Closed-Loop Insulin Delivery Using a Subcutaneous Glucose Sensor and Intra-Peritoneal Insulin Delivery: A Feasibility Study Testing a New Model for the Artificial Pancreas.

  1. Eric Renard, MD, PHD (renard.amtim{at}wanadoo.fr)1,
  2. Jerome Place1,
  3. Martin Cantwell, BSC2,
  4. Hugues Chevassus, Pharm D3 and
  5. Cesar C. Palerm, PHD2
  1. 1Endocrinology Department, CHU Montpellier & UMR CNRS 5232, University of Montpellier, Montpellier, France
  2. 2Medtronic Diabetes, Northridge, CA, USA
  3. 3INSERM Clinical Investigation Centre 001, CHU Montpellier, Montpellier, France

    Abstract

    Objective: Attempts to build an artificial pancreas by using subcutaneous (SC) insulin delivery from a portable pump guided by an SC glucose sensor have confronted delays and variability of insulin absorption. We tested closed-loop intra-peritoneal (IP) insulin infusion from an implanted pump driven by an SC glucose sensor via a proportional-integral-derivative (PID) algorithm.

    Research design and methods: Two-day closed-loop therapy (except for a 15-minute pre-meal manual bolus) was compared with a one-day control phase with intra-peritoneal open-loop insulin delivery, according to randomized order, in a hospital setting in eight type 1 diabetic patients treated by implanted pumps. Percentage of time spent with blood glucose in the 4.4–6.6 mmol/L range was the primary endpoint.

    Results: During the closed-loop phases, the percentage of time spent with blood glucose in the 4.4–6.6 mmol/L range was significantly higher: 39.1±4.5 vs. 27.7±6.2% (mean ± SEM, p=0.05), and overall dispersion of blood glucose values was reduced between patients. Better closed-loop glucose control came from the time periods excluding the two early postprandial hours with higher % time within 4.4–6.6 mmol/L: 46.3±5.3 vs. 28.6±7.4 (p=0.025) and lower mean blood glucose levels: 6.9±0.3 vs. 7.9±0.6 mmol/L (p=0.036). Time spent with blood glucose below 3.3 mmol/L was low and similar for both investigational phases.

    Conclusions: Our results demonstrate the feasibility of IP insulin delivery for an artificial β-cell and support the need for further study. Moreover, according to a semi-automated mode, the features of the pre-meal bolus in terms of timing and amount warrant further research.

    Footnotes

      • Received June 12, 2009.
      • Accepted October 10, 2009.

    This Article

    1. Diabetes Care
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