Forty-one burn patients were divided into inhalation injury and non-inhalation injury groups.It was found that in the inhalation injury group,TXB2 level and TXB2/G-keto-PGF1? ratio in plasma and lung tissue were significantly elevated,circulatory platelet aggregate ratio markedly decreased,and blood viscosity greatly increased.Histopathologically,congestion,edema,hemorrhage and thrombosis were seen in lung tissue.The changes of TXB2 level and TXB2/6-keto-PGF1?ratio were parallel to the clinical course of the development of respiratory failure in the patients with body surface burns complicated with inhalation injury.It is believed that the imbalance of TXA2/PGI2 is one of the factors of respiratory failure in severe body surface burns complicated with inhalation injury.