Study on pulmonary injury due to acute H2S inhalation and its therapeutic scheme

Pulmonary injury after acute H2S inhalation was studied with bronchoalveolar lavage（BAL）,ultracentrifuge,and optical and electron microscopy.The changes of the activities oflactate dehydrogenase,alkaline and acid phosphatase,and angiotension converting enzymes inBAL fluid were used as the indicator of cellular damages,those of leucocytic count and the indi-cator of inflammatory response,and those of the concentration of protein and Evans blue as theindicator of vascular permeability.In addition the effects of H2S on lipid peroxidation,naturalantioxidative system and energy substances and the changes of phospholipid concentration inBAL fluid were also observed.The results were as follows:1.Inhalation of H2S exerted a severe cytotoxic effect on the lung tissues resulting in dam-ages on various types of cells and a severe edematogenic effect on lung parenchyma.2.The development of pulmonary edema in H2S intoxication resulted from a combination ofdifferent pathogenic factors.3.The biochemical changes and their recovery occurred earlier than the pathologicalchanges and their recovery.The efficacy of 6 categories of drugs including 25 medicaments against H2S intoxication wasevaluated in mice,and 10 drugs were found to be prophylactically effective.The effects of vari-ous methemoglobin-forming agents and some other drugs were also studied in their treatment ofH2S intoxication in rabbits and dogs.It was concluded that methemoglobin-forming agentscould be used as specific antidotes but could not provent or alleviate the lung damages due toH2S inhalation unless they were administered in association with dexamethasone,vitamin E oranisodamine.A scheme of the medical treatment for H2S intoxication was presented.