A predictive model for optimal continuous positive airway pressure in the treatment of pure moderate to severe obstructive sleep apnea in China.

BACKGROUND: Numerous predictive formulas based on different ethnics have been developed to determine continuous positive airway pressure (CPAP) for patients with obstructive sleep apnea (OSA) without laboratory-based manual titrations. However, few studies have focused on patients with OSA in China. Therefore, this study aimed to develop a predictive equation for determining the optimal value of CPAP for patients with OSA in China. METHODS: 526 pure moderate to severe OSA patients with attended CPAP titrations during overnight polysomnogram were spited into either formula derivation (419 patients) or validation (107 patients) group according to the treatment time. Predictive model was created in the derivation group, and the accuracy of the model was tested in the validation group. RESULTS: Apnea hypopnea index (AHI), body mass index (BMI), longest apnea time (LAT), and minimum percutaneous oxygen saturation (minSpO2) were considered as independent predictors of optimal CPAP through correlation analysis and multiple stepwise regression analysis. The best equation to predict the optimal value of CPAP was: CPAPpred = 7.581 + 0.020*AHI + 0.101*BMI + 0.015*LAT-0.028*minSpO2 (R2 = 27.2%, p < 0.05).The correlation between predictive CPAP and laboratory-determined manual optimal CPAP was significant in the validation group (r = 0.706, p = 0.000). And the pressure determined by the predictive formula did not significantly differ from the manually titrated pressure in the validation cohort (10 ± 1 cmH2O vs. 11 ± 3 cmH2O, p = 0.766). CONCLUSIONS: The predictive formula based on AHI, BMI, LAT, and minSpO2 is useful in calculating the effective CPAP for patients with pure moderate to severe OSA in China to some extent.

The level of carbon dioxide is the determinant of successful noninvasive ventilation pressure titration in patients with nonhypercapnic primary central sleep apnea: a case report.

Primary central sleep apnea is classified as nonhypercapnic central sleep apnea. High loop gain, lower CO2 reserves, and other reasons can lead to hypocapnia in patients who develop intermittent hyperventilation during sleep. Therefore, it is necessary to monitor nocturnal CO2 level for these patients. We report a female patient diagnosed with nonhypercapnic primary central sleep apnea who complained of snoring, apnea, and excessive daytime sleepiness. With the monitoring of transcutaneous partial pressure of CO2, manual noninvasive ventilation pressure titration was performed with continuous positive airway pressure, bilevel positive airway pressure in a spontaneous-timed mode, and adaptive servo-ventilation mode for 3 nights, respectively. Only adaptive servo-ventilation mode could stabilize the transcutaneous partial pressure of CO2 above the apneic threshold (approximately 40 mm Hg) with successfully eliminating central apnea events. It is concluded that the level of CO2 is the determinant of successful noninvasive ventilation pressure titration in patients with nonhypercapnic central sleep apnea. CITATION: Han X, Zhao D, Wang J, Wang Y, Dong L, Chen B-y. The level of carbon dioxide is the determinant of successful noninvasive ventilation pressure titration in patients with nonhypercapnic primary central sleep apnea: a case report. J Clin Sleep Med. 2022;18(1):319-324.

Obstructive sleep apnea and respiratory center regulation abnormality.

PURPOSE: Obstructive sleep apnea (OSA) is a complex disease in which phenotypic analysis and understanding pathological mechanisms facilitate personalized treatment and outcomes. However, the pathophysiology responsible for this robust observation is incompletely understood. The objective of the present work was to review how respiratory center regulation varies during sleep and wakeness in patients with OSA. DATA SOURCES: We searched for relevant articles up to December 31, 2019 in PubMed database. METHODS: This review examines the current literature on the characteristics of respiratory center regulation during wakefulness and sleep in OSA, detection method, and phenotypic treatment for respiratory center regulation. RESULTS: Mechanisms for ventilatory control system instability leading to OSA include different sleep stages in chemoresponsiveness to hypoxia and hypercapnia and different chemosensitivity at different time. One can potentially stabilize the breathing center in sleep-related breathing disorders by identifying one or more of these pathophysiological mechanisms. CONCLUSIONS: Advancing mechanism research in OSA will guide symptom research and provide alternate and novel opportunities for effective treatment for patients with OSA.

Treatment-emergent central sleep apnea: a unique sleep-disordered breathing.

Treatment-emergent central sleep apnea (TECSA) is a specific form of sleep-disordered breathing, characterized by the emergence or persistence of central apneas during treatment for obstructive sleep apnea. The purpose of this review was to summarize the definition, epidemiology, potential mechanisms, clinical characteristics, and treatment of TECSA. We searched for relevant articles up to January 31, 2020, in the PubMed database. The prevalence of TECSA varied widely in different studies. The potential mechanisms leading to TECSA included ventilatory control instability, low arousal threshold, activation of lung stretch receptors, and prolonged circulation time. TECSA may be a self-limited disorder in some patients and could be resolved spontaneously over time with ongoing treatment of continuous positive airway pressure (CPAP). However, central apneas persist even with the regular CPAP therapy in some patients, and new treatment approaches such as adaptive servo-ventilation may be necessary. We concluded that several questions regarding TECSA remain, despite the findings of many studies, and it is necessary to carry out large surveys with basic scientific design and clinical trials for TECSA to clarify these irregularities. Further, it will be vital to evaluate the baseline demographic and polysomnographic data of TECSA patients more carefully and comprehensively.

Slow-wave sleep is associated with incident hypertension in patients with obstructive sleep apnea: a cross-sectional study.

OBJECTIVE: This study aimed to examine the association between slow-wave sleep ([SWS] N3 stage) and the risk of hypertension in patients with obstructive sleep apnea (OSA) or primary snorers. METHODS: A retrospective cross-sectional study of 1145 participants who were evaluated for suspected OSA at our Sleep Medical Center were included. Among these participants, 1022 had OSA and 123 were primary snorers. Logistic regression modeling was performed to evaluate the association between the prevalence of hypertension and combined OSA and SWS based on polysomnographic measurements. RESULTS: Patients with OSA in the lowest SWS quartile (quartile 1, < 2.0%) showed a two-fold increased risk of hypertension after adjustment for confounding factors compared with primary snorers (odds ratio, 2.13 [95% confidence interval 1.54-2.06]). In logistic analysis stratified according to SWS quartiles, there was no significant difference in the risk of hypertension between patients with OSA and primary snorers in quartile 1. However, in the highest quartile (quartile 4), SWS was significantly associated with incident hypertension in patients with OSA rather than primary snorers. CONCLUSION: SWS is associated with prevalent hypertension in patients with OSA. Notably, a low proportion of SWS confers a stronger association with incident hypertension than OSA.

A novel enzyme-assisted ultrasonic approach for highly efficient extraction of resveratrol from Polygonum cuspidatum.

Resveratrol is a promising multi-biofunctional phytochemical, which is abundant in Polygonum cuspidatum. Several methods for resveratrol extraction have been reported, while they often take a long extraction time accompanying with poor extraction yield. In this study, a novel enzyme-assisted ultrasonic approach for highly efficient extraction of resveratrol from P. cuspidatum was developed. According to results, the resveratrol yield significantly increased after glycosidases (Pectinex® or Viscozyme®) were applied in the process of extraction, and better extraction efficacy was found in the Pectinex®-assisted extraction compared to Viscozyme®-assisted extraction. Following, a 5-level-4-factor central composite rotatable design with response surface methodology (RSM) and artificial neural network (ANN) was selected to model and optimize the Pectinex®-assisted ultrasonic extraction. Based on the coefficient of determination (R(2)) calculated from the design data, ANN model displayed much more accurate in data fitting as compared to RSM model. The optimum conditions for the extraction determined by ANN model were substrate concentration of 5%, acoustic power of 150W, pH of 5.4, temperature of 55°C, the ratio of enzyme to substrate of 3950 polygalacturonase units (PGNU)/g of P. cuspidatum, and reaction time of 5h, which can lead to a significantly high resveratrol yield of 11.88mg/g.

Formoterol as reliever medication in asthma: a post-hoc analysis of the subgroup of the RELIEF study in East Asia.

BACKGROUND: As-needed formoterol can effectively relieve asthma symptoms. Since budesonide/formoterol is available as maintenance and reliever therapy in Asia, formoterol is now being used as-needed, but always with concomitant inhaled corticosteroids. The objective of this analysis was to assess the safety and efficacy of formoterol therapy in patients in East Asia (China, Indonesia, Korea, the Philippines and Singapore) with asthma. METHODS: Post-hoc analyses of data from the East Asian population of the RELIEF (REal LIfe EFfectiveness of Oxis® Turbuhaler® as-needed in asthmatic patients; study identification code: SD-037-0699) study were performed. RESULTS: This sub-group comprised 2834 randomised patients (formoterol n = 1418; salbutamol n = 1416) with mean age 35 years; 50.7% were male. 2678 patients completed the study. There was no significant difference in the total number of adverse events (AEs) reported in the formoterol and salbutamol groups (21.3% vs 20.9% of patients; p = 0.813), nor in the total number of serious AEs and/or discontinuations due to AEs (4.6% vs 5.5%, respectively; p = 0.323). Compared with salbutamol, formoterol was associated with a significantly longer time to first exacerbation (hazard ratio 0.86; p = 0.023) and a 14% reduction in the risk of any exacerbation (p < 0.05). Relative to salbutamol, mean adjusted reliever medication use throughout the study was significantly lower in the formoterol group (p = 0.017) and the risk of increased asthma medication use was 20% lower with formoterol (p = 0.005). CONCLUSIONS: Among patients with asthma in East Asia, as-needed formoterol and salbutamol had similar safety profiles but, compared with salbutamol, formoterol reduced the risk of exacerbations, increased the time to first exacerbation and reduced the need for reliever medication.

Hippocampal mitogen-activated protein kinase activation is associated with intermittent hypoxia in a rat model of obstructive sleep apnea syndrome.

Obstructive sleep apnea syndrome (OSAS), characterized by intermittent hypoxia/re­oxygenation, may impair the cerebral system. Although mitogen­activated protein kinase (MAPK) signaling was observed to have a key role in hypoxia­induced brain injury, the intracellular events and their underlying mechanisms for intermittent hypoxia/re­oxygenation-associated damage to hippocamal MAPKs, including extracellular signal­regulated kinase (ERK)1/2, P38MAPK and c­Jun N­terminal kinase (JNK) remain to be elucidated and require further investigation. A total of five rats in each sub­group were exposed to intermittent hypoxia or continued hypoxia for 2, 4, 6 or 8 weeks. Histological, immunohistochemical and biological analyses were performed to assess nerve cell injury in the hippocampus. Surviving CA1 pyramidal cells were identified by hematoxylin and eosin staining. The levels of phosphorylated ERK1/2, P38MAPK and JNK were detected by western blotting. B­cell lymphoma 2 (Bcl­2) and Bcl­2­associated X protein (Bax) in neural cells were examined by immunohistochemistry. The malondialdehyde (MDA) contents and superoxide dismutase (SOD) activities were measured by thiobarbituric acid and xanthine oxidation methods, respectively. Under continued hypoxia, the levels of phospho­ERK1/2 peaked at the fourth week and then declined, whereas phospho­P38MAPK and JNK were detected only in the late stages. By contrast, under intermittent hypoxia, ERK1/2, P38MAPK and JNK were activated at all time-points assessed (2, 4, 6 and 8 weeks). The levels of phospho­ERK1/2, P38MAPK and JNK were all higher in the intermittent hypoxia groups than those in the corresponding continued hypoxia groups. Bcl­2 was mainly increased and reached the highest level at six weeks in the continued hypoxia group. Of note, Bcl­2 rapidly increased to the peak level at four weeks, followed by a decrease to the lowest level at the eighth week in the intermittent hypoxia group. Bax was generally increased at the late stages under continued hypoxia, but increased at all time-points under the intermittent hypoxia conditions. The two types of hypoxia induced an increase in the MDA content, but a decrease in SOD activity. Marked changes in these two parameters coupled with markedly reduced surviving cells in the hippocampus in a time­dependent manner were observed in the intermittent hypoxia group in comparison with the continued hypoxia group. OSAS­induced intermittent hypoxia markedly activated the MAPK signaling pathways, which were triggered by oxidative stress, leading to abnormal expression of downstream Bcl­2 and Bax, and a severe loss of neural cells in the hippocampus.

Double-Blind Randomized Trial of Pirfenidone in Chinese Idiopathic Pulmonary Fibrosis Patients.

Idiopathic pulmonary fibrosis (IPF) lacks effective treatment. Pirfenidone has been used to treat IPF patients. N-acetylcysteine (NAC) exerts antioxidant and antifibrotic effects on IPF cases.This study is a double-blind, modified placebo-controlled, randomized phase II trial of pirfenidone in Chinese IPF patients. We randomly assigned the enrolled Chinese IPF patients with mild to moderate impairment of pulmonary function to receive either oral pirfenidone (1800 mg per day) and NAC (1800 mg per day) or placebo and NAC (1800 mg per day) for 48 weeks. The primary endpoints were the changes in forced vital capacity (FVC) and walking distance and the lowest SPO2 during the 6-minute walk test (6MWT) at week 48. The key secondary endpoint was the progression-free survival time. This study is registered in ClinicalTrials.gov as number NCT01504334.Eighty-six patients were screened, and 76 cases were enrolled (pirfenidone + NAC: 38; placebo + NAC: 38). The effect of pirfenidone treatment was significant at the 24th week, but this effect did not persist to the 48th week. At the 24th week, the mean decline in both FVC and ΔSPO2 (%) during the 6MWT in the pirfenidone group was lower than that in the control group (-0.08 ± 0.20 L vs -0.22 ± 0.29 L, P = 0.02 and -3.44% ± 4.51% vs -6.29% ± 6.06%, P = 0.03, respectively). However, there was no significant difference between these 2 groups at the 48th week (-0.15 ± 0.25 L vs -0.25 ± 0.28 L, P = 0.11 and -4.25% ± 7.27% vs -5.31% ± 5.49%, P = 0.51, respectively). The pirfenidone treatment group did not achieve the maximal distance difference on the 6MWT at either the 24th or the 48th week. But pirfenidone treatment prolonged the progression-free survival time in the IPF patients (hazard ratio = 1.88, 95% confidence interval: 1.092-3.242, P = 0.02). In the pirfenidone group, the adverse event (AE) rate (52.63%) was higher than that in the control group (26.3%, P = 0.03). Rash was more common in the pirfenidone group (39.5% vs 13.2%, P = 0.02).Compared with placebo combined with high-dose NAC, pirfenidone combined with high-dose NAC prolonged the progression-free survival of Chinese IPF patients with mild to moderate impairment of pulmonary function. (ClinicalTrials.gov number, NCT01504334).

Cheyne-Stokes respiration during sleep: mechanisms and potential interventions.

Cheyne-Stokes respiration is characterized by a typical waxing and waning pattern in breathing amplitude, interspersed with central apnoeas or hypopnoeas. This article reviews current knowledge regarding Cheyne-Stokes respiration with a particular emphasis on the mechanisms and latest methods of intervention.

Systematic and endothelial inflammation and endothelial progenitor cell levels in emphysematous rats exposed to intermittent hypoxia.

BACKGROUND: This study aimed to develop an overlap syndrome rat model with intermittent hypoxia (IH) exposure as seen in obstructive sleep apnea, on a base of preexisting emphysema caused by 16 wk of smoke exposure to determine whether IH and emphysema existing simultaneously play overlapped roles on systematic/endothelial inflammation and endothelial damage. METHODS: Sixty male Wistar rats were divided into 4 groups of 15 each, labeled according to exposure conditions as control, IH, emphysema, and overlap groups. In these animals, electroencephalogram monitoring and preliminary experiments to obtain arterial blood gas values were performed. Serum concentrations of tumor necrosis factor (TNF)-α and interleukin (IL)-6, TNF-α and IL-6 concentrations in the culture medium, Ras homology A mRNA expression levels of endothelial cells from right common carotid artery, and ratio of carotid intima-media thickness of whole thickness of vascular wall expressed in percent (C-IMT) (%) values were evaluated. Subsequently, circulating endothelial progenitor cells (EPCs) within rat peripheral blood and bone marrow were measured with flow cytometry. RESULTS: The serum and endothelial concentrations of TNF-α and IL-6 and the levels of endothelial Ras homology A mRNA have statistically significant results described as overlap>emphysema>IH>control. The levels of EPCs in rat peripheral blood and bone marrow have statistically significant results described as overlap>IH>emphysema>control. C-IMT (%) values from right common carotid artery are the highest in the overlap group and the lowest in the control group. There is no statistical difference when comparing the IH and the emphysema groups. CONCLUSIONS: Regardless of whether IH and emphysema exposure are mechanistically synergistic, this overlap elicits a more severe systematic/endothelial inflammation and endothelial damage; meanwhile, a robust mobilization of EPCs is demonstrated, which is not to mean a robust adherent and repairing capability.

Noninvasive ventilation with complex critical care ventilator in the treatment of acute exacerbation of chronic obstructive pulmonary disease.

OBJECTIVE: To compare the clinical effect of noninvasive positive-pressure ventilation (NIPPV), delivered via critical care ventilator or miniventilator, in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). METHODS: Prospective comparison study. Patients with AECOPD underwent NIPPV via: miniventilator with BiLevel positive airway pressure (BiPAP; Group A); critical care ventilator with pressure support ventilation and positive end expiratory pressure (PSV + PEEP; Group B); critical care ventilator with pressure-synchronized intermittent mandatory ventilation (P-SIMV)+PSV + PEEP (Group C). Physiological parameters were recorded before, during and after ventilation. RESULTS: Patients in Group C (n = 21) showed significantly better improvements in physiological parameters (compared with pretreatment values) than those in Group B (n = 20) or Group A (n = 22). CONCLUSION: NIPPV delivered via critical care ventilator has a better treatment effect than miniventilator NIPPV in patients with AECOPD. The use of P-SIMV + PSV + PEEP mode provides a significantly better treatment effect than PSV + PEEP alone.

A study of noninvasive positive-pressure mechanical ventilation in the treatment of acute lung injury with a complex critical care ventilator.

OBJECTIVE: To test the hypothesis that there would be better clinical outcomes following the treatment of patients with acute lung injury (ALI) using noninvasive positive-pressure mechanical ventilation (NIPPV) delivered via a complex critical care ventilator compared with a conventional mini-ventilator. METHODS: Patients with ALI who required NIPPV were prospectively enrolled and randomly divided between three intervention groups: group A was ventilated using a mini-ventilator; groups B and C were ventilated using a complex critical care ventilator using different settings. Clinical parameters were recorded before and after 8 h of mechanical ventilation. RESULTS: A total of 51 patients with ALI were enrolled in the study. Clinical parameters in groups B and C underwent greater improvements than those in group A. Group C demonstrated the lowest treatment failure rate (23.5%). Failure rates were highest in group A (58.8%). CONCLUSION: The findings of this present study suggest that there were more satisfactory clinical outcomes following the treatment of patients with ALI when NIPPV was delivered using a complex critical care ventilator compared with a conventional mini-ventilator.

Effects of varying degrees of intermittent hypoxia on proinflammatory cytokines and adipokines in rats and 3T3-L1 adipocytes.

OBJECTIVES: Intermittent hypoxia (IH), resulted from recurring episodes of upper airway obstruction, is the hallmark feature and the most important pathophysiologic pathway of obstructive sleep apnea (OSA). IH is believed to be the most important factor causing systemic inflammation. Studies suggest that insulin resistance (IR) is positively associated with OSA. In this study, we hypothesized that the recurrence of IH might result in cellular and systemic inflammation, which was manifested through the levels of proinflammatory cytokines and adipokines after IH exposure, and because IR is linked with inflammation tightly, this inflammatory situation may implicate an IR status. METHODS: We developed an IH 3T3-L1 adipocyte and rat model respectively, recapitulating the nocturnal oxygen profile in OSA. In IH cells, nuclear factor kappa B (NF-κB) DNA binding reactions, hypoxia-inducible factor-1α (HIF-1α), glucose transporter-1 (Glut-1), necrosis factor alpha (TNF-α), interleukin (IL) -6, leptin, adiponectin mRNA transcriptional activities and protein expressions were measured. In IH rats, blood glucose, insulin, TNF-α, IL-6, leptin and adiponectin levels were analyzed. RESULTS: The insulin and blood glucose levels in rats and NF-κB DNA binding activities in cells had significantly statistical results described as severe IH>moderate IH>mild IH>sustained hypoxia>control. The mRNA and protein levels of HIF-1α and Glut-1 in severe IH group were the highest. In cellular and animal models, both the mRNA and protein levels of TNF-α, IL-6 and leptin were the highest in severe IH group, when the lowest in severe IH group for adiponectin. CONCLUSIONS: Oxidative stress and the release of pro-inflammatory cytokines/adipokines, which are the systemic inflammatory markers, are associated with IH closely and are proportional to the severity of IH. Because IR and glucose intolerance are linked with inflammation tightly, our results may implicate the clinical relationships between OSA and IR.

Optimized ultrasound-assisted extraction of phenolic compounds from Polygonum cuspidatum.

In this study the phenolic compounds piceid, resveratrol and emodin were extracted from P. cuspidatum roots using ultrasound-assisted extraction. Multiple response surface methodology was used to optimize the extraction conditions of these phenolic compounds. A three-factor and three-level Box-Behnken experimental design was employed to evaluate the effects of the operation parameters, including extraction temperature (30-70 °C), ethanol concentration (40%-80%), and ultrasonic power (90-150 W), on the extraction yields of piceid, resveratrol, and emodin. The statistical models built from multiple response surface methodology were developed for the estimation of the extraction yields of multi-phenolic components. Based on the model, the extraction yields of piceid, resveratrol, and emodin can be improved by controlling the extraction parameters. Under the optimum conditions, the extraction yields of piceid, resveratrol and emodin were 10.77 mg/g, 3.82 mg/g and 11.72 mg/g, respectively.

Predictors of long-term adherence to continuous positive airway pressure therapy in patients with obstructive sleep apnea and cardiovascular disease in the SAVE study.

STUDY OBJECTIVES: To determine the clinical variables that best predict long- term continuous positive airway pressure (CPAP) adherence among patients with cardiovascular disease who have obstructive sleep apnea (OSA). DESIGN: 12-mo prospective within-trial observational study. SETTING: Centers in China, Australia, and New Zealand participating in the Sleep Apnea cardioVascular Endpoints (SAVE) study. PATIENTS: There were 275 patients age 45-70 y with cardiovascular disease (i.e., previously documented transient ischemic attack, stroke, or coronary artery disease) and OSA (4% oxygen desaturation index (ODI) > 12) who were randomized into the CPAP arm of the SAVE trial prior to July 1, 2010. METHODS: Age, sex, country of residence, type of cardiovascular disease, baseline ODI, severity of sleepiness, and Hospital Anxiety and Depression Scale (HADS) scores plus CPAP side effects and adherence at 1 mo were entered in univariate analyses in an attempt to identify factors predictive of CPAP adherence at 12 mo. Variables with P < 0.2 were then included in a multivariate analysis using a linear mixed model with sites as a random effect and 12-mo CPAP use as the dependent outcome variable. MEASUREMENTS AND RESULTS: CPAP adherence at 1, 6, and 12 mo was (mean ± standard deviation) 4.4 ± 2.0, 3.8 ± 2.3, and 3.3 ± 2.4 h/night, respectively. CPAP use at 1 mo (effect estimate ± standard error, 0.65 ± 0.07 per h increase, P < 0.001) and side effects at 1 mo (-0.24 ± 0.092 per additional side effect, P = 0.009) were the only independent predictors of 12- mo CPAP adherence. CONCLUSION: Continuous positive airway pressure use in patients with coexisting cardiovascular disease and moderate to severe obstructive sleep apnea decreases significantly over 12 months. This decline can be predicted by early patient experiences with continuous positive airway pressure (i.e., adherence and side effects at 1 month), raising the possibility that intensive early interventions could improve long-term continuous positive airway pressure compliance in this patient population. CLINICAL TRIALS REGISTER: Clinical Trials, http://www.clinicaltrials.gov, NCT00738179.

[The prevalence and risk factors of bronchiectasis in residents aged 40 years old and above in seven cities in China].

OBJECTIVE: To investigate the prevalence and risk factors of bronchiectasis in urban city of China. METHODS: A cross-sectional survey was conducted in 17 urban areas in Beijing, Shanghai, Tianjin, Chongqing cities, and Guangdong, Liaoning, Shanxi provinces. In this study, urban population-based cluster samples were randomly selected from each city/province. In the selected city communities, all residents at least 40 years old were recruited, interviewed with questionnaires and tested with spirometry. Each participant was asked whether he/she was ever diagnosed as bronchiectasis by physician, whether had symptoms of respiratory diseases and possible risk factors, etc. RESULT: Data of 10 811 participants was enrolled for analysis, with a response rate of 75.4% (10 811/14 337). The overall prevalence of physician-diagnosed bronchiectasis was 1.2% (135/10 811), with 1.5% (65/4382) in male and 1.1% (70/6429) in female, without statistical difference in gender (χ² = 3.289, P = 0.070). Prevalence of bronchiectasis increased with age (χ² = 31.029, P < 0.001). There were no statistical significances in crude prevalences of bronchiectasis among cities (χ² = 10.572, P = 0.103), while there was a significant difference among cities after adjustment with confounders (Wald value = 22.116, P = 0.001), by using logistic regression analysis. Logistic regression analysis showed, bronchiectasis was significantly associated with elder ( ≥ 70 years vs 40-49 years; OR = 4.11, 95% CI 2.29-7.36), the family history of respiratory diseases (having two subjects with respiratory diseases in family vs no suffered relatives; OR = 2.04, 95% CI 1.06-3.94), respiratory infection during childhood (suffering two kinds of respiratory diseases vs never; OR = 4.89, 95% CI 2.03-11.81), exposure to coal (OR = 2.30, 95% CI 1.17-4.52), chronic pharyngitis (OR = 3.96, 95% CI 1.38-11.40) and pulmonary tuberculosis (OR = 3.07, 95% CI 1.89-4.98), heart diseases (OR = 1.64, 95% CI 1.11-2.42) and lung cancer(OR = 18.61, 95% CI 7.67-45.18). CONCLUSION: The prevalence of bronchiectasis in population aged 40 years old and above in urban area in China is high and associated with multiple factors such as age, family history of respiratory diseases, respiratory infection during childhood, exposure to coal, chronic pharyngitis, pulmonary tuberculosis, heart diseases, lung cancer and so on.

Complex sleep apnea syndrome.

Complex sleep apnea syndrome (CompSAS) is a distinct form of sleep-disordered breathing characterized as central sleep apnea (CSA), and presents in obstructive sleep apnea (OSA) patients during initial treatment with a continuous positive airway pressure (CPAP) device. The mechanisms of why CompSAS occurs are not well understood, though we have a high loop gain theory that may help to explain it. It is still controversial regarding the prevalence and the clinical significance of CompSAS. Patients with CompSAS have clinical features similar to OSA, but they do exhibit breathing patterns like CSA. In most CompSAS cases, CSA events during initial CPAP titration are transient and they may disappear after continued CPAP use for 4~8 weeks or even longer. However, the poor initial experience of CompSAS patients with CPAP may not be avoided, and nonadherence with continued therapy may often result. Treatment options like adaptive servo-ventilation are available now that may rapidly resolve the disorder and relieve the symptoms of this disease with the potential of increasing early adherence to therapy. But these approaches are associated with more expensive and complicated devices. In this review, the definition, potential plausible mechanisms, clinical characteristics, and treatment approaches of CompSAS will be summarized.

Value of autofluorescence imaging videobronchoscopy in detecting lung cancers and precancerous lesions: a review.

Bronchoscopy technology is a desirable method for detecting lung cancers arising in the central airways. Most early cancers and precancerous lesions are not visible on conventional white-light bronchoscopy (WLB). Autofluorescence bronchoscopy (AFB) is a newly developed technology that exploits the difference in autofluorescence intensity between normal and tumorous tissues to detect bronchial cancers and precancerous lesions. Several types of AFB systems have been used in clinical practice, and autofluorescence imaging videobronchoscopy (AFI) is one of these AFBs. In most of the studies on AFB other than AFI, AFB has provided a much higher sensitivity but a lower specificity than WLB. Regarding AFI, recent studies have reported controversial results on the sensitivity and specificity for detecting cancers and precancerous lesions, compared with WLB. In this paper we describe the working mechanisms and characteristics of AFBs, mainly AFI, and the diagnostic performance of AFI, compared with WLB, other AFBs, and narrow-band imaging, for detecting lung cancers and precancerous lesions.