Understanding glycemic control in the critically ill: 2011 update

Risk and reward: extending stochastic glycaemic control intervals to reduce workload

Background

STAR is a model-based, personalised, risk-based dosing approach for glycaemic control (GC) in critically ill patients. STAR provides safe, effective control to nearly all patients, using 1–3 hourly measurement and intervention intervals. However, the average 11–12 measurements per day required can be a clinical burden in many intensive care units. This study aims to significantly reduce workload by extending STAR 1–3 hourly intervals to 1 to 4-, 5-, and 6-hourly intervals, and evaluate the impact of these longer intervals on GC safety and efficacy, using validated in silico virtual patients and trials methods. A Standard STAR approach was used which allowed more hyperglycaemia over extended intervals, and a STAR Upper Limit Controlled approach limited nutrition to mitigate hyperglycaemia over longer intervention intervals.

Results

Extending STAR from 1–3 hourly to 1–6 hourly provided high safety and efficacy for nearly all patients in both approaches. For STAR Standard, virtual trial results showed lower % blood glucose (BG) in the safe 4.4–8.0 mmol/L target band (from 83 to 80%) as treatment intervals increased. Longer intervals resulted in increased risks of hyper- (15% to 18% BG > 8.0 mmol/L) and hypo- (2.1% to 2.8% of patients with min. BG < 2.2 mmol/L) glycaemia. These results were achieved with slightly reduced insulin (3.2 [2.0 5.0] to 2.5 [1.5 3.0] U/h) and nutrition (100 [85 100] to 90 [75 100] % goal feed) rates, but most importantly, with significantly reduced workload (12 to 8 measurements per day). The STAR Upper Limit Controlled approach mitigated hyperglycaemia and had lower insulin and significantly lower nutrition administration rates.

Conclusions

The modest increased risk of hyper- and hypo-glycaemia, and the reduction in nutrition delivery associated with longer treatment intervals represent a significant risk and reward trade-off in GC. However, STAR still provided highly safe, effective control for nearly all patients regardless of treatment intervals and approach, showing this unique risk-based dosing approach, modulating both insulin and nutrition, to be robust in its design. Clinical pilot trials using STAR with different measurement timeframes should be undertaken to confirm these results clinically.

Independent Association of Glucose Variability With Hospital Mortality in Adult Intensive Care Patients: Results From the Australia and New Zealand Intensive Care Society Centre for Outcome and Resource Evaluation Binational Registry

Supplemental Digital Content is available in the text.

Wide variations in blood glucose excursions in critically ill patients may influence adverse outcomes such as hospital mortality. However, whether blood glucose variability is independently associated with mortality or merely captures the excess risk attributable to hyperglycemic and hypoglycemic episodes is not established. We investigated whether blood glucose variability independently predicted hospital mortality in nonhyperglycemic critical care patients.

Diabetes Is Not Associated With Increased 90-Day Mortality Risk in Critically Ill Patients With Sepsis

OBJECTIVES

To determine the association of pre-existing diabetes, hyperglycemia, and hypoglycemia during the first 24 hours of ICU admissions with 90-day mortality in patients with sepsis admitted to the ICU.

DESIGN

We used mixed effects logistic regression to analyze the association of diabetes, hyperglycemia, and hypoglycemia with 90-day mortality (n = 128,222).

SETTING

All ICUs in the Netherlands between January 2009 and 2014 that participated in the Dutch National Intensive Care Evaluation registry.

PATIENTS

All unplanned ICU admissions in patients with sepsis.

INTERVENTIONS

The association between 90-day mortality and pre-existing diabetes, hyperglycemia, and hypoglycemia, corrected for other factors, was analyzed using a generalized linear mixed effect model.

MEASUREMENTS AND MAIN RESULTS

In a multivariable analysis, diabetes was not associated with increased 90-day mortality. In diabetes patients, only severe hypoglycemia in the absence of hyperglycemia was associated with increased 90-day mortality (odds ratio, 2.95; 95% CI, 1.19-7.32), whereas in patients without pre-existing diabetes, several combinations of abnormal glucose levels were associated with increased 90-day mortality.

CONCLUSIONS

In the current retrospective large database review, diabetes was not associated with adjusted 90-day mortality risk in critically ill patients admitted with sepsis.

Challenges of Inpatient Glycemic Control

Hyperglycemia occurs in more than 30% of hospitalized patients. The condition has been associated with higher mortality and poor outcomes. Systems to effectively treat dysglycemia have been put into place, although many focus on critical care areas. The purpose of this article is to provide an overview of the challenges for glycemic control in non-critical care areas. Standardized order sets, critical pathways, professional education, and collaborative systems can support improved control.

Efficacy and safety of glucose control with Space GlucoseControl in the medical intensive care unit--an open clinical investigation

BACKGROUND

We aimed to investigate the performance of the Space GlucoseControl system (SGC) (B. Braun, Melsungen, Germany) in medical critically ill patients. The SGC is a nurse-driven, computer-assisted device for glycemic control combining infusion pumps with the enhanced Model Predictive Control algorithm.

SUBJECTS AND METHODS

The trial was designed as a single-center, open clinical investigation in a nine-bed medical intensive care unit in a tertiary center in Graz, Austria. Efficacy was assessed by percentage of time within the target range (4.4-8.3 mmol/L; primary end point), mean blood glucose, and sampling interval. Safety was assessed by the number of hypoglycemic episodes (≤2.2 mmol/L).

RESULTS

Twenty mechanically ventilated patients (age, 63±16 years; body mass index, 31.0±10.7 kg/m(2); Acute Physiology and Chronic Health Evaluation II score, 25.4±6.3; 14 males; six with diabetes) were included for a period of 7.0±3.6 days. Time within target range was 83.4±8.9% (mean±SD), and mean arterial blood glucose was 6.8±0.4 mmol/L. No severe hypoglycemic episodes (<2.2 mmol/L) occurred, and the percentage of time within 2.2 and 3.3 mmol/L was low (0.03±0.07%). The sampling interval was 2.0±0.4 h. The mean insulin dose was 93.5±80.1 IU/day, and the adherence to the given insulin dose advice was high (98.3%). A total of 11 unintended therapy interruptions (0.08 events/treatment day) caused by software problems occurred in four patients.

CONCLUSIONS

SGC is a safe and efficient method to control blood glucose in critically ill patients in the medical intensive care unit.

Glucose measurement of intensive care unit patient plasma samples using a fixed-wavelength mid-infrared spectroscopy system

OBJECTIVE

Glycemic control is a rapidly developing field in intensive care medicine with the aim of reducing mortality, morbidity, and cost. Current intensive care unit (ICU) glucose measurement technologies are susceptible to interference from medications, volume expanders, and other substances present in critically ill patients. We hypothesized that a fixed-wavelength mid-infrared (mid-IR) spectroscopy system would be accurate for measuring glucose levels of ICU patients.

RESEARCH DESIGN AND METHODS

This is a prospective investigation of plasma samples from two different institutions treating a heterogeneous population of ICU patients. The first 292 samples were collected from 86 patients admitted to Stamford Hospital, and the next 352 samples were collected from 75 patients from three ICUs at the University of Maryland. Plasma samples were measured on a Fourier-transform infrared or a proprietary spectrometer, with a glucose prediction algorithm to correct for spectral interference, which were compared with reference measurements taken using a YSI 2300 glucose analyzer.

RESULTS

Glucose values ranged from 24 to 343 mg/dl. Numerous medications and injury/disease states were observed in the patient populations, with metoprolol, fentanyl, and multiple organ failure the most prevalent. Despite these interferents, there was a high correlation (r ≥ 0.94) and low standard error (≤12.8 mg/dl) between the predicted glucose values and those of the YSI 2300 STAT Plus reference instrument in the three studies. A total of 95.1% of the 644 values in the three studies met International Organization for Standardization 15197 criteria.

CONCLUSION

These results suggest that a fixed-wavelength mid-IR spectrometer can measure glucose accurately in the plasma of ICU patients.