Text this: Effect of external application of Rhubarb at Shenque (CV8) in the treatment of abdominal distension in patients with chronic obstructive pulmonary disease with syndrome of phlegm-heat obstructing lung (大黄外敷神阙穴治疗慢性阻塞性肺疾病痰热壅肺型患者腹胀的效果)