Clinical,physiological And Imaging Features Of Toxic Gas Induced Lung Injury

Background: Diverse clinical factors contribute to acute lung injury(ALI),which is associated with high mortality in the absence of timely and effective care.In normal human lung,inhalation of toxic gas or fumes during industrial accidents can result in pulmonary injury.While inhalation of chlorine may cause respiratory tract injury,Nitrogen oxide has been reported to induce damage to surrounding lung tissue,distal airway and alveolar.Although there are many researches on chlorine and nitric acid poisoning,none has investigate the clinical feature,physiologic and radiographic changes in such a population.Objective: to investigate the clinical feature,physiologic and radiographic changes In patients with gas poisoning,and to explore orrelation between small airway dysfunction and length of stay in hospital.Methods: sixty-two patients with either chlorine poisoning or nitrate poisoning admitted to our hospital from Jan 2010 to Dec 2016 were assessed.The measurements obtained included clinical symptoms and signs,laboratory results,lung function tests and chest CT imaging features.Data of normal distribution were expressed with mean± standard deviation(x ± s).Statistical inference was performed by t test。The enumeration data were statistically analyzed byχ2test or Fisher exact probability method,and Pearson correlation analysis used to analyze correlation,with P <0.05 as designation of statistically significant difference.Results: Our study included 62 patients [40 males(64.52%);22 females(35.48%)],79.03% of whom were high school graduates,with ages ranging from 21 to 50 years old.The patients with dizziness and / or headache and fatigue symptoms were higher than those with nitric oxide poisoning,and the two groups had statistical significance(P < 0.05)。There was no significant difference in vital signs between two kinds of gas poisoning patients,and there was no statistical significance(P > 0.05).Patients with pulmonary rales were higher than chlorine poisoning patients(P < 0.05).There was no significant difference between the two groups in white blood cell count,neutrophil percentage,hemoglobin,platelet,CRP,PCT,creatinine and urea nitrogen.Nitrate poisoning patients with alanine aminotransferase and aspartate aminotransferase were more than the number of chlorine poisoning patients.(P < 0.05).There was no significant difference in arterial blood gas between the two groups(P >0.05).CT mosaic perfusion,centrilobular nodules and reticular opacity were significantly more frequent in patients with chlorine poisoning than in those with nitrate toxicity(P <0.05).Forced expiratory flow at 75% of forced vital capacity(FEF75%)expressed as a percent of predicted(FEF 75% predicted)was negatively correlated with the treatment duration in both chlorine poisoning r =-0.6204(P =0.0103)and nitrate toxicity r =-0.8506(P = 0.0005).Conclusion:(1)The chest CT images are different after poisoning by the two gases.(2)Chlorine gas and nitric acid fumes,both of which are pulmonary irritant with intermediate water solubility,can cause acute lung damage including small airway dysfunction.(3)Treatment strategies aiming at normalizing measures of pulmonary function tests(i.e.,FEF75%)could potentially improve outcomes in patients with either Chlorine or nitric acid poisoning.