Neonatal Research, Murdoch Childrens Research Institute, Melbourne, Australia.
Intensive Care Med. 2012 Feb;38(2):308-15. doi: 10.1007/s00134-011-2421-z. Epub 2011 Nov 26.
Diagnosis of pneumothorax relies on clinical suspicion and chest X-ray, and is often delayed. We aimed to determine whether electrical impedance tomography (EIT) can accurately identify the presence of surgically created pneumothoraces before significant changes in clinical parameters.
Six anesthetized and muscle-relaxed piglets with surfactant-depleted lungs were studied. Following chest drain insertion into the right ventral chest, 10-20 ml aliquots of air were instilled into the pleural space to a maximum volume of 200 ml. The pneumothorax was drained by attaching a Heimlich valve to the chest drain. At each instillation and after draining the pneumothorax, global and regional end-expiratory intra-thoracic volumes (EEV) were measured using respiratory inductive plethysmography (RIP) and EIT concurrently with [Formula: see text], heart rate and blood pressure.
A significantly greater change in both global EEV(RIP) and EEV within the right ventral quadrant was seen at all volume instillations, from as little as 10 ml, compared with all other quadrants. There was no difference in EEV within the left ventral and both dorsal quadrants. Sp(O)(2) fell below 90% at 100 ml instillation. Tachycardia occurred at 140 ml instillation. EIT identified a 60% resolution of pneumothoraces within 60 s of attachment of the Heimlich valve.
EIT accurately detects very small pneumothoraces before physiological parameters change.
气胸的诊断依赖于临床怀疑和胸部 X 光检查，而且常常会出现延迟。我们旨在确定在临床参数发生显著变化之前，电阻抗断层成像（EIT）是否可以准确识别出已手术形成的气胸。
研究了 6 只麻醉和肌肉松弛的肺表面活性物质耗竭的小猪。在右侧腹侧胸部插入胸腔引流管后，向胸腔内注入 10-20ml 的空气，最大容量为 200ml。通过将海姆利希阀连接到胸腔引流管来排出气胸。在每次注入和排出气胸后，使用呼吸感应体积描记法（RIP）和 EIT 同时测量[Formula: see text]、心率和血压，以测量呼气末的全球和区域性胸腔内容积（EEV）。
与所有其他象限相比，在所有容量注入时，全球 EEV（RIP）和右侧腹侧象限内的 EEV 都发生了显著更大的变化，即使是仅注入 10ml 的空气时也是如此。在左侧腹侧和两个背侧象限内的 EEV 没有差异。Sp（O）（2）在注入 100ml 时降至 90%以下。心动过速发生在注入 140ml 时。EIT 在连接海姆利希阀后 60 秒内准确识别出 60%的气胸缓解。
EIT 在生理参数发生变化之前，能准确检测到非常小的气胸。
