Brock Beate, Fuchs Patricia, Kamysek Svend, Walther Udo, Traxler Selina, Pugliese Giovanni, Miekisch Wolfram, Schubert Jochen K, Trefz Phillip
Rostock Medical Breath Research Analytics and Technologies (ROMBAT), Department of Anaesthesiology and Intensive Care Medicine, Rostock University Medical Centre, 18057 Rostock, Germany.
Ambulance and Rescue Service, Rostock District Administration, Mecklenburg-Vorpommern, 18209 Bad Doberan, Germany.
Metabolites. 2022 May 31;12(6):502. doi: 10.3390/metabo12060502.
Regional anaesthesia is well established as a standard method in clinical practice. Currently, the local anaesthetics of amino-amide types such as prilocaine are frequently used. Despite routine use, complications due to overdose or accidental intravenous injection can arise. A non-invasive method that can indicate such complications early would be desirable. Breath gas analysis offers great potential for the non-invasive monitoring of drugs and their volatile metabolites. The physicochemical properties of o-toluidine, the main metabolite of prilocaine, allow its detection in breath gas. Within this study, we investigated whether o-toluidine can be monitored in exhaled breath during regional anaesthesia in an animal model, if correlations between o-toluidine and prilocaine blood levels exist and if accidental intravenous injections are detectable by o-toluidine breath monitoring. Continuous o-toluidine monitoring was possible during regional anaesthesia of the cervical plexus and during simulated accidental intravenous injection of prilocaine. The time course of exhaled o-toluidine concentrations considerably differed depending on the injection site. Intravenous injection led to an immediate increase in exhaled o-toluidine concentrations within 2 min, earlier peak and higher maximum concentrations, followed by a faster decay compared to regional anaesthesia. The strength of correlation of blood and breath parameters depended on the injection site. In conclusion, real time monitoring of o-toluidine in breath gas is possible by means of PTR-ToF-MS. Since simulated accidental intravenous injection led to an immediate increase in exhaled o-toluidine concentrations within 2 min and higher maximum concentrations, monitoring exhaled o-toluidine may potentially be applied for the non-invasive real-time detection of accidental intravenous injection of prilocaine.
区域麻醉作为临床实践中的一种标准方法已得到广泛认可。目前，经常使用诸如丙胺卡因等氨基酰胺类局部麻醉药。尽管常规使用，但仍可能出现因用药过量或意外静脉注射导致的并发症。一种能够早期指示此类并发症的非侵入性方法将是理想的。呼气气体分析为药物及其挥发性代谢物的非侵入性监测提供了巨大潜力。丙胺卡因的主要代谢物邻甲苯胺的物理化学性质使其能够在呼气中被检测到。在本研究中，我们调查了在动物模型的区域麻醉过程中，是否可以在呼出气体中监测邻甲苯胺，邻甲苯胺与丙胺卡因血药浓度之间是否存在相关性，以及通过邻甲苯胺呼气监测是否可检测到意外静脉注射。在颈丛区域麻醉期间以及模拟丙胺卡因意外静脉注射期间，可以对邻甲苯胺进行连续监测。呼出邻甲苯胺浓度的时间进程根据注射部位的不同而有很大差异。静脉注射导致呼出邻甲苯胺浓度在2分钟内立即升高，峰值出现更早且最高浓度更高，随后与区域麻醉相比衰减更快。血液和呼气参数的相关性强度取决于注射部位。总之，通过质子转移反应-飞行时间质谱（PTR-ToF-MS）可以实时监测呼出气体中的邻甲苯胺。由于模拟意外静脉注射导致呼出邻甲苯胺浓度在2分钟内立即升高且最高浓度更高，监测呼出邻甲苯胺可能潜在地应用于丙胺卡因意外静脉注射的非侵入性实时检测。
