Leopold Jan Hendrik, Philipp Alois, Bein Thomas, Redel Andreas, Gruber Michael, Schultz Marcus J, Abu-Hanna Ameen, Brinkman Paul, Janssen Hans-Gerd, Bos Lieuwe D J
Dept of Intensive Care Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands.
Dept of Intensive Care, University Hospital Regensburg, Regensburg, Germany.
ERJ Open Res. 2019 Apr 1;5(2). doi: 10.1183/23120541.00134-2018. eCollection 2019 Apr.
It is highly uncertain whether volatile organic compounds (VOCs) in exhaled breath of critically ill intensive care unit patients are formed in the lung locally, in the air compartment or lung tissue, or elsewhere in the body and transported to the lung the bloodstream. We compared VOC mixtures in exhaled breath and in air coming from extracorporeal support devices in critically ill patients to address this issue.
First, we investigated whether it was safe to connect an electronic nose (eNose) or a gas sampling pump to extracorporeal support membranes. Then, breath and air from extracorporeal support devices were collected simultaneously for continuous monitoring of VOC mixtures using an eNose. In addition, samples for gas chromatography/mass spectrometry (GC-MS) analysis were taken daily at the two measurement sites.
10 critically ill patients were monitored for a median (interquartile range) duration of 73 (72-113) h; in total, we had 887 h of air sampling. The eNose signals of breath correlated moderately with signals of air from the extracorporeal support devices (R=0.25-0.44). After GC-MS analysis, 96 VOCs were found both in breath and air from the extracorporeal support devices; of these, 29 (30%) showed a significant correlation (p<0.05) between the two measurement sites, of which 17 were identified. VOCs that did not correlate were found in a higher concentration in breath than in air from the extracorporeal support devices.
This study suggests VOC analysis in the extracorporeal circulation is safe, and that VOCs of nonpulmonary origin can be measured in the breath and in the extracorporeal circulation of critically ill patients. For VOCs that did not correlate between the two measurement sites, the breath concentration was higher, suggesting pulmonary production of these molecules in a highly selected population of patients that received extracorporeal support.
重症监护病房患者呼出气体中的挥发性有机化合物（VOCs）是在肺部局部、空气腔室或肺组织中形成，还是在身体其他部位形成并通过血液运输到肺部，目前极不确定。我们比较了重症患者呼出气体和体外支持设备中的空气所含的VOC混合物，以解决这一问题。
首先，我们研究了将电子鼻（eNose）或气体采样泵连接到体外支持膜上是否安全。然后，同时收集来自体外支持设备的呼出气体和空气，使用电子鼻对VOC混合物进行连续监测。此外，每天在两个测量位点采集用于气相色谱/质谱（GC-MS）分析的样本。
对10名重症患者进行了监测，中位（四分位间距）时长为73（72 - 113）小时；总共进行了887小时的空气采样。呼出气体的电子鼻信号与体外支持设备空气的信号呈中度相关（R = 0.25 - 0.44）。经过GC-MS分析，在呼出气体和体外支持设备的空气中均发现了96种VOC；其中，29种（30%）在两个测量位点之间显示出显著相关性（p < 0.05），其中17种已被鉴定。在呼出气体中发现的不相关VOC浓度高于体外支持设备空气中的浓度。
本研究表明体外循环中的VOC分析是安全的，并且在重症患者的呼出气体和体外循环中可以测量非肺源性的VOC。对于在两个测量位点之间不相关的VOC，呼出气体中的浓度更高，这表明在接受体外支持的特定患者群体中，这些分子是由肺部产生的。
