Numerical and clinical accuracy of a continuous glucose monitoring system during intravenous insulin therapy in the surgical and burn intensive care units.
BACKGROUND
Intensive insulin therapy (IIT) for glycemic control in critically ill patients has been shown to be beneficial. Continuous glucose monitoring systems (CGMSs) have been approved as an adjunct to complement standard glucose monitoring in type 2 diabetes mellitus. This study was designed to evaluate the accuracy of a real-time CGMS (DexCom STS) in the intensive care unit (ICU). We also evaluated its reliability and accuracy using a hyperinsulinemic-euglycemic and a hyperglycemic clamp study.


METHODS
Nineteen patients were enrolled in this 7-day study [13 = surgical intensive care unit (SICU), 6 = burn intensive care unit (BICU)]. The patients were on IIT for at least 2 h prior the subcutaneous sensor insertion. Mean age and body mass index for SICU and BICU patients were 60.3 +/- 3.7 and 64.5 +/- 6.2 years and 36.6 +/- 5.0 and 33.85 +/- 3.4 kg/m2, respectively. DexCom accuracy was analyzed separately for the Johnson & Johnson (J&J) calibration finger sticks, Roche Accucheck finger sticks, and the Hitachi 917 analyzer measurements on serum using Clarke error grid analysis and Bland-Altman analysis. In the clamp studies, 20 patients were enrolled, and the data were analyzed similarly.


RESULTS
There were 1065 pairs of DexCom-Accucheck, 232 pairs of DexCom-J&J, and 84 pairs of DexCom-Hitachi in ICU patients. For DexCom-Accucheck, 68.26% of the pairs fell into zone A, 31.83% into zone B, and 0.75% into zone C. There were no values in zones D or E. From the 1102 matching DexCom-Beckman pairs in clamp studies, 42.29% were in zone A, 55.90% were in zone B, and 4.08% were in zone C.


CONCLUSIONS
Despite the high percentage of measurements in zones A and B, underestimation of hypoglycemia by DexCom measurements makes it an unreliable device in the ICU setting.
Rabiee
Atoosa
A
Department of Surgery, Johns Hopkins Bayview Medical Center, Baltimore, Maryland 21224, USA. arabiee1@jhmi.edu
Andreasik
Virginia
V
Abu-Hamdah
Rania
R
Galiatsatos
Panagis
P
Khouri
Zeina
Z
Gibson
B Robert
BR
Andersen
Dana K
DK
Elahi
Dariush
D
D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis*; D016638:Critical Illness; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy; D005260:Female; D005947:Glucose / Q000032:analysis; D015309:Glucose Clamp Technique; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D007328:Insulin / Q000008:administration & dosage* / Q000627:therapeutic use; D007332:Insulin Infusion Systems; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation*
D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; D005947:Glucose