[Effect of electroacupuncture on small airway function in patients with stable chronic obstructive pulmonary disease]

To observe the regulatory effect of electroacupuncture (EA) on small airway function and exercise tolerance in patients with stable chronic obstructive pulmonary disease (COPD).

A total of 62 patients with stable COPD were randomized into an observation group (31 cases, 1 case dropped off) and a control group (31 cases, 5 cases dropped off). On the base of routine medication and aerobic exercise, the patients of the two groups all received EA at Danzhong (CV 17), Rugen (ST 18), Guanyuan (CV 4), Zhongwan (CV 12), Tianshu (ST 25) and Yingchuang (ST 16). In the observation group, filiform needles were used and inserted perpendicularly, 3 mm in depth. In the control group, the placebo needling method was performed, in which the needle was not inserted through skin at each point. In both groups, electric stimulation with low-frequency electronic pulse instrument was exerted, with continuous wave, 2 Hz in frequency, lasting 30 min each time in the two groups. The treatment was given once every other day, 3 times a week, for 14 treatments totally. Before and after treatment, the following indexes were compared in patients between the two groups, i.e. the lung function indexes (forced expiratory volume in first second [FEV1], forced vital capacity [FVC], the ratio of FEV1 to FVC [FEV1/FVC], maximal voluntary ventilation [MVV], the percentage of maximal expiratory flow [MEF] at 25% of FVC exhaled [MEF25], MEF50 and MEF75 in predicted value), cardiopulmonary exercise test indexs (metabolic equivalent [METS], oxygen uptake per kg body weight [VO₂/kg], minute ventilation [V_E], the percentage of oxygen pulse [VO₂/HR] in predictd value, maximal minute ventilation [V_Emax], ventilatory equivalent for oxygen [V_E/VO₂], ventilatory equivalent for carbon dioxide [V_E/VCO₂]), 6-minute walk distance (6MWD), the total score of COPD assessment test (CAT), the modified British Medical Research Council (mMRC) score and COPD comprehensive grade.

After treatment, FVC%, MVV%, MEF75%, MEF50%, VO₂/kg%, METs%, V_Emax, VO₂/HR%, 6MW and the total CAT score were all improved as compared with those before treatment in the observation group (P<0.05, P<0.01). After treatment, MEF75% and the total CAT score were reduced as compared with those before treatment in the control group (P<0.05). After treatment, MVV%, MEF50%, VO₂/kg%, METs%, V_Emax and 6MWD in the observation group were all better than those in the control group (P<0.05, P<0.01).

Electroacupuncture can improve the respiratory function and exercise tolerance in COPD patients through removing small airway obstruction and increasing ventilation.