0．2MPa压力下纯氧机械通气对犬肺CT影像的影响

Effects of pure oxygen mechanical ventilation under the pressure of 0.2MPa on canine pulmonary CT images

目的 通过观察试验犬在高压氧（hyperbaric oxygen, HBO）机械通气前后双肺CT影像学改变，探讨高压氧对肺影像学的影响。方法 健康成年犬40只，按数字表法随机分为4组，高压氧组、常压氧组、高压空气组和常压空气组，每组10只。不同干预条件下，机械通气结束前后进行胸部CT扫描，利用PACS（picture archiving and communication systems）影像学系统对相关区域CT值变化进行分析。结果 机械通气后高压氧组[（－220.83±44.01） HUs]和常压氧组[（－328.50±30.76） HUs]犬肺尾部CT值增加，提示肺通气不足，与机械通气前[（－553.54±45.72）、（－534.32±40.23） HUs]比较差异具有统计学意义（P〈0.05）；与常压氧组相比，高压氧组试验犬双肺尾部CT值增加更明显，甚至达肺不张的标准，差异具有统计学意义（P〈0.05）。结论 机械通气犬高压氧组与常压氧组均出现肺影像学改变；机械通气犬高压氧组较常压氧组肺CT影响改变更明显，提示肺通气不足，甚至出现肺不张。

Objective To compare the CT changes in lungs among mechanically-ventilated dogs before and after a single hyperbaric oxygen exposure, and investigate the effects of HBO on lungs.Methods Forty healthy adult dogs were randomly divided into 4 groups： the hyperbaric oxygen （HBO） group, the normabaric oxygen （NBO） group, the hyperbaric air group and the normabaric air group. All the dogs were mechanically ventilated and CT scan on lungs were taken before and after the session to compare the CT value by Picture Archiving and Communication System on different lung parts.Results There was no significant difference between all the groups of apical and median fields of lung CT values （P〉0.05）. In HBO and NBO groups, deficiency of pulmonary aeration developed preferentially in caudal lung fields. Compared with the NBO group, the changes of HBO group were more dramatic. There were significant differences in CT values between HBO and NBO groups（P〈0.05）.Conclusions Compared with NBO, ventilating at 0.2 MPa caused much more significant deficient aerations of the lungs.