Experimental Study Of The Effects Of Different Lung Protective Ventilation Strategies On Attenuating Ventilator-induced Lung Injury In Acute Lung Injury Models

[OBJECTIVE] To investigate the effects of different lungprotective ventilatory strategies on attenuating ventilator-induced lung injury in ALI animal models.[METHODS] 30 Male rabbits were randomly divided intofive groups: conventional ventilation group (injected oleic acid ,V_T: 13¹5ml/kg, PEEP: 0cmH₂O), low tidal volume group +PEEP group (injected oleic acid, V_T: 8ml/kg, PEEP: 8cmH₂O) , prone position group (injected oleic acid,V_T: 8ml/kg, PEEP:0cmH₂O), prone position + low tidal volume group +PEEP (injected oleic acid, V_T: 8ml/kg, PEEP:0cmH₂O), and control group (without injecting oleic acid, V_T:13¹5ml/kg, PEEP:0cmH₂O), with each group having 6 rabbits. After tracheotomy, the rabbits were ventilated with Servo 900Cventilator (infant modes).Part 1 To investigate the changes of respiratory mechanics,homodynamic mechanics, arterial blood gas indexes during the different lung protective ventilation and conventional ventilation.Part 2 To investigate the changes of TNF- α , IL-1 β , IL-6 in bronchial alveolar lavage fluids (BALF) during the different lung protective ventilation and conventional ventilation.Part 3 To investigate the changes of ALP, LDH, cholesterol, triglycerd, and phosphatide in bronchial alveolar lavage fluid (BALF) and in serum during the different lung protective ventilation and conventional ventilation.[RESUILS]1 After lung injury, the data of respiratory mechanics and oxygenation index were significantly getting worsen. After receiving lung protective ventilation (including low tidal volume + PEEP, prone position + low tidal volume + PEEP), these indexes obviously improved. Although there showed ameliorating trends in the data of prone position ventilation group, but compared with lung protective ventilation, they were also having statistical differences in the three groups.2 After lung injury, the levels of TNF- α , IL-1 β . IL-6, ALP, LDH, cholesterol, triglycerd and phosphatide from BALF of the conventional ventalition group, low tidal volume group +PEEP group, prone position group and prone position + low tidal volume group +PEEP group obviously increased. The results of lung protective ventilation (including low tidal volume + PEEP ventilation and proneposition + low tidal volume + PEEP ventilation) showed that the concentrations of TNF- a , IL-1 P , IL-6, ALP, LDH, cholesterol, triglycerd and phosphatide in the BALF obviously decreased compared to conventional ventilation group and prone position group .3 After lung injury, in animal serum, we found that the results of ALP, triglycerd increased and the results of LDH, cholesterol and phosphatide decreased. The results of receiving lung protective ventilation (including low tidal volume + PEEP ventilation and prone position + low tidal volume + PEEP ventilation) showed that the level of ALP in the serum decreased and the levels of triglycerd and LDH in the serum increased, at the same time cholesterol, phosphatide in the serum did not descreased compared to prone position ventilation group and conventional ventilation group.4 Through analyzing the correlation coefficient of all data, we found that: (1) the concentrations of TNF- a , IL-1 ï¿¡ , IL-6 had positive correlation with that of ALP, LDH, cholesterol, triglycerd and phosphatide in the BALF. (2) the levels of TNF- a , IL-1 3 and IL-6 had positive correlation with that of ALP and had negative correlation with that of LDH, cholesterol, triglycerd and phosphatide in serum.(3) the levels of TNF- a , IL-1 {3 and IL-6 had positive correlation with the changes of airway peak pressure and airway plat pressure, and had negative correlation with the changes of oxygenation index and compliance.[CONCLUSION] Low tidal volume + PEEP ventilation...