潮气涨落幅度对家兔RDS肺的影响

The effects of tidal fluctuation on RDS lung in rabbits

The effects of different tidal fluctuations on RDS lung induced by saline lavage in rabbits were investigated. The animal subjects were divided into A, B and C groups according to the tidal fluctuations from low to high respectively. The gas exchange, pulmonary mechanics and histopathology were observed. The results showed that the Pao2 was larger than 53-3 kPa in all groups, but CO, retention existed in group A. Two hours after the lavage, the P~V loop of groups A and B reached approximately to normal and group C had an inflection on the inflation limb and an increased hysteresis. The wet/dry weight ratio of the lung in all the groups increased successively and there was a significant difference between groups A and C (P<0.05 ). The interstital edema, congestion and infiltration of flammation cells were similar in all the three groups examined by light microscope. Group C showed hyaline membrance formation and infusion in alveoli. It is concluded that large tidal fluctuation (group C) can superimposes additional damage on the pulmonary injury during mechanical ventilation and that low tidal fluctuation ( group A) can protect the lung from pulmonary edema and prevent formation of hyaline membrance.