Background and Goal of Study: Glucose control (GC) in critically ill patients has been the topic of an intense debate since the 2000s. GC remains an important therapeutic goal in clinically ill patients, despite an ongoing debate regarding the optimum target ranges. GC in the intensive care unit (ICU) requires frequent and correct glucose monitoring. An accurate real-time continuous glucose monitoring system (CGMS) might improve the management and treatment of hypoglycemia, hyperglycemia, and glucose variability in this group of patients. The aim of this systematic review (SR) is to report available clinical relevance of continuous glucose monitoring in adult ICU patients.
Materials and Methods: A literature search of PubMed database was carried out using 10 key words: continuous glucose monitoring & ICU patients; tight glycaemic control & ICU patients; hypoglycaemia & ICU patients; intravascular glucose monitoring & ICU patients; glucose target & ICU patients; “closed-loop” monitoring in glycaemic monitoring; diabetes in ICU patients; critically ills & blood glucose; intravascular microdialysis; glucose control metrics in ICU patients. The following filters were used: all full text clinical trials, written in  English language, published between 01/01/2000 and 10/31/2016 on the human genre concerning adult patients. Prospective and Retrospective Observations were also included. Two authors (VS and FB) independently screened and assessed retrieved papers. Only clinical reports (RCTs, prospective and retrospective studies and case reports) were selected. 
Results and discussion:  A total of 4548 papers were examined, 197 were filtered, of which 182 were excluded and 15 were selected as suitable for the present SR. Selected papers were categorized into 3 subchapters: 1. CGMS and glycaemic variability; 2. Closed-loop system; 3. GCMS in cardiac surgery. These studies have shown that often an accurate GCMS allows a better management of glycaemia in ICU patients.
Conclusion: Using CGMS to improve glucose control in the ICU requires continuous glucose measurement combined with an insulin algorithm that allows glucose rescue in response to unexpected hypoglycaemia or hyperglycaemia episodes. This method might improve even glucose control with regard to glucose variability. Future versions of CGMS will need real-time data analysis, fast warm-up, and less frequent calibrations to be used in the clinical setting.

Continuous glucose monitoring in critical care: state of the art and role of glucose control