Clinical cerebral microdialysis: a methodological study
Clinical cerebral microdialysis: a methodological study
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DOI：
10.3171/jns.2000.93.1.0037
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发表时间：
2000-07-01
影响因子：
4.1
通讯作者：
Pickard, JD
中科院分区：
文献类型：
--
作者：
Hutchinson, PJ;O'Connell, MT;Pickard, JD
目的。临床微透析能够监测神经外科患者的脑细胞外化学环境。该技术引入不同医院的神经外科病房后，应用方法出现了差异。有几个变量需要考虑，包括导管膜的长度、灌注液的类型、灌注液的流速以及样本的在线分析与延迟分析。本研究的目的如下：1）确定不同导管特性对物质浓度的影响；2）通过改变流速并外推至零流速来确定相对回收率和真实的细胞外浓度；3）比较使用床边酶分析仪获得的物质浓度与离线高效液相色谱（HPLC）获得的物质浓度。
方法。使用一种特殊设计的螺栓将两根相邻的微透析导管置入头部受伤或病情严重的蛛网膜下腔出血且正在接受通气的患者的额叶皮质。一根参考导管（膜长10毫米，以0.3微升/分钟的速度灌注林格氏液）在所有研究中保持不变。另一根导管在膜长（10毫米或30毫米）、灌注液（林格氏液或生理盐水）和流速（0.1 - 1.5微升/分钟）方面有所不同。通过在线分析确定冷冻样本对物质浓度的影响，然后在-70℃储存3个月后再次分析。使用床边酶分析仪测定的样本使用HPLC重新评估以确定谷氨酸浓度。
结论。两根在膜长、灌注液和流速方面相同的相邻微透析导管显示出相同的结果。灌注液的变化以及样本的冷冻和解冻并未导致物质浓度的差异。导管长度对物质回收率有显著影响。流速的变化使得能够使用一种改进的外推至零流速方法来计算相对回收率。对于所有分析物，在0.3微升/分钟时回收率约为70%，在1微升/分钟（10毫米膜）时回收率约为30%。使用酶分析仪获得的谷氨酸结果与HPLC的结果显示出良好的相关性。
Object. Clinical microdialysis enables monitoring of the cerebral extracellular chemistry of neurosurgical patients. Introduction of the technique into different hospitals' neurosurgical units has resulted in variations in the method of application. There are several variables to be considered, including length of the catheter membrane, type of perfusion fluid, flow rate of perfusion fluid, and on-line compared with delayed analysis of samples. The objects of this study were as follows: 1) to determine the effects of varying catheter characteristics on substance concentration; 2) to determine the relative recovery and true extracellular concentration by varying the flow rate and extrapolating to zero flow; and 3) to compare substance concentration obtained using a bedside enzyme analyzer with that of off-line high-performance liquid chromatography (HPLC).Methods. A specially designed bolt was used to conduct two adjacent microdialysis catheters into the frontal cortex of patients with head injury or poor-grade subarachnoid hemorrhage who were receiving ventilation. One reference catheter (10-mm membrane, perfused with Ringer's solution at 0.3 mu l/minute) was constant for all studies. The other catheter was varied in terms of membrane length (10 mm or 30 mm), perfusion fluid (Ringer's solution or normal saline), and flow rate (0.1-1.5 mu l/minute). The effect of freezing the samples on substance concentration was established by on-line analysis and then repeated analysis after storage at - 70 degrees C for 3 months. Samples assayed with the bedside enzyme analyzer were reassessed using HPLC for the determination of glutamate concentrations.Conclusions. Two adjacent microdialysis catheters that were identical in membrane length, perfusion fluid, and flow rate showed equivalent results. Variations in perfusion fluid and freezing and thawing of samples did not result in differences in substance concentration. Catheter length had a significant impact: on substance recovery. Variations in flow rate enabled the relative recovery to be calculated using a modification of the extrapolation-to-zero-flow method. The recovery was approximately 70% at 0.3 mu l/minute and 30% at 1 mu l/minute (10-mm membrane) for all analytes. Glutamate results obtained with the enzyme analyzer showed good correlation with those from HPLC.