Closed-loop insulin delivery using a subcutaneous glucose sensor and intraperitoneal insulin delivery: feasibility study testing a new model for the artificial pancreas.
OBJECTIVE
Attempts to build an artificial pancreas by using subcutaneous insulin delivery from a portable pump guided by an subcutaneous glucose sensor have encountered delays and variability of insulin absorption. We tested closed-loop intraperitoneal insulin infusion from an implanted pump driven by an subcutaneous glucose sensor via a proportional-integral-derivative (PID) algorithm.


METHODS
Two-day closed-loop therapy (except for a 15-min pre-meal manual bolus) was compared with a 1-day control phase with intraperitoneal open-loop insulin delivery, according to randomized order, in a hospital setting in eight type 1 diabetic patients treated by implanted pumps. The percentage of time spent with blood glucose in the 4.4-6.6 mmol/l range was the primary end point. RESULTS During the closed-loop phases, the mean +/- SEM 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%, P = 0.05), and overall dispersion of blood glucose values was reduced among patients. Better closed-loop glucose control came from the time periods excluding the two early postprandial hours with a higher percentage of time in the 4.4-6.6 mmol/l range (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 <3.3 mmol/l was low and similar for both investigational phases.


CONCLUSIONS
Our results demonstrate the feasibility of intraperitoneal insulin delivery for an artificial beta-cell and support the need for further study. Moreover, according to a semiautomated mode, the features of the pre-meal bolus in terms of timing and amount warrant further research.
Endocrinology Department, Le Centre Hospitalier Universitaire Montpellier, Montpellier, France. renard.amtim@wanadoo.fr
Eric
E
Renard
Jerome
J
Place
Martin
M
Cantwell
Hugues
H
Chevassus
Cesar C
CC
Palerm
D000293:Adolescent; D000328:Adult; D000368:Aged; D015374:Biosensing Techniques / Q000379:methods*; D001786:Blood Glucose / Q000032:analysis*; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D015918:Infusion Pumps, Implantable; D007263:Infusions, Parenteral / Q000379:methods*; D007328:Insulin / Q000008:administration & dosage* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000379:methods*; D019397:Pancreas, Artificial; D055815:Young Adult
D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin