Objective To investigate the effects of transient plateau factor on acute lung injury induced by phosgene poisoning in rabbits.Methods Forty New Zealand white rabbits of both sexes,aged 2.0-2.5 kg,were randomly divided into 4 groups (n =10 each) using a random number table:control group (group C),plateau factor group (group H),phosgene poisoning group (group P),and phosgene poisoning and plateau factor group (group HP).In group H,the rabbits were exposed to a simulated altitude of 33000 m for 2 h.In group P,the rabbits were exposed to phosgene for 3 min only.In group HP,the rabbits were exposed to phosgene for 33 min and then to a simulated altitude of 3000 m for 2 h.Respiratory rate (RR) was recorded and blood samples were taken before exposure to phosgene (T1),after exposure to phosgene (T2),and at 0,1 and 6 h after onset of exposure to a simulated altitude of 33000 m (T3-5) for determination of PaO2 and oxygenation index (OI) was calculated.The chests were opened at T5 and lungs removed for determination of lung water content (LC) and for microscopic examination.Lung coefficient (LC) was calculated.Results Compared with C group,RR was significantly increased at T3 in group H (P ＜ 0.05),and RR was increased and OI was decreased at T2-5 in P and HP groups (P ＜ 0.05 or 0.01).Compared with P group,RR was increased and OI was decreased at T3-5 in HP group (P ＜ 0.05 or 0.01).LW and LC were significantly higher in P and HP groups than in group C,and in HP group than in group P (P ＜ 0.05 or 0.01).The microscopic examination showed that pathological changes were observed in P and HP groups,however,the changes were severer in HP group.Conclusion Transient plateau factor can obviously aggravate the degree of acute lung injury induced by phosgene poisoning in rabbits.