不同潮气量联合呼气末正压通气对急性肺损伤犬小肠的影响

Effect of mechanical ventilation with different tidal volume on small intestine in dogs suffering from acute lung injury

目的比较大、小潮气量（VT）机械通气（MV）对急性肺损伤（ALI）犬小肠组织的影响。方法用静脉注射油酸法制备犬ALI模型，制模成功后随机分为两组，分别接受不同VT的MV，通气时间均为6h。小VTMV组（LV组，n=6）：VT 6ml／kg，呼气末正压（PEEP）10cm H2O（1cmH2O=0．098kPa）；大VTMV组（HV组，n=6）：VT20ml／kg，PEEP10cmH2O。通气6h后放血处死动物，开腹取小肠组织，用苏木素-伊红（HE）染色，观察组织病理学改变；用原位末端缺刻标记法（TUNEL）观察小肠组织细胞凋亡情况。结果机械通气6h后HV组ALI犬小肠胀气明显；而LV组无此表现；LV组小肠损伤评分低于HV组[（3．17±0．75）分比（2．00±0．89）分]，差异有统计学意义（P〈0．01）；但各组犬小肠组织细胞凋亡均罕见。结论大VT通气可诱导小肠功能不全；小VT通气在一定程度上可避免出现小肠功能障碍。

Objective To compare the effect of different tidal volume （VT） on intestinal tissue in oleic acid-induced acute lung injury （ALI） dogs undergoing mechanical ventilation （MV）. Methods ALI was induced with oleic acid in dogs. While all of them were undergoing MV, they were randomized into two groups： low VT group （n = 6）, with VT 6 ml/kg, positive end-expiratory pressure （PEEP） 10 cm H2O （1cm H2O= 0. 098 kPa）, and large VT group （n=6）, with VT 20 ml/kg, PEEP 10 cm H2O. MV with different VT was maintained for 6 hours. After 6 hours, dogs were sacrificed by exsanguination. Pathological changes in small bowel tissues were observed with hematoxylin and eosin （HE） staining, and cellular apoptosis detected with terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling （TUNEL） in situ apoptosis determination. Results After 6-hour MV, the degree of flatulence was severe in the large VT group, but no flatulence was observed in the low VT group. Bowel injury score was lower in the low VT group than in large VT group [（3. 17±0. 75） scores vs. （2. 00±0. 89） scores]. There was significant difference between two groups （P〈0.01）. Apoptosis-positive cells were rare in the small bowel tissues in both groups. Conclusion MV with large VT can induce bowel dysfunction, in contrast low VT MV does not produce small bowel dysfunction.