This trial was designed to evaluate the performance of Echo's Symphony CGM System in thirty-two (32) post-surgical patients in the critical care setting at four investigational sites. Three enrolled patients who were administered an IV formulation of acetaminophen were subsequently excluded from the study based on an observed interference with the glucose sensor. The skin of each patient was prepared using the skin preparation device, and a Symphony CGM sensor was then applied to the prepared site. During the 24-hour study period, a maximum of thirty reference blood samples were taken from arterial line catheters and measured on a YSI 2300 STAT Plus Glucose Analyzer as a reference. The data collected by Symphony was blinded to study subjects and investigational institution clinical staff. At the conclusion of the study period, the prepared skin sites were inspected for redness or other undesirable effects immediately following sensor removal, and again 7 days after sensor removal.
Continuous data from the Symphony CGM System were compared to reference measurements from the YSI 2300 STAT Plus Glucose Analyzer. Those reference measurements were paired with the Symphony results through a data analysis algorithm. Data from the three subjects with the observed IV acetaminophen interference were excluded from the analysis, as these subjects were not considered evaluable due to the interference issue. The primary statistical analytical tools used to evaluate the performance of Symphony were MARD and CG-EGA. Numerical accuracy is measured using MARD, an error calculation tool that was used to measure the absolute value of the average relative difference between Symphony and the reference measurements, on a percentage basis. The CG-EGA is a categorization of all data pairs based on the clinical significance of the accuracy. Accurate readings result in the same clinical decision when based on the CGM value versus the blood glucose value. Benign errors lead to the same clinical outcome as accurate readings even though the actual clinical decision may differ. Erroneous readings lead to clinical errors. CGM performance is measured as the sum of accurate readings and benign errors.