Department of Traumatology, University of Szeged, Szeged, Hungary, Semmelweis street 6., Szeged, 6725 Hungary.
National Academy of Scientist Education, Pacsirta str 31., Szeged, 6724 Hungary.
Injury. 2024 Sep;55 Suppl 3:111456. doi: 10.1016/j.injury.2024.111456. Epub 2024 Sep 17.
Identification of severe blood loss and hemorrhagic shock in polytrauma patients poses a key challenge for trauma teams across the world, as there are just a few objective parameters, on which clinicians can rely. We investigated the relationship between exhaled air methane (CH) concentration and blood loss in a polytrauma patient. Decreased blood flow in the superior mesenteric artery (SMA) is one of the first compensatory responses to blood loss. Gases produced by the anaerobic flora of the intestinal segment supplied by the SMA are the primary source of exhaled CH, which diffuses through the intestinal microvessels into the circulation and is finally eliminated through the lungs. We hypothesized that diminution of exhaled CH indicates blood loss and tested our theory in a severely injured patient.
Exhaled CH concentrations of a severely injured patient were measured using a photoacoustic spectroscope (PAS) attached to the exhalation side of the breathing circuit. The primary objective was to investigate the relationship between exhaled CH and conventional indicators of hemorrhage including hemoglobin (Hb) levels, base deficit (BD) values and vital parameters (heart rate and systolic blood pressure) in the early phase of in-hospital care (first 4 h).
A severely injured patient was admitted with unstable hemodynamic parameters and incomplete left lower limb amputation, (Injury Severity Score: 38, 74/36 mmHg, 76 bpm). At the time of arrival, considerably lower CH levels were detected (22,800 PAU) in the exhaled air. During the first 4 h fluid and massive blood resuscitation, the exhaled CH levels were continuously rising in parallel with Htc and Hb values. Corresponding to these changes, BD values displayed a decreasing tendency.
Our study was conducted to characterize the changes in exhaled air CH concentration in response to hemorrhagic shock and to provide data on a viable clinical use of an experimental technique. According to our results, the real-time detection of exhaled air CH concentration is an applicable and promising technique for the early detection of bleeding and hemorrhagic shock in severely injured patients. Further research on large sample size and refinement of the PAS technique is required.
在全球范围内，创伤团队都面临着一个关键挑战，即识别多发伤患者的严重失血和失血性休克，因为只有少数客观参数可供临床医生依赖。我们研究了多发伤患者呼气甲烷（CH）浓度与失血之间的关系。肠系膜上动脉（SMA）血流量减少是对失血的最初代偿反应之一。SMA 供应肠段的厌氧菌群产生的气体是呼气 CH 的主要来源，它通过肠微血管扩散到循环中，最终通过肺部排出。我们假设呼气 CH 的减少表明失血，并在一名严重受伤的患者中验证了我们的理论。
使用连接到呼吸回路呼气侧的光声光谱仪（PAS）测量严重受伤患者的呼气 CH 浓度。主要目的是在院内治疗的早期（前 4 小时）研究呼气 CH 与包括血红蛋白（Hb）水平、碱缺失（BD）值和生命体征（心率和收缩压）等常规出血指标之间的关系。
一名严重受伤的患者因不稳定的血流动力学参数和不完全的左下肢截肢（损伤严重程度评分：38，74/36 mmHg，76 次/分）入院。到达时，呼气中检测到的 CH 水平明显较低（22,800 PAU）。在最初的 4 小时液体和大量输血复苏期间，呼气 CH 水平持续升高，与 Htc 和 Hb 值平行。与这些变化相对应，BD 值呈下降趋势。
我们的研究旨在描述呼气 CH 浓度对失血性休克的变化特征，并提供一种可行的临床应用实验技术的数据。根据我们的结果，实时检测呼气 CH 浓度是一种适用于早期检测严重受伤患者出血和失血性休克的有前途的技术。需要进一步进行大样本量的研究和 PAS 技术的改进。
