蒸气吸入损伤犬高频喷射通气时两种不同方向气流通气效果观察

VVentilation effects of added jet air flows in different directions during expiratory phase on dogs with steam inhalation injury.

制备犬蒸气吸入损伤模型,比较高频喷射通气时两种不同方向的喷射气流对呼吸、循环的不同影响,以了解气管内高频双向喷射通气机理。根据在呼气期增加气流的方向不同而分三种模式:模式一为对照组,呼气期不增加任何气流;模式二,为呼气期增加反向气流;模式三,呼气期增加正向气流。实验结果表明,模式二通气效果优于模式一,表现为 CO_2排出明显增加(P<0.01),PaCO_2明显减少(P<0.01),其机理可能是由于死腔减少。模式三与模式一比较解剖死腔和生理死腔虽然也有所减少,但通气效果反而恶化,其原因可能与呼气末正压及功能残气增加有关。我们初步认为,对于已发生Ⅱ型呼衰的吸入性损伤,宜用高频(正反)双向喷射通气,不宜采用高频喷射通气+呼气末正压的通气方式。

Nine dogs injured by inhaling steam were subjected to high frequency jet ventilation.Jet airflows of different directions were added during the expiratory phase ,and their effects on respiration, circulation and improvment in ventilation efficiency of dogs with inhalation injury were compared,and the assessment of the mechanism of high frequency two-way jet ventilation in the trachea was made. According to the direction of added airflow during expiratory phase,the animal models were classified into three groups:Model A,the control group,without any added airflow;Model B,airflow opposite to the direction of ventilation was added;Model C,airflow of the same direction was added.The results showed:①Model B,with its CO_2 elimination(V_(CO_2))increased significantly(P<0.01)and PaCO_2 de- creased significantly(P<0.01),was preferable to Model A.This might be due to the reduction of dead space.②)Model C,although there was slightly reduced anatomical and physiological dead space as com- pared with model A,showed worse ventilation effects.The mechanism was probably related to increase in PEEP(from 0.20±0.10 to 0.59±0.08kPa) and FRC(from 433±59 to 504±7.0ml).It is suggest- ed that high frequency two-way jet ventilation is preferable for the treatment of inhalation injury with type Ⅱ respiratory failure rather than high frequency ventilation with PEEP.