Putative Delays in Interstitial Fluid (ISF) Glucose Kinetics Can Be Attributed to the Glucose Sensing Systems Used to Measure Them Rather than the Delay in ISF Glucose Itself

Voskanyan, Gayane; Keenan, D. Barry; Mastrototaro, John J.; Steil, Garry M.

doi:10.1177/193229680700100507

Cited by 35 publications

(19 citation statements)

References 10 publications

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“…The argument at that time, revisited here, is that the filters per se add delay. 21 The model has been independently used by Facchinetti and associates 4,22 and Wei and coworkers. 23 For the ISF glucose profile simulated here, the blood to ISF gradient was arbitrarily set to be 0.8 and the ISF delay to be 12 min ( Figure 2B).…”

Section: Discussionmentioning

confidence: 99%

Use of Subcutaneous Interstitial Fluid Glucose to Estimate Blood Glucose: Revisiting Delay and Sensor Offset

Rebrin

Sheppard

Steil

2010

J Diabetes Sci Technol

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128

117

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Background: Estimates for delays in the interstitial fluid (ISF) glucose response to changes in blood glucose (BG) differ substantially among research groups. We review these findings along with arguments that continuous glucose monitoring (CGM) devices used to measure ISF delay contribute to the variability. We consider the impact of the ISF delay and review approaches to correct for it, including strategies pursued by the manufacturers of these devices. The focus on how the manufacturers have approached the problem is motivated by the observation that clinicians and researchers are often unaware of how the existing CGM devices process the ISF glucose signal. Methods: Numerous models and simulations were used to illustrate problems related to measurement and correction of ISF glucose delay. Results: We find that (1) there is no evidence that the true physiologic ISF glucose delay is longer than 5–10 min and that the values longer than this can be explained by delays in CGM filtering routines; (2) the primary impact of the true ISF delay is on sensor calibration algorithms, making it difficult to estimate calibration factors and offset (OS) currents; (3) inaccurate estimates of the sensor OS current result in overestimation of sensor glucose at low values, making it difficult to detect hypoglycemia; (4) many device companies introduce nonlinear components into their filters, which can be expected to confound attempts by investigators to reconstruct BG using linear deconvolution; and (5) algorithms advocated by academic groups are seldom compared to algorithms pursued by industry, making it difficult to ascertain their value. Conclusions: The absence of any direct comparisons between existing and new algorithms for correcting ISF delay and sensor OS current is, in part, due to the difficulty in extracting relevant details from industry patents and/or extracting unfiltered sensor signals from industry products. The model simulation environment, where all aspects of the signal can be derived, may be more appropriate for developing new filtering and calibration strategies. Nevertheless, clinicians, academic researchers, and the industry would benefit from collaborating when evaluating those strategies.

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Section: Discussionmentioning

confidence: 99%

Use of Subcutaneous Interstitial Fluid Glucose to Estimate Blood Glucose: Revisiting Delay and Sensor Offset

Rebrin

Sheppard

Steil

2010

J Diabetes Sci Technol

Self Cite

128

117

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“…Weinstein and associates 62 noted that the mean average relative deviation between venous glucose (based on a laboratory reference reading) and sensor glucose is minimized when data are time shifted by 12.6 minutes. Voskanyan and colleagues 63 noted that sensor filtering algorithms can add a significant lag when high rates of glucose change are being studied, and the physiological blood/interstitial fluid lag may have been overestimated in several articles based on the Medtronic CGMS.…”

Section: Blood and Interstitial Fluid Glucose Dynamics And Sensor Lagmentioning

confidence: 99%

Continuous Glucose Monitoring: Real-Time Algorithms for Calibration, Filtering, and Alarms

Bequette

2010

Journal of Diabetes Science and Technology

169

110

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“…While the physiologic lag from serum glucose to interstitial fluid is estimated to be about 5 min [33,34], the value displayed on the CGM receiver typically lags behind capillary BG by an average of 15 min [35] due to the transit time of interstitial glucose through the sensor membrane (1-2 min) and filtering of the signal by the CGM device (3-12 min) [36]. The lag time is especially relevant during rapid glucose changes (>2 mg/dl/min) and may be different during a rise versus fall in BG [37]. Another component contributing to the lag time is the filter imposed by the sensor software because of 'noisy' sensors.…”

Section: Calibrationmentioning

confidence: 95%

Real-Time Continuous Glucose Monitoring in Adult Outpatients

Bonomo¹,

Grassi²,

Bartolo³

et al. 2014

Frontiers in Diabetes

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With real-time continuous glucose monitoring (RTCGM), the patient has a continuous picture of glucose concentrations -dynamic information with important predictive value. It is in fact a typical 'patient-oriented' tool that permits a more aggressive therapeutic approach and makes it easier to adapt therapy immediately. Currently approved RTCGM devices consist of three main components: a glucose sensor, a transmitter, and a receiver monitor. The system is defined as minimally invasive because it requires insertion into the subcutaneous cellular tissue of a fine needle to measure the glucose in the interstitial fluid directly or via an external sensor. A correct selection of patients is one of the most important factors in determining a successful application of this innovative technology. For this purpose, there are already consensus statements in a number of countries with regard to the indications of these systems. The criteria for identification of candidates are usually divided into three main categories: pediatric/adolescent, adult patients (both in the general population of type 1 diabetes and in specific settings), and pregnant women or women in the preconception period. RTCGM opens up extremely interesting prospects that are destined to radically change the concept of clinical self-management of diabetes. Considering the technical progress towards overcoming the current limitations (essentially: not optimal accuracy, invasiveness, and costs) which currently prevent its widespread use, we can expect wide diffusion of this form of monitoring in the coming years.

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Putative Delays in Interstitial Fluid (ISF) Glucose Kinetics Can Be Attributed to the Glucose Sensing Systems Used to Measure Them Rather than the Delay in ISF Glucose Itself

Cited by 35 publications

References 10 publications

Use of Subcutaneous Interstitial Fluid Glucose to Estimate Blood Glucose: Revisiting Delay and Sensor Offset

Use of Subcutaneous Interstitial Fluid Glucose to Estimate Blood Glucose: Revisiting Delay and Sensor Offset

Continuous Glucose Monitoring: Real-Time Algorithms for Calibration, Filtering, and Alarms

Real-Time Continuous Glucose Monitoring in Adult Outpatients

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