[Connotation of Xiao Chaihu Decoction combined with Maxing Shigan Decoction based on severe cases and modern pathophysiological mechanism and application for severe pulmonary infection and acute exacerbation of chronic obstructive pulmonary disease in critical care medicine].

Xiao Chaihu Decoction combined with Maxing Shigan Decoction is a classic herbal formula. All of them are derived from Treatise on Cold Damage(Shang Han Lun) by ZHANG Zhong-jing. This combination has the effects of harmonizing lesser yang, relieving exterior syndrome, clearing lung heat, and relieving panting. It is mainly used for treating the disease involving the triple-Yang combination of diseases and accumulation of pathogenic heat in the lung. Xiao Chaihu Decoction combined with Maxing Shigan Decoction is a classic combination for the treatment of exogenous diseases involving the triple-Yang combination. They are commonly used in exogenous diseases, especially in the north of China. This combination is also the main treatment strategy for coronavirus disease 2019(COVID-19) accompanied by fever and cough. Maxing Shigan Decoction is a classical herbal formula for treating the syndrome of phlegm-heat obstructing the lung. "Dyspnea after sweating" suggests the accumulation of pathogenic heat in the lung. Patients with mild symptoms may develop cough and asthma along with forehead sweating, and those in critical severe may develop whole-body sweating, especially the front chest. Modern medicine believes that the above situation is related to lung infection. "Mild fever" refers to syndromes rather than pathogenesis. It does not mean that the heat syndrome is not heavy, instead, it suggests that severe heat and inflammation have occurred. The indications of Xiao Chaihu Decoction combined with Maxing Shigan Decoction are as follows.(1) In terms of diseases, it is suitable for the treatment of viral pneumonia, bronchopneumonia, lobar pneumonia, mycoplasma pneumonia, COVID-19 infection, measles with pneumonia, severe acute respiratory syndrome(SARS), avian influenza, H1N1 influenza, chronic obstructive pulmonary disease with acute exacerbation, pertussis, and other influenza and pneumonia.(2) In terms of syndromes, it can be used for the syndromes of bitter mouth, dry pharynx, vertigo, loss of appetite, vexation, vomiting, and fullness and discomfort in the chest and hypochondrium. It can also be used to treat alternate attacks of chill and fever and different degrees of fever, as well as chest tightness, cough, asthma, expectoration, dry mouth, wanting cold drinks, feeling agitated, sweating, yellow urine, dry stool, red tongue, yellow or white fur, and floating, smooth, and powerful pulse, especially the right wrist pulse.