Ringer Simone K, Ohlerth Stefanie, Carrera Inés, Mauch Jacqueline, Spielmann Nelly, Bettschart-Wolfensberger Regula, Weiss Markus
Section Anesthesiology, Equine Department, Vetsuisse Faculty University of Zurich, Zurich, Switzerland.
Department for Small Animals, Clinic of Diagnostic Imaging, Vetsuisse Faculty University of Zurich, Zurich, Switzerland.
Paediatr Anaesth. 2016 Sep;26(9):909-18. doi: 10.1111/pan.12956. Epub 2016 Jun 27.
Hypotension (HT) and/or hypocapnia (HC) are frequent complications occurring during pediatric anesthesia and may cause cerebral injury in the developing brain.
The aim of this study is to investigate the effects of HT and/or HC on perfusion and metabolism in the developing brain.
Twenty-eight piglets were randomly allocated to four groups: control (C), HT, HC, and hypotension and hyocapnia (HTC). Anesthesia was induced and maintained using sevoflurane. Fentanyl was added for instrumentation. Piglets were fully monitored and their lungs were artificially ventilated. Before treatment, conventional magnetic resonance imaging (MRI), dynamic susceptibility-contrast-enhanced T2*-weighted MRI (DSC-MRI), and single voxel proton MR spectroscopy ((1) H MRS) were performed. Hypotension (mean arterial blood pressure: 30 ± 3 mmHg) was induced by blood withdrawal and nitroprusside infusion, and hyperventilation was used to induce HC (PaCO2 : 2.7-3.3 kPa). (1) H MRS and DSC-MRI were repeated immediately once treatment goals were achieved and 120 min later. Radiologists were blinded to the groups. DSCI-MRI and (1) H MRS analyses were performed in the thalamus, occipital and parietal lobe, hippocampus, and watershed areas.
In comparison to C, mean time to peak (TTP) increased with HTC in all brain areas as assessed with DSC-MRI (n = 26). Using (1) H MRS, a significant decrease in N-acetyl aspartate, choline, and myoinositol, as well as an increase in glutamine-glutamate complex (Glx) were detected independent of group. Compared to C, changes were more pronounced for Glx (due to an increase in glutamate) and myoinositol with HTC, for N-acetyl aspartate with HT, and for Glx with HC. No lactate signal was present.
The combination of HT and HC during sevoflurane anesthesia resulted in alteration of cerebral perfusion with signs of neuronal dysfunction and early neuronal ischemia. HT and HC alone also resulted in signs of metabolic disturbances despite the absence of detectable cerebral perfusion alterations.
低血压（HT）和/或低碳酸血症（HC）是小儿麻醉期间常见的并发症，可能会对发育中的大脑造成脑损伤。
本研究旨在探讨HT和/或HC对发育中大脑灌注和代谢的影响。
28只仔猪随机分为四组：对照组（C）、HT组、HC组和低血压合并低碳酸血症组（HTC）。使用七氟醚诱导并维持麻醉。添加芬太尼用于器械操作。对仔猪进行全面监测，并对其肺部进行人工通气。治疗前，进行常规磁共振成像（MRI）、动态磁敏感对比增强T2*加权MRI（DSC-MRI）和单体素质子磁共振波谱（（1）H MRS）检查。通过放血和输注硝普钠诱导低血压（平均动脉血压：30±3 mmHg），并通过过度通气诱导HC（动脉血二氧化碳分压：2.7 - 3.3 kPa）。一旦达到治疗目标，立即重复进行（1）H MRS和DSC-MRI检查，并在120分钟后再次检查。放射科医生对分组情况不知情。在丘脑、枕叶和顶叶、海马体以及分水岭区域进行DSCI-MRI和（1）H MRS分析。
与C组相比，通过DSC-MRI评估（n = 26），HTC组所有脑区的平均达峰时间（TTP）均增加。使用（1）H MRS检测到，无论分组如何，N-乙酰天门冬氨酸、胆碱和肌醇均显著降低，谷氨酰胺-谷氨酸复合物（Glx）增加。与C组相比，HTC组的Glx（由于谷氨酸增加）和肌醇变化更为明显，HT组的N-乙酰天门冬氨酸变化更为明显，HC组的Glx变化更为明显。未出现乳酸信号。
七氟醚麻醉期间HT和HC联合作用导致脑灌注改变，伴有神经元功能障碍和早期神经元缺血迹象。尽管未检测到脑灌注改变，但单独的HT和HC也导致了代谢紊乱迹象。
