Model-based insulin and nutrition administration for tight glycaemic control in critical care.
OBJECTIVE
Present a new model-based tight glycaemic control approach using variable insulin and nutrition administration.


BACKGROUND
Hyperglycaemia is prevalent in critical care. Current published protocols use insulin alone to reduce blood glucose levels, require significant added clinical effort, and provide highly variable results. None directly address both the practical clinical difficulties and significant patient variation seen in general critical care, while also providing tight control.


METHODS
The approach presented manages both nutritional inputs and exogenous insulin infusions using tables simplified from a model-based, computerised protocol. Unique delivery aspects include bolus insulin delivery for safety and variable enteral nutrition rates. Unique development aspects include the use of simulated virtual patient trials created from retrospective data. The model, protocol development, and first 50 clinical case results are presented.


RESULTS
High qualitative correlation to within +/-10% between simulated virtual trials and published clinical results validates the overall approach. Pilot tests covering 7358 patient hours produced an average glucose of 5.9 +/- 1.1 mmol/L. Time in the 4-6.1 mmol/L band was 59%, with 84% in 4.0-7.0 mmol/L, and 92% in 4.0-7.75 mmol/L. The average feed rate was 63% of patient specific goal feed and the average insulin dose was 2.6U/hour. There was one hypoglycaemic measurement of 2.1 mmol/L. No departures from protocol or clinical interventions were required at any time.


CONCLUSIONS
Modulating both low dose insulin boluses and nutrition input rates challenges the current practice of using only insulin in larger doses to reduce hyperglycaemic levels. Clinical results show very tight control in safe glycaemic bands. The approach could be readily adopted in any typical ICU.
Chase
J Geoffrey
JG
University of Canterbury, Department of Mechanical Engineering, Centre for Bio-Engineering, Christchurch, New Zealand. geoff.chase@canterbury.ac.nz
Shaw
Geoffrey M
GM
Lotz
Thomas
T
LeCompte
Aaron
A
Wong
Jason
J
Lin
Jessica
J
Lonergan
Timothy
T
Willacy
Michael
M
Hann
Christopher E
CE
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000378:metabolism*; D015331:Cohort Studies; D003198:Computer Simulation; D003422:Critical Care; D016638:Critical Illness; D004750:Enteral Nutrition; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000628:therapy*; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013813:Therapy, Computer-Assisted / Q000379:methods
D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin