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首页> 外文期刊>The Internet Journal of Neuromonitoring >Near-Infrared Spectroscopy (NIRS): Validation and Technical Aspects in Documentation of Brain Death
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Near-Infrared Spectroscopy (NIRS): Validation and Technical Aspects in Documentation of Brain Death

机译：近红外光谱（NIRS）：脑死亡记录的验证和技术方面

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Declaration of brain death follows a certain set of examinations. Most common confirmatory tests are the EEG, transcranial Doppler sonosgraphy or cerebral angiography. This case report describes special dynamic features of near infrared spectrocopic (NIRS) parameters in a 46-year-old intensive care patient after severe head injury. Introduction Brain death is declared when brainstem reflexes, motor responses, and respiratory drive are absent in a normothermic, nondrugged comatose patient with a known irreversible massive brain lesion and no contributing metabolic derangements [1,2]. There is fairly uniform agreement regarding the criteria for the clinical evaluation of brain death, although there is considerable variation in the use of additional physiologic tests. In Europe 11 of 25 guidelines require a confirmatory test for the diagnosis [1].Due to its noninvasive nature and the portability of the equipment, near-infrared spectroscopy (NIRS) has gained widespread recognition as a technique for monitoring oxygenation of brain tissue in infants and adults [3]. In the present case report we describe special dynamic features of NIRS-parameters in a 46-year-old intensive care patient after severe head injury. Materials and Methods SubjectOne patient (46 years, male) from the intensive care unit after severe head injury was investigated in the preterminal phase using different neuromonitoring equipment (NIRS, ultrasound Doppler sonography) [4]. Near-Infrared Spectroscopy (NIRS)One of the most important NIRS-device from the clinical point of view was first described in 1977 by F.F. J?bsis in the U.S. [5]. Ten years passed since a near infrared oxygenation monitor (NIRO monitor) was launched in Japan. Since then, a number of improvements in NIRO monitors were implemented. The system we used contains 4 laser diodes for measuring wavelengths of 775, 825, 850 and 904 nm. With a temporal resolution of 0.5 sec the near infrared spectroscope (NIRO 300; Hamamatsu Photonics, Hamamatsu, Japan) reflects cerebral changes in oxygenated (ΔO2Hb) and deoxygenated hemoglobin (ΔHHb), total hemoglobin (ΔcHb = ΔO2Hb + ΔHHb) and oxidated cytochrome c oxidase aa3 (ΔCtOx) in μmol, calculated with Lambert-Beer's Principle [3].In order to measure tissue oxygenation index (TOI = O2Hb/cHb) values, a special probe has been developed. An emission probe made of fiber optics irradiates laser beams, and a detection probe which is placed several centimeters from the emission probe detects faint light that has passed through tissues. The detection probe has a light sensor (photodiode) consisting of three small sensors. The TOI values are calculated from the slope of light attenuation along the distance from the emitting point [6]. Transcranial Doppler SonographyCerebral blood flow profiles were measured using a Multi-Dop T device (DWL Electronic Systems, USA). A bilateral and multidirectional TCD monitoring arrangement to simultaneously and continuously monitor blood flow velocities in different extra- and intracranial arteries has been developed [7]. Results Case ReportAfter severe head injury and admission to the intensive care unit, the clinical status deteriorated and the patient developed the clinical criteria of brain death. The patient showed complete areflexia of the cranial nerves and no signs of integrated spinal motor function. Clinical EEG was diagnosed as isoelectric and no components of brainstem auditory evoked potentials could be recorded. TCD showed residual perfusion in the right and left middle cerebral arteries. In addition residual blood flow profiles in the right supratrochlear artery were found. However, in the left posterior cerebral artery a systolic spike pattern was observed (compare Fig. 1 and [4]).
机译：宣布脑死亡需要经过一系列检查。最常见的确认性检查是EEG，经颅多普勒超声检查或脑血管造影。该病例报告描述了46岁重症颅脑损伤后重症监护患者的近红外光谱（NIRS）参数的特殊动态特征。引言正常人，非药物性昏迷患者中已知存在不可逆的大块脑部病变且无新陈代谢紊乱[1,2]时，如果脑干反射，运动反应和呼吸驱动不存在，则宣布为脑死亡。关于脑死亡的临床评估标准存在相当一致的共识，尽管在使用其他生理测试方面存在很大差异。在欧洲，有25项指南中的11项需要进行确认性测试才能诊断[1]。由于其无创性和设备的便携性，近红外光谱（NIRS）作为一种监测脑组织氧合的技术已得到广泛认可。婴儿和成人[3]。在本病例报告中，我们描述了46岁重症颅脑损伤后重症监护患者中NIRS参数的特殊动态特征。材料和方法对象在重症晚期头部重症监护病房的一名患者（46岁，男性）在终末期使用不同的神经监测设备（NIRS，超声多普勒超声检查）进行了研究[4]。近红外光谱（NIRS）从临床角度来看，最重要的NIRS设备之一是由F.F.于1977年首次描述。美国的Jbsis [5]。自日本推出近红外氧化监测仪（NIRO监测仪）以来已过去了十年。从那时起，对NIRO监视器进行了许多改进。我们使用的系统包含4个激光二极管，用于测量775、825、850和904 nm的波长。近红外光谱仪（NIRO 300; Hamamatsu Photonics，日本滨松，日本）的时间分辨率为0.5秒，可反映出氧合（ΔO2Hb）和脱氧血红蛋白（ΔHHb），总血红蛋白（ΔcHb=ΔO2Hb+ΔHHb）和氧化细胞色素c氧化酶aa3（ΔCtOx）的单位为μmol，用Lambert-Beer原理[3]计算。为了测量组织的氧合指数（TOI = O2Hb / cHb），已开发出一种特殊的探针。由光纤制成的发射探针发射激光束，并且与发射探针相距几厘米的检测探针可以检测穿过组织的微弱光。检测探头具有由三个小传感器组成的光传感器（光电二极管）。 TOI值是根据光衰减沿距发射点的距离的斜率计算得出的[6]。经颅多普勒超声检查使用Multi-Dop T设备（DWL电子系统，美国）测量大脑的血流曲线。已经开发了一种双向和多方向的TCD监测装置，可以同时连续监测不同颅外动脉和颅内动脉的血流速度[7]。结果病例报告严重的头部受伤并进入重症监护室后，临床状况恶化，患者制定了脑死亡的临床标准。该患者表现出完全的颅神经反射力，无脊柱运动功能综合体征。临床脑电图被诊断为等电，并且脑干听觉诱发电位的成分均未记录。 TCD显示左右中脑动脉有残余灌注。另外，在右上肱上动脉中发现了残留的血流曲线。然而，在左后脑动脉中观察到收缩期峰值模式（比较图1和[4]）。

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