Glycemic control in the ICU: a multicenter survey

Performance evaluation of three i-SENS glucometers using arterial blood samples compared with the YSI 2300 Glucose Analyzer

Background

Capillary blood is the most commonly used sample for point‐of‐care (POC) glucometers. However, in critically ill patients, the glucose levels measured from capillary blood may not be reliable. Thus, we aimed to evaluate and compare the accuracy of glucose levels measured with POC glucometers and the YSI 2300 glucose analyzer using leftover arterial blood samples.

Methods

In total, 100 leftover heparinized arterial blood samples were used to evaluate the performance of three i‐SENS glucometers (BAROzen H Expert plus, CareSens PRO, and CareSens H Beat) and the ACCU‐CHEK^® Inform II glucometer. The reference value was obtained using the YSI 2300 glucose analyzer. The results were analyzed based on International Organization for Standardization 15197:2013 guidelines.

Results

More than 95% of results obtained using POC glucometers were within ±15 mg/dL of the reference value for glucose concentrations <100 mg/dL and within ±15% of the reference value for glucose concentrations ≥100 mg/dL. In the consensus error grid analysis, more than 99% of results were found to be within zones A and B. An excellent correlation was found between the values obtained using POC glucometers and the YSI 2300 glucose analyzer (R² > .99).

Conclusion

The i‐SENS glucometers showed stable and accurate results when leftover arterial blood samples were used. Therefore, POC glucometers could be useful in critical care settings, such as intensive care units, where arterial samples are routinely used.

The practice of glycaemic control in intensive care units: A multicentre survey of nursing and medical professionals

AIMS AND OBJECTIVES

To determine the views of nurses and physicians working in intensive care units (ICU) about the aims of glycaemic control and use of their protocols.

BACKGROUND

Evidence about the optimal aims and methods for glycaemic control in ICU is controversial, and current local protocols guiding practice differ between ICUs, both nationally and internationally. The views of professionals on glycaemic control can influence their practice.

DESIGN

Cross-sectional, multicentre, survey-based study.

METHODS

An online short survey was sent to all physicians and nurses of seven ICUs, including questions on effective glycaemic control, treatment of hypoglycaemia and deviations from protocols' instructions. STROBE reporting guidelines were followed.

RESULTS

Over half of the 40 respondents opined that a patient spending <75% admission time within the target glycaemic levels constituted poor glycaemic control. Professionals with more than 5 years of experience were more likely to rate a patient spending 50%-74% admission time within target glycaemic levels as poor than less experienced colleagues. Physicians were more likely to rate a patient spending <50% admission time within target as poor than nurses. There was general agreement on how professionals would rate most deviations from their protocols. Nurses were more likely to rate insulin infusions restarted late and incorrect dosage of rescue glucose as major deviations than physicians. Most professionals agreed on when they would treat hypoglycaemia.

CONCLUSIONS

When surveyed on various aspects of glycaemic control, ICU nurses and physicians often agreed, although there were certain areas of disagreement, in which their profession and level of experience seemed to play a role.

RELEVANCE TO CLINICAL PRACTICE

Differing views on glycaemic control amongst professionals may affect their practice and, thus, could lead to health inequalities. Clinical leads and the multidisciplinary ICU team should assess and, if necessary, address these differing opinions.

Integrated sensor-augmented pump therapy systems [the MiniMed® Paradigm™ Veo system and the Vibe™ and G4® PLATINUM CGM (continuous glucose monitoring) system] for managing blood glucose levels in type 1 diabetes: a systematic review and economic evaluation

BACKGROUND

In recent years, meters for continuous monitoring of interstitial fluid glucose have been introduced to help people with type 1 diabetes mellitus (T1DM) to achieve better control of their disease.

OBJECTIVE

The objective of this project was to summarise the evidence on the clinical effectiveness and cost-effectiveness of the MiniMed(®) Paradigm™ Veo system (Medtronic Inc., Northridge, CA, USA) and the Vibe™ (Animas(®) Corporation, West Chester, PA, USA) and G4(®) PLATINUM CGM (continuous glucose monitoring) system (Dexcom Inc., San Diego, CA, USA) in comparison with multiple daily insulin injections (MDIs) or continuous subcutaneous insulin infusion (CSII), both with either self-monitoring of blood glucose (SMBG) or CGM, for the management of T1DM in adults and children.

DATA SOURCES

A systematic review was conducted in accordance with the principles of the Centre for Reviews and Dissemination guidance and the National Institute for Health and Care Excellence Diagnostic Assessment Programme manual. We searched 14 databases, three trial registries and two conference proceedings from study inception up to September 2014. In addition, reference lists of relevant systematic reviews were checked. In the absence of randomised controlled trials directly comparing Veo or an integrated CSII + CGM system, such as Vibe, with comparator interventions, indirect treatment comparisons were performed if possible.

METHODS

A commercially available cost-effectiveness model, the IMS Centre for Outcomes Research and Effectiveness diabetes model version 8.5 (IMS Health, Danbury, CT, USA), was used for this assessment. This model is an internet-based, interactive simulation model that predicts the long-term health outcomes and costs associated with the management of T1DM and type 2 diabetes. The model consists of 15 submodels designed to simulate diabetes-related complications, non-specific mortality and costs over time. As the model simulates individual patients over time, it updates risk factors and complications to account for disease progression.

RESULTS

Fifty-four publications resulting from 19 studies were included in the review. Overall, the evidence suggests that the Veo system reduces hypoglycaemic events more than other treatments, without any differences in other outcomes, including glycated haemoglobin (HbA1c) levels. We also found significant results in favour of the integrated CSII + CGM system over MDIs with SMBG with regard to HbA1c levels and quality of life. However, the evidence base was poor. The quality of the included studies was generally low, often with only one study comparing treatments in a specific population at a specific follow-up time. In particular, there was only one study comparing Veo with an integrated CSII + CGM system and only one study comparing Veo with a CSII + SMBG system in a mixed population. Cost-effectiveness analyses indicated that MDI + SMBG is the option most likely to be cost-effective, given the current threshold of £30,000 per quality-adjusted life-year gained, whereas integrated CSII + CGM systems and Veo are dominated and extendedly dominated, respectively, by stand-alone, non-integrated CSII with CGM. Scenario analyses did not alter these conclusions. No cost-effectiveness modelling was conducted for children or pregnant women.

CONCLUSIONS

The Veo system does appear to be better than the other systems considered at reducing hypoglycaemic events. However, in adults, it is unlikely to be cost-effective. Integrated systems are also generally unlikely to be cost-effective given that stand-alone systems are cheaper and, possibly, no less effective. However, evidence in this regard is generally lacking, in particular for children. Future trials in specific child, adolescent and adult populations should include longer term follow-up and ratings on the European Quality of Life-5 Dimensions scale at various time points with a view to informing improved cost-effectiveness modelling.

STUDY REGISTRATION

PROSPERO Registration Number CRD42014013764.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Cost-effectiveness of once daily GLP-1 receptor agonist lixisenatide compared to bolus insulin both in combination with basal insulin for the treatment of patients with type 2 diabetes in Norway

BACKGROUND

Lixisenatide is a potent, selective and short-acting once daily prandial glucagon-like peptide-1 receptor agonist which lowers glycohemoglobin and body weight by clinically significant amounts in patients with type 2 diabetes treated with basal insulin, with limited risk of hypoglycemia.

OBJECTIVE

To assess the cost-effectiveness of lixisenatide versus bolus insulin, both in combination with basal insulin, in patients with type 2 diabetes in Norway.

METHODS

The IMS CORE Diabetes Model, a non-product-specific and validated simulation model, was used to make clinical and cost projections. Transition probabilities, risk adjustments and the progression of complication risk factors were derived from the UK Prospective Diabetes Study, supplemented with Norwegian data. Patients were assumed to receive combination treatment with basal insulin, lixisenatide or bolus insulin therapy for 3 years, followed by intensification of a basal-bolus insulin regimen for their remaining lifetime. Simulated healthcare costs, taken from the public payer perspective, were derived from microcosting and diagnosis related groups, discounted at 4% per annum and reported in Norwegian krone (NOK). Productivity costs were also captured based on extractions from the Norwegian Labor and Welfare Administration. Health state utilities were derived from a systematic literature review. Sensitivity and scenario analyses were performed.

RESULTS

Lixisenatide in combination with basal insulin was associated with increased quality-adjusted life years (QALYs) and reduced lifetime healthcare costs compared to bolus insulin in combination with basal insulin in patients with Type 2 diabetes, and can be considered dominant. The net monetary benefit of lixisenatide versus bolus insulin was NOK 39,369 per patient. Results were sensitive to discounting, the application of excess body weight associated disutility and uncertainty surrounding the changes in HbA1c.

CONCLUSIONS

Lixisenatide may be considered an economically efficient therapy in combination with basal insulin in the Norwegian setting, due to cost savings, weight loss and associated gains in health-related quality of life.

Analytic evaluation of a new glucose meter system in 15 different critical care settings

BACKGROUND

Maintaining appropriate glycemic control in critically ill patients reduces morbidity and mortality. The use of point-of-care (POC) glucose devices is necessary to obtain rapid results at the patient's bedside. However, the devices should be thoroughly tested in the intended population before implementation. The use of POC glucose meters in critically ill patients has been questioned both in the literature and by regulatory agencies. The aim of this study was to determine if the ACCU-CHEK® Inform II system (Roche Diagnostics) POC glucose meter demonstrated the desired accuracy and precision, as defined by Clinical and Laboratory Standards Institute guideline POCT12-A3, in a large number of critically ill patients from multiple intensive care settings at two academic medical centers.

METHODS

A total of 1200 whole blood meter results from 600 patients were compared with central laboratory plasma values. Whole blood aliquots from venous samples were used to obtain duplicate meter results with the remaining sample being processed to obtain plasma for central laboratory testing within 5 min of meter testing.

RESULTS

A total of 1185 (98.8%) of the new meter's glucose values were within ± 12.5% (± 12 mg/dl for values ≥ 100 mg/dl) of the comparative laboratory glucose values, and 1198 (99.8%) were within ± 20% (± 20 mg/dl for values <100 mg/dl).

CONCLUSIONS

Considering the large number of patients from numerous critical care units examined, the new glucose meter system appears to have sufficient analytic accuracy for use in critically ill patients.

Relationship between perioperative glycemic control and postoperative infections

Perioperative hyperglycemia in critically ill surgery patients increases the risk of postoperative infection (POI), which is a common, and often costly, surgical complication. Hyperglycemia is associated with abnormalities in leukocyte function, including granulocyte adherence, impaired phagocytosis, delayed chemotaxis, and depressed bactericidal capacity. These leukocyte deficiencies are the cause of infection and improve with tight glycemic control, which leads to fewer POIs in critically ill surgical patients. Tight glycemic control, such as intensive insulin therapy, has a risk of hypoglycemia. In addition, the optimal targeted blood glucose range to reduce POI remains unknown. Since 2006, we have investigated tight perioperative blood glucose control using a closed-loop artificial endocrine pancreas system, to reduce POI and to avoid hypoglycemia. In this Topic Highlight, we review the relationship between perioperative glycemic control and POI, including the use of the artificial pancreas.

Intensive versus conventional insulin therapy: a randomized controlled trial in medical and surgical critically ill patients

OBJECTIVE

The role of intensive insulin therapy in medical surgical intensive care patients remains unclear. The objective of this study was to examine the effect of intensive insulin therapy on mortality in medical surgical intensive care unit patients.

DESIGN

Randomized controlled trial.

SETTINGS

Tertiary care intensive care unit.

PATIENTS

Medical surgical intensive care unit patients with admission blood glucose of > 6.1 mmol/L or 110 mg/dL.

INTERVENTION

A total of 523 patients were randomly assigned to receive intensive insulin therapy (target blood glucose 4.4-6.1 mmol/L or 80-110 mg/dL) or conventional insulin therapy (target blood glucose 10-11.1 mmol/L or 180-200 mg/dL).

MEASUREMENTS AND MAIN OUTCOMES

The primary end point was intensive care unit mortality. Secondary end points included hospital mortality, intensive care unit and hospital length of stay, mechanical ventilation duration, the need for renal replacement therapy and packed red blood cells transfusion, and the rates of intensive care unit acquired infections as well as the rate of hypoglycemia (defined as blood glucose < or = 2.2 mmol/L or 40 mg/dL). There was no significant difference in intensive care unit mortality between the intensive insulin therapy and conventional insulin therapy groups (13.5% vs. 17.1%, p = 0.30). After adjustment for baseline characteristics, intensive insulin therapy was not associated with mortality difference (adjusted hazard ratio 1.09, 95% confidence interval 0.70-1.72). Hypoglycemia occurred more frequently with intensive insulin therapy (28.6% vs. 3.1% of patients; p < 0.0001 or 6.8/100 treatment days vs. 0.4/100 treatment days; p < 0.0001). There was no difference between the intensive insulin therapy and conventional insulin therapy in any of the other secondary end points.

CONCLUSIONS

Intensive insulin therapy was not associated with improved survival among medical surgical intensive care unit patients and was associated with increased occurrence of hypoglycemia. Based on these results, we do not advocate universal application of intensive insulin therapy in intensive care unit patients.

TRIAL REGISTRATION

Current Controlled Trials registry (ISRCTN07413772) http://www.controlled-trials.com/ISRCTN07413772/07413772; 2005.

Glycemic control in the ICU

Glycemic control clearly improves outcome in critically ill patients. Remaining questions are how tight the control must be to obtain the most benefit without increasing the risk for severe hypoglycemia, and whether an acuity level exists in which this benefit is not clearly visualized. In other words, is this benefit only seen in severely ill patients? The authors believe that clinical trials with ICU lengths of stay of 3 days or less make showing a clinical benefit difficult. Rather, they believe that clinical benefit is seen in higher acuity patients whose ICU length of stay is directly related to the reversal of the inflammatory systemic response rather than the disease or injury alone. Finally, the issue remains of how to obtain a TGC in the 80 to 110 mg/dL range without achieving a less-than-acceptable incidence of hypoglycemia. The answer may well lie with the introduction of continuous glucose monitors that will allow measurements to be obtained every 15 to 30 minutes without introducing an increased workload to the nursing staff. Many of these devices, such as the Optiscanner, which measures plasma glucose continuously, are on the horizon and should be approved by the FDA in 2008.

Practice and perception--a nationwide survey of therapy habits in sepsis

OBJECTIVE

To simultaneously determine perceived vs. practiced adherence to recommended interventions for the treatment of severe sepsis or septic shock.

DESIGN

One-day cross-sectional survey.

SETTING

Representative sample of German intensive care units stratified by hospital size.

PATIENTS

Adult patients with severe sepsis or septic shock.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Practice recommendations were selected by German Sepsis Competence Network (SepNet) investigators. External intensivists visited intensive care units randomly chosen and asked the responsible intensive care unit director how often these recommendations were used. Responses "always" and "frequently" were combined to depict perceived adherence. Thereafter patient files were audited. Three hundred sixty-six patients on 214 intensive care units fulfilled the criteria and received full support. One hundred fifty-two patients had acute lung injury or acute respiratory distress syndrome. Low-tidal volume ventilation < or = 6 mL/kg/predicted body weight was documented in 2.6% of these patients. A total of 17.1% patients had tidal volume between 6 and 8 mL/kg predicted body weight and 80.3% > 8 mL/kg predicted body weight. Mean tidal volume was 10.0 +/- 2.4 mL/kg predicted body weight. Perceived adherence to low-tidal volume ventilation was 79.9%. Euglycemia (4.4-6.1 mmol/L) was documented in 6.2% of 355 patients. A total of 33.8% of patients had blood glucose levels < or = 8.3 mmol/L and 66.2% were hyperglycemic (blood glucose > 8.3 mmol/L). Among 207 patients receiving insulin therapy, 1.9% were euglycemic, 20.8% had blood glucose levels < or = 8.3 mmol/L, and 1.0% were hypoglycemic. Overall, mean maximal glucose level was 10.0 +/- 3.6 mmol/L. Perceived adherence to strict glycemic control was 65.9%. Although perceived adherence to recommendations was higher in academic and larger hospitals, actual practice was not significantly influenced by hospital size or university affiliation.

CONCLUSIONS

This representative survey shows that current therapy of severe sepsis in German intensive care units complies poorly with practice recommendations. Intensive care unit directors perceive adherence to be higher than it actually is. Implementation strategies involving all intensive care unit staff are needed to overcome this gap between current evidence-based knowledge, practice, and perception.

Improvement in glycemic control and outcome corresponding to intensive insulin therapy protocol development

BACKGROUND

Intensive insulin therapy (IIT) has been shown to reduce mortality and morbidity in longer stay, critically ill patients. However, this has been demonstrated in a single site, whereas two multicentric studies have been terminated prematurely mainly due to hypoglycemia. Other difficulties with IIT include efficacy of glycemic control. This report describes how IIT can be improved by protocol simplification and removal of glucose supplementation.

METHODS

A clinical information system established at each bedspace guided staff through the IIT algorithms. Time spent within predefined glycemic ranges was calculated assuming a linear trend between successive measurements. Three groups were investigated retrospectively: IIT1 protocol,(1) an updated IIT2 version, and intuitive nurse dosing of conventional insulin therapy (CIT).

RESULTS

Fifty consecutive, critically ill patients were included in each study group. Patient characteristics were similar in each group. The frequency of CIT and IIT2 blood glucose measurements were 11.6 and 11.5 measurements per day, respectively, while the IIT1 measurements were more frequent (14.5 measurements per day). The mean proportion of time spent in the target glycemic range (4.4-6.1 mmol/liter) was highest in the IIT2 group (34.9%), as compared to the IIT1 (22.9%) and CIT groups (20.3%) (p <.001). Survival at 28 days was 74.5% for IIT2 (highest), 68% for IIT1, and 48% for CIT (p = .02). There were a similar number of those experiencing a severe hypoglycemic event in each group.

CONCLUSIONS

IIT protocol optimization was associated with increased glycemic control and improved 28-day survival. The better optimized IIT2 protocol provided tighter control than either the IIT1 or CIT protocol, without increased sampling or incidence of hypoglycemia. The clinical effectiveness of the IIT algorithm appeared to be improved by simplifying the protocol to meet the needs of the critical care unit.

Accuracy of bedside glucometry in critically ill patients: influence of clinical characteristics and perfusion index

OBJECTIVES

To determine the accuracy of bedside glucose strip assay on capillary blood and on whole blood and to identify factors predictive of discrepancies with the laboratory method.

PATIENTS AND METHODS

We conducted a prospective 3-month (July 1-September 30, 2003) study in 85 consecutive patients who required blood glucose monitoring. Values obtained with a glucose test strip on capillary blood and on whole blood were compared with those obtained in the laboratory during serial blood sampling (up to 4 samples per patient). The test strip values were considered to disagree significantly with the laboratory values when the difference exceeded 20%. Clinical and biological parameters and the perfusion index, based on percutaneous oxygen saturation monitoring, were recorded when each sample was obtained.

RESULTS

Capillary glucose values conflicted with laboratory reference values in 15% of samples. A low perfusion index was predictive of conflicting values (P=.04). Seven percent of values obtained with glucose strip on whole-blood samples conflicted with laboratory reference values; factors associated with these discrepancies were mean arterial hypotension (P=.007) and generalized mottling (P=.04).

CONCLUSION

Bedside blood glucose values must be interpreted with care in critically ill patients. A low perfusion index, reflecting peripheral hypoperfusion, is associated with poor glucose strip performance. Bedside measurements in whole blood seem to be most reliable, except in patients with arterial hypotension and generalized mottling.

Improvement of Glucose Control in the Intensive Care Unit: An Interdisciplinary Collaboration Study

Background Strict glycemic control in critically ill patients is challenging for both physicians and nurses.

Objectives To determine the effect of focused education of intensive care staff followed by implementation of a glucose control protocol.

Methods A prospective observational study in a medical intensive care unit in a university hospital. After intensive education of nurses and physicians, a glucose control protocol with a nurse-managed insulin therapy algorithm was developed and implemented. Every measured blood glucose value and insulin dose per hour and per day were documented in 36 patients before and 44 patients after implementation of the protocol.

Results Median blood glucose levels decreased after implementation of the protocol (133 vs 110 mg/dL; P &lt; .001). The amounts of time when patients’ blood glucose levels were less than 110 mg/dL and less than 150 mg/dL increased after implementation of the protocol (8% vs 44%; 75% vs 96%; P&lt;.001). The median use of insulin increased after implementation of the protocol (28 vs 35 IU/day; P=.002). Diabetic patients had higher median blood glucose levels than did nondiabetic patients both before (138 vs 131 mg/dL) and after (115 vs 108 mg/dL; P&lt;.001) implementation, although median insulin use also increased (before implementation, 33 vs 26 IU/day; P=.04; after implementation, 46 vs 30 IU/day; P &lt; .001).

Conclusions Use of a collaboratively developed glucose control protocol led to decreased median blood glucose levels and to longer periods of normoglycemia. Despite increased insulin use, glucose control was worse in diabetic patients.

Tight glycaemic control by an automated algorithm with time-variant sampling in medical ICU patients

OBJECTIVE

Tight glycaemic control (TGC) in critically ill patients improves clinical outcome, but is difficult to establish The primary objective of the present study was to compare glucose control in medical ICU patients applying a computer-based enhanced model predictive control algorithm (eMPC) extended to include time-variant sampling against an implemented glucose management protocol.

DESIGN

Open randomised controlled trial.

SETTING

Nine-bed medical intensive care unit (ICU) in a tertiary teaching hospital.

PATIENTS AND PARTICIPANTS

Fifty mechanically ventilated medical ICU patients.

INTERVENTIONS

Patients were included for a study period of up to 72 h. Patients were randomised to the control group (n = 25), treated by an implemented insulin algorithm, or to the eMPC group (n = 25), using the laptop-based algorithm. Target range for blood glucose (BG) was 4.4-6.1 mM. Efficacy was assessed by mean BG, hyperglycaemic index (HGI) and BG sampling interval. Safety was assessed by the number of hypoglycaemic-episodes < 2.2 mM. Each participating nurse filled-in a questionnaire regarding the usability of the algorithm.

MEASUREMENTS AND MAIN RESULTS

BG and HGI were significantly lower in the eMPC group [BG 5.9 mM (5.5-6.3), median (IQR); HGI 0.4 mM (0.2-0.9)] than in control patients [BG 7.4 mM (6.9-8.6), p < 0.001; HGI 1.6 mM (1.1-2.4), p < 0.001]. One hypoglycaemic episode was detected in the eMPC group; no such episodes in the control group. Sampling interval was significantly shorter in the eMPC group [eMPC 117[Symbol: see text]min (+/- 34), mean (+/- SD), vs 174 min (+/- 27); p < 0.001]. Thirty-four nurses filled-in the questionnaire. Thirty answered the question of whether the algorithm could be applied in daily routine in the affirmative.

CONCLUSIONS

The eMPC algorithm was effective in maintaining tight glycaemic control in severely ill medical ICU patients.

Evaluation of diabetes management in a rural community hospital

OBJECTIVE

To evaluate the effectiveness of implementing standardized insulin protocols in a small, rural community hospital.

METHODS

This retrospective review was performed on charts of 300 inpatients who received insulin treatment while hospitalized between January 1, 2006, and June 30, 2006. For patients who met the inclusion criteria, the collected information included the following: serum glucose level at hospital admission, glucose level that initiated the treatment protocol, time-to-fasting euglycemia, time-to-random euglycemia, and method of insulin administration. Comparisons were performed between the effectiveness of the new insulin protocols and routine insulin treatment orders.

RESULTS

A total of 168 patients met the study inclusion criteria. The mean glucose concentration that triggered initiation of insulin treatment was 262 mg/dL, which is significantly higher (P<.001) than levels recommended by the American Diabetes Association (ADA) and the American College of Endocrinology (ACE). There was a statistically significant relationship (P = .007) between time-to-fasting euglycemia and length of hospital stay. Implementation of the standardized insulin protocol did not improve the achievement of fasting euglycemia (P = .753). Most patients never reached the target glucose level goals despite the use of standardized protocol.

CONCLUSION

Significant delays in initiating the insulin protocol and frequent failure in achieving target glucose levels demonstrate delayed recognition of hyperglycemia by hospital staff as well as ineffective use of standardized insulin protocols. Protocol improvement and increased hospital staff education concerning appropriate hospital target glucose levels are required to achieve ADA/ACE recommendations in small community hospitals.

Blood glucose control in critical care patients - a review of the literature

The role of hyperglycaemia in critical illness, and its corresponding treatment, has been an area of controversy, fuelled by conflicting research findings. The aims of this study were to critically evaluate the literature and present an historical review of the sequence of published papers relating to blood glucose control in critical care. Their subsequent impact together with the implications for patient care is discussed. This article is based on a systematic review of papers relating to glycaemic control in critical care patients. The review was conducted using the MedLine, CINAHL and EMBASE databases using key search terms (details of the search terms can be found after the conclusion of the paper) for the period 1950-2006. The searches resulted in 4863 papers being screened for relevance to the historic progression of glycaemic management in critical care patients, by title and then abstract. Of these, 209 were accessed, and their reference lists were snowballed for further papers. Papers that were repeatedly quoted throughout the literature and were therefore considered important in the historical development of accepted critical care practice were finally subjected to rigorous appraisal. These totalled 91 papers and included 18 randomized controlled trials, an additional 28 research papers, 25 editorials and 20 reviews. This critical evaluation of published work indicates that the evidence for the benefit of this therapy may not be as compelling as previously indicated, and its widespread use may have been premature. From a nursing perspective, this demonstrates the importance of maintaining a questioning attitude to new therapies and reviewing best practice in the light of evolving evidence.

Clinical experience with tight glucose control by intensive insulin therapy

OBJECTIVE

To describe the current status and the clinical data related to the effects of tight glucose control by intensive insulin therapy in critically ill patients.

DESIGN

Review article.

SETTING

University hospital.

PATIENTS

Medical and surgical critically ill patients in whom a correlation between blood glucose and outcome variables were searched.

INTERVENTIONS

Tight glucose control by intensive insulin therapy.

MEASUREMENTS AND MAIN RESULTS

In contrast to the decreases in mortality and to low severity of adverse effects reported when insulin rate was titrated to keep blood glucose between 80 and 110 mg/dL, the benefits were not confirmed in multicenter prospective studies. Retrospective data found an association between a mean blood glucose level of <140-150 mg/dL and improved outcome. Currently unanswered issues include the optimal target for blood glucose, the effects of high blood glucose variability, the risks and hazards of hypoglycemia, and the potential influence of the underlying disorder on the effects of tight glucose control.

CONCLUSIONS

Recommendations regarding the practical aspects of tight glucose control by intensive insulin therapy cannot be presently issued. An intermediate target level for blood glucose of 140-180 mg/dL seems to be associated with the lowest risk-to-benefit ratio.

Intensive insulin therapy for acute hyperglycemia

There is growing evidence that control of hyperglycemia in the critically ill patient improves outcome. Normalizing blood glucose levels decreases the risk of developing sepsis, end-organ damage, and hospital mortality. Critical care clinicians must be familiar with current and benchmark research supporting control of hyperglycemia and use this knowledge to ensure appropriate application of evidence-based practice for decreasing or preventing complications in the critically ill patient. This article describes the effects of hyperglycemia and discusses the evidence supporting tight glycemic control in such patients. The necessary steps to implement an intensive insulin therapy protocol for control of acute hyperglycemia are detailed.

Poor glycemic control is associated with increased mortality in critically ill trauma patients

Glycemic control improves outcome in cardiac surgical patients and after myocardial infarction or stroke. Hyperglycemic predicts poor outcome in trauma, but currently no data exist on the effect of glycemic control in critically ill trauma patients. In our intensive care unit (ICU), we use a subcutaneous sliding scale insulin protocol to achieve glucose levels <140 mg/dL. We hypothesized that aggressive glycemic control would be associated with improved outcome in critically ill trauma patients. At our urban Level 1 trauma center, a retrospective study was conducted of all injured patients admitted to the surgical ICU >48 hours during a 6-month period. Data were collected for mechanism of injury, age, diabetic history, Injury Severity Score (ISS), and APACHE II score. All blood glucose levels, by laboratory serum measurement or by point-of-care finger stick, were collected for the entire ICU stay. Outcome data (mortality, ICU and hospital length of stay, ventilator days, and complications) were collected and analyzed. Patients were stratified by their preinjury diabetic history and their level of glucose control (controlled <140 mg/dL vs non-controlled > or =141 mg/dL) and these groups were compared. During the study period, 103 trauma patients were admitted to the surgical ICU >48 hours. Ninety (87.4%) were nondiabetic. Most (83.5%) sustained blunt trauma. The average age was 50 +/- 21 years, the average ISS was 22 +/- 12, and the average APACHE II was 16 +/- 9. The average glucose for the population was 128 +/-25 mg/dL. Glycemic control was not attained in 27 (26.2%) patients; 19 (70.4%) of these were nondiabetic. There were no differences in ISS or APACHE II for controlled versus non-controlled patients. However, non-controlled patients were older. Mortality was 9.09 per cent for the controlled group and was 22.22 per cent for the non-controlled group. Diabetic patients were older and less severely injured than nondiabetics. For nondiabetic patients, mortality was 9.86 per cent in controlled patients and 31.58 per cent in non-controlled patients (P < 0.05). Also, urinary tract infections were more prevalent and complication rates overall were higher in nondiabetic patients with noncontrolled glucose levels. Nonsurvivors had higher average glucose than survivors (P < 0.03). Poor glycemic control is associated with increased morbidity and mortality in critically ill trauma patients; this is more pronounced in nondiabetic patients. Age may be a factor in these findings. Subcutaneous sliding scale insulin alone may be inadequate to maintain glycemic control in older critically ill injured patients and in patients with greater physiologic insult. Prospective assessment is needed to further clarify the benefits of aggressive glycemic control, to assess the optimal mode of insulin delivery, and to better define therapeutic goals in critically ill, injured patients.

Fatal neuroglycopaenia after accidental use of a glucose 5% solution in a peripheral arterial cannula flush system

A patient on an Intensive Care Unit who was recovering from multiple organ failure was being given an intravenous infusion of insulin to maintain normoglycaemia. On her 20th day in the unit, she suddenly became unresponsive. A cerebrovascular accident was suspected as other clinical and laboratory parameters remained normal apart from a blood glucose value of 20.6 mmol.l(-1). The insulin infusion rate had been increased to treat hyperglycaemia. Subsequent bedside finger prick blood testing suggested that the blood sugar was low but no numerical reading was provided. Repeat blood glucose analysis using a further sample drawn from the arterial line and measured in the blood gas analyser gave a value of 10.1 mmol.l(-1). Confirmatory laboratory blood tests revealed severe hypoglycaemia (0.1 mmol.l(-1)) and intravenous glucose 50% was given immediately. Examination showed that a glucose 5% solution had been inadvertently used in the arterial cannula flush system rather than saline, contaminating earlier samples drawn from the arterial line and giving falsely high blood glucose values. The prolonged period of severe hypoglycaemia led to neuroglycopaenia and irreversible brain injury. The patient died 9 days later without regaining consciousness. Such a complication has not previously been reported in this context and has particular significance given the increasing use of insulin therapy to maintain normoglycaemia in critically ill patients.

Failure to achieve glycemic control despite intensive insulin therapy in a medical ICU: incidence and influence on ICU mortality

OBJECTIVE

Intensive insulin therapy reduces mortality in subgroups of intensive care unit (ICU) patients, and awareness of the importance of blood glucose level (BGL) control has increased among ICU physicians and nurses. The impact of insulin treatment strategies on mortality may be influenced by their efficacy in achieving the target BGL range. We assessed the efficacy of an insulin treatment strategy in maintaining BGL within the target range, and we compared ICU mortality in patients who did and did not reach the BGL target.

DESIGN

Prospective cohort study.

SETTING

12-bed medical ICU in a tertiary teaching hospital.

PATIENTS AND PARTICIPANTS

Adults consecutively admitted over a 9-month period to an ICU where standard care included an insulin treatment strategy aimed at maintaining BGL<or=7 mmol/l.

MEASUREMENTS AND MAIN RESULTS

105 patients were included. Median SAPS II was 45 (31-54). Failure to control BGL (mean capillary BGL >7 mmol/l after initial hyperglycemia correction) occurred in 32 patients (31.1%) and was associated with a significant increase in ICU mortality (56.2 vs. 23.3% in patients with successful BGL control). In the multivariate analysis, failure to control BGL independently predicted death in the ICU (OR 5.9, 2.1-16.6, p<0.001).

CONCLUSIONS

Failure to control BGL despite intensive insulin therapy was common and independently associated with ICU mortality. Failure to control BGL may considerably affect the overall impact of insulin treatment strategies on mortality.

Current controversies around tight glucose control in critically ill patients

PURPOSE OF REVIEW

This review updates our knowledge on the benefits and risks of tight glucose control by intensive insulin therapy in critically ill patients, as well as discussing unanswered questions related to the subject.

RECENT FINDINGS

At the cellular level, the toxic effects of elevated and highly variable glucose concentration are related to an increase in oxidative stress and to several toxic intracellular derivates generated as by-products of the glycolytic pathway. Clinically, several recent studies have suggested that the optimal target for blood glucose may be higher than the 'normal' values of 4.4-6.1 mmol/l for various categories of patients. Also, the variability in glucose level appears to be an important determinant of glucose toxicity. Conflicting data on the hazards of hypoglycaemia are emerging.

SUMMARY

Practical recommendations for the implementation of tight glucose control using intensive insulin therapy cannot be disseminated until questions relating to optimal blood glucose level and the corresponding categories of patients have been resolved. The issues of glucose variability and the most efficient method of preventing hypoglycaemia will probably represent important parameters for comparing the safety and quality of protocols used for tight glucose control.

Impact of bolus application of low-dose hydrocortisone on glycemic control in septic shock patients

OBJECTIVE

To determine whether glycemic control is less feasible when hydrocortisone is given as a bolus compared with continuous application in septic shock patients.

DESIGN

Observational prospective pilot study.

SETTING

Fourteen-bed surgical university hospital ICU.

PATIENTS

Sixteen consecutive patients with septic shock receiving a continuous infusion of 200 mg hydrocortisone/day and an infusion regime of insulin keeping blood glucose below 150 mg/dl.

INTERVENTION

Blood glucose and insulin infusion were adjusted to steady state before intervention. At baseline, the continuous hydrocortisone infusion was replaced with a single bolus of 50 mg hydrocortisone. During a subsequent 6-h period, blood glucose was monitored hourly and insulin infusion was kept constant. Afterwards, hydrocortisone application and adjustment of blood glucose was resumed according to standard treatment.

RESULTS

Mean blood glucose in steady state at baseline immediately prior to intervention was 128 mg/dl (range 114-141 mg/dl; 95% confidence interval). After bolus injection of hydrocortisone, blood glucose increased significantly within 6 h with peak levels of 154 mg/dl (range 132-178 mg/dl; p<0.01). Blood glucose returned to baseline with restoration of continuous hydrocortisone infusion. There were marked inter-individual variations with peak glucose values up to 254 mg/dl, but no significant difference in intra-individual glucose variability before and after bolus injection of hydrocortisone.

CONCLUSIONS

Bolus injections of hydrocortisone may induce significant increases of blood glucose in patients with septic shock. The individual response is highly variable and we speculate that repetitive boluses would induce marked undulation of blood glucose. In terms of glycemic-control strategies, a continuous infusion of hydrocortisone seems to be preferable.

Lowering of glucose in critical care: a randomized pilot trial

BACKGROUND

Similar to cardiac surgery patients, medical-surgical critically ill patients may benefit from intensive insulin therapy. The objectives of this pilot trial were to evaluate the feasibility of a randomized trial of intensive insulin therapy with respect to (a) achieving target glucose values in the 2 ranges of 5 to 7 and 8 to 10 mmol/L and (b) uncovering problems with the protocol in anticipation of a larger trial.

SETTING

The trial was conducted in a 15-bed medical-surgical university-affiliated intensive care unit (ICU).

METHODS

We included patients older than 18 years, expected to be in ICU for more than 72 hours, with a glucose value of more than 10 mmol/L within 48 hours of ICU admission. Exclusion criteria were diabetic ketoacidosis, severe hepatic failure or hepatic resection, pancreatitis, glucose of less than 2.2 mmol/L on admission to hospital, insulin infusion on admission to ICU, planned withdrawal of life support, and inability to obtain informed consent. Patients underwent concealed random allocation to a target glucose range of 5 to 7 or 8 to 10 mmol/L using pretested algorithms of insulin infusions. Dedicated glucometer measurement of arterial glucose values was calibrated daily to values measured in the laboratory.

RESULTS

We enrolled 20 patients with a mean (SD) Acute Physiology and Chronic Health Evaluation (APACHE) II score of 32 (10.2); 14 were insulin-dependent pre-ICU, and all were medical admissions. Mean glucose values were different in the 2 groups (7.1 +/- 2.6 vs 9.4 +/- 2.1 mmol/L, P < .001). Although the intensive insulin therapy group had more glucose measurements performed than the control group, a similar proportion of values were within the target range (682 [42.4%] of 1607 values in the 5- to 7-mmol/L range; 250 [38.7%] of 660 values in the 8- to 10-mmol/L range, P = .35). Glucose values of less than 2.5 mmol/L developed 7 times in 5 patients, 4 of whom were in the intensive insulin therapy group; however, no adverse consequences were documented. As expected, there were no differences in clinically important outcomes.

CONCLUSIONS

In this pilot trial of ICU patients with high illness severity, glucose values were in the 2 target ranges only 40% of the time, using well-accepted initiation and maintenance insulin infusion algorithms. A large randomized trial of glycemic control is feasible in this population to examine clinically important outcomes, but will require refined insulin algorithms and more comprehensive behavior change strategies to achieve target values.

Intensive insulin therapy in intensive care: an example of the struggle to implement evidence-based medicine

Schultz and colleagues discuss the factors hindering implementation of intensive insulin therapy.

Implementing tight glucose control after coronary artery bypass surgery

BACKGROUND

The clinical benefit of tight glucose control has been demonstrated in diabetic patients. In adopting an approach of tight glucose control for all cardiac surgery patients at Beth Israel Deaconess Medical Center, we encountered several challenges, including defining good glucose control, meaningfully measuring control, and assessing the impact of variables that may affect control.

METHODS

An interdisciplinary team used an insulin protocol to achieve tight glucose control of cardiac surgery patients in the operating room and intensive care unit as part of an effort to reduce sternal wound infections. Good control was defined as glucose less than 130 mg/dL for more than 50% of measured time.

RESULTS

Eight hundred eighteen patients underwent coronary artery bypass grafting between November 2002 and August 2004. Seven hundred thirty-seven (90%) received insulin. Fifty-seven percent did not have a preoperative diagnosis of diabetes. The trigger for insulin initiation was decreased sequentially from 150 mg/dL to 110 mg/dL, but the measure of good control remained the same: glucose less than 130 mg/dL. The factor most highly predictive of glucose being well controlled was the protocol with the 110 mg/dL trigger for insulin (p < 0.001). Patient factors such as age, ejection fraction, preoperative angiotensin-converting enzyme inhibitor or beta-blocker use, or time on cardiopulmonary bypass were not significantly associated with glucose control. During the course of the protocols, the rate of mediastinitis decreased from 1.6% to 0%.

CONCLUSIONS

Key elements to implementing tight glucose control include having a standard protocol and metrics to track protocol performance. This practice improved control and was associated with a marked reduction in mediastinitis.

Barriers to Glucose Control in the Intensive Care Unit

Despite published evidence supporting glycemic control in critically ill patients, achieving euglycemia remains a problem in the intensive care units (ICUs) of many institutions. Clinicians seeking to implement the findings of published evidence in their practice face many potential barriers that make euglycemia difficult to achieve in patients in the ICU. Developing a comprehensive understanding of the many barriers to ICU glucose control can aide clinicians in attempting to change practice and improve patient outcomes. Barriers to ICU glucose control include the role of different health professionals in glucose management, communication among health care professionals, guidelines, protocols, ICU culture, fear of hypoglycemia, glucose monitoring, education, systems analysis, health care resources, nutritional needs, and drug utilization. By ensuring compliance, changing ICU culture, developing guidelines and protocols, and incorporating a multidisciplinary approach, clinicians can achieve glycemic control in the critically ill population and improve patient outcomes.

Analysis of blood glucose measurements using capillary and arterial blood samples in intensive care patients

OBJECTIVE

To analyse agreement between two methods for blood glucose measurement in intensive care patients: capillary blood using a reagent strip and glucometer with arterial blood using a blood gas analyser.

DESIGN AND SETTING

Prospective, single-centre, observational study in a 12-bed tertiary referral intensive care unit.

MEASUREMENTS

Blood glucose levels were measured in consecutive patients using simultaneous measurements of capillary blood samples using glucometry and from a multi-electrode arterial blood gas analyser. An a priori subgroup of patients with tissue hypoperfusion was identified (defined as systolic blood pressure <90 mmHg or vasopressor dependency). A total of 493 paired measurements were obtained; 75 of these were from patients with systemic hypoperfusion.

RESULTS

Overall, the mean difference (bias) was 0.12 mmol/l (2.15 mg/dl) and precision 0.77 mmol/l (13.8 mg/dl); 95% limits of agreement were -0.14 and 1.66 mmol/l (-2.5 and 29.8 mg/dl). In patients with systemic hypoperfusion the bias was 0.24 mmol/l (4.0 mg/dl) and precision 0.9 mmol/l (16.2 mg/dl); 95% limits of agreement -2.05 and 1.58 mmol/l (36.8 and 28.4 mg/dl).

CONCLUSIONS

In a general population of intensive care patients, there is statistical agreement between blood glucose measured from capillary blood glucometry and arterial blood gas analysis. However, in patients with systemic hypoperfusion, the accuracy of agreement between these two measurement techniques may be such that that biochemical hypoglycaemia (<2.5 mmol/l, 44.9 mg/dl) may go undetected if used interchangeably.

Tight blood glucose control: a recommendation applicable to any critically ill patient?

The issue of tight glucose control with intensive insulin therapy in critically ill patients remains controversial. Although compelling evidence supports this strategy in postoperative patients who have undergone cardiac surgery, the use of tight glucose control has been challenged in other situations, including in medical critically ill patients and in those who have undergone non-cardiac surgery. Similarly, the mechanisms that underlie the effects of high-dose insulin are not fully elucidated. These arguments emphasize the need to study the effects of tight glucose control in a large heterogeneous cohort of intensive care unit patients.

Inpatient management of hospitalized patients with type 2 diabetes

Over the past 4 years, the scientific literature addressing issues relevant to inpatient hyperglycemia and its management has grown dramatically but remains incomplete. The growing interest in inpatient diabetes management is particularly pertinent given the epidemic rise in the prevalence of type 2 diabetes and the associated increase in the proportion of inpatients carrying this diagnosis. The benefits of aggressive glucose control are well-established in certain admission categories. These benefits likely apply to many other admission diagnoses, but remain unproven at this time. Similarly, the best methods of glucose control remain uncertain in the various inpatient settings. Intensive insulin infusion therapy is becoming the standard care in the intensive care unit setting. Its use is also growing in less acute inpatient settings but requires further study. Inpatient subcutaneous insulin recommendations are general based on experience gained in the outpatient setting but offer a practical, physiologic approach.