Department of Anesthesiology, University Hospital RWTH, Aachen, Germany.
Respir Physiol Neurobiol. 2012 Oct 15;184(1):16-26. doi: 10.1016/j.resp.2012.07.006. Epub 2012 Jul 20.
Lung protective ventilation in acute lung injury (ALI) focuses on using low tidal volumes and adequate levels of positive end-expiratory pressure (PEEP). Identifying optimal pressure is difficult because pressure-volume (PV) relations differ regionally. Precise analysis demands local measurements of pressures and related alveolar morphologies. In a porcine model of surfactant depletion (n=24), we combined measuring static pressures with endoscopic microscopy and electrical impedance tomography (EIT) to examine regional PV loops and morphologic heterogeneities between healthy (control group; CON) and ALI lungs ventilated with low (LVT) or high tidal volumes (HVT). Quantification included indices for microscopy (Volume Air Index (VAI), Heterogeneity and Circularity Index), EIT analysis and calculation of regional compliances due to generated PV loops. We found that: (1) VAI decreased in lower lobe after ALI, (2) electrical impedance decreased in dorsal regions and (3) PV loops differed regionally. Further studies should prove the potentials of these techniques on individual respiratory settings and clinical outcome.
急性肺损伤（ALI）中的肺保护性通气策略侧重于使用小潮气量和适当水平的呼气末正压（PEEP）。由于压力-容积（PV）关系在区域上存在差异，因此确定最佳压力非常困难。精确的分析需要对压力和相关肺泡形态进行局部测量。在一个表面活性剂耗竭的猪模型（n=24）中，我们结合了静态压力测量与内镜显微镜和电阻抗断层成像（EIT），以检查健康（对照组；CON）和接受低（LVT）或高潮气量（HVT）通气的 ALI 肺之间的区域 PV 环和形态异质性。定量分析包括显微镜指标（容积空气指数（VAI）、异质性和圆形度指数）、EIT 分析和由于生成的 PV 环而计算的区域顺应性。我们发现：（1）ALI 后下叶的 VAI 降低，（2）背侧区域的电阻抗降低，（3）PV 环存在区域差异。进一步的研究应该证明这些技术在个体呼吸设置和临床结果方面的潜力。
