[Sequential syndrome differentiation by eliminating pathogen and strengthening vital Qi on the basis of acute exacerbation of chronic obstructive pulmonary disease risk window].

Chronic obstructive pulmonary disease (COPD) remains a severe public health problem. Acute exacerbation of COPD (AECOPD) is a major factor that influences the process of COPD. Strengthening the treatment of AECOPD is very essential. AECOPD risk window (AECOPD-RW) refers to the period from AECOPD remission to the time before the stable phase. The condition is very unstable. Symptoms are relieved but continually exist. The lung function has not restored to the levels of the stable phase. The inflammatory reactions continually exist. In this period patients are most liable to suffer from AECOPD, resulting in higher hospital admission rate and higher mortality. Dispelling pathogens should be taken as the main principle for AECOPD treatment. However, when it transforms from AECOPD to AECOPD-RW, strengthening the body resistance should be taken as the main principle. The proposal of AECOPD-RW has provided new thoughts and strategies for COPD. In this period deficiency syndrome dominates, most being lingering pathogens due to deficient vital qi. Qi deficiency and qi-yin deficiency are the most common syndromes, involving Fei, Pi, and Shen. Deficiency of both Fei and Shen dominates, complicated with phlegm and stasis. Therefore, the treatment principle of AECOPD-RW should focus on tonifying the deficiency and strengthening the body resistance, assisted with dissipating phlegm and activating blood circulation.