A quiet revolution in intensive care is challenging one of medicine's most persistent routines.
For decades, the management of blood sugar in critically ill patients has followed a seemingly logical pattern: check frequently, adjust quickly. The intensive care unit (ICU) became a place where hourly glucose measurements were the gold standard, with nurses diligently waking patients throughout the night to ensure their safety. But what if this round-the-clock vigilance was actually missing the bigger picture? Emerging research is now challenging this long-held practice, suggesting that we may have been over-monitoring without necessarily improving outcomes.
The story of glycemic control in critically ill patients has been one of dramatic shifts. The early 2000s saw great enthusiasm for extremely tight blood sugar control, but this approach ultimately revealed unexpected dangers—particularly the risk of dangerous hypoglycemic episodes that could cause more harm than the elevated glucose levels they sought to treat 5 .
Today, a new paradigm is emerging—one that emphasizes smart monitoring rather than frequent monitoring, and safety over rigidity. The latest evidence suggests that stepping back from strict hourly measurements might actually provide safer, more effective care while preserving patients' precious sleep and reducing the workload on overwhelmed nursing staff. This isn't about doing less; it's about being smarter.
When the body experiences severe stress through trauma, surgery, infection, or other critical illnesses, it unleashes a complex hormonal response that profoundly affects blood sugar regulation. This phenomenon, known as stress-induced hyperglycemia, represents a fundamental disturbance in the body's carefully balanced glucose control systems.
Under normal circumstances, our bodies maintain blood glucose within a remarkably narrow range—typically between 3.9-6.1 mmol/L (70-110 mg/dL) 5 . This balance is maintained through the coordinated action of hormones like insulin (which lowers blood sugar) and glucagon, epinephrine, and cortisol (which raise it).
The body releases massive amounts of cortisol and adrenaline, which actively work to increase blood glucose levels
The body's cells become less responsive to insulin, making it harder to clear glucose from the bloodstream
The release of pro-inflammatory substances further interferes with insulin signaling
The traditional approach of hourly glucose monitoring emerged from good intentions—the desire to quickly identify and correct abnormal glucose levels in highly vulnerable patients. However, the accumulating evidence suggests that this strategy may be both excessive and counterproductive.
The 2024 Society of Critical Care Medicine (SCCM) guidelines mark a significant departure from this once-standard practice. Rather than mandating fixed hourly checks, the guidelines now recommend frequent monitoring specifically "during periods of glycemic instability" while implicitly allowing for less frequent checks when patients are stable 1 . This distinction represents a more nuanced, patient-tailored approach to glucose management.
The updated guidelines specifically advise against targeting intensive glucose levels (4.4-7.7 mmol/L or 80-139 mg/dL) in favor of more conventional targets (7.8-11.1 mmol/L or 140-200 mg/dL) 1 . This change acknowledges that the risks of aggressive treatment—particularly hypoglycemia—often outweigh the benefits of tight control.
The most comprehensive evidence review comes from the 2024 SCCM guideline update, which methodically evaluated the best available research on glycemic control in critically ill patients 1 . A 22-member multiprofessional panel conducted a systematic review of the literature, assessing evidence quality using the rigorous GRADE methodology before making their recommendations.
The panel found that the evidence supported individualized approaches rather than rigid protocols. For adult patients, they specifically suggested "frequent (≤1 hour) glucose monitoring compared with monitoring at intervals greater than hourly… during periods of glycemic instability" 1 . The crucial distinction is the focus on instability—acknowledging that stable patients may not require such intensive surveillance.
For pediatric patients, the evidence was even more definitive. The panel stated they "make no recommendation regarding frequent BG monitoring (interval ≤1 hour) or less frequent (>1 hour) in pediatric critically ill patients on insulin infusion therapy" 1 .
A groundbreaking 2025 study published in Endocrine Practice provides perhaps the most compelling evidence for changing our approach to glucose monitoring 4 . The research investigated the use of real-time continuous glucose monitoring (rtCGM) integrated with an insulin infusion computer calculator in 35 critically ill adults.
The study design was elegant in its simplicity: compare traditional point-of-care (POC) glucose testing with continuous monitoring using the Dexcom G7 system. The continuous monitor provided updated glucose readings every few minutes without requiring fingersticks or blood draws.
The patients in the rtCGM group achieved outstanding glucose control: 82.8% time in range (70-180 mg/dL), with only 0.5% time below range (<70 mg/dL) 4 . This demonstrates that less intrusive monitoring can actually yield superior safety profiles.
| Parameter | Traditional POC Testing | Continuous Glucose Monitoring |
|---|---|---|
| Monitoring frequency | Intermittent (typically 1-2 hours) | Continuous (every few minutes) |
| Mean turnaround time | ~5 minutes | ~3 seconds |
| Nurse preference | Baseline | 100% preferred CGM with POC over POC alone 4 |
| Data provided | Single point in time | Trends and patterns |
| Glycemic Parameter | Result |
|---|---|
| Mean glucose | 141.9 mg/dL |
| Time in range (70-180 mg/dL) | 82.8% |
| Time above range (>180 mg/dL) | 14.5% |
| Time below range (<70 mg/dL) | 0.5% |
The remarkable accuracy of the continuous monitoring system—with 99.6% of values falling within clinically acceptable error zones—combined with dramatically improved workflow efficiency presents a compelling case for rethinking how we monitor glucose in critically ill patients 4 .
The movement away from rigid hourly glucose checks is enabled by advances in both technology and protocols. The modern approach to glycemic control in critical care relies on several key components:
The SCCM guidelines strongly recommend "the use of a protocol that includes explicit decision support tools over a protocol with no such tools in critically ill adults receiving IV insulin infusions" 1 .
For acute management of hyperglycemia in critically ill patients, continuous IV insulin infusion remains the preferred method 1 . This approach allows for precise titration and rapid adjustment when needed.
The most significant shift is toward personalized glycemic targets based on a patient's specific condition and pre-hospital glycemic control.
| Guideline | Target Population | Recommended Range |
|---|---|---|
| SCCM 2024 | General critically ill adults | 7.8-11.1 mmol/L (140-200 mg/dL) 1 |
| American Diabetes Association 2025 | General critically ill adults | 7.8-10.0 mmol/L (140-180 mg/dL) 8 |
| American Diabetes Association 2025 | Selected critically ill adults | More stringent targets if achievable safely 8 |
The evidence for moving away from rigid hourly glucose monitoring isn't just theoretical—implementation projects are demonstrating real-world success. A recent best practice implementation project at a tertiary hospital in China showed how adopting evidence-based glycemic control practices could significantly improve outcomes 2 .
The project used the JBI Evidence Implementation Framework to address barriers to best practice. Through staff education, protocol development, and workflow redesign, the hospital achieved dramatic improvements in compliance with best practices. One criterion saw compliance increase from 0% to 100%, while others showed substantial gains 6 . This demonstrates that changing long-standing practices about monitoring frequency is not only possible but can yield impressive results.
Nurses reported that the new approaches increased efficiency and improved safety, with all surveyed nurses preferring the new methods over traditional approaches alone 4 . This highlights how evidence-based practice can benefit both patients and healthcare providers.
The evolution of glycemic monitoring in critically ill patients—from rigid hourly checks to individualized, technology-enhanced approaches—represents a broader shift in critical care toward personalized, patient-centered treatment. The evidence now clearly suggests that indiscriminate hourly measurements may not be necessary for safe and effective glycemic control, particularly with the advent of continuous monitoring technologies.
As the SCCM guidelines conclude, "Further research is required to evaluate the role of individualized glycemic targets, continuous glucose monitoring systems, explicit decision support tools, and standardized glycemic control metrics" 1 . The future of glycemic control lies not in watching the clock, but in watching the patient—using technology wisely to provide the right care at the right time, without unnecessary intrusion.
This approach promises better outcomes for patients, more satisfying work for healthcare providers, and more efficient use of healthcare resources—a rare triple win in medicine that deserves our attention and implementation.