Brock Beate, Kamysek Svend, Silz Josephine, Trefz Phillip, Schubert Jochen K, Miekisch Wolfram
Department of Anaesthesia and Intensive Care Medicine, Rostock University Medical Center, Schillingallee 35, D-18057 Rostock, Germany.
J Breath Res. 2017 Jan 9;11(1):016005. doi: 10.1088/1752-7163/aa53b2.
Analysis of exhaled VOCs can provide information on physiology, metabolic processes, oxidative stress and lung diseases. In critically ill patients, VOC analysis may be used to gain complimentary information beyond global clinical parameters. This seems especially attractive in mechanically ventilated patients frequently suffering from impairment of gas exchange. This study was intended to assess (a) the effects of recruitment maneuvers onto VOC profiles, (b) the correlations between electrical impedance tomography (EIT) data and VOC profiles and (c) the effects of recruitment onto distribution of ventilation. Eleven mechanically ventilated patients were investigated during lung recruitment after cardiac surgery. Continuous breath gas analysis by means of PTR-ToF-MS, EIT and blood gas analyses were performed simultaneously. More than 300 mass traces could be detected and monitored continuously by means of PTR-ToF-MS in every patient. Exhaled VOC concentrations varied with recruitment induced changes in minute ventilation and cardiac output. Ammonia exhalation depended on blood pH. The improvement in dorsal lung ventilation during recruitment ranged from 9% to 110%. Correlations between exhaled concentrations of acetone, isoprene, benzene sevoflurane and improvement in regional ventilation during recruitment were observed. Extent and quality of these correlations depended on physico-chemical properties of the VOCs. Combination of continuous real-time breath analysis and EIT revealed correlations between exhaled VOC concentrations and distribution of ventilation. This setup enabled immediate recognition of physiological and therapeutic effects in ICU patients. In a perspective, VOC analysis could be used for non-invasive control and optimization of ventilation strategies.
呼出挥发性有机化合物（VOCs）的分析可以提供有关生理、代谢过程、氧化应激和肺部疾病的信息。在危重症患者中，VOC分析可用于获取超出整体临床参数的补充信息。这在经常存在气体交换受损的机械通气患者中似乎特别有吸引力。本研究旨在评估（a）肺复张手法对VOC谱的影响，（b）电阻抗断层扫描（EIT）数据与VOC谱之间的相关性，以及（c）肺复张对通气分布的影响。对11例心脏手术后进行肺复张的机械通气患者进行了研究。同时通过质子转移反应-飞行时间质谱（PTR-ToF-MS）进行连续呼出气分析、EIT和血气分析。通过PTR-ToF-MS可在每位患者中连续检测和监测300多条质量轨迹。呼出的VOC浓度随肺复张引起的分钟通气量和心输出量变化而变化。氨的呼出取决于血液pH值。肺复张期间背部肺通气的改善范围为9%至110%。观察到丙酮、异戊二烯、苯、七氟醚呼出浓度与肺复张期间局部通气改善之间的相关性。这些相关性的程度和质量取决于VOC的物理化学性质。连续实时呼气分析与EIT的结合揭示了呼出VOC浓度与通气分布之间的相关性。这种设置能够立即识别ICU患者的生理和治疗效果。从长远来看，VOC分析可用于无创控制和优化通气策略。
