Continuous tissue glucose monitoring correlates with measurement of intermittent capillary glucose in patients with distributive shock

Abstract

Background: Intermittent glycemic measurements in patients admitted to the intensive care unit (ICU) can result in episodes of severe hypoglycemia or in a poor control of glycemia range. We designed a study to assess accuracy and reliability of continuous monitoring of tissue glucose for patients with distributive shock.

Methods: Consecutive patients admitted to the ICU with a diagnosis of distributive shock and the need of insulin infusion for glycemic control were included in the study. These patients were implanted a Continuous Glucose Control Monitoring System (CGMS) with the sensor inserted subcutaneously into the abdominal wall. CGMS values were recorded every 5min. Capillary glucose (CG) was monitored for adjusting insulin perfusion according to the ICU protocol. Correlation between both methods was assessed.

Results: A total of 11,673 CGMS and 348 CG values were recorded. In five patients, CGMS failed to detect tissue glucose. A glucose value <3.33mmol/l (<60mg/dl) was observed in 3.6% of CGMS and in 0.29% CG values. 295 pairs of measurements were included in the statistical analysis for correlation assessment. The intraclass correlation coefficient was 0.706. The Pearson correlation coefficient was 0.71 (p<0.0001, 95% CI 0.65-0.76). The mean of differences between both measurement methods was 0.22mmol/l (3.98mg/dl) (95% CI 0.66-7.31).

Conclusions: When the Continuous Glucose Control Monitoring System (CGMS) is able to obtain data (75% of the patients), there is correlation between the values obtained by this method and capillary blood glucose in patients with distributive shock. CGMS can detect more episodes of glycemic excursions outside the normal range than intermittent capillary glucose monitoring. Variables that may impair glucose metabolism and peripheral soft tissues perfusion could impair CGMS measurements.

Keywords: Capillary glucose; Critical illness; Distributive shock; Enfermo crítico; Glucosa capilar; Glucosa tisular; Glucose monitoring; Hipoglucemia; Hypoglycemia; Monitorización de la glucosa; Shock distributivo; Tissue glucose.