Putensen Christian, Wrigge Hermann, Zinserling Jörg
Department of Anaesthesiology and Intensive Care Medicine, University of Bonn, Germany.
Curr Opin Crit Care. 2007 Jun;13(3):344-50. doi: 10.1097/MCC.0b013e328136c1e2.
Computed tomography (CT) in patients with acute respiratory distress syndrome has shown that intrapulmonary gas is not homogeneously distributed. Although regional ventilation can be studied by isotope and magnetic resonance techniques while aeration of the lungs can be imaged using CT, these techniques are not available at the bedside. Recently, electrical impedance tomography has been introduced as a true bedside technique which provides information on regional ventilation distribution.
Electrical impedance tomography can reliably determine regional ventilation in healthy lungs and various models of induced lung injury when compared with CT, electron beam CT, and single photon emission CT. In healthy volunteers and patients with acute lung injury, relative impedance changes on the electrical impedance tomography image demonstrate an excellent correlation with regional changes in lung air content detected by CT. In a limited number of patients with respiratory dysfunction, gas exchange was found to improve when electrical impedance tomography was used to adjust ventilator settings, improving regional ventilation and avoiding tidal alveolar collapse.
In view of recently published data, it can be concluded that, in critically ill patients, electrical impedance tomography determines reliable regional ventilation. Therefore, this technique has the potential to become a valuable bedside tool.
计算机断层扫描（CT）用于急性呼吸窘迫综合征患者时显示，肺内气体分布并不均匀。虽然可通过同位素和磁共振技术研究局部通气情况，且利用CT可对肺部通气进行成像，但这些技术无法在床边使用。最近，电阻抗断层成像技术作为一种真正的床边技术被引入，可提供有关局部通气分布的信息。
与CT、电子束CT和单光子发射CT相比，电阻抗断层成像技术能够可靠地测定健康肺部以及多种诱导性肺损伤模型中的局部通气情况。在健康志愿者和急性肺损伤患者中，电阻抗断层成像图像上的相对阻抗变化与CT检测到的肺部空气含量局部变化具有极佳的相关性。在少数呼吸功能障碍患者中，当使用电阻抗断层成像技术调整呼吸机设置时，气体交换得到改善，局部通气得到改善且避免了肺泡周期性萎陷。
鉴于最近发表的数据，可以得出结论，在危重病患者中，电阻抗断层成像技术能够测定可靠的局部通气情况。因此，这项技术有可能成为一种有价值的床边工具。
