Near continuous glucose monitoring (CGM) in ICU patients may reduce incidence and severity of hypoglycemia, according to a recent study.
Researchers performed a cluster-randomized crossover trial in a hospital in Belgium with four separate ICUs to determine the effect of near CGM on the safety and quality of glycemic control in the ICU setting. Adults who were expected to have an ICU stay of at least three days and who had persistent hyperglycemia (defined as a blood glucose level above 150 mg/dL [8.3 mmol/L]) for up to six hours after admission, were receiving insulin, or both were included in the study. All patients had a peripheral venous catheter placed and connected to a CGM sensor.
With a crossover design, the four ICUs were randomly assigned in pairs to a period of glycemic control with blinded monitors (intermittent monitoring group) or a period of glycemic control with unblinded monitors (CGM group). In the CGM group, the insulin infusion rate was adjusted using the blood glucose values on the display, while in the intermittent glucose monitoring group, it was adjusted based on intermittent blood glucose readings. The target glucose range in both cases was 90 to 150 mg/dL (5.0 to 8.3 mmol/L). The main outcome measures were proportion of time in the desired glucose range, frequency of a blood glucose level less than 70 mg/dL (3.9 mmol/L), and the time spent with blood glucose values less than 70 mg/dL (3.9 mmol/L), all according to blood glucose values measured by the CGM device. The study was conducted between July 2014 and June 2015.
Edwards Lifesciences, the manufacturer of the CGM equipment used in the study, provided funding to two of the study authors or their institutions; of these two authors, one was also a former employee who reported equity ownership in the company. The study results were published online April 19 by Critical Care Medicine.
A convenience sample of 100 patients was recruited, but 23 patients did not have a suitable peripheral vein for catheter placement. The remaining 77 patients were included in the study, 39 in the CGM group and 38 in the intermittent monitoring group. The mean age was 62 and 60 years, respectively, with more men in the CGM group than in the intermittent monitoring group (80% vs. 66%, respectively). Overall, 43,107 blood glucose values were recorded. The two groups spent a similar amount of time in the desired glucose range, and glycemic variability was also similar. However, hypoglycemia incidence was lower in the CGM group than in the intermittent monitoring group (20.5% of patients vs. 39.5% of patients), as was the time spent with a blood glucose value below 70 mg/dL (3.9 mmol/L) (0.4% vs. 1.6%; P<0.05). No patient in either group experienced severe hypoglycemia, defined as a blood glucose value below 40 mg/dL (2.2 mmol/L).
The authors noted that they did not have data on insulin treatment, that they did not look at clinical outcome variables besides ICU mortality, and that they did not formally elicit feedback from the nursing staff regarding the intervention. However, they concluded that CGM led to lower incidence and severity of hypoglycemia and was therefore associated with safer glycemic control in this group of critically ill patients in the ICU.