Clinical Evaluation of Alternative-Site Glucose Measurements in Patients After Major Cardiac Surgery

  1. Martin Ellmerer, PHD1,
  2. Martin Haluzik, MD2,
  3. Jan Blaha, MD2,
  4. Jaromir Kremen, MD2,
  5. Stepan Svacina, PHD2,
  6. Wolfgang Toller, MD3,
  7. Julia Mader, MD1,
  8. Lukas Schaupp, PHD4,
  9. Johannes Plank, MD1 and
  10. Thomas Pieber, MD1
  1. 1Department of Internal Medicine, Medical University Graz, Graz, Austria
  2. 2Faculty of Medicine, Charles University, Prague, Czech Republic
  3. 3Anesthesia and Intensive Care, Medical University Graz, Graz, Austria
  4. 4Joanneum Research, Graz, Austria
  1. Address correspondence and reprint requests to Martin Ellmerer, Department of Internal Medicine, Medical University Graz, Stiftingtalstr. 24, A-8010 Graz, Austria. E-mail: martin.ellmerer{at}healthgate.at

Abstract

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.

RESEARCH DESIGN AND 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.

Footnotes

  • A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.

    The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

    • Accepted February 16, 2006.
    • Received December 5, 2005.
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