Wang Youqing, Percival Matthew W, Dassau Eyal, Zisser Howard C, Jovanovic Lois, Doyle Francis J
Department of Chemical Engineering, University of California, Santa Barbara, California, USA.
J Diabetes Sci Technol. 2009 Sep 1;3(5):1099-108. doi: 10.1177/193229680900300513.
Modern insulin pump therapy for type 1 diabetes mellitus offers the freedom to program several basal profiles that may accommodate diurnal ariability in insulin sensitivity and activity level. However, these basal profiles do not change even if a pending hypoglycemic or hyperglycemic event is foreseen. New insulin pumps could receive a direct feed of glucose values from a continuous glucose monitoring (CGM) system and could enable dynamic basal adaptation to improve glycemic control.
The proposed method is a two-step procedure. After the design of an initial basal profile, an adaptation of the basal rate is suggested as a gain multiplier based on the current CGM glucose value and its rate of change (ROC). Taking the glucose value and its ROC as axes, a two-dimensional plane is divided into a nine-zone mosaic, where each zone is given a predefined basal multiplier; for example, a basal multiplier of zero indicates a recommendation to shut off the pump.
The proposed therapy was evaluated on 20 in silico subjects (ten adults and ten adolescents) in the Food and Drug Administration-approved UVa/Padova simulator. Compared with conventional basal therapy, the proposed basal adjustment improved the percentage of glucose levels that stayed in the range of 60-180 mg/dl for all 20 subjects. In addition, the adaptive basal therapy reduced the average blood glucose index values.
The proposed therapy provides the flexibility to account for insulin sensitivity variations that may result from stress and/or physical activities. Because of its simplicity, the proposed method could be embedded in a chip in a future artificial pancreatic beta cell or used in a "smart" insulin pump.
1型糖尿病的现代胰岛素泵疗法能够灵活设置多种基础输注量模式，以适应胰岛素敏感性和活动水平的昼夜变化。然而，即便预见到即将发生低血糖或高血糖事件，这些基础输注量模式也不会改变。新型胰岛素泵可以从连续血糖监测（CGM）系统直接获取血糖值，并能够实现基础输注量的动态调整，以改善血糖控制。
所提出的方法分两步进行。在设计初始基础输注量模式后，根据当前CGM血糖值及其变化率（ROC），建议将基础输注率调整为一个增益乘数。以血糖值及其ROC为坐标轴，将二维平面划分为九个区域的网格，每个区域都给定一个预定义的基础乘数；例如，基础乘数为零表示建议关闭泵。
在食品药品监督管理局批准的弗吉尼亚大学/帕多瓦模拟器中，对20名虚拟受试者（10名成年人和10名青少年）评估了所提出的疗法。与传统基础疗法相比，所提出的基础调整方法使所有20名受试者血糖水平维持在60 - 180mg/dl范围内的百分比得到了改善。此外，适应性基础疗法降低了平均血糖指数值。
所提出的疗法能够灵活应对因压力和/或身体活动可能导致的胰岛素敏感性变化。由于其简单性，所提出的方法未来可嵌入人工胰腺β细胞的芯片中，或用于“智能”胰岛素泵。
