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World J Diabetes. May 15, 2023; 14(5): 528-538
Published online May 15, 2023. doi: 10.4239/wjd.v14.i5.528
What, why and how to monitor blood glucose in critically ill patients
Deven Juneja, Desh Deepak, Prashant Nasa
Deven Juneja, Institute of Critical Care Medicine, Max Super Speciality Hospital, Saket, New Delhi 110017, India
Desh Deepak, Department of Critical Care, King's College Hospital, Dubai 340901, United Arab Emirates
Prashant Nasa, Department of Critical Care, NMC Speciality Hospital, Dubai 7832, United Arab Emirates
Prashant Nasa, Department of Critical Care, College of Medicine and Health Sciences, Al Ain 15551, United Arab Emirates
Author contributions: Juneja D and Deepak D performed the majority of the writing, prepared the tables and performed data accusation; Nasa P provided the input in writing the paper and reviewed the manuscript.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Deven Juneja, DNB, FCCP, MBBS, Director, Institute of Critical Care Medicine, Max Super Speciality Hospital, Saket, 1 Press Enclave Road, New Delhi 110017, India. devenjuneja@gmail.com
Received: November 18, 2022
Peer-review started: November 18, 2022
First decision: January 17, 2023
Revised: January 17, 2023
Accepted: March 7, 2023
Article in press: March 7, 2023
Published online: May 15, 2023
Processing time: 177 Days and 23.6 Hours
Abstract

Critically ill patients are prone to high glycemic variations irrespective of their diabetes status. This mandates frequent blood glucose (BG) monitoring and regulation of insulin therapy. Even though the most commonly employed capillary BG monitoring is convenient and rapid, it is inaccurate and prone to high bias, overestimating BG levels in critically ill patients. The targets for BG levels have also varied in the past few years ranging from tight glucose control to a more liberal approach. Each of these has its own fallacies, while tight control increases risk of hypoglycemia, liberal BG targets make the patients prone to hyperglycemia. Moreover, the recent evidence suggests that BG indices, such as glycemic variability and time in target range, may also affect patient outcomes. In this review, we highlight the nuances associated with BG monitoring, including the various indices required to be monitored, BG targets and recent advances in BG monitoring in critically ill patients.

Keywords: Blood glucose; Continuous glucose monitoring; Critical care; Glycaemic indices; Hypoglycaemia; Intensive care unit

Core Tip: Blood glucose (BG) monitoring is a vital component of critical care management. Even non-diabetic critically ill patients are prone to glycemic fluctuations necessitating frequent blood sampling and BG monitoring. Multiple medications, presence of underlying comorbidities and organ dysfunctions, and rapidly changing patient condition make BG control challenging in critically ill patients. Even the commonly used capillary blood sampling for BG monitoring may not be reliable in these patients. In addition to the established parameters of hypoglycemia and hyperglycemia, newer glycemic indices like glycemic variability and time in target range have also been recognized to affect outcomes of critically ill patients, further complicating BG monitoring. Devices for continuous glucose monitoring are also being increasingly tested in these patients, and their use in conjunction with artificial intelligence-based devices may provide a solution to comprehensive glucose control in the future.