induced collagen synthesis in human lung fibroblasts.

Gas exchange in disease: asthma, chronic obstructive pulmonary disease, cystic fibrosis, and interstitial lung disease

Ventilation-perfusion (VA/Q) inequality is the underlying abnormality determining hypoxemia and hypercapnia in lung diseases. Hypoxemia in asthma is characterized by the presence of low VA/Q units, which persist despite improvement in airway function after an attack. This hypoxemia is generally attenuated by compensatory redistribution of blood flow mediated by hypoxic vasoconstriction and changes in cardiac output, however, mediator release and bronchodilator therapy may cause deterioration. Patients with chronic obstructive pulmonary disease have more complex patterns of VA/Q inequality, which appear more fixed, and changes in blood flow and ventilation have less benefit in improving gas exchange efficiency. The inability of ventilation to match increasing cardiac output limits exercise capacity as the disease progresses. Deteriorating hypoxemia during exacerbations reflects the falling mixed venous oxygen tension from increased respiratory muscle activity, which is not compensated by any redistribution of VA/Q ratios. Shunt is not a feature of any of these diseases. Patients with cystic fibrosis (CF) have no substantial shunt when managed according to modern treatment regimens. Interstitial lung diseases demonstrate impaired oxygen diffusion across the alveolar-capillary barrier, particularly during exercise, although VA/Q inequality still accounts for most of the gas exchange abnormality. Hypoxemia may limit exercise capacity in these diseases and in CF. Persistent hypercapnic respiratory failure is a feature of advancing chronic obstructive pulmonary disease and CF, closely associated with sleep disordered breathing, which is not a prominent feature of the other diseases. Better understanding of the mechanisms of hypercapnic respiratory failure, and of the detailed mechanisms controlling the distribution of ventilation and blood flow in the lung, are high priorities for future research.

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.

Exercise as part of a cystic fibrosis therapeutic routine

The role of exercise in cystic fibrosis (CF) is well established, and over the last three decades it has become an important component in the management of all individuals with CF. The role of exercise as a prognostic indicator or therapeutic tool is an important area of research interest in CF care internationally. This article summarizes the currently available evidence regarding exercise capacity in CF, the potential effects of exercise on health outcomes in CF and the challenges faced when trying to incorporate exercise into a CF therapeutic routine, and highlights some methods to facilitate the incorporation of exercise into CF therapeutic routines.

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.

Effect of night symptoms and disease severity on subjective sleep quality in children with non-cystic-fibrosis bronchiectasis

BACKGROUND

Night-time symptoms and hypoxemia during sleep may affect sleep quality in children with chronic lung disease such as bronchiectasis. Poor sleep quality may impair growth, learning, and emotional development of children. Our aim was to assess the sleep quality and associated factors in children with non-cystic fibrosis bronchiectasis.

METHODS

Fifty-four patients with bronchiectasis and age-matched controls were included to the study. Pittsburgh Sleep Quality Index (PSQI) and Pediatric Sleep Questionnaire (PSQ) were used to evaluate sleep quality and presence of sleep disordered breathing. A global sum of 5 or more according to PSQI indicated a poor sleep quality. A cut-off value of 0.33 in PSQ was used to identify pediatric sleep disordered breathing. Association between PSQI, pulmonary function tests, symptoms and HRCT scores were evaluated.

RESULTS

Thirty-seven percent of patients with bronchiectasis and 17% of patients in the control group had poor sleep quality (P < 0.05). Patients with sputum and wheezing had poorer sleep scores (P = 0.003 and P = 0.005). The association of wheezing and breathlessness during night time with sleep quality tended to be significant (P = 0.05). Twenty-two percent of patients with bronchiectasis and 9% of controls had sleep disordered breathing (P = 0.003). Bronchiectasis patients who snored had poorer sleep quality (P < 0.001) and patients with wheezing had significantly higher rate of snoring (P = 0.04). Children with worse HRCT scores also had worse sleep quality (r = 0.28, P = 0.04).

CONCLUSIONS

Patients with bronchiectasis have disturbed sleep associated with severity of disease. Night symptoms increase the risk of poor sleep quality. Sleep disordered breathing and sleep quality should be assessed in these patients.

Domiciliary oxygen for children

Domiciliary oxygen is used increasingly in pediatric practice, and the largest patient group to receive it is ex-premature babies with chronic neonatal lung disease. Because of a scarcity of good evidence to inform clinicians, there is a lack of consensus over many issues, even those as fundamental as the optimum target oxygen saturation. Nevertheless, many children benefit from receiving supplemental oxygen at home, particularly because it helps to keep them out of the hospital.

Factors that correlate with sleep oxygenation in children with cystic fibrosis

OBJECTIVE

Cystic fibrosis (CF) patients may develop hypoxemia during sleep. Limited information is available on nocturnal oxygen saturation in CF children with less severe lung disease. The aim of this study was to investigate the degree of nocturnal oxygen desaturation and factors that correlate with nocturnal oxygenation in CF children with normal pulmonary function tests (PFTs) or mild to moderate lung disease.

METHOD

Awake resting and post-exercise SpO2 were measured by pulse oximetry. Each patient had overnight oximetry monitorization at home. Six minutes walk test (6MWT), Shwachman-Kulczycki (S-K), Brasfield and computed tomography (CT) scores, blood gas analysis and nutritional status of patients were evaluated.

RESULTS

Twenty-four patients with a median age of 9.5 years were included. Nocturnal mean SpO2 did not differ according to the severity of lung disease based on PFT. However, lowest SpO2 obtained was lower in children with both mild and moderate lung disease compared to normals (87.4% vs. 91.7%, respectively, p = 0.009). 95.8% of CF children with normal PFT or mild to moderate lung disease had desaturation events during sleep. Nocturnal mean SpO2 correlated with S-K (Spearman's rho = 0.64, p < 0.0001), Brasfield (Spearman's rho = 0.31, p = 0.007) and CT scores (Spearman's rho = -0.67, p < 0.0001) as well as PaO2 (Spearman's rho = 0.28, p = 0.021), SaO2 (Spearman's rho = 0.28, p = 0.023), z-score of weight (Spearman's rho = 0.23, p = 0.20) and height (Spearman's rho = 0.20, p = 0.30), there was no correlation with 6MWT.

CONCLUSIONS

In CF children with normal PFT or mild-to-moderate lung disease, nocturnal oxygenation may correlate with S-K, Brasfield and CT scores as well as PaO2, SaO2, z-score of weight and height.

Mucoviscidose : du bon usage des explorations fonctionnelles respiratoires

INTRODUCTION

Neonatal screening for cystic fibrosis (CF) leads to early dedicated specialist care for all patients.

BACKGROUND

Pulmonary function tests (PFT) are mandatory for routine monitoring of CF patients. The aim of this article is to review the current guidelines for PFTs in CF, particularly the type of test, the age and the clinical status of the patient.

VIEWPOINT

The regular use of spirometry is generally accepted. Many other tests are used but their clinical value in the routine follow-up of CF patients remains to be established.

CONCLUSION

Further efforts should be made to evaluate the value of PFTs in CF, particularly in very young children.

Preventing or reducing late side effects of radiation therapy: radiobiology meets molecular pathology

Radiation therapy has curative or palliative potential in roughly half of all incident solid tumours, and offers organ and function preservation in most cases. Unfortunately, early and late toxicity limits the deliverable intensity of radiotherapy, and might affect the long-term health-related quality of life of the patient. Recent progress in molecular pathology and normal-tissue radiobiology has improved the mechanistic understanding of late normal-tissue effects and shifted the focus from initial-damage induction to damage recognition and tissue remodelling. This stimulates research into new pharmacological strategies for preventing or reducing the side effects of radiation therapy.