Impact of shock requiring norepinephrine on the accuracy and reliability of subcutaneous continuous glucose monitoring

To evaluate the impact of circulatory shock requiring norepinephrine therapy on the accuracy and reliability of a subcutaneous continuous glucose monitoring system (CGMS) in critically ill patients. A prospective, validation study of a medical intensive care unit at a university hospital was carried out. Continuous glucose monitoring was performed subcutaneously in 50 consecutive patients on intensive insulin therapy (IIT), who were assessed according to the a priori strata of circulatory shock requiring norepinephrine therapy or not. A total of 736 pairs of sensor glucose (SG)/blood glucose (BG) values were analysed (502 without and 234 with norepinephrine therapy). For all values, repeated measures Bland-Altman analysis showed a mean difference of 0.08 mmol/l (limits of agreement: -1.26 and 1.43 mmol/l). Circulatory shock requiring norepinephrine therapy did not influence the relation of arterial BG with SG in a multivariable random effects linear regression analysis. The covariates norepinephrine dose, body mass index (BMI), glucose level and severity of illness also had no influence. Insulin titration grid analysis showed that 98.6% of the data points were in the acceptable treatment zone. No data were in the life-threatening zone. Circulatory shock requiring norepinephrine therapy, as well as other covariates, had no influence on the accuracy and reliability of the CGMS in critically ill patients.