Serum vitamin D levels in patients with obstructive sleep apnea syndrome and level changes after continuous positive airway pressure therapy.

PURPOSE: Patients with obstructive sleep apnea syndrome (OSAS) have been found to exhibit lower serum vitamin D levels, even when the control groups are matched for confounding conditions. However, contradictory studies are also present. This study aimed to compare serum 25-hydroxyvitamin D (25(OH)D) levels between adult patients with OSAS and non-apneic controls and to evaluate the changes in 25(OH)D levels after 3 and 12 months of continuous positive airway pressure (CPAP) therapy. METHODS: The study was comprised of 30 patients with OSAS and 30 controls. Serum 25(OH)D levels were determined at baseline and after 3 and 12 months of CPAP therapy in all patients with OSAS. For analysis, patients with OSAS were divided into subgroups by adherence, with adherence defined as CPAP usage for > 4 h per night on at least 70% of nights. RESULTS: The 25(OH)D levels were not significantly different between OSAS and control groups at baseline. 25(OH)D levels did not change after 3 and 12 months of CPAP therapy. Patients who were CPAP-adherent showed less reduction in 25(OH)D levels compared with non-adherent ones (21.18 ± 9.3 vs. 12.13 ± 3.8 ng/mL, p = 0.022) after 1 year. The 25(OH)D levels were significantly correlated with higher daily CPAP usage at 3 and 12 months. Mean daily CPAP usage was a significant predictor of serum 25(OH)D levels at 12 months. CONCLUSIONS: Patients with OSAS who demonstrated good CPAP adherence showed significantly higher 25(OH)D levels after 1 year compared with those not adequately using CPAP. Long-term good CPAP adherence and highly daily CPAP usage positively affected 25(OH)D levels in patients with OSAS.

Phenotypes of comorbidity in OSAS patients: combining categorical principal component analysis with cluster analysis.

Phenotyping obstructive sleep apnea syndrome's comorbidity has been attempted for the first time only recently. The aim of our study was to determine phenotypes of comorbidity in obstructive sleep apnea syndrome patients employing a data-driven approach. Data from 1472 consecutive patient records were recovered from our hospital's database. Categorical principal component analysis and two-step clustering were employed to detect distinct clusters in the data. Univariate comparisons between clusters included one-way analysis of variance with Bonferroni correction and chi-square tests. Predictors of pairwise cluster membership were determined via a binary logistic regression model. The analyses revealed six distinct clusters: A, 'healthy, reporting sleeping related symptoms'; B, 'mild obstructive sleep apnea syndrome without significant comorbidities'; C1: 'moderate obstructive sleep apnea syndrome, obesity, without significant comorbidities'; C2: 'moderate obstructive sleep apnea syndrome with severe comorbidity, obesity and the exclusive inclusion of stroke'; D1: 'severe obstructive sleep apnea syndrome and obesity without comorbidity and a 33.8% prevalence of hypertension'; and D2: 'severe obstructive sleep apnea syndrome with severe comorbidities, along with the highest Epworth Sleepiness Scale score and highest body mass index'. Clusters differed significantly in apnea-hypopnea index, oxygen desaturation index; arousal index; age, body mass index, minimum oxygen saturation and daytime oxygen saturation (one-way analysis of variance P < 0.0001). Binary logistic regression indicated that older age, greater body mass index, lower daytime oxygen saturation and hypertension were associated independently with an increased risk of belonging in a comorbid cluster. Six distinct phenotypes of obstructive sleep apnea syndrome and its comorbidities were identified. Mapping the heterogeneity of the obstructive sleep apnea syndrome may help the early identification of at-risk groups. Finally, determining predictors of comorbidity for the moderate and severe strata of these phenotypes implies a need to take these factors into account when considering obstructive sleep apnea syndrome treatment options.

Non-Invasive Ventilation (NIV) and Homeostatic Model Assessment (HOMA) Index in Stable Chronic Obstructive Pulmonary Disease (COPD) Patients with Chronic Hypercapnic Respiratory Failure: A Pilot Study.

The effects of Non-invasive Ventilation (NIV) on Insulin Resistance (IR) in stable Chronic Obstructive Pulmonary Disease (COPD) patients have not been fully explored. The aim of this study was to assess the effects of NIV on IR and adiponectin levels during one year application of NIV in stable COPD patients with Chronic Hypercapnic Respiratory Failure. Twenty-five (25) stable COPD patients with Chronic Hypercapnic Respiratory Failure and with no self-reported comorbidities completed the study. NIV was administered in the spontaneous/timed mode via a full face mask using a bi-level positive airway pressure system. Spirometry, blood pressure, arterial blood gases, dyspnea, daytime sleepiness, serum fasting glucose and insulin levels were assessed. IR was assessed with the calculation of the Homeostatic Model Assessment (HOMA) index. Adiponectin was measured with radioimmunoassay. Study participants were re-evaluated on the first, third, sixth, ninth and twelfth month after the initial evaluation. There was a significant improvement in FEV1 values from the first month (34.1 ± 11.6% vs 37 ± 12.3%, p = 0.05). There was a significant decrease in IR by the ninth month of NIV use (3.4 ± 2.3 vs 2.2 ± 1.4, p < 0.0001), while adiponectin levels significantly improved from the first month of NIV use. Stepwise regression analysis revealed that baseline HOMA index was associated with paCO2 (ß = 0.07 ± 0.02, p = 0.001), while baseline adiponectin levels were associated with FVC (ß = 0.05 ± 0.02, p = 0.035) and the concentration of serum bicarbonate (HCO3-) (-ß = 0.18 ± 0.06, p = 0.002). Insulin sensitivity and glucose metabolism as well as adiponectin levels improved along with the improvements in respiratory failure.

The DJ-1 protein as a candidate biomarker in obstructive sleep apnea syndrome.

BACKGROUND: Oxidative stress has a central role in the pathophysiology of obstructive sleep apnea syndrome (OSAS). The DJ-1 protein functions as a sensor of oxidative stress, acting both as a reactive oxygen species scavenger (ROS) and an antioxidative response regulator. The aim of our study is to determine the serum levels of DJ-1 in OSAS patients and assess possible correlations with their clinical, demographical, and biochemical characteristics. METHODS: The study included 120 subjects from the Sleep Disorder Laboratory of the University Hospital of Thessaly (100 males vs 20 females, mean age 48±10, Apnea-Hypopnea Index (AHI)>5 episodes per hour of sleep). Subjects underwent full-night polysomnography (PSG) followed by morning blood sampling. Serum DJ-1 levels were determined via ELISA kits. Statistical analysis was performed using SPSS 19. RESULTS: The median DJ-1 levels were 56.7 ng/mL (IQR, 34.9-99.3 ng/mL). Statistically significant correlations were detected between DJ-1's levels and AHI (Spearman's rho=0.189, P=0.04), Desaturation Index (DI; Spearman's rho=0.239, P=0.012), and serum low-density lipoprotein (LDL) (Spearman's rho=-0.205, P=0.042). CONCLUSIONS: DJ-1 may be a useful biomarker in OSAS due to its correlations with AHI and DI. The correlation with serum LDL warrants further investigation regarding possible implications in OSAS patients' cardiovascular comorbidities.

Memory Foam Pillow as an Intervention in Obstructive Sleep Apnea Syndrome: A Preliminary Randomized Study.

Specific pillow use is a seldom studied or controlled factor in the setting of sleep disordered breathing. The aim of this study was to investigate the effect of different pillows [own pillow (OP), memory foam pillow (MFP), generic laboratory pillow (LP)] on polysomnography (PSG)-derived parameters in patients with Obstructive Sleep Apnea Syndrome (OSAS). Thirty-two consecutive patients with OSAS were randomly allocated into two groups with randomized pillow usage [Group A: 3 h with LP and 3 h with OP (Age: 53.8 ± 12.5 years, BMI: 32.1 ± 4.6 kg/m2); Group B: 3 h with LP and 3 h with MFP (Age: 52.0 ± 6.3 years, BMI: 30.6 ± 2.2 kg/m2)]. Statistically significant differences between pillow types were detected in desaturation index and heart rate. In Group B (with MFP), a statistically significant decrease of 47.0 ± 15.9% was observed in snoring events (p < 0.05) and 10.6 ± 6.7% in their duration (p < 0.05) compared to LP. On the other hand, group A with OP recorded a decrease of 29.1 ± 32.1% in snoring events and 32.5 ± 33.1% in duration, but these values were not statistically significant (p > 0.05) compared to LP. These findings indicate that pillow type and usage, often uncontrolled in OSAS studies (contribution to the field), may impact several PSG parameters and are related to a snoring subtype of the syndrome. Secondly, they indicate that a focus on the treatment of the snoring OSAS subtype warrants further dedicated investigation.

Association between Interleukin-6 and vitamin D serum levels in patients with obstructive sleep apnea syndrome and impact of long-term continuous positive airway pressure therapy on biomarker levels.

OBJECTIVE: Hypoxia induces interleukin-6 (IL-6) production in obstructive sleep apnea syndrome (OSAS). Low serum 25 hydroxyvitamin D (25(OH)D) levels have been linked to OSAS susceptibility. Serum 25(OH)D levels have been negatively correlated with serum IL-6 levels in patients with chronic inflammation. No data exist to assess whether there is a correlation between 25(OH)D and IL-6 serum levels in OSAS, while the impact of continuous positive airway pressure (CPAP) therapy on IL-6 or 25(OH)D levels needs further investigation. We aimed to compare the serum 25(OH)D and IL-6 levels between OSAS patients and controls, examine a possible correlation between 25(OH)D and IL-6 levels and the changes of their concentrations after twelve months of CPAP therapy in OSAS patients. METHODS: 15 newly-diagnosed OSAS patients and 15 non-apneic controls were recruited. Serum IL-6 and 25(OH)D levels were measured in the study population at baseline and twelve months after CPAP initiation in OSAS patients. RESULTS: IL-6 levels were elevated in OSAS patients than controls and were positively and negatively correlated with body mass index (BMI) and minimum oxyhemoglobin saturation (minSpO2), respectively. Diabetes mellitus, BMI and minSpO2 independently predicted IL-6 levels. No difference was found in 25(OH)D levels between groups. No correlation between IL-6 and 25(OH)D levels was detected. Effective CPAP therapy did not impact IL-6 or 25(OH)D levels after one year in OSAS patients. CONCLUSIONS: No correlation between IL-6 and 25(OH)D levels was found. IL-6 levels were significantly elevated in OSAS patients than the controls and positively correlated with BMI, diabetes mellitus, and nocturnal hypoxemia.

Noninvasive ventilation in chronic respiratory failure: effects on quality of life.

BACKGROUND: Noninvasive ventilation (NIV) has been found to be an essential technique to treat chronic respiratory failure (CRF) resulting from restrictive thoracic disorders (RTD). The last decades were characterized by the expansion of NIV to treat patients suffering from various other conditions, such as chronic obstructive pulmonary disease (COPD) and obesity hypoventilation syndrome (OHS). OBJECTIVES: The aim of this study was to evaluate the effect of NIV on health-related quality of life (HRQoL) of patients with CRF during 2 years and to identify parameters associated with changes in HRQoL. METHODS: Ninety-one patients with CRF [35 COPD; 17 RTD; 28 OHS; 11 neuromuscular diseases (NMD)] participated. HRQoL was assessed with the SF-36 questionnaire. Additional measurements included blood gases, pulmonary function tests, dyspnea, daytime sleepiness, exacerbations and hospitalizations. The patients were evaluated every 3-6 months. RESULTS: Improvements in SF-36 physical component summary (PCS, p < 0.0001) and mental component summary (MCS, p < 0.0001) scores in RTD and MCS in OHS (p = 0.01) and COPD (p = 0.003) were observed by the third month. PCS in OHS and COPD patients improved by the sixth month (p = 0.003 and p < 0.0001, respectively). NMD patients did not present improvements in HRQoL. Improvements in HRQoL were associated with improvements in PaO(2) and dyspnea in COPD patients, and with total hours of daily ventilator use, improvement in dyspnea, pressure support and expiratory positive airway pressure in RTD patients. CONCLUSION: Home NIV is consistently effective in improving HRQoL and physiological parameters in patients with CRF. Randomized trials to identify subgroups of COPD responders are justified by our results.

Intergenic SNPs in Obstructive Sleep Apnea Syndrome: Revealing Metabolic, Oxidative Stress and Immune-Related Pathways.

There is strong evidence supporting the contribution of genetic factors to obstructive sleep apnea syndrome (OSAHS) susceptibility. In the current study we analyzed both in a clinical cohort and in silico, four single nucleotide polymorphisms SNPs, rs999944, rs75108997, rs35329661 and rs116133558 that have been associated with OSAHS. In 102 patients with OSAHS and 50 healthy volunteers, genetic testing of the above polymorphisms was performed. Polymorphism rs116133558 was invariant in our study population, whereas polymorphism rs35329661 was more than 95% invariant. Polymorphism rs999944 displayed significant (>5%) variance in our study population and was used in the binary logistic regression model. In silico analyses of the mechanism by which these three SNPs may affect the pathophysiology of OSAHS revealed a transcriptomic network of 274 genes. This network was involved in multiple cancer-associated gene signatures, as well as the adipogenesis pathway. This study, uncover a regulatory network in OSAHS using transcriptional targets of intergenic SNPs, and map their contributions in the pathophysiology of the syndrome on the interplay between adipocytokine signaling and cancer-related transcriptional dysregulation.

Alzheimer's Disease in Patients with Obstructive Sleep Apnea Syndrome.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is a disorder with high prevalence among adults and is an independent risk factor for various diseases, especially those affecting the central nervous system (CNS). Continuous positive airway pressure (CPAP) is usually the optimal choice of treatment for OSAS. Alzheimer's disease (AD) is a neurodegenerative disease affecting a large proportion of the elderly population. The purpose of this study was to collect information concerning the two pathological entities and investigate the effectiveness of CPAP in the treatment of AD. MATERIALS AND METHODS: In this review, Twenty articles were found concerning OSAS and AD, of which one article was about treatment with donepezil and seven articles considered treatment with CPAP. RESULTS: Serious OSAS and short sleep duration are associated with a high risk of developing dementia. Respiratory distress during sleep is associated with developing mild cognitive impairment at younger ages. The cerebrovascular damage of AD patients is correlated with the severity of OSAS. Lower cerebrospinal fluid levels are associated with memory disturbances and oxygen saturation parameters in patients with OSAS-AD. Continuous use of CPAP is related to the delayed onset of cognitive impairment and is suggested as an effective method of protecting cognitive function, depression, sleep quality and architecture, and daytime sleepiness in AD patients with good compliance. Treatment of CPAP patients with OSAS-AD is suggested as an effective method of protecting cognitive function. CONCLUSION: Clinicians dealing with AD patients should consider CPAP treatment when OSAS coexists.

25-hydroxyvitamin D levels in patients with obstructive sleep apnea and continuous positive airway pressure treatment: a brief review.

The aim of the present study is to summarize the information available, to time, regarding the relationship between obstructive sleep apnea (OSA) and vitamin-D (vD) levels. Moreover, the association between vD deficiency and OSA severity will also be examined. At the end of the present study the possible advantageous effect of CPAP on vD-levels will be summarized. Extensive literature search was conducted in PubMed, Scopus, The Cochrane Library and Embase database. 13 articles were found concerning OSA and vD, of which 2 articles included treatment with a CPAP. Patients with OSA exhibit low levels of vD in the blood serum, and women present an even lower mean value than men. Lack of VD in blood serum seems to be related to the severity of the OSA syndrome, and to the short duration of sleep. OSA patients with concurrent metabolic syndrome exhibit lower serum vD-levels, as compared with those without metabolic syndrome. Long-term continuous positive airway pressure treatment (CPAP) treatment can increase vD-levels in male OSA patients while no change is observed in women. OSA patients demonstrate lower levels of vD in multiple studies. The severity of the OSA may be associated with vD-levels and deficiency, however more studies are needed to assess that relationship due to contradictions in current bibliography. CPAP can increase vD-levels in male patients. The relation between vD and OSA and/or CPAP is important but recent; therefore further research is needed about the exact relationship to be clarified. Also, the effect of gender hormones on vD regulation in OSA patients should be further investigated.

Nasal continuous positive airway pressure treatment reduces systemic oxidative stress in patients with severe obstructive sleep apnea syndrome.

OBJECTIVE: To evaluate whether nasal continuous positive airway pressure (nCPAP) reduces oxidative stress in patients with severe obstructive sleep apnea (OSA) syndrome. MATERIALS AND METHODS: Forty-six patients with severe OSA (AHI> or =30) requiring nasal CPAP treatment and 46 controls (subjects without OSA and with mild OSA as defined by an AHI<15) were enrolled. Oxidative stress was evaluated in blood samples with a commercially available automated spectrophotometric assay (D-ROMs test, Diacron, Grosseto, Italy). Blood samples were collected the evening before (10:00 p.m.) and the morning after (07:00 a.m.) a diagnostic polysomnography. Patients with severe OSA syndrome were subsequently submitted to a second polysomnography with nasal CPAP titration the following night. Using the same schedule we collected blood samples from the patients the morning after the nCPAP titration and after two months of nCPAP treatment. RESULTS: Patients with severe OSA presented higher levels of oxidative stress than patients with AHI<15 in the evening and in the morning (357.57+/-13.07 UCarr vs. 319.28+/-12.66 UCarr, p=0.038, and 371.83+/-12.83 UCarr vs. 328.09+/-11.76 UCarr, p=0.014, respectively). Patients with severe OSA presented a significant reduction the levels of oxidative stress the morning after the nCPAP titration study (371.83+/-12.83 UCarr vs. 298.21+/-9.62 UCarr, p=0.001) and this reduction was further preserved after a period of two months of nCPAP treatment (293.72+/-6.55 UCarr, p=0.001 vs. baseline). Statistically significant correlations were observed between levels of oxidative stress and nocturnal polysomnography (NPSG) markers as oxygen desaturation index (ODI), arousal index (AI), lowest oxygen saturation of hemoglobin, and mean oxygen saturation of hemoglobin. CONCLUSIONS: Patients with severe OSA syndrome presented increased systemic oxidative stress. A single night of nCPAP treatment significantly reduced the levels of oxidative stress in patients with severe OSA syndrome, and this reduction was maintained at least after two months of nCPAP treatment.

The use of cardiopulmonary exercise testing in identifying the presence of obstructive sleep apnea syndrome in patients with compatible symptomatology.

The aim of this study was to investigate the relationship between cardiopulmonary exercise testing (CPET) and the presence of obstructive sleep apnea syndrome (OSAS) in order to provide an innovative tool to identify patients with OSAS. A prospective nested case control design was adopted. A consecutive population of male volunteers referred to a Sleep Unit was subjected to nocturnal polysomnography, full lung function testing and maximal CPET. A stepwise linear discriminant function analysis (DFA) was applied to construct a model which could identify individuals with moderate-to-severe OSAS from healthy controls. The total of 30 volunteers formed the OSAS and 24 the non-OSAS groups. Demographic and somatometric parameters were similar between groups. Patients presented with lower Expiratory Reserve Volume (ERV: 106.7 ± 28.3 vs. 123.9 ± 22.1, p < 0.001), Leg FatigueBorg scale (3.9 ± 1.1 vs. 6.1 ± 1.4, p < 0.001), VO2peak(25.0 ± 5.9 vs. 32.9 ± 7.2 ml/kg-1/min-1, p < 0.001), peak breathing frequency (31.0 ± 5.8 vs. 35.5 ± 7.3 1/min-1, p < 0.001) and peak heart rate (151.1 ± 17.7 vs. 171.2 ± 12.6 beats/min-1, p < 0.001) compared to controls, but higher peak end-tidal CO2 (PETCO2peak:38.6 ± 4.2 vs. 35.0 ± 4.9 mmHg, p = 0.043) and peak systolic (SBP:188.3 ± 21.9 vs. 173.1 ± 17.9 mmHg, p = 0.009) and diastolic (DBP: 91.3 ± 8.2 vs. 85.4 ± 8.2 mmHg, p = 0.011) blood pressure. Stepwise DFA indicated that ERV% of predicted (0.372), PETCO2peak (-0.376), SpO2resting (0.0667), Leg Fatigue Borg scale (0.564), HRpeak (0.530) and DBPpeak (-0.543) could separate the two groups, with an overall predictive accuracy of 96.3%. Selected CPET parameters (ERV% of predicted, PETCO2peak, SpO2resting, HRpeak, DBPpeak and Leg FatigueBorg Scale) are independently associated with OSAS presence and could discriminate patients with and without this disorder.

One-year non-invasive ventilation in chronic hypercapnic COPD: effect on quality of life.

The data on long-term application of non-invasive ventilation (NIV) in patients with chronic respiratory failure due to COPD are contradictory. We evaluated the effect of the addition of NIV to optimal treatment for 1 year on the quality of life of stable hypercapnic COPD patients. NIV was offered to 49 of 58 initially enrolled consecutive patients, of whom 22 refused NIV and comprised the standard treatment group whereas 27 received NIV. Quality of life was assessed with the SF-36 questionnaire. Additional measurements included blood gases, pulmonary function tests, dyspnea, daytime sleepiness, exacerbations and hospitalizations. The NIV group showed a significant improvement in quality of life in the third month, both in the Physical (31+/-4 to 38+/-8, p<0.0001) and the Mental Component Summary Score (28+/-7 to 40+/-10, p=0.009), that was maintained until the twelfth month. PaCO2 decreased by the first month in the NIV group (54+/-4.5 to 44.6+/-5.6 mmHg, p<0.0001), and PaO2 rose during the sixth month (58.9+/-5.7 to 64.4+/-6.5 mmHg, p=0.004). Dyspnea and diurnal sleepiness improved significantly. No significant improvements were observed in the control group. Patients on NIV spent less days in the hospital compared to controls. NIV when added to optimal medical treatment has beneficial effects on quality of life in stable hypercapnic COPD patients, with additional improvements in arterial blood gases, dyspnea and daytime sleepiness.

Hypercapnic COPD patients and NIV at home: is there any benefit? Using the CAT and BODE index in an effort to prove benefits of NIV in these patients.

Introduction: The benefits of long-term noninvasive ventilation (NIV) in stable COPD with chronic hypercapnic respiratory failure (CHRF) have been debated for many years due to the conflicting results observed in these patients. Materials and methods: We investigated the effects of domiciliary NIV in stable hypercapnic COPD patients for a period of 1 year using COPD Assessment Test (CAT), BODE Index, and the number of acute exacerbations. NIV was administered in 57 stable COPD patients with CHRF in the spontaneous/timed mode. Spirometry, 6 minute walk test, Medical Research Council dyspnea scale, arterial blood gases, number of acute exacerbations, BODE Index, and CAT were assessed. Study participants were reassessed in the 1st, 6th, and 12th months after the initial evaluation. Results: There was a significant improvement in COPD exacerbations (p<0.001), CAT (p<0.001), PO2 (p<0.001), PCO2 (p<0.001), and Medical Research Council dyspnea scale (p<0.001) in 1 year of follow-up. BODE Index was improved in the first 6 months (5.8±2.2 vs 4.8±2.4, p<0.001), but the improvement was not maintained. Conclusion: In conclusion, domiciliary NIV in stable COPD patients with CHRF has beneficial effect on CAT, arterial blood gases, and number of acute exacerbations in a year of NIV use at home. A significant improvement in BODE Index from baseline to 12 months was found in patients aged >70 years, while for those aged <70, the improvement was not maintained after the sixth month.

Non-invasive ventilation in chronic hypercapnic COPD patients with exacerbation and a pH of 7.35 or higher.

BACKGROUND: Current guidelines suggest the use of non-invasive ventilation (NIV) in hypercapnic chronic obstructive pulmonary disease (COPD) exacerbations in patients presenting with a pH of 7.25-7.35. The aim of this study was to investigate the role of NIV in COPD patients with chronic hypercapnic respiratory failure admitted to the hospital with acute exacerbations and an arterial pH of 7.35 or higher. METHODS: Forty-seven COPD patients with chronic hypercapnic respiratory failure admitted for exacerbations and with a pH of 7.35 or higher were randomized to receive standard medical therapy (control group) or medical therapy plus NIV (NIV group). Arterial blood gases were measured at baseline, after 1 h, 6 h, 12 h, 24 h, 48 h, and at discharge. Need for admission to intensive care unit (ICU), death, and duration of hospitalization were recorded. The final analysis included 42 patients (21 controls and 21 NIV patients). RESULTS: NIV resulted in a shorter hospital stay (5.5+/-2.6 vs 10.1+/-4.4 days for controls, p=0.0004). Two patients from the control group were admitted to the ICU and one eventually died, whereas all NIV patients were successfully discharged. The NIV group showed a faster improvement in PaCO(2) and pH. At discharge, the NIV group had a lower PaCO(2) (6.5+/-0.6 kPa vs 7.5+/-1.1 kPa, p=0.01) but a comparable pH (7.43+/-0.03 vs 7.43+/-0.04, p=0.93). PaO(2) and PaO(2)/FiO(2) levels showed similar improvement in both groups at discharge. CONCLUSION: Early administration of NIV in COPD patients with chronic hypercapnic respiratory failure admitted for acute exacerbations with a pH of 7.35 or higher results in a reduced hospital stay and faster improvement of arterial blood gases.

Sleep apnoea syndrome and early stage cirrhosis: a pilot study.

OBJECTIVES: Hepatic encephalopathy in patients with end-stage liver cirrhosis is associated with alterations in sleep patterns. Cirrhosis may also affect pulmonary function and it might be involved in the development of obstructive sleep apnoea syndrome (OSAS) in patients with ascites. We carried out a study to evaluate the presence of OSAS in cirrhotic patients without evidence of ascites (early stage cirrhosis). METHODS: We investigated 20 patients with Child A or B cirrhosis (19 and one, respectively) and 10 non-cirrhotic patients with chronic viral hepatitis (disease control group). All subjects were interviewed and underwent a thorough physical examination, a full polysomnographic study and a pulmonary function testing by spirometry. Serum samples were also obtained in order to determine the liver function tests. RESULTS: The presence of OSAS and inverted sleep patterns was similar in cirrhotic patients and disease controls. However, significant correlations were revealed between age and hypopnoeas per hour of sleep; age and the Apneas/Hypopneas Index (AHI); age and FEV1/FVC; gamma-glutamyl transpeptidase and FEV1/FVC; and total bilirubin and total sleep time. CONCLUSIONS: Early stage cirrhosis is not associated with sleep disorders and OSAS. However, total bilirubin levels might be a useful laboratory marker for early assessment of disturbance in sleep patterns and therefore of subclinical hepatic encephalopathy in Child A cirrhosis.

Age, Body Mass Index, and Daytime and Nocturnal Hypoxia as Predictors of Hypertension in Patients With Obstructive Sleep Apnea.

A growing body of evidence links obstructive sleep apnea (OSA) with hypertension. The authors performed a retrospective cohort study using the University Hospital of Larissa Sleep Apnea Database (1501 patients) to determine predictors of in-laboratory diagnosed OSA for development of hypertension. Differences in continuous variables were assessed via independent samples t test, whereas discrete variables were compared by Pearson's chi-square test. Multivariate analysis was performed via discriminant function analysis. There were several significant differences between hypertensive and normotensive patients. Age, body mass index, comorbidity, daytime oxygen saturation, and indices of hypoxia during sleep were deemed the most accurate predictors of hypertension, whereas apnea-hypopnea index and desaturation index were not. The single derived discriminant function was statistically significant (Wilk's lambda=0.771, χ(2) =289.070, P<.0001). Daytime and nocturnal hypoxia as consequences of chronic intermittent hypoxia play a central role in OSA-related hypertension and should be further evaluated as possible severity markers in OSA.

Comparison of blood pressure measurements in children with and without habitual snoring.

Higher or similar systolic and/or diastolic blood pressure has been recorded in children with sleep apnea compared to subjects with primary snoring or in those with primary snoring compared to controls. To investigate the association between blood pressure and habitual snoring, we studied children in four randomly selected schools in central Greece. A symptom questionnaire was answered by parents, and children's weight, height, and blood pressure were measured. Seven hundred and sixty children (4-14 years old; 352 female) were recruited. Fifty of 760 (6.6%) participants were snoring more than 3 nights/week (habitual snorers). Mean (+/- SD) systolic blood pressure was 106.9 (+/-10.6) mmHg in habitual snorers vs. 107 (+/- 12) in nonhabitual snorers (P > 0.05). Mean diastolic blood pressure was 61.9 (+/- 7.6) in the former vs. 61.8 (+/- 6.8) in the latter (P > 0.05). While age, gender, and body mass index were significant predictors of systolic blood pressure in a general linear model, snoring was not. Similarly, that gender and body mass index but not snoring were significant predictors of diastolic blood pressure. In a community sample of children, habitual snorers do not have higher morning systolic or diastolic blood pressure than nonhabitual snorers.

Antioxidant capacity in obstructive sleep apnea patients.

OBJECTIVES: Obstructive sleep apnea syndrome (OSA) results in oxygen desaturation and arousal from sleep. Free oxygen radicals are highly reactive molecules, which can be produced by the OSA phenomenon known as hypoxia/reoxygenation. Hypoxic conditions, such as OSA, may also result in transient depletion of cellular reductants, which constitute a main line of antioxidant defense. Both apneas and hypopneas usually end in arousal, where reoxygenation causes the production of reactive oxygen species (free radicals). Living organisms have developed complex antioxidant systems to counteract reactive oxygen species and to reduce their damage. We evaluated the antioxidant capacity in serum from OSA patients and healthy people in order to confirm the hypothesis that there is a relationship between oxidative stress and OSA. MATERIALS AND METHODS: A physician interviewed 25 participants, determining age, smoking habits and symptoms such as excessive daytime sleepiness and snoring. Physical examination and polysomnography were performed during patients' hospitalization. Antioxidant capacity was measured in blood samples by Trolox Equivalent Antioxidant Capacity assay. RESULTS: Seventeen out of 25 subjects had an apnea/hypopnea index (AHI) greater than 10 (OSA group). The measurement of antioxidant capacity did not differ between the OSA patients and our healthy sample (of 25 subjects, seven with an AHI less than 10). Furthermore, patients with severe OSA (AHI >20, N=14) had linearly negative correlation between antioxidant capacity in their blood samples and AHI (R=-0.551, P=0.041). CONCLUSIONS: Reduced antioxidant capacity in serum is an index of excessive oxidative stress. Patients with severe OSA have reduced values of antioxidant capacity.

Yellow nail syndrome or diffuse lymphatic network disease.

We report a man aged 68 years old with pneumothorax and chronic bilateral pleural effusion in association with a history of yellow nails. The diagnosis of yellow nail syndrome based on yellow nails, lymphedema, chronic pleural effusion and intestinal lymphangiectasia.