From the Department of Anesthesiology (Y.C.), the Positron Emission Tomography Center (W.B.), and the Department of Anesthesiology (J.Z.), Huashan Hospital, Fudan University, Shanghai, China; and the Laboratory for Space Environment and Physical Science, Harbin Institute of Technology, Harbin, China (X.L.).
Anesthesiology. 2019 Oct;131(4):850-865. doi: 10.1097/ALN.0000000000002876.
Loss of consciousness during anesthesia reduces local and global rate of cerebral glucose metabolism. Despite this, the influence of gradual anesthetic-induced changes on consciousness across the entire brain metabolic network has barely been studied. The purpose of the present study was to identify specific cerebral metabolic patterns characteristic of different consciousness/anesthesia states induced by intravenous anesthetic propofol.
At various times, 20 Sprague-Dawley adult rats were intravenously administered three different dosages of propofol to induce different anesthetic states: mild sedation (20 mg · kg · h), deep sedation (40 mg · kg · h), and deep anesthesia (80 mg · kg · h). Using [F]fluorodeoxyglucose positron emission tomography brain imaging, alterations in the spatial pattern of metabolic distribution and metabolic topography were investigated by applying voxel-based spatial covariance analysis and graph-theory analysis.
Evident reductions were found in baseline metabolism along with altered metabolic spatial distribution during propofol-induced anesthesia. Moreover, graph-theory analysis revealed a disruption in global and local efficiency of the metabolic brain network characterized by decreases in metabolic connectivity and energy efficiency during propofol-induced deep anesthesia (mild sedation global efficiency/local efficiency = 0.6985/0.7190, deep sedation global efficiency/local efficiency = 0.7444/0.7875, deep anesthesia global efficiency/local efficiency = 0.4498/0.6481; mild sedation vs. deep sedation, global efficiency: P = 0.356, local efficiency: P = 0.079; mild sedation vs. deep anesthesia, global efficiency: P < 0.0001, local efficiency: P < 0.0001; deep sedation vs. deep anesthesia, global efficiency: P < 0.0001, local efficiency: P < 0.0001). A strong spatial correlation was also found between cerebral metabolism and metabolic connectivity strength, which decreased significantly with deepening anesthesia level (correlation coefficients: mild sedation, r = 0.55, deep sedation, r = 0.47; deep anesthesia, r = 0.23; P < 0.0001 between the sedation and deep anesthesia groups).
The data revealed anesthesia-related alterations in spatial and topologic organization of metabolic brain network, as well as a close relationship between metabolic connectivity and cerebral metabolism during propofol anesthesia. These findings may provide novel insights into the metabolic mechanism of anesthetic-induced loss of consciousness.
麻醉期间意识丧失会降低局部和全局脑葡萄糖代谢率。尽管如此，麻醉诱导引起的意识逐渐变化对整个脑代谢网络的影响几乎没有被研究过。本研究的目的是确定静脉麻醉异丙酚诱导的不同意识/麻醉状态下特有的特定脑代谢模式。
在不同时间，20 只 Sprague-Dawley 成年大鼠静脉给予三种不同剂量的异丙酚，以诱导不同的麻醉状态：轻度镇静（20mg·kg·h）、深度镇静（40mg·kg·h）和深度麻醉（80mg·kg·h）。使用[F]氟脱氧葡萄糖正电子发射断层扫描脑成像，通过体素空间协方差分析和图论分析研究代谢分布和代谢地形的空间模式变化。
在异丙酚诱导的麻醉过程中，发现基线代谢明显降低，代谢空间分布发生改变。此外，图论分析显示，代谢脑网络的全局和局部效率受到破坏，表现为异丙酚诱导的深度麻醉（轻度镇静全局效率/局部效率=0.6985/0.7190，深度镇静全局效率/局部效率=0.7444/0.7875，深度麻醉全局效率/局部效率=0.4498/0.6481）中代谢连通性和能量效率降低。异丙酚诱导的深度镇静（轻度镇静全局效率/局部效率=0.6985/0.7190，深度镇静全局效率/局部效率=0.7444/0.7875，深度麻醉全局效率/局部效率=0.4498/0.6481）中代谢连通性和能量效率降低。异丙酚诱导的深度镇静（轻度镇静全局效率/局部效率=0.6985/0.7190，深度镇静全局效率/局部效率=0.7444/0.7875，深度麻醉全局效率/局部效率=0.4498/0.6481）中代谢连通性和能量效率降低。（轻度镇静 vs. 深度镇静，全局效率：P=0.356，局部效率：P=0.079；轻度镇静 vs. 深度麻醉，全局效率：P<0.0001，局部效率：P<0.0001；深度镇静 vs. 深度麻醉，全局效率：P<0.0001，局部效率：P<0.0001）。还发现大脑代谢与代谢连通性强度之间存在很强的空间相关性，随着麻醉水平的加深而显著降低（相关系数：轻度镇静，r=0.55，深度镇静，r=0.47；深度麻醉，r=0.23；P<0.0001 之间镇静和深度麻醉组）。
研究结果揭示了麻醉相关的代谢脑网络空间和拓扑组织的改变，以及异丙酚麻醉期间代谢连通性和大脑代谢之间的密切关系。这些发现可能为麻醉诱导意识丧失的代谢机制提供新的见解。
