An Insulin Infusion Protocol in Critically Ill Cardiothoracic Surgery Patients

Nurse led protocols for control of glycaemia in critically ill patients: A systematic review

BACKGROUND

Blood glucose control in critically ill patients is challenging and can affect clinical outcomes. Several manual as well as automated approaches have been proposed over the time, however nursing staff still covers the key-role for optimization of glycemia throughout adjustment of insulin infusion and administration.

AIM

Systematic review to compare the efficacy/the effects of nurse led insulin infusion protocols versus standard approaches in patients admitted in the intensive care unit.

METHODS

All relevant studies evaluating nurse directed protocols for insulin administration in critically ill adults. Data was independently extracted and collected through a dedicated electronic form. The following outcomes have been recorded: the number (or percentage) of glycaemia measurements within the target range; the number of hypo- and hyper-glycaemic events, separately; the mean glycaemia; the lowest and highest glycemia values recorded; the time to reach the glycaemia target; the ICU length of stay and the ICU and the long-term (>30 days) mortality. Statistical analysis was conducted on the summary statistics of the selected articles (eg, means, medians, proportions). Unpaired nonparametric continuous data were compared through the Mann-Whitney U-test.

RESULTS

Glycaemic control as well as ICU length of stay and mortality are similar in both patients' groups. Specifically, the group of patients treated with standard modalities include those treated with doctors led protocols, paper charts or software-based approaches.

CONCLUSION

Overall, nurse led insulin protocols can effectively control blood glucose level among critically ill patients.

Methodology for the analysis and comparison of protocols for glycaemic control in intensive care

RATIONALE, AIMS, AND OBJECTIVES

The practice of glycaemic control of critically ill patients admitted to intensive care units (ICUs) is guided by clinical management protocols, designed locally by the ICUs. These protocols differ significantly in their aims and methods. The aim of this study was to develop a standardized methodology for the systematic and objective analysis and comparison of protocols for glycaemic control implemented in any ICU.

METHOD

The protocols for glycaemic control implemented in seven ICUs of a UK-based ICU network were analysed using techniques of inductive content analysis, through an open coding process and the framework method. This involved the identification and classification of protocol instructions for glycaemic control, as well as of the processes and decisions pertaining to each of these instructions. These were used to develop a framework for the structured and systematic description and comparison of the protocols' contents, and to develop a technique for the protocols' graphic visualization.

RESULTS

The following elements were identified or developed: (1) 35 quantifiable variables and 11 non-quantifiable subjects that could be present in an ICU protocol for glycaemic control, to be used as a framework for the description and comparison of contents; (2) a technique for condensing a protocol into a single, comprehensive flowchart; (3) using these flowcharts, a method for assessing the complexity and comprehensiveness of the protocols.

CONCLUSIONS

The methodology developed in this study will allow for any future work analysing the contents of glycaemic control protocols to be carried out in a structured and standardized way. This may be done either as a standalone study, or as the essential first step in any investigation on the impact of new protocols. In turn, the methodology will facilitate the performance of regional, national, and international comparisons, demonstrating the usefulness of this study at a global scale.

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.

Performance of a 2-step insulin infusion protocol with adjustment of insulin doses for Asians in the medical intensive care unit following cardiothoracic surgery

Background

Most previous insulin infusion protocols are titrated for Westerners and are not simple to follow. In this study, we tested the efficacy and safety of our simple insulin infusion protocol utilizing lower insulin doses for Asians.

Methods

A total of 152 patients with type 2 diabetes undergoing cardiothoracic surgery were included. After surgery, blood glucose (BG) was initially managed according to our algorithm protocol, and subsequently by the post-algorithm protocol. Insulin infusion rates in the algorithm protocol were titrated in two steps according to (1) current BG levels and (2) the difference between current and previous BG levels. In the post-algorithm protocol, insulin lispro was injected subcutaneously in addition to intravenous insulin infusion according to BG levels. The efficacy was assessed as achievement rates of two target BG ranges (140-199 and 80-199 mg/dL), and safety was assessed as hypoglycemia (< 70 mg/dL) and protocol error rates.

Results

With the use of the algorithm protocol, 58.7% of 1749 BG measurements achieved a range of 140-199 mg/dL, and 95.9% achieved levels within the 80-199 mg/dL range. Hypoglycemia and protocol error rates were 0.47 and 0.51%, respectively. With the post-algorithm protocol, 48.7 and 98.3% of 898 BG measurements achieved each target range. Hypoglycemia and protocol error rates were 0.78 and 0.22%, respectively. Severe hypoglycemia (< 40 mg/dL) was not observed.

Conclusions

Our insulin infusion protocol seems to be efficacious, safe, and widely feasible for Asian patients because of its simplicity and lower insulin dose.

Non-diabetic clinical applications of insulin

BACKGROUND

Introducing a new drug to the market is a time-consuming process, is complex, and involves consumption of a lot of resources. Therefore, discovering new uses for the old drugs (i.e. drug repurposing) benefits the patients by providing them time-tested drugs. With developments in insulin therapy still happening, it is worth keeping up to date on trends in the use of this powerful glucose-lowering agent. The aim of this article is to explore the potential non-diabetic clinical applications of insulin.

METHODS

Literature survey was carried out through the various scientific journals publishing experimental and clinical research papers regarding the diverse applications of insulin other than in diabetes mellitus. These applications include both therapeutic as well as diagnostic uses of insulin. The relevant information collected from these publications was paraphrased in the present paper.

RESULTS

On studying the literature, the non-diabetic uses of insulin include the following: wound healing, parenteral nutrition, antiaging, body building, cardioprotection in acute coronary syndromes, insulin tolerance test to test the hypothalamo-pituitary-adrenal axis functioning, cell culture, cancer treatment, organ preservation, and management of septic shock, calcium channel, β-blocker overdose and other critical illnesses in intensive care units.

CONCLUSIONS

This review attempts to survey some interesting new applications of insulin other than in diabetes mellitus.

The intraoperative glycemic response to intravenous insulin during noncardiac surgery: a subanalysis of the DeLiT randomized trial

Patient characteristics may affect patients' response to insulin. We examined the impact of body weight and presence of diabetes on the response to insulin during noncardiac surgery. We studied 202 patients who were enrolled in the DeLiT Trial and received intraoperative intravenous insulin. Univariable and multivariable analyses (Bonferroni corrected) assessed the relationship between patient's response to the initial intraoperative I.V. bolus of regular insulin and the factors of interest. Blood glucose concentrations decreased 8.3 ± 10mg/dL (0.46 ± 0.56mmol/L) per unit of I.V. insulin in 30minutes. The response to insulin was similar in patients with or without diabetes (adjusted mean difference [97.5% confidence interval], 0.2 [-3.9, 4.2] mg/dL, 0.01 [-0.22, 0.24] mmol/L; P = .93). No relationship was found between insulin response and body weight (P=0.38). Our results suggest that adjustment for body weight and the presence of diabetes may not improve intraoperative insulin treatment algorithms.

Assessment of quality of glycemic control in intensive care patients treated with an insulin infusion at a teaching hospital

OBJECTIVE

To describe the quality of glycemic control in patients in intensive care units (ICUs) treated with an intravenous (IV) insulin infusion at a teaching hospital.

METHOD

This retrospective study included patients admitted to the ICU and treated with an IV insulin infusion for at least 12 h between August 1 and November 30, 2011. Medical charts were reviewed. The primary quality indicator for glycemic control was the mean percent of blood glucose values per patient in the 6.1 to 8 mmol/L target range.

RESULTS

A total of 351 patients were included; 61.5% of subjects had no known diabetes. Admissions were mainly for surgery (61.3%). The mean Acute Physiology and Chronic Health Evaluation (APACHE) II score was 16.8±7.3. The mean percent of blood glucose values per patient in the 6.1 to 8 mmol/L range was 35% for all subjects and 26.2% for patients with diabetes. If a target of 6.1 to 10 mmol/L was considered, those values became 63% and 54.6%. At least 1 episode of hyperglycemia (>10 mmol/L), hypoglycemia (<4 mmol/L) or severe hypoglycemia (<2.2 mmol/L) was documented in 68%, 9% and 1% of subjects, respectively. Glycemic variability (SD) was 1.9 mmol/L, and the median hyperglycemic index was 0.77 (interquartile [IQ]: 0.24 to 1.63).

CONCLUSION

The quality of glycemic control in patients in the ICU at our hospital needs to be improved. A new computerized IV insulin protocol is currently being tested.

Glucose control in the ICU: is there a time for more ambitious targets again?

During the last 2 decades, the treatment of hyperglycemia in critically ill patients has become one of the most discussed topics in the intensive medicine field. The initial data suggesting significant benefit of normalization of blood glucose levels in critically ill patients using intensive intravenous insulin therapy have been challenged or even neglected by some later studies. At the moment, the need for glucose control in critically ill patients is generally accepted yet the target glucose values are still the subject of ongoing debates. In this review, we summarize the current data on the benefits and risks of tight glucose control in critically ill patients focusing on the novel technological approaches including continuous glucose monitoring and its combination with computer-based algorithms that might help to overcome some of the hurdles of tight glucose control. Since increased risk of hypoglycemia appears to be the major obstacle of tight glucose control, we try to put forward novel approaches that may help to achieve optimal glucose control with low risk of hypoglycemia. If such approaches can be implemented in real-world practice the entire concept of tight glucose control may need to be revisited.

Risk of postoperative hypoglycemia in cardiovascular surgical patients receiving computer-based versus paper-based insulin therapy

OBJECTIVE

To evaluate the safety and efficacy of replacing a paper-based protocol with a computer-guided glucose management system (CGMS) for the treatment of postoperative hyperglycemia in the cardiovascular intensive care unit (CVICU).

METHODS

With use of a before-and-after analysis, adult patients (≥18 years) discharged from the CVICU and treated with the paper protocol were compared with patients discharged from the CVICU and treated with the CGMS. Of the 1,648 patients analyzed, 991 were in the CGMS group. Clinical end points were evaluated by using the Wilcoxon test. Unadjusted and adjusted hazard ratios (HRs) for each hypoglycemic end point were calculated from Cox models with use of the proportional hazards regression procedure, and clinical end points were adjusted for potential confounders.

RESULTS

Patients treated with the paper protocol were 6 times as likely to experience clinical hypoglycemia (blood glucose ≤70 mg/dL) as patients treated with the CGMS (adjusted HR = 6.06; P<.0001) and more than 7 times as likely to experience severe hypoglycemia (blood glucose ≤40 mg/dL) (adjusted HR = 7.59; P=.01). Despite the increased risk of hypoglycemia, no significant difference in length of stay or mortality was observed between the groups.

CONCLUSION

CGMS treatment of postoperative hyperglycemia in CVICU patients can successfully attain goal glucose levels with a significant reduction in hypoglycemia in comparison with a paper protocol. This association persists after controlling for covariates.

Protocol-directed insulin infusion sliding scales improve perioperative hyperglycaemia in critical care

Perioperative hyperglycaemia is associated with poor outcomes in patients undergoing cardiac surgery. Frequent postoperative hyperglycaemia in cardiac surgery patients has led to the initiation of an insulin infusion sliding scale for quality improvement.

A systematic review was conducted to determine whether a protocol-directed insulin infusion sliding scale is as safe and effective as a conventional practitioner-directed insulin infusion sliding scale, within target blood glucose ranges.

A literature survey was conducted to identify reports on the effectiveness and safety of an insulin infusion protocol, using seven electronic databases from 2000 to 2012: MEDLINE, CINAHL, EMBASE, the Cochrane Library, the Joanna Briggs Institute Library and SIGLE. Data were extracted using pre-determined systematic review and meta-analysis criteria.

Seven research studies met the inclusion criteria. There was an improvement in overall glycaemic control in five of these studies. The implementation of protocols led to the achievement of blood glucose concentration targets more rapidly and the maintenance of a specified target blood glucose range for a longer time, without any increased frequency of hyperglycaemia. Of the seven studies, four used controls and three had no controls.

In terms of the meta-analysis carried out, four studies revealed a failure of patients reaching target blood glucose levels (P < 0.0005) in the control group compared with patients in the protocol group. The risk of hypoglycaemia was significantly reduced (P <0.00001) between studies.

It can be concluded that the protocol-directed insulin infusion sliding scale is safe and improves blood glucose control when compared with the conventional practitioner-directed insulin infusion sliding scale. This study supports the adoption of a protocol-directed insulin infusion sliding scale as a standard of care for post-cardiac surgery patients.

Safe insulin use in the hospital setting

Inpatients have a high rate of diabetes (12%-26%) and hyperglycemia (~38%). All patients should have their glycosylated hemoglobin (A1C) checked on admission to help differentiate between long-term and new-onset hyperglycemia. Good glycemic control throughout the hospital stay is associated with decreases in short- and long-term risk of mortality, inpatient complications, length of hospital stay, and health care costs. Insulin is first-line therapy for hyperglycemia; patients with hyperglycemia should be managed using either intravenous (IV) or subcutaneous (SC) insulin algorithms. A hypoglycemia management protocol should be in place at the hospital for safety purposes. For successful glycemic control, insulin algorithms should have dynamic scales, require frequent glucose monitoring, and be simple and easy to use. The algorithm should address transitioning patients from IV to SC insulin and a discharge plan. Insulin analogues are preferred for basal, mealtime, and correction doses instead of human insulins (regular and NPH) because analogues have a more predictable absorption and action profile and less pharmacokinetic fluctuation. Institutions can increase safe insulin use by utilizing insulin algorithms, preprinted order sets, and hypoglycemia protocols; by supporting patient and health care provider education; and by implementing needle-stick prevention techniques.

Compliance with surgical care improvement project blood glucose--a marker for euglycemia, but does it put our patients at risk?

To improve outcomes in open heart surgery (OHS) patients, the Surgical Care Improvement Project (SCIP) requires 6 am postoperative day (POD) 1 and 2 blood glucose (BG) to be ≤200mg/dL. This study examined risk factors for SCIP noncompliance when using an insulin infusion protocol (IIP) and evaluated this SCIP metric as a surrogate for glycemic control. The authors divided 99 consecutive OHS patients, all subjected to 1 uniform IIP, into 2 groups: Group 1-SCIP compliant (n=79) and Group 2-SCIP noncompliant (n=20). They determined mean BG for the first 48 postoperative hours, percent of total time with hyperglycemia (% time BG >200mg/dL) for each group, and assessed risk of SCIP noncompliance as relates to multiple risk factors including intensity of IIP application, and switching to subcutaneous (SQ) insulin prior to 6 am on POD 2. Group 1 had lower mean BG than Group 2 and percent of total time with hyperglycemia, P<0.0001. Multivariate analysis showed diabetes, obesity in nondiabetics, and switching to SQ insulin prior to 6 am on POD 2 to be risk factors for SCIP noncompliance. The 6 am BG values on POD 1 or POD 2 each correlated with average postoperative BG, and compliance with the SCIP BG metric was associated with virtually uniform BG ≤200mg/dL. IIP application was not significantly different between groups (P=0.2). Only patients who had been switched to SQ insulin prior to 6 am POD 2 were noncompliant at 6 am on POD 2. There were hypoglycemic events (BG <70mg/dL) in 15 of 99 patients (15%), 12 of whom (80%) were in Group 1. Noncompliance with this SCIP measure occurred more frequently in patients with diabetes or, if nondiabetic, in those patients with obesity. A trend toward increased insulin assessments in the SCIP noncompliant group suggests that 1 uniform IIP for all patients may not be effective. By not requiring the reporting of hypoglycemia, SCIP may inadvertently be exposing patients to harm.

Nurse-led implementation of a safe and effective intravenous insulin protocol in a medical intensive care unit

BACKGROUND

Recent evidence has linked tight glucose control to worsened clinical outcomes among adults in intensive care units.

OBJECTIVE

To evaluate the effectiveness and safety of a nurse-led intravenous insulin protocol designed to achieve conservative blood glucose control in patients in a medical intensive care unit.

METHODS

A nurse-led intravenous insulin protocol was developed, targeting blood glucose levels at 110 to 149 mg/dL. Hypoglycemia was defined as a blood glucose level less than 70 mg/dL. Patients admitted to the medical intensive care unit who required an insulin infusion were enrolled in the study. Blood glucose levels in those patients were compared with levels in 153 historical control patients admitted to the unit in the 12 months before the protocol was implemented who required an insulin infusion.

RESULTS

Ninety-six patients were enrolled and treated with the protocol. The protocol and control groups had similar characteristics at baseline. More measurements in the protocol group than in the control group (46.3% vs 36.1%, P<.001) were within the target glucose range (110-149 mg/dL). Hyperglycemia (blood glucose ≥200 mg/dL) occurred less often in the protocol group than in the control group (14.8% vs 20.1%, P=.003). Hypoglycemic events (blood glucose <70 mg/dL) also occurred less often in the protocol group (0.07% vs 0.83%, P<.001).

CONCLUSIONS

Implementation of a nurse-led, conservative intravenous insulin protocol in the medical intensive care unit is effective and safe and markedly reduces the rate of hypoglycemia.

Glycemic management in the inpatient setting

Hyperglycemia occurs frequently in hospitalized patients and affects patient outcomes, including mortality, inpatient complications, hospital length of stay, and overall hospital costs. Various degrees of glycemic control have been studied and consensus statements from the American Diabetes Association/American Association of Clinical Endocrinologists and The Endocrine Society recommend a target blood glucose range of 140 to 180 mg/dL in most hospitalized patients. Insulin is the preferred modality for treating all hospitalized patients with hyperglycemia, as it is adaptable to changing patient physiology over the course of hospitalization. Critically ill patients should receive intravenous insulin infusion, and all noncritically ill patients with hyperglycemia (individuals with and without diabetes) should be managed using a subcutaneous insulin algorithm with basal, nutritional, and correctional dose components. Hypoglycemia remains a limiting factor to achieving optimal glycemic targets. Similar to hyperglycemia, hypoglycemia is an independent risk factor for poor outcomes in hospitalized patients. Improvement in glycemic control throughout the hospital includes efforts from all health care providers. Institutions can encourage safe insulin use by using insulin algorithms, preprinted order sets, and hypoglycemia protocols, as well as by supporting patient and health care provider education.

The correlation between peri-operative hyperglycemia and mortality in cardiac surgery patients: a systematic review

BACKGROUND

Hyperglycemia occurs frequently in patients undergoing cardiac surgery. It has been identified as a risk factor for increased peri-operative morbidity and mortality.

AIM

To review the evidence of the correlation of peri-operative hyperglycemia with mortality in cardiac surgery patients and to discuss the main results in order to provide evidence-based knowledge for the appropriate glycemic control.

METHODS

We searched the electronic databases MEDLINE, CINAHL and EMBASE in June 2010. The material of our study was articles published between 1 January 1990 and 31 May 2010, which investigated the correlation between peri-operative hyperglycemia and in-hospital and/or 30-day cardiac surgery mortality.

RESULTS

Out of the 16 reviewed articles in our study, 12 (75%) significantly associated hyperglycemia and inadequate blood glucose control with increased mortality. In addition, four of the reviewed articles were controlled randomized trials and among them only one demonstrated strong correlation between poor glycemic control and mortality. No study was multi-centre and the reviewed articles were characterized by different definitions of peri-operative hyperglycemia, different intensity and duration of the applied therapy and heterogeneity of the population.

CONCLUSION

It is clear that peri-operative hyperglycemia is harmful for cardiac surgery patients. The significant shortage of randomized controlled trials, the absence of multicentre studies, the different definitions of peri-operative hyperglycemia, the different intensity and duration of the applied insulin therapy protocol and the heterogeneity of the studied population (diabetics and non-diabetics) are significant limitations, which could explain the inconsistent findings of the literature. These limitations indicate the need for further research.

Perioperative tight glycemic control: the challenge of bariatric surgery patients and the fear of hypoglycemic events

BACKGROUND

Tight glycemic control (TGC) is rapidly becoming a standard of care for all hospitalized patients. However, fear of hypoglycemia has proven a potent barrier to adoption of such initiatives by physicians and medical staff. Henry Ford Hospital has pursued aggressive glycemic control for all hospital patients. Because the initial standard TGC protocol (TGCP) was insufficient to improve glycemic control in our bariatric surgery patients, we hypothesized that a more intensive protocol would be necessary to improve glycemic control for this group.

METHODS

As part of an institutional quality control project involving TGC, we reviewed medical records for the bariatric surgery patients at our hospital. We divided the populations into three subgroups: prior to TGC (A), initial hospital rollout TGC (B), and intensive bariatric TGC protocol (C). Patient populations were compared using hospital administrative databases and clinical chart review. Metrics for successful glycemic control included percent hypoglycemia (glucose <50 mg/dL), in-range percent (glucose 80-150 mg/dL), mild hyperglycemia (glucose 151-250 mg/dL), and major hyperglycemia (glucose >250 mg/dL).

RESULTS

The percent in range for group C improved to 71% but was not statistically different from the values for groups A and B. The incidence of hyperglycemia was significantly decreased in group C as compared with groups A and B at both the minor (20% vs 31% and 27%) and major levels (1% vs 4% and 2%) (p < 0.001).There were no differences in the rates of hypoglycemia.

CONCLUSION

As an ongoing quality improvement process, our institution has pursued TGC for all of its patients. Glucose control in bariatric surgery patients is resistant to standard TGCPs. An initial intensive TGCP can be safely implemented in bariatric surgery patients with no increase in the number of hypoglycemic events. This work represents follow-up of several plan, do, check, act (PDCA) cycles related to improvement with a hospital-wide TGCP.

The interaction of chronic and acute glycemia with mortality in critically ill patients with diabetes

OBJECTIVES

The relationship between hyperglycemia and mortality is altered by the presence of diabetes mellitus. Biological adjustment to preexisting hyperglycemia might explain this phenomenon. We tested whether the degree of preexisting hyperglycemia would modulate the association between glycemia and outcome during critical illness in patients with diabetes mellitus.

DESIGN

Retrospective observational study.

SETTING

Two tertiary intensive care units.

PATIENTS

Four hundred fifteen critically ill diabetic patients with HbA1c levels measured within 3 months of intensive care unit admission.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There were 9,946 blood glucose measurements in this study cohort (glucose measured 6.7 times per day; every 3.6 hrs on average). The median preadmission HbA1c level was 7.0%. There was no significant difference in HbA1c levels (p = .17) or time-weighted average of blood glucose concentrations (p = .49) between survivors and nonsurvivors. The time-weighted average of blood glucose concentrations during intensive care unit stay for nonsurvivors was lower than that of survivors when the HbA1c was >6.8%. In multivariate analysis, we found that there was a significant interaction between HbA1c and the time-weighted glucose level, indicating that the relationship between HbA1c and mortality changed according to the levels of time-weighted average of blood glucose concentrations (p = .008). As a consequence, in patients with higher (>7%) preadmission levels of HbA1c, the higher the time-weighted acute glucose concentration during intensive care unit stay (>10 mmol/L), the lower the hospital mortality compared with the lower HbA1c cohort (<7%).

CONCLUSIONS

In patients with diabetes mellitus admitted to intensive care units, there was a significant interaction between preexisting hyperglycemia and the association between acute glycemia and mortality. These observations generate the hypothesis that glucose levels that are considered safe and desirable in other patients might be undesirable in diabetic patients with chronic hyperglycemia. Further studies are required to confirm or refute our findings.

Time and degree of glycemic derangement are associated with increased mortality in trauma patients in the setting of tight glycemic control

BACKGROUND

Tight glucose control (TGC) may reduce mortality in critically ill trauma patients. We hypothesize that euglycemia is beneficial, and a measure considering time and degree of hyperglycemia is most associated with mortality.

METHODS

We performed a review of intensive care unit trauma patients admitted for more than 3 days between January 2005 and December 2007 on a TGC protocol with a goal of 80 to 110 mg/dL. Hyperglycemic, hypoglycemic, and euglycemic time ranges, and area of interpolated curves above and below 80 to 110 mg/dL were assessed. Associations with mortality were based on logistic regression models adjusted for age, injury severity score, and admission Glasgow Coma Scale score.

RESULTS

A total of 546 patients were identified, and 68 (13%) died. Time spent as hyperglycemic (P = .29) and hyperglycemic area under the curve (P = .58) were not associated with mortality; hyperglycemic area/time (P = .01) was associated with mortality. Regarding hypoglycemia, area over the curve (P = .009) and time spent as hypoglycemic (P = .002) were associated with mortality.

CONCLUSIONS

TGC prevents prolonged, high degrees of hyperglycemia; avoiding hypoglycemia likely provides mortality benefit for trauma patients.

Impaired glucose tolerance in pediatric burn patients at discharge from the acute hospital stay

Hyperglycemia, secondary to the hypermetabolic stress response, is a common occurrence after thermal injury. This stress response has been documented to persist up to 9 months postburn. The purpose of this study was to measure insulin sensitivity in severely burned children before discharge when wounds are 95% healed. Twenty-four children, aged 4 to 17 years, with burns > or = 40% TBSA underwent a 2-hour oral glucose tolerance test before discharge from the acute pediatric burn unit. Plasma glucose and insulin levels as well as the Homeostasis Model Assessment for Insulin Resistance (HOMAIR) were compared with published oral glucose tolerance test data from healthy, nonburned children. There was a significant difference between severely burned children and nonburned, healthy children with respect to the HOMAIR. Severely burned children had a HOMAIR of 3.53 +/- 1.62 compared with the value in nonburned, healthy children of 1.28 +/- 0.16 (P < .05). Insulin resistance secondary to the hypermetabolic stress response persists in severely burned children when burn wounds are at least 95% healed. The results of this study warrant future investigations into therapeutic options for the burned child during the rehabilitative phase of their care after injury.

Analytic review: glucose controversies in the ICU

Hyperglycemia is common in critical illness and has been associated with increased morbidity and mortality. An era of tight glucose control began when intensive insulin therapy was shown to improve outcomes in a single-center randomized trial. More recently, with the publication of additional studies, questions have been raised regarding the efficacy and safety of intensive glycemic management. This article will review the biologic mechanisms that may help us understand why and how hyperglycemia and insulin are relevant in critical illness. We will then explore insights gleaned from available clinical trials. Finally, we will discuss specific areas of controversy that relate to the implementation of glycemic control in the intensive care unit, such as the ideal glucose target and the importance of hypoglycemia.

Gender Differences in Glucose Variability after Severe Trauma

Gender differences in the physiological response to trauma can affect outcome. Both hyperglycemia and blood glucose (BG) variability predict a poor outcome after trauma. This study examined the hypothesis that both BG levels and the degree of BG variability after trauma are gender-specific and correlate with mortality and morbidity. A retrospective observational cohort study of 1915 trauma patients requiring critical care was performed. Admission BG as well as all BG values obtained during the first week while in the intensive care unit were analyzed. In each patient, the mean BG and the degree of BG variability were calculated. A total of 1560 males and 355 females were studied with an overall mortality rate of 12 per cent. Seventy-six per cent of deaths had a BG greater than 125 mg/dL on admission and as BG variability worsened, the mortality rate also increased. There was a significant difference in male BG variability when comparing survivors with nonsurvivors. Female BG variability did not predict mortality. Failed glucose homeostasis is an important marker of endocrine dysfunction after severe injury. Increased BG variability in males is associated with a higher mortality rate. In females, mortality cannot be predicted based on BG levels or BG variability. These data have significant implications for gender-related differences in postinjury management.

Glucose Meter Performance Criteria for Tight Glycemic Control Estimated by Simulation Modeling

Background: Glucose meter analytical performance criteria required for safe and effective management of patients on tight glycemic control (TGC) are not currently defined. We used simulation modeling to relate glucose meter performance characteristics to insulin dosing errors during TGC.

Methods: We used 29 920 glucose values from patients on TGC at 1 institution to represent the expected distribution of glucose values during TGC, and we used 2 different simulation models to relate glucose meter analytical performance to insulin dosing error using these 29 920 initial glucose values and assuming 10%, 15%, or 20% total allowable error (TEa) criteria.

Results: One-category insulin dosing errors were common under all error conditions. Two-category insulin dosing errors occurred more frequently when either 20% or 15% TEa was assumed compared with 10% total error. Dosing errors of 3 or more categories, those most likely to result in hypoglycemia and thus patient harm, occurred infrequently under all error conditions with the exception of 20% TEa.

Conclusions: Glucose meter technologies that operate within a 15% total allowable error tolerance are unlikely to produce large (≥3-category) insulin dosing errors during TGC. Increasing performance to 10% TEa should reduce the frequency of 2-category insulin dosing errors, although additional studies are necessary to determine the clinical impact of such errors during TGC. Current criteria that allow 20% total allowable error in glucose meters may not be optimal for patient management during TGC.

Comparisons of different insulin infusion protocols: a review of recent literature

PURPOSE OF REVIEW

To provide an update on the currently available insulin infusion protocols for treatment of hyperglycemia in critically ill patients and to discuss the major differences and similarities among them.

RECENT FINDINGS

We identified a total of 26 protocols, 20 of which used manual blood-glucose calculations, and six that used computerized algorithms. The major differences and similarities among the insulin infusion protocols were in the following areas: patient characteristics, target glucose level, time to achieve target glucose level, incidence of hypoglycemia, rationale for adjusting the rates of insulin infusion, and methods of blood-glucose measurements. Several computerized protocols hold promise for safer achievement of glycemic targets.

SUMMARY

Insulin infusion is the most effective method for controlling hyperglycemia in critically ill patients. Clinicians should utilize a validated insulin infusion protocol that is well tolerated, and is most appropriate and practical for their institution based on the resources that are available.

A prospective randomised multi-centre controlled trial on tight glucose control by intensive insulin therapy in adult intensive care units: the Glucontrol study

PURPOSE

An optimal target for glucose control in ICU patients remains unclear. This prospective randomized controlled trial compared the effects on ICU mortality of intensive insulin therapy (IIT) with an intermediate glucose control.

METHODS

Adult patients admitted to the 21 participating medico-surgical ICUs were randomized to group 1 (target BG 7.8-10.0 mmol/L) or to group 2 (target BG 4.4-6.1 mmol/L).

RESULTS

While the required sample size was 1,750 per group, the trial was stopped early due to a high rate of unintended protocol violations. From 1,101 admissions, the outcomes of 542 patients assigned to group 1 and 536 of group 2 were analysed. The groups were well balanced. BG levels averaged in group 1 8.0 mmol/L (IQR 7.1-9.0) (median of all values) and 7.7 mmol/L (IQR 6.7-8.8) (median of morning BG) versus 6.5 mmol/L (IQR 6.0-7.2) and 6.1 mmol/L (IQR 5.5-6.8) for group 2 (p < 0.0001 for both comparisons). The percentage of patients treated with insulin averaged 66.2 and 96.3%, respectively. Proportion of time spent in target BG was similar, averaging 39.5% and 45.1% (median (IQR) 34.3 (18.5-50.0) and 39.3 (26.2-53.6)%) in the groups 1 and 2, respectively. The rate of hypoglycaemia was higher in the group 2 (8.7%) than in group 1 (2.7%, p < 0.0001). ICU mortality was similar in the two groups (15.3 vs. 17.2%).

CONCLUSIONS

In this prematurely stopped and therefore underpowered study, there was a lack of clinical benefit of intensive insulin therapy (target 4.4-6.1 mmol/L), associated with an increased incidence of hypoglycaemia, as compared to a 7.8-10.0 mmol/L target. (ClinicalTrials.gov # NCT00107601, EUDRA-CT Number: 200400391440).

[Repercussions and management of perioperative hyperglycemia in cardiac surgery]

Surgery produces a neuroendocrine stress response that affects resistance to insulin, reduces insulin secretion, and increases the release of glucose from the liver. This situation can trigger hyperglycemia in both diabetics and nondiabetics. Hyperglycemia has been linked to an increase in the morbidity and mortality among patients who undergo cardiac surgery, and the benefits of correcting hyperglycemia in this setting by means of intensive insulin therapy are well documented. This review discusses various aspects of hyperglycemia, particularly the evidence supporting stricter control of this condition in patients undergoing cardiac surgery. Furthermore, based on the available data and recommendations, and our clinical experience, we suggest therapeutic strategies to improve the control of hyperglycemia in these patients.

Comparison of three protocols for tight glycemic control in cardiac surgery patients

OBJECTIVE

We performed a randomized trial to compare three insulin-titration protocols for tight glycemic control (TGC) in a surgical intensive care unit: an absolute glucose (Matias) protocol, a relative glucose change (Bath) protocol, and an enhanced model predictive control (eMPC) algorithm.

RESEARCH DESIGN AND METHODS

A total of 120 consecutive patients after cardiac surgery were randomly assigned to the three protocols with a target glycemia range from 4.4 to 6.1 mmol/l. Intravenous insulin was administered continuously or in combination with insulin boluses (Matias protocol). Blood glucose was measured in 1- to 4-h intervals as requested by the protocols.

RESULTS

The eMPC algorithm gave the best performance as assessed by time to target (8.8 +/- 2.2 vs. 10.9 +/- 1.0 vs. 12.3 +/- 1.9 h; eMPC vs. Matias vs. Bath, respectively; P < 0.05), average blood glucose after reaching the target (5.2 +/- 0.1 vs. 6.2 +/- 0.1 vs. 5.8 +/- 0.1 mmol/l; P < 0.01), time in target (62.8 +/- 4.4 vs. 48.4 +/- 3.28 vs. 55.5 +/- 3.2%; P < 0.05), time in hyperglycemia >8.3 mmol/l (1.3 +/- 1.2 vs. 12.8 +/- 2.2 vs. 6.5 +/- 2.0%; P < 0.05), and sampling interval (2.3 +/- 0.1 vs. 2.1 +/- 0.1 vs. 1.8 +/- 0.1 h; P < 0.05). However, time in hypoglycemia risk range (2.9-4.3 mmol/l) in the eMPC group was the longest (22.2 +/- 1.9 vs. 10.9 +/- 1.5 vs. 13.1 +/- 1.6; P < 0.05). No severe hypoglycemic episode (<2.3 mmol/l) occurred in the eMPC group compared with one in the Matias group and two in the Bath group.

CONCLUSIONS

The eMPC algorithm provided the best TGC without increasing the risk of severe hypoglycemia while requiring the fewest glucose measurements. Overall, all protocols were safe and effective in the maintenance of TGC in cardiac surgery patients.

Nurses' perceptions of glycemic control in patients who have undergone cardiac surgery

BACKGROUND/SIGNIFICANCE

Previous work investigating the effect of glycemic control in patients who underwent cardiac surgery has demonstrated that obtaining and maintaining blood glucose values between 80 and 120 is imperative in achieving excellent clinical outcomes in a patient who have undergone cardiac surgery. However, the caregiver's workload associated with meeting this goal is only now beginning to be understood.

METHODS

This qualitative study used focus groups held on 3 consecutive days to interview nurses in the cardiovascular intensive care unit and cardiovascular step-down unit about their thoughts on glycemic control.Three research questions were developed to help guide the focus group discussions.

RESULTS

Ten nurses, 3 from cardiovascular intensive care unit and 7 from cardiovascular step-down unit, participated in the focus groups and saturation was accomplished. The essence of the nurses' message was that they recognize glycemic control as a very important part of their patient care. However, to be able to perform this intervention, they need available equipment, a designated person to obtain all blood glucose values, periodic updates on patient outcomes related to glycemic control, and a less intrusive way to draw the patients' blood.

CONCLUSION

The ability of the nurses to obtain glycemic control is hindered by the lack of time, lack of necessary resources/equipment, lack of knowledge about the long-term outcomes resulting from glycemic control, and the discomfort to patients caused by the frequent blood draws. Hospitals need to investigate alternative mechanisms that will assist the nurse in meeting this goal.

Safety and Efficacy of Intensive Insulin Therapy in Patients with Thermal Injury

Purpose

To evaluate the safety and efficacy of intensive insulin therapy (IIT) versus traditional corrective insulin management (CIM) for the treatment of hyperglycemia in adult patients with thermal injury who are under intensive care.

Methods

Using a searchable pharmacy database, a retrospective, observational chart review was conducted of adult patients who were admitted to the surgical burn service intensive care unit (ICU) at the University of North Carolina Hospitals (UNCH) from January 2004 through December 2005 and who had received insulin therapy.

Results

Seventy-one patients qualified for analysis. The average morning serum blood glucose value while patients were receiving IIT, defined as 80 to 110 mg/dL, was 107 mg/dL compared with 124 mg/dL while patients were receiving CIM ( P < 0.001). Of morning serum blood glucose values taken, 49% were within the target range in patients receiving IIT compared with 34% in patients receiving CIM ( P < 0.001). No significant differences were found between the 2 groups with regard to mortality, ICU stay, or hospital stay. More patients experienced hypoglycemia (blood glucose value less than 50 mg/dL) while receiving IIT compared with CIM (36.4% vs 31.3%; P = 0.732); however, none of the patients had symptomatic hypoglycemia. There was a significantly higher rate of hypoglycemia among nonsurvivors compared with survivors (66.7% vs 26.4%; P = 0.006).

Conclusion

IIT lowers average morning blood glucose in the thermal injury population when compared with CIM. Differences in hypoglycemic events were observed in this review; however, none of the episodes were symptomatic. Although further study is needed, IIT appears to be a safe and effective method of controlling serum blood glucose values in this specialized population.

Assessing the performance of handheld glucose testing for critical care

BACKGROUND

We assessed the performance of a point-of-care (POC) glucose meter system (GMS) with multitasking test strip by using the locally-smoothed (LS) median absolute difference (MAD) curve method in conjunction with a modified Bland-Altman difference plot and superimposed International Organization for Standardization (ISO) 15197 tolerance bands. We analyzed performance for tight glycemic control (TGC).

METHODS

A modified glucose oxidase enzyme with a multilayer-gold, multielectrode, four-well test strip (StatStriptrade mark, NOVA Biomedical, Waltham, MA) was used. There was no test strip calibration code. Pragmatic comparison was done of GMS results versus paired plasma glucose measurements from chemistry analyzers in clinical laboratories. Venous samples (n = 1,703) were analyzed at 35 hospitals that used 20 types of chemistry analyzers. Erroneous results were identified using the Bland-Altman plot and ISO 15197 criteria. Discrepant values were analyzed for the TGC interval of 80-110 mg/dL.

RESULTS

The GMS met ISO 15197 guidelines; 98.6% (410 of 416) of observations were within tolerance for glucose <75 mg/dL, and for > or =75 mg/dL, 100% were within tolerance. Paired differences (handheld minus reference) averaged -2.2 (SD 9.8) mg/dL; the median was -1 (range, -96 to 45) mg/dL. LS MAD curve analysis revealed satisfactory performance below 186 mg/dL; above 186 mg/dL, the recommended error tolerance limit (5 mg/dL) was not met. No discrepant values appeared. All points fell in Clarke Error Grid zone A. Linear regression showed y = 1.018x - 0.716 mg/dL, and r2 = 0.995.

CONCLUSIONS

LS MAD curves draw on human ability to discriminate performance visually. LS MAD curve and ISO 15197 performance were acceptable for TGC. POC and reference glucose calibration should be harmonized and standardized.

A systematic review on quality indicators for tight glycaemic control in critically ill patients: need for an unambiguous indicator reference subset

Introduction

The objectives of this study were to systematically identify and summarize quality indicators of tight glycaemic control in critically ill patients, and to inspect the applicability of their definitions.

Methods

We searched in MEDLINE^® for all studies evaluating a tight glycaemic control protocol and/or quality of glucose control that reported original data from a clinical trial or observational study on critically ill adult patients.

Results

Forty-nine studies met the inclusion criteria; 30 different indicators were extracted and categorized into four nonorthogonal categories: blood glucose zones (for example, 'hypoglycaemia'); blood glucose levels (for example, 'mean blood glucose level'); time intervals (for example, 'time to occurrence of an event'); and protocol characteristics (for example, 'blood glucose sampling frequency'). Hypoglycaemia-related indicators were used in 43 out of 49 studies, acting as a proxy for safety, but they employed many different definitions. Blood glucose level summaries were used in 41 out of 49 studies, reported as means and/or medians during the study period or at a certain time point (for example, the morning blood glucose level or blood glucose level upon starting insulin therapy). Time spent in the predefined blood glucose level range, time needed to reach the defined blood glucose level target, hyperglycaemia-related indicators and protocol-related indicators were other frequently used indicators. Most indicators differ in their definitions even when they are meant to measure the same underlying concept. More importantly, many definitions are not precise, prohibiting their applicability and hence the reproducibility and comparability of research results.

Conclusions

An unambiguous indicator reference subset is necessary. The result of this systematic review can be used as a starting point from which to develop a standard list of well defined indicators that are associated with clinical outcomes or that concur with clinicians' subjective views on the quality of the regulatory process.

Efficacy and safety of modified Yale insulin infusion protocol in Japanese diabetic patients after open-heart surgery

To our knowledge, there is currently no insulin infusion protocol for critically ill patients especially designed for Asian diabetics although many such protocols are used in Western countries. In this study, we modified the Yale insulin infusion protocol taking into consideration the characteristics of Japanese diabetics and hospital environment. We tested the modified protocol in 40 type 2 diabetic patients after elective open-heart surgery (MY group) comparing with 35 type 2 diabetic patients under empirical blood glucose control (EC group). Analyses of 1656 blood glucose measurements during insulin infusion revealed that percentage of samples that showed achievement of target blood glucose level (80-140 mg/dl) was higher under MY (78+/-15%, n=870) than EC (57+/-23%, n=786, p<0.0001). On the other hand, the percentage of samples in which blood glucose was less than 60 mg/dl was comparable in the two groups (MY: 0.5+/-5.9 per thousand, EC: 5.1+/-18.5 per thousand). None of the patients with hypoglycemia showed significant clinical adverse effects. In conclusion, our modified Yale insulin infusion protocol is effective and safe for tight blood glucose control in Japanese diabetic patients after open-heart surgery.

Designing and implementing insulin infusion protocols and order sets

Influential trials and guidelines supporting the value of glucose control in hospital settings, particularly in the intensive care and postoperative settings, has led to the widespread adoption of intravenous infusions of human regular insulin. As groups have attempted to study the outcomes or to explore improved methods for improved glucose control, a number of insulin infusion protocols (IIPs) have been reported and validated. Now, many institutions are attempting to translate this experience into clinical practice in a systematic manner. The intent of this discussion is to highlight the authors' practical view of best practices in development and use of IIPs. As the implementation of IIPs has progressed, it has become apparent that this is not a simple process. It requires a carefully planned, inclusive, and continuous effort striving to attain effective glucose control while avoiding severe hypoglycemia. Whereas there are limitations in the literature comparing the IIPs, we identify design elements and implementation methods that increase the chances for staff acceptance and safe attainment of glycemic goals. Most importantly, this must be a team effort with attention to the numerous potential pitfalls that can disrupt the process and place patients at risk. In many cases, it is best to start more conservatively and methodically intensify the protocol. Continuous assessment of protocol errors, adverse events, staff satisfaction, and outcomes is vital to overall success.

Dynamic tight glycemic control during and after cardiac surgery is effective, feasible, and safe

BACKGROUND

Tight blood glucose control reduces mortality and morbidity in critically ill patients, but intraoperative glucose control during cardiac surgery is often difficult, and risks hypoglycemia. In this study, we evaluated the safety and efficacy of a nurse-driven insulin protocol (the Aalst Glycemia Insulin Protocol) for achieving a target glucose level of 80-110 mg/dL during cardiac surgery and in the intensive care unit (ICU).

METHODS

We included 483 nondiabetics and 168 diabetics scheduled for cardiac surgery with cardiopulmonary bypass. To anticipate rapid perioperative changes in insulin requirement and/or sensitivity during surgery, we developed a dynamic algorithm presented in tabular form, with rows representing blood glucose ranges and columns representing insulin dosages based on the patients' insulin sensitivity. The algorithm adjusts insulin dosage based on blood glucose level and the projected insulin sensitivity (e.g., reduced sensitivity during cardiopulmonary bypass and normalizing sensitivity after surgery).

RESULTS

A total of 18,893 blood glucose measurements were made during and after surgery. During surgery, the mean glucose level in nondiabetic patients was within targeted levels except during (112 +/- 17 mg/dL) and after rewarming (113 +/- 19 mg/dL) on cardiopulmonary bypass. In diabetics, blood glucose was decreased from 121 +/- 40 mg/dL at anesthesia induction to 112 +/- 26 mg/dL at the end of surgery (P < 0.05), with 52.9% of patients achieving the target. In the ICU, the mean glucose level was within targeted range at all time points, except for diabetics upon ICU arrival (113 +/- 24 mg/dL). Of all blood glucose measurements (operating room and ICU), 68.0% were within the target, with 0.12% of measurements in nondiabetics and 0.18% in diabetics below 60 mg/dL. Hypoglycemia < 50 mg/dL was avoided in all but four (0.6%) patients (40 mg/dL was the lowest observed value).

CONCLUSIONS

The Aalst Glycemia Insulin Protocol is effective for maintaining tight perioperative blood glucose control during cardiac surgery with minimal risk of hypoglycemia.

Tight glycaemic control: a prospective observational study of a computerised decision-supported intensive insulin therapy protocol

INTRODUCTION

A single centre has reported that implementation of an intensive insulin protocol, aiming for tight glycaemic control (blood glucose 4.4 to 6.1 mmol/l), resulted in significant reduction in mortality in longer stay medical and surgical critically ill patients. Our aim was to determine the degree to which tight glycaemic control can be maintained using an intensive insulin therapy protocol with computerized decision support and to identify factors that may be associated with the degree of control.

METHODS

At a general adult 22-bed intensive care unit, we implemented an intensive insulin therapy protocol in mechanically ventilated patients, aiming for a target glucose range of 4.4 to 6.1 mmol/l. The protocol was integrated into the computerized information management system by way of a decision support program. The time spent in each predefined blood glucose band was estimated, assuming a linear trend between measurements.

RESULTS

Fifty consecutive patients were investigated, involving analysis of 7,209 blood glucose samples, over 9,214 hours. The target tight glycaemic control band (4.4 to 6.1 mmol/l) was achieved for a median of 23.1% of the time that patients were receiving intensive insulin therapy. Nearly half of the time (median 48.5%), blood glucose was within the band 6.2 to 7.99 mmol/l. Univariate analysis revealed that body mass index (BMI), Acute Physiology and Chronic Health Evaluation (APACHE) II score and previous diabetes each explained approximately 10% of the variability in tight glycaemic control. BMI and APACHE II score explained most (27%) of the variability in tight glycaemic control in the multivariate analysis, after adjusting for age and previous diabetes.

CONCLUSION

Use of the computerized decision supported intensive insulin therapy protocol did result in achievement of tight glycaemic control for a substantial percentage of each patient's stay, although it did deliver 'normoglycaemia' (4.4 to about 8 mmol/l) for nearly 75% of the time. Tight glycaemic control was difficult to achieve in critically ill patients using this protocol. More sophisticated methods such as continuous blood glucose monitoring with automated insulin and glucose infusion adjustment may be a more effective way to achieve tight glycaemic control. Glycaemia in patients with high BMI and APACHE II scores may be more difficult to control using intensive insulin therapy protocols. Trial registration number 05/Q0505/1.