Assessment of changes in blood glucose concentration with intravascular microdialysis

Abstract

Blood glucose and its variability of is a major prognostic factor associated with morbidity. We hypothesized that intravenous microdialysis incorporated in a central venous catheter (CVC) would be interchangeable with changes in blood glucose measured by the reference method using a blood gas analyzer. Microdialysis and central venous blood glucose measurements were simultaneously recorded in high-risk cardiac surgical patients. The correlation between absolute values was determined by linear regression and the Bland-Altman test for repeated measurements was used to compare bias, precision, and limits of agreement. Changes in blood glucose measurement were evaluated by four-quadrant plot and trend interchangeability methods (TIM). In the 23 patients analyzed, the CVC was used as part of standard care with no complications. The correlation coefficient for absolute values (N = 99) was R = 0.91 (P < 0.001). The bias, precision and limits of agreement were - 9.1, 17.4 and - 43.2 to 24.9 mg/dL, respectively. The concordance rate for changes in blood glucose measurements (N = 77) was 85% with the four-quadrant plot. The TIM showed that 14 (18%) changes of blood glucose measurements were uninterpretable. Among the remaining 63 (82%) interpretable changes, 23 (37%) were interchangeable, 13 (20%) were in the gray zone, and 27 (43%) were not interchangeable. Microdialysis using a CVC appears to provide imprecise absolute blood glucose values with risk of insulin misuse. Moreover, only one third of changes in blood glucose measurements were interchangeable with the reference method using the TIM.

Comparison of Intravenous Microdialysis and Standard Plasma Sampling for Monitoring of Vancomycin and Meropenem Plasma Concentrations—An Experimental Porcine Study

“…Intravenous microdialysis has previously been used to evaluate metabolites (e.g., lactate, glucose, pyruvate, and creatinine) [ 8 , 16 , 17 , 18 , 19 , 20 ], antibiotics (e.g., glycopeptides, aminoglycosides, and cephalosporins) [ 5 , 6 , 21 ], and antifungals (e.g., fluconazole) [ 22 ]. Studies investigating metabolites have primarily reported lower metabolite concentrations obtained by intravenous microdialysis in comparison to standard plasma sampling [ 16 , 17 , 18 , 19 , 20 ], although one study found a good correlation [ 21 ]. For flomoxef and fluconazole, comparable concentrations were found with the two sampling methods [ 21 , 22 ].…”

Accuracy and stability of an arterial sensor for glucose monitoring in a porcine model using glucose clamp technique

“…To date, only few intravascular glucose monitoring techniques and devices -mainly using central venous and intraarterial access -have been tested and might overcome issues observed in subcutaneous glucose monotoring [18][19][20][21] . The few studies that directly compared the performance of intraarterial and subcutaneous CGM show conflicting results: one study showed superior performance of the intraarterial system whereas the other study showed comparable performance 22,23 .…”

“…Reported accuracy data on central venous catheter based continuous glucose monitoring varies largely between studies and use of different accuracy metrics make a comparison difficult 18,22,24 . It can be hypothesized that the superior performance of systems using the intravascular rather than the subcutaneous space can be attributed to the physiological lag-time between compartments also seen in non-critical illness but might be aggrieved due to alterations in subcutaneous microcirculation in critically illness and largely depend on tissue perfusion 15,25 .…”