Real-time continuous glucose monitoring in pediatric patients during and after cardiac surgery.
OBJECTIVE
Given the demonstrated benefit of euglycemia in critically ill patients as well as the risk for hypoglycemia during insulin infusion in children, we sought to validate a subcutaneous sensor for real-time continuous glucose monitoring in pediatric patients during and after cardiac surgery.


METHODS
Children up to 36 months of age who were undergoing cardiac bypass surgery were recruited. After anesthetic induction, a continuous glucose-monitoring system sensor (CGMS, Medtronic Minimed, Northridge, CA) was inserted subcutaneously. Sensors remained in place for up to 72 hours. Arterial blood glucose was measured intermittently in the central laboratory (Bayer Rapidlab 860, Tarrytown, NY). Sensor data, after prospective calibration with 6-hourly laboratory values using the proprietary Medtronic Minimed Guardian RT algorithm, were compared with all laboratory glucose values. Statistical analysis was performed to test whether sensor performance was affected by body temperature, inotrope dose, or body-wall edema.


RESULTS
Twenty patients were enrolled in the study for a total of 40 study days and 246 paired sensor and laboratory glucose values. Consensus error grid analysis demonstrated that 72.0% of sensor value comparisons were within zone A (no effect on clinical action), and 27.6% of comparisons were within zone B (altered clinical action of little or no effect on outcome), with a mean absolute relative deviation of 17.6% for all comparisons. One comparison (0.4%) was in zone C (altered clinical action likely to affect outcome). No significant correlations were found between sensor performance and body temperature, inotrope dose, or body-wall edema. All patients tolerated the sensors well without bleeding or tissue reaction.


CONCLUSIONS
Guardian RT real-time subcutaneous blood glucose measurement is safe and potentially useful for continuous glucose monitoring in critically ill children. Subcutaneous sensors performed well in the setting of hypothermia, inotrope use, and edema. These sensors facilitate identifying and following the effects of interventions to control blood glucose.
Piper
Hannah G
HG
Department of Surgery, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts 02115, USA.
Alexander
Jamin L
JL
Shukla
Avinash
A
Pigula
Frank
F
Costello
John M
JM
Laussen
Peter C
PC
Jaksic
Tom
T
Agus
Michael S D
MS
D000465:Algorithms; D001786:Blood Glucose / Q000032:analysis*; D002138:Calibration; D006348:Cardiac Surgical Procedures; D003199:Computer Systems; D016638:Critical Illness; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods*; D011184:Postoperative Period; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D001786:Blood Glucose