Clinical evaluation of alternative-site glucose measurements in patients after major cardiac surgery.
OBJECTIVE
Tight glycemic control improves outcome in critically ill patients but requires frequent glucose measurements. Subcutaneous adipose tissue (SAT) has been characterized as promising for glucose monitoring in diabetes, but it remains unknown whether it can also be used as an alternative site in critically ill patients. The present study was performed to clinically evaluate the relation of glucose in SAT compared with arterial blood in patients after major cardiac surgery.


METHODS
Forty critically ill patients were investigated at two clinical centers after major cardiac surgery. Arterial blood and SAT microdialysis samples were taken in hourly intervals for a period of up to 48 h. The glucose concentration in dialysate was calibrated using a two-step approach, first using the ionic reference technique to calculate the SAT glucose concentration (SATg) and second using a one-point calibration procedure to obtain a glucose profile comparable to SAT-derived blood glucose (BgSAT). Clinical validation of the data was performed by introducing data analysis based on an insulin titration algorithm.


RESULTS
Correlation between dialysate glucose and blood glucose (median 0.80 [interquartile range 0.68-0.88]) was significantly improved using the ionic reference calibration technique (SATg vs.blood glucose 0.90 [0.83-0.94]; P < 0.001). Clinical evaluation of the data indicated that 96.1% of glucose readings from SAT would allow acceptable treatment according to a well-established insulin titration protocol.


CONCLUSIONS
The results indicate good correlation between SATg and blood glucose in patients after major cardiac surgery. Clinical evaluation of the data suggests that with minor limitations, glucose from SAT can be used to establish tight glycemic control in this patient group.
Ellmerer
Martin
M
Department of Internal Medicine, Medical University Graz, Stiftingtalstrasse 24, A-8010 Graz, Austria. martin.ellmerer@healthgate.at
Haluzik
Martin
M
Blaha
Jan
J
Kremen
Jaromir
J
Svacina
Stepan
S
Toller
Wolfgang
W
Mader
Julia
J
Schaupp
Lukas
L
Plank
Johannes
J
Pieber
Thomas
T
D000368:Aged; D001786:Blood Glucose / Q000032:analysis*; D001794:Blood Pressure; D002138:Calibration; D006348:Cardiac Surgical Procedures; D016638:Critical Illness; D005260:Female; D006339:Heart Rate; D006801:Humans; D007279:Injections, Subcutaneous; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods*; D011184:Postoperative Period
D001786:Blood Glucose