Objective To explore the difference in pulmonary function between overlap syndrome and chronic obstructive pulmonary disease (COPD) in patients. Methods One-hundred-ninty-four patients came from respiratory department in Tianjin Medical University General Hospital, from October 2012 to August 2014, were included in this study. After inquisition of medical history, evaluation of lung function and polysomnography (PSG), patients were divided into overlap syndrome (OS, n=78) group, COPD group (n=76) and healthy control group (n=40). The indexes of lung function and the pulse oscillation index of pulmonary function were compared between three groups. Results Values of the peak expiratory flow rate (PEF) and the remaining 75%FVC when expiratory flow rate (MEF75) were significantly decreased in OS group than those of COPD group (P<0.05). Patients with sleep apnea hypopnea index (AHI)≥30 times/h showed significantly decreased MEF25 and the maximum mid expiratory flow (MMEF) in OS group than those of COPD group (P<0.05). Values of the total impedance (Zrs), the resonant frequency (Fres), viscosity resistance when oscillation frequency was 5 Hz (R5), R20 were significantly increased in OS group than those of COPD group (P<0.05). Patients with AHI≥30 times/h were increased significantly than COPD group in R5-R20 and X5 besides Zrs, Fres, R5, R20. Conclusion There is more serious airway obstruction in patients with OS than that in patients with COPD. Severe sleep disordered breathing can aggravate small airway obstruction in patients with COPD.

Objective To develope a novel rabbit carotid body and carotid common artery model in vivo for the simulation of various intermittent hypoxia (IH) intensities, IH durations, IH reoxygenation (ROX) durations and continuous hypoxia (CH) modes.Methods Forty-five adult New Zealand rabbits (2.5～3.0 kg) were anesthetized while spontaneous breathing kept intact.The tissue surrounding the fight earetid common artery and carotid sinus nerve (CSN) were cleared and "single" chemoreceptor bundle of the CSN was revealed.Then suction electrodes were placed and CSN afferent activity was monitored and recorded carefully.The fight common carotid artery was exposed, cannulated to distal part and its proximal part was ligated.Preparations were challenged by changing the PO2 of the gas mixture equilibrating the perfusate.Alternatively perfusion (2 mL/min) of equilibrated porfusate bubbled with normoxia or hypoxia gas mixtures formed IH/ROX cycles in carotid common artery,simulating the pattern of hypoxic episodes seen in obstructive sleep apnea syndrome (OSAS), or with continuously perfusing hypoxia perfusate to form CH modes.All the perfusing procedures were regulated by a customized computer-controlled set and monitored using O2 gas analyzer.After the systematic exposures, carotid body, carotid common artery part distal to cannula,and carotid bifurcation were harvested as samples.Results The frequencies and average amplitudes of CSN chemoreceptor bundles afferent activities with normoxia peffusion were (0.17±0.03) impulse/s and (46.2±4.4) μV, and with hypoxia perfusion were (0.6±0.09) impulse/s and (87.4±6.6) μV, respectively.PO2 was (139±1.5) nun Hg in normoxia perfusate and (35.2±1.3) mm Hg in hypoxia perfusate.Conclusion This new carotid body and carotid common artery model is a valuable tool to study neurological and biochemical changes in various IH and CH modes.

The key treatment for overlap syndrome should focus on maximizing the therapeutic effect of each condition and concentrate of interventions that have showed benefit in both diseases. The goal of therapy includes the improvement in objective data including the reduction in sleep fragmentation, exacerbation rate, hospitalization frequency and mortality, and subjective data such as daytime functioning, quality of life and sleep quality. At present, the treatment of overlap syndrome is mainly rely on the positive airway pressure to improve ventilatory capacity and gas exchange function. Oxygen therapy as auxiliary treatment can alleviate hypoxemia. The key of drug therapy is to dilate the bronchus, clear secretions, reduce in?flammatory response to improve the ventilation function. Meanwhile, daily exercise and dietary habits of life activity are indis?pensable in the treatment of the disease as important supporting role to improve the motor function and the quality of life in patients.

Objective To discuss the influence of smoking on fractional exhaled nitric oxide (FeNO) expression in pa-tients with chronic airway inflammation. Methods According to the clinical history and characteristics of lung function, 206 patients were divided into asthma and chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) group (n=37), COPD group (n=124) and asthma group (n=45). Meanwhile, 40 people accepted healthy physical examination were used as the control group (n=40). Then persons were sub-divided into smokers or nonsmokers according to the situation of smoking. The FeNO value and pulmonary function index were compared between the four groups, and the FeNO value was compared between smokers and nonsmokers respectively. The smoking index and FeNO value of smokers were measured for correlation analysis. Results (1)The FeNO values were significantly higher in ACOS group and asthma group than those of COPD group and the control group (32.6±9.9 and 37.6±10.9 vs 18.7±9.8 and 14.4±4.3,F=68.082,P<0.05). However, there were no significant differences in FeNO value between ACOS group and asthma group, and between COPD group and the control group. (2) The FEV1/FVC was significantly lower in ACOS group, COPD group and asthma group than that of control group, while the FEV1/FVC was significantly lower in ACOS group and COPD group than that of asthma group(P<0.05). There was no significant difference in FEV1% between ACOS group, COPD group and asthma group(P>0.05). (3) The Fe-NO value was significantly lower in smokers of COPD group and ACOS group than that of non-smokers(P<0.05). However, there was no significant difference in FeNO value between smokers and nonsmokers in asthma group and the control group (P>0.05). (4)The smoking index and FeNO value were negatively correlated in COPD group, but there were no obvious cor-relation in smoking index and FeNO values between other groups. Conclusion Smoking can lead to the reduction of FeNO value in COPD and ACOS patients. The detection of FeNO is helpful for the differentiating COPD combined asthma.