Keenan D Barry, Mastrototaro John J, Voskanyan Gayane, Steil Garry M
Medtronic MiniMed, Northridge, California 91325, USA.
J Diabetes Sci Technol. 2009 Sep 1;3(5):1207-14. doi: 10.1177/193229680900300528.
Through the use of enzymatic sensors-inserted subcutaneously in the abdomen or ex vivo by means of microdialysis fluid extraction-real-time minimally invasive continuous glucose monitoring (CGM) devices estimate blood glucose by measuring a patient's interstitial fluid (ISF) glucose concentration. Signals acquired from the interstitial space are subsequently calibrated with capillary blood glucose samples, a method that has raised certain questions regarding the effects of physiological time lags and of the duration of processing delays built into these devices. The time delay between a blood glucose reading and the value displayed by a continuous glucose monitor consists of the sum of the time lag between ISF and plasma glucose, in addition to the inherent electrochemical sensor delay due to the reaction process and any front-end signal processing delays required to produce smooth traces. Presented is a review of commercially available, minimally invasive continuous glucose monitors with manufacturer reported device delays. The data acquisition process for the Medtronic MiniMed (Northridge, CA) continuous glucose monitoring system-CGMS Gold-and the Guardian RT monitor is described with associated delays incurred for each processing step. Filter responses for each algorithm are examined using in vitro hypoglycemic and hyperglycemic clamps, as well as with an analysis of fast glucose excursions from a typical meal response. Results demonstrate that the digital filters used by each algorithm do not cause adverse effects to fast physiologic glucose excursions, although nonphysiologic signal characteristics can produce greater delays.
通过使用皮下插入腹部的酶传感器或通过微透析液提取进行离体检测，实时微创连续血糖监测（CGM）设备通过测量患者的组织间液（ISF）葡萄糖浓度来估算血糖。从组织间隙获取的信号随后用毛细血管血糖样本进行校准，这种方法引发了一些关于生理时间滞后以及这些设备内置处理延迟持续时间影响的问题。血糖读数与连续血糖监测仪显示值之间的时间延迟包括ISF与血浆葡萄糖之间的时间滞后之和，此外还包括由于反应过程导致的固有电化学传感器延迟以及产生平滑轨迹所需的任何前端信号处理延迟。本文综述了市售的微创连续血糖监测仪以及制造商报告的设备延迟情况。描述了美敦力MiniMed（加利福尼亚州诺斯里奇）连续血糖监测系统-CGMS Gold和Guardian RT监测仪的数据采集过程以及每个处理步骤产生的相关延迟。使用体外低血糖和高血糖钳夹以及对典型进餐反应中快速血糖波动的分析来检查每种算法的滤波器响应。结果表明，每种算法使用的数字滤波器不会对快速生理性血糖波动产生不利影响，尽管非生理性信号特征可能会产生更大的延迟。
