预防医学慢性支气管炎课件.ppt

* In COPD, irreversible damage causes the alveolar walls and supports to lose elasticity compared with the normal condition. The airways are partly collapsed and occluded, an effect made worse by reversible cholinergic constriction.1 As a result, deflation is slower, and so the alveolus only partly deflates over the course of an exhalation. Global Initiative for Chronic Obstructive Lung Disease. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease. NHLBI/WHO workshop report. 2001. /workshop/toc.html. Accessed: 14 November 2003. * In the normal state, inhalation is balanced by exhalation. There is no dynamic hyperinflation. * COPD patients suffer from reduced expiratory flow. As a result, the lungs may not fully empty before the next breath begins. This is particularly likely if the patient has to breathe faster as a result of physical activity.1 Because the lungs do not fully empty, they become progressively over inflated with each breath. This process is known as air trapping, which leads to hyperinflation.1 Air trapping reduces the ability of the patient to breathe in, which causes the sensation of breathlessness that typifies the disease. ODonnell DE, Webb K. The etiology of dyspnea during exercise in COPD. Pulmonary and Critical Care Update 14, Lesson 15./downloads/education/online/Vol14_13_18.pdf. Accessed 24 February 2004. * ? PMA Calverley * FEV1/FVC是轻度气流受限的一项敏感指标 FEV1占预计值的百分比中、重度气流受限的良好指标 深吸气量（IC） 死腔/潮气量比值　（VD/VT) 一氧化碳弥散量　(DLco ) 肺内分流率(Qs/Qt) * Studies using cycle ergometry have shown that IC at rest and during exercise is the best spirometric predictor of exertional dyspnea intensity and exercise endurance.1,2 ODonnell DE, Lam M, Webb KA. Spirometric correlates of improvement in exercise performance after anticholinergic therapy in chronic obstructive pulmonary disease. Am J Respir Crit Care Med 1999; 160:542-549. ODonnell DE, Lam M, Webb KA. Measurement of symptoms, lung hyperinflation, and end