Artificial Pancreas for Control of BG and Insulin Levels in Hospitalized Patients with Diabetes and Stress Hyperglycemia

Abstract : Regulatory approvals have been obtained and updated from the Universities IRB Army's HSRRB and FDA (approved IDE) to study the Telemetry Glucose Monitoring System (TGMS) and Vascular Glucose Monitoring System (VGMS) in 12 diabetic patients undergoing major surgery. Study investigators anesthesiologists surgeons research nurses technicians and clinical nurses were educated and trained to manage the sensors and collect the required blood samples and clinical data safely. There were significant delays in initiating patient recruitment due to the regulatory approval process and technical problems at Medtronic MiniMed supplying sterile VGMS sensors. We received sterile sensors from Medtronic 11/23/05 and recruited the first diabetic study subject (A2) on 11/28/05. Six TGMS sensors and one VGMS sensor where implanted 1 hour before surgery. Reference blood samples where obtained approximately every 20 minutes from a radial artery (RA) catheter every 60 minutes from central venous (CV) and RA catheters and every 3 hours from a capillary fingerstick CV and RA catheters. Blood samples where analyzed for glucose lactate pH PaO2 PaCO2 SaO2 hemoglobin and electrolytes. Plasma samples where frozen for subsequent measurement of insulin and fatty acid levels. In general all 7 sensors functioned well throughout the 60 hours of data collection. The 7 sensor output signals moved in parallel over a wide range of BG values (63 mg/dl to 218 mg/dl) and clinical situations (Figures 1-3). Technical issues that caused two briefs of sensor data loss have been resolved. Analysis of sensor glucose vital sign and other blood analyze data is ongoing.