体位改变对兔急性肺损伤生理和病理的影响

Physiological and pathological effects of body position changes on experimental acute lung injury in rabbits

目的:观察不同体位下兔油酸型急性肺损伤(ALI)模型肺生理功能和肺病理的改变。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血压、心率和动脉血氧分压、呼吸力学、肿瘤坏死因子(TNF-α)和白细胞介素-6(IL-6)的变化以及病理的改变。结果:在实验结束时Ⅳ组的心率(176.13±26.55)beats/min低于Ⅲ组(217.75±14.44)beats/min,P<0.05;Ⅲ、Ⅳ组的动脉血氧分压(157.75±51.19和166.08±37.07)mmHg、肺的顺应性(2.75±0.89和2.63±0.74)mL/cmH2O高于Ⅱ组动脉血氧分压(86.59±23.82)mmHg和肺的顺应性(1.63±0.52)mL/cmH2O,P<0.05;Ⅲ、Ⅳ组的肺内分流(20.94±5.23和18.06±5.28)%低于Ⅱ组(29.30±7.54)%,P<0.05;Ⅳ组的气道峰压(19.63±2.45)cmH2O高于Ⅲ组(16.00±2.27)cmH2O,P<0.05;Ⅱ、Ⅳ组TNF-α(3.12±0.83和2.59±0.79)μg/L显著高于对照组(1.36±0.34)μg/L,P<0.05,而Ⅲ组(1.84±0.46)μg/L和对照组差别无显著;3个实验组的动脉血氧分压与肺的顺应性呈明显正相关,与肺内分流呈明显负相关。Ⅱ组光镜下见背侧水肿比腹侧重,Ⅲ组腹侧水肿比背侧重,Ⅳ组腹背侧病变大体一致。结论:俯卧位和旋转体位能改善ALI肺的顺应性、减少肺内分流,改善氧合;但俯卧位比旋转体位安全并能减少TNF-α的产生。体位改变可使肺水肿的分布发生变化。

AIM： To study the effects of body position on the physiological and pathological changes in an oleie acid - induced acute lung injury （ALl） model. METHODS： One control group and three experimental groups were set up in which the rabbits were put on supine, prone and rotation, respectively. The changes of blood pressure, heart rate and partial pressure of arterial oxygen, lung mechanics, eytokines in the course of experiment and pathologic changes were observed. RESULTS： At the end of experiment, heart rate in rotated rabbits was lower than that in prone rabbits [ （ 176.13 ± 26.55） beats/min vs （217.75 ± 14.44） beats/min, P 〈 0.05 ]. Partial pressure of arterial oxygen and lung compliance in prone and rotated rabbits were higher than that in supine rabbits [ （ 157.75±51.19） mmHg and （166.08±37.07） mmHg vs （86.59±23.82） mmHg, （2.75±0.89） mL/cmH2O and （2.63±0.74） mL/cmH2O vs （1.63±0.52） mL/cmH2O, respectively, P 〈 0.05], but intrapulmonary shunt was just up side down. Airway peak inspiration pressure in rotated rabbits was higher than that in prone group rabbits, [ （ 19.63 ± 2.45） cmH2O vs （16.03±2.27） cmH2O, P 〈 0.05 ]. TNF-α in supine and rotated rabbits was higher than that in control rabbits, [ （3.12±0.83 and 2.59±0.79）μg/L vs （1.36±0.34）μg/L], but it was not the case in prone rabbits. Partial pressure of arterial oxygen was positive correlation to lung compliance and negative correlation to intrapulmonary shunt. Dorsal lung edema was more severe than ventral in group 2, ventral lung edema was more severe than dorsal in group 3 and lung edema was diffused in group 4. CONCLUSIONS： Prone and rotation positions increased lung compliance and decreased intrapulmonary shunt accompanied with oxygenation improvement in ALl model, but prone was safer than rotation position, the former can inhibit the secretion of TNF - α. The distribution of lung edema changed with body position changes.