Meier Torsten, Luepschen Henning, Karsten Jan, Leibecke Thorsten, Grossherr Martin, Gehring Hartmut, Leonhardt Steffen
Department of Anesthesiology, University Medical Center Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany.
Intensive Care Med. 2008 Mar;34(3):543-50. doi: 10.1007/s00134-007-0786-9. Epub 2007 Jul 25.
To investigate whether electrical impedance tomography (EIT) is capable of monitoring regional lung recruitment and lung collapse during a positive end-expiratory pressure (PEEP) trial.
Experimental animal study of acute lung injury.
Six pigs with saline-lavage-induced acute lung injury.
An incremental and decremental PEEP trial at ten pressure levels was performed. Ventilatory, gas exchange, and hemodynamic parameters were automatically recorded. EIT and computed tomography (CT) scans of the same slice were simultaneously taken at each PEEP level.
A significant correlation between EIT and CT analyses of end-expiratory gas volumes (r=0.98 up to 0.99) and tidal volumes (r=0.55 up to r=0.88) could be demonstrated. Changes in global and regional tidal volumes and arterial oxygenation (PaO2/FiO2) demonstrated recruitment/derecruitment during the trial, but at different onsets. During the decremental trial, derecruitment first occurred in dependent lung areas. This was indicated by lowered regional tidal volumes measured in this area and by a decrease of PaO2/FiO2. At the same time, the global tidal volume still continued to increase, because the increase of ventilation of the non-dependent areas was higher than the loss in the dependent areas. This indicates that opposing regional changes might cancel each other out when combined in a global parameter.
EIT is suitable for monitoring the dynamic effects of PEEP variations on the regional change of tidal volume. It is superior to global ventilation parameters in assessing the beginning of alveolar recruitment and lung collapse.
研究电阻抗断层成像（EIT）是否能够在呼气末正压（PEEP）试验期间监测局部肺复张和肺萎陷情况。
急性肺损伤的实验动物研究。
六只通过生理盐水灌洗诱导急性肺损伤的猪。
在十个压力水平下进行递增和递减PEEP试验。自动记录通气、气体交换和血流动力学参数。在每个PEEP水平同时进行同一层面的EIT和计算机断层扫描（CT）。
EIT与CT对呼气末气体量（r = 0.98至0.99）和潮气量（r = 0.55至r = 0.88）的分析之间存在显著相关性。在试验期间，整体和局部潮气量以及动脉氧合（PaO2/FiO2）的变化显示出肺复张/肺萎陷，但起始时间不同。在递减试验中，肺萎陷首先发生在重力依赖区。这通过该区域测量的局部潮气量降低以及PaO2/FiO2降低得以表明。与此同时，整体潮气量仍持续增加,因为非重力依赖区通气量的增加高于重力依赖区通气量的减少。这表明，当合并为一个整体参数时，相反区域的变化可能会相互抵消。
EIT适用于监测PEEP变化对局部潮气量变化的动态影响。在评估肺泡复张和肺萎陷的起始方面，它优于整体通气参数。
