A prolonged run-in period of standard subcutaneous microdialysis ameliorates quality of interstitial glucose signal in patients after major cardiac surgery

Abstract

We evaluated a standard subcutaneous microdialysis technique for glucose monitoring in two critically ill patient populations and tested whether a prolonged run-in period improves the quality of the interstitial glucose signal. 20 surgical patients after major cardiac surgery (APACHE II score: 10.1 ± 3.2) and 10 medical patients with severe sepsis (APACHE II score: 31.1 ± 4.3) were included in this investigation. A microdialysis catheter was inserted in the subcutaneous adipose tissue of the abdominal region. Interstitial fluid and arterial blood were sampled in hourly intervals to analyse glucose concentrations. Subcutaneous adipose tissue glucose was prospectively calibrated to reference arterial blood either at hour 1 or at hour 6. Median absolute relative difference of glucose (MARD), calibrated at hour 6 (6.2 (2.6; 12.4) %) versus hour 1 (9.9 (4.2; 17.9) %) after catheter insertion indicated a significant improvement in signal quality in patients after major cardiac surgery (p < 0.001). Prolonged run-in period revealed no significant improvement in patients with severe sepsis, but the number of extreme deviations from the blood plasma values could be reduced. Improved concurrence of glucose readings via a 6-hour run-in period could only be achieved in patients after major cardiac surgery.

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

“…www.nature.com/scientificreports www.nature.com/scientificreports/ In contrast to measuring interstitial glucose concentrations in otherwise healthy people with diabetes, sensor performance might differ in critical illness e.g. due to altered tissue perfusion in sepsis 15,36 . Thus, intravenous or intraarterial glucose sensing might be a more reliable alternative as vascular access is granted in the majority of critically ill patients.…”

“…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 . Although intravascular CGM systems are not affected by tissue lag time 26 and sensor inaccuracy due to fluid retention, their use in clinical practice is still limited to four approved devices (GlucoClear by Edwards Life Sciences [Irvine, CA, USA] 27 , Glysure System by Glysure [Abingdon, Oxfordshire, UK] 20 , Eirus by Maquet Getinge Group [Rastatt, Germany] 28 and Optiscanner 5000 by Optiscan [Hayward, CA, USA]) 29 in Europe 30 .…”