Chronic obstructive pulmonary disease (COPD) is one of the common chronic airway disorders, which accounts for the third to fourth cause of death worldwide. Recently, the focuses of researches are on the multi-factorial risks for development of COPD, mechanisms related to COPD development, early detection and early intervention of COPD, individualized use of long-term maintenance medications as well as phenotypes of acute exacerbation of COPD and their corresponding management. There are huge amount of COPD patients with variety of risk factors or different phenotypes in China, which makes it possible to establish a network for cohort study or real life registration study of COPD. The results will provide new information on the characteristics of COPD in China. Individualized treatment could be recommended according to the phenotypes or endotypes information. All these new findings or progresses could provide impetus for improvement of the ability of research and clinical management of COPD to the worldwide top level.
Objective To investigate the effects of different inspiratory rise time during noninvasive positive pressure ventilation ( NPPV) on work of breathing in patients with acute exacerbation of chronic obstructive pulmonary disease ( COPD) . Methods Eleven patients with acute exacerbation of COPD received different inspiratory rise time ( 0. 1sec, 0. 3sec, 0. 5sec) during NPPV. The changes of inspiratory muscle effort and breathing pattern of the patients were observed. Results The average respiratory rate,minute ventilation, and tidal volume were higher during NPPV compared with spontaneous breathing. But the changes of average minute ventilation and tidal volume were not significant ( P gt; 0. 05) . The pressure time product ( PTP) , transdiaphragmatic pressure ( Pdi) , and work of breathing of inspiratory muscle reduced significantly during different inspiratory rise time as compared with spontaneous breathing ( P lt;0. 01) . PTP,Pdi, and work of breathing reduced 59. 2% , 62. 7% , and 49% respectively when inspiratory rise time was 0. 1sec. They reduced more significantly during inspiratory rise time of 0. 1sec. Conclusions The present study confirms NPPV can unload inspiratory muscles in patients with acute exacerbation of COPD. It is more effective to reduce inspiratory load when inspiratory rise time is set at 0. 1sec while the patients feel most comfortable.
Objective To investigate the effects of positive end-expiratory pressure (PEEP) level on end-expiratory lung volume (EELV) during assisted ventilation in chronic obstructive pulmonary disease （COPD） patients，to provide physiological evidence to guide optimal setting of PEEP level in clinical practice.Methods Eight intubated patients with acute exacerbation of COPD were recruited for the study when the patients were in relatively stable condition after treatment.The static intrinsic PEEP (PEEPistat) and dynamic intrinsic PEEP (PEEPidyn) were measured by using airway occlusion method and esophageal balloon-tipped catheter technique,respectively.Changes in EELV (ΔEELV) were measured with inspiratory capacity (IC) method.Relations between PEEP level and ΔEELV were analyzed by curve estimation method.Results ΔEELV as a function of level of PEEP was shown as a sigmoid model.The low inflection points of the curves when PEEP levels were expressed as PEEP/PEEPistat ratio，PEEP/PEEPidyn ratio or actual PEEP setting (PEEP-a) were 0.74，0.76 or 3.6 cm H2O,respectively.The corresponding ΔEELV expressed as ΔEELV/IC（%） were 9.6%，9.1% and 7.4%,respectively.Conclusions In AECOPD patients demanding mechanical ventilation，the changes of lung volume (ΔEELV) in response to progressive increase of PEEP level were shown to be a sigmoid model.Setting PEEP level at 0.74 of PEEPistat，or 0.76 of PEEPidyn can avoid the steep increase of lung volume.
Objective To evaluate the effects of inhaled bronchodilators on respiratory mechanics in moderate and severe chronic obstructive pulmonary disease（COPD） patients during eupnea.Methods Twenty moderate to severe COPD subjects were divided into three groups.Lung function，Borg score，breathing pattern and respiratory mechanics indexes were measured at baseline and 30 min after inhaled placebo，salbutamol 400 μg (or ipratropium 80 μg)，and ipratropium 80 μg (or salbutamol 400 μg) in sequence at interval as specified in different groups.Results In all groups，inhaled bronchodilators improved lung function (FEV1，FVC，IC) (Plt;0.05)，decreased Pdi，Peso，PTPdi，PTPeso and Raw (Plt;0.05，respectively)，in comparison with placebo.The reduction of PTPeso was positively correlated with the reduction of Peso (r=0.713，Plt;0.01）and Raw (r=0.602，Plt;0.01).Borg score decreased after inhaled bronchodilators (Plt;0.05).The reduction of dyspnea was positively correlated with the reduction of inspiratory work of breathing (ΔPTPeso%) (r=0.339，Plt;0.05) and Raw (ΔRaw) (r=0.358，Plt;0.05)，while was not associated with the changes of FEV1，FVC and IC.Conclusions In COPD patients，inhaled bronchodilators can reduce inspiratory work of breathing and airway resistance，the reduction of inspiratory work of breathing contributed to the reduction of airway resistance.Alleviation of dyspnea by inhaled bronchodilators is suggested to be ascribed to reduction of airway resistance and inspiratory work of breathing.