Frerichs I, Hahn G, Schröder T, Hellige G
Department of Anaesthesiological Research, Centre of Anaesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Germany.
Intensive Care Med. 1998 Aug;24(8):829-36. doi: 10.1007/s001340050673.
To apply electrical impedance tomography (EIT) and the new evaluation approach (the functional EIT) in monitoring the development of artificial lung injury.
Acute experimental trial.
Operating room for animal experimental studies at a university hospital.
Five pigs (41.3 +/- 4.1 kg, mean body weight +/- SD).
The animals were anaesthetised and mechanically ventilated. Sixteen electrodes were attached on the thoracic circumference and used for electrical current injection and surface voltage measurement. Oleic acid was applied sequentially (total dose 0.05 ml/kg body weight) into the left pulmonary artery to produce selective unilateral lung injury.
The presence of lung injury was documented by significant changes of PaCO2 (40.1 mmHg vs control 37.1 mmHg), PaO2 (112.3 mmHg vs 187.5 mmHg), pH (7.35 vs 7.42), mean pulmonary arterial pressure (29.2 mmHg vs 20.8 mmHg) and chest radiography. EIT detected 1) a regional decrease in mean impedance variation over the affected left lung (-41.4% vs control) and an increase over the intact right lung (+ 20.4% vs control) indicating reduced ventilation of the affected, and a compensatory augmented ventilation of the unaffected lung and 2) a pronounced fall in local baseline electrical impedance over the injured lung (-20.6% vs control) with a moderate fall over the intact lung (-10.0% vs control) indicating the development of lung oedema in the injured lung with a probable atelectasis formation in the contralateral one.
The development of the local impairment of pulmonary ventilation and the formation of lung oedema could be followed by EIT in an experimental model of lung injury. This technique may become a useful tool for monitoring local pulmonary ventilation in intensive care patients suffering from pulmonary disorders associated with regionally reduced ventilation, fluid accumulation and/or cell membrane changes.
应用电阻抗断层成像（EIT）及新的评估方法（功能性EIT）监测人工肺损伤的发展。
急性实验性试验。
某大学医院的动物实验手术室。
5头猪（平均体重41.3±4.1千克，平均体重±标准差）。
动物麻醉后进行机械通气。在胸廓周围附着16个电极，用于注入电流和测量表面电压。将油酸按顺序（总剂量0.05毫升/千克体重）注入左肺动脉以产生选择性单侧肺损伤。
通过动脉血二氧化碳分压（40.1毫米汞柱vs对照37.1毫米汞柱）、动脉血氧分压（112.3毫米汞柱vs 187.5毫米汞柱）、pH值（7.35 vs 7.42）、平均肺动脉压（29.2毫米汞柱vs 20.8毫米汞柱）的显著变化及胸部X线检查记录肺损伤的存在。EIT检测到：1）受影响的左肺平均阻抗变化区域降低（-41.4% vs对照），完整的右肺平均阻抗变化区域增加（+20.4% vs对照），表明受影响肺的通气减少，未受影响肺出现代偿性通气增强；2）损伤肺局部基线电阻抗明显下降（-20.6% vs对照），完整肺局部基线电阻抗中度下降（-10.0% vs对照），表明损伤肺出现肺水肿，对侧肺可能形成肺不张。
在肺损伤实验模型中，EIT可追踪肺通气局部损害的发展及肺水肿的形成。该技术可能成为监测患有与局部通气减少、液体蓄积和/或细胞膜变化相关肺部疾病的重症监护患者局部肺通气的有用工具。
