实验性急性肺损伤体位效应及其肺CT改变

Effect of body position changes on spiral CT scan in rabbits with oleic acid-induced acute lung injury

目的:观察不同体位下急性肺损伤(ALI)肺的氧合功能、呼吸力学、肺CT等的变化,探讨不同体位的效应和机制。方法:采用油酸型ALI兔模型,分为正常对照组(Ⅰ组)、仰卧位油酸组(Ⅱ组)、俯卧位油酸组(Ⅲ组)、旋转体位油酸组(Ⅳ组),观察各组兔实验过程中动脉氧分压、呼吸力学和血压、心率的变化。并分别进行肺CT扫描加以分析。结果:Ⅳ组的心率在实验结束时比Ⅲ组显著降低(P<0.05);Ⅲ、Ⅳ组的动脉氧分压、肺的顺应性比Ⅱ组增高(P<0.05);Ⅲ、Ⅳ组肺内分流比Ⅱ组明显降低(P<0.05);Ⅳ组的气道峰压比Ⅲ组为高(P<0.05);Ⅱ、Ⅲ、Ⅳ组的动脉氧分压与肺的顺应性成明显正相关,与肺内分流成明显负相关;ALI兔肺CT呈明显的重力依赖效应,体位的变化对肺CT的影响非常迅速,连续旋转后兔肺重力依赖作用减轻。结论:俯卧位和旋转体位均能改善兔油酸型ALI肺的氧合;旋转体位能减轻压迫性肺不张的程度。

Objective：To study the effect of body position changes on respiratory mechanics, oxygenation, and CT images in rabbits with oleic acid-induced acute lung injury （ALI）. Methods：Thirty-two New Zealand white rabbits were randomly divided into 4 groups：group Ⅰ （normal control）, group Ⅱ （in supine position ）, group Ⅲ （ in prone position ）, and group Ⅳ （in rotation position）. The changes of partial pressure of arterial oxygen,respiratory mechanics,blood pressure,heart rate,and CT images of the lung were analyzed. Results：At the end of experiment, the heart rate in group Ⅳ was significantly lower than that in group Ⅲ （P 〈 0.05）. Compared with groupⅡ, in groups Ⅲ and Ⅳ ,the partial pressure of arterial oxygen and lung compliance were significantly higher,but the intrapulmonary shunt was significantly lower （P 〈 0.05 ）. The peak inspiration pressure in group Ⅳ was significantly higher than that in group Ⅲ （P 〈 0.05）. The par6al pressure of arterial oxygen was positively correlated to lung compliance and negatively correlated to intrapulmonary shunt in groups Ⅱ , Ⅲ, and Ⅳ. The CT scan showed the lung injury regions were gravity-dependent distribution,and the CT scan changed rapidly with the body position. Conclusion： Prone and rotation positions can improve the oxygenation in rabbits with ALI, and the continuous rotation position can decrease the extent of compressive lung collapse in ALI.