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New System Controls Overnight Glucose Levels in Type 1 Diabetes

Aug 23, 2012
 

Researchers have developed a new automated, portable glucose control system which safely manages overnight glucose levels in adolescents and young adults with type 1 diabetes…. 

Medtronic has developed the Portable Glucose Control System (PGCS), which consists of two subcutaneous glucose sensors, a control algorithm operating from a Blackberry smartphone platform, a Bluetooth radiofrequency translator and a Medtronic insulin pump.

Dr. Timothy W. Jones from The University of Western Australia in Perth and colleagues investigated the safety and efficacy of the PGCS, focusing on overnight glucose control, in a 16-night study of eight adolescents and young adults with type 1 diabetes.

Plasma glucose during overnight PGCS control averaged 6.4 mmol/L (115 mg/dL). It was maintained between 3.9 and 8 mmol/L (70 and 144 mg/dL) 78% of the time, fell below 3.9 mmol/L 7% of the time, and exceeded 8 mmol/L 15% of the time.

Glycemic control during use of the PGCS was superior to home overnight open-loop control before the study; on closed-loop control, glucose values remained between 3.9 and 8 mmol/L 85% of the time, compared to just 47% on open-loop control (p=0.0001).

Investigator intervention was required on 7 of the 16 nights — 4 nights (2 subjects) because sensor fault detection requested finger-stick calibration, 2 nights because of loss of Bluetooth connection (1 subject), and 1 night because of hypoglycemia in a subject who had given himself a preprandial bolus before an evening meal that he did not finish and subsequently required rescue carbohydrates.

"This study represents progress toward the development of an automated, portable, closed-loop system for outpatient use," the researchers conclude in their report. "Further study is necessary to determine the optimum fault detection settings to maximize patient safety yet minimize disruption to the operation of the closed-loop system."

Published online before print August 8, 2012, doi: 10.2337/dc12-0761 Diabetes Care August 8, 2012