Blood glucose control in the intensive care unit: benefits and risks

Birkenfeld A, Sponholz C, A. Müller U, von Loeffelholz C. Blood Sugar Targets in Surgical Intensive Care—Management and Special Considerations in Patients With Diabetes

BACKGROUND

30-80% of patients being treated in intensive care units in the perioperative period develop hyperglycemia. This stress hyperglycemia is induced and maintained by inflammatory-endocrine and iatrogenic stimuli and generally requires treatment. There is uncertainty regarding the optimal blood glucose targets for patients with diabetes mellitus.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed and Google Scholar.

RESULTS

Patients in intensive care with pre-existing diabetes do not benefit from blood sugar reduction to the same extent as metabolically healthy individuals, but they, too, are exposed to a clinically relevant risk of hypoglycemia. A therapeutic range from 4.4 to 6.1 mmol/L (79-110 mg/dL) cannot be justified for patients with diabetes mellitus. The primary therapeutic strategy in the perioperative setting should be to strictly avoid hypoglycemia. Neurotoxic effects and the promotion of wound-healing disturbances are among the adverse consequences of hyperglycemia. Meta-analyses have shown that an upper blood sugar limit of 10 mmol/L (180 mg/dL) is associated with better outcomes for diabetic patients than an upper limit of less than this value. The target range of 7.8-10 mmol/L (140-180 mg/dL) proposed by specialty societies for hospitalized patients with diabetes seems to be the best compromise at present for optimizing clinical outcomes while avoiding hypoglycemia. The method of choice for achieving this goal in intensive care medicine is the continuous intravenous administration of insulin, requirng standardized, high-quality monitoring conditions.

CONCLUSION

Optimal blood sugar control for diabetic patients in intensive care meets the dual objectives of avoiding hypoglycemia while keeping the blood glucose concentration under 10 mmol/L (180 mg/dL). Nutrition therapy in accordance with the relevant guidelines is an indispensable pre - requisite.

Glucose control in the ICU

PURPOSE OF REVIEW

Critically ill patients usually develop hyperglycemia, which is associated with adverse outcome. Controversy exists whether the relationship is causal or not. This review summarizes recent evidence regarding glucose control in the ICU.

RECENT FINDINGS

Despite promising effects of tight glucose control in pioneer randomized controlled trials, the benefit has not been confirmed in subsequent multicenter studies and one trial found potential harm. This discrepancy could be explained by methodological differences between the trials rather than by a different case mix. Strategies to improve the efficacy and safety of tight glucose control have been developed, including the use of computerized treatment algorithms.

SUMMARY

The ideal blood glucose target remains unclear and may depend on the context. As compared with tolerating severe hyperglycemia, tight glucose control is well tolerated and effective in patients receiving early parenteral nutrition when provided with a protocol that includes frequent, accurate glucose measurements and avoids large glucose fluctuations. All patient subgroups potentially benefit, with the possible exception of patients with poorly controlled diabetes, who may need less aggressive glucose control. It remains unclear whether tight glucose control is beneficial or not in the absence of early parenteral nutrition.

Nutrition Support and Tight Glucose Control in Critically Ill Children: Food for Thought!

Numerous studies have examined the strategy of tight glucose control (TGC) with intensive insulin therapy (IIT) to improve clinical outcomes in critically ill adults and children. Although early studies of TGC with IIT demonstrated improved outcomes at the cost of elevated hypoglycemia rates, subsequent studies in both adults and children have not demonstrated any benefit from such a strategy. Differences in patient populations, variable glycemic targets, and glucose control protocols, inconsistency in attaining these targets, heterogeneous intermittent sampling, and measurement techniques, and variable expertise in protocol implementation are possible reasons for the contrasting results from these studies. Notably, differences in modes of nutrition support may have also contributed to these disparate results. In particular, combined use of early parenteral nutrition (PN) and a strategy of TGC with IIT may be associated with improved outcomes, while combined use of enteral nutrition (EN) and a strategy of TGC with IIT may be associated with equivocal or worse outcomes. This article critically examines published clinical trials that have employed a strategy of TGC with IIT in critically ill children to highlight the role of EN vs. PN in influencing clinical outcomes including efficacy of TGC, and adverse effects such as occurrence of hypoglycemia and hospital acquired infections. The perspective afforded by this article should help practitioners consider the potential importance of mode of nutrition support in impacting key clinical outcomes if they should choose to employ a strategy of TGC with IIT in critically ill children with hyperglycemia.

Blood glucose control using a computer-guided glucose management system in allogeneic hematopoietic cell transplant recipients

Allogeneic hematopoietic cell transplantation (HCT) is a potentially curative treatment for patients with hematological malignancies. However, is associated with substantial rates of morbidity and mortality. We and others have shown that malglycemia is associated with adverse transplant outcome. Therefore, improving glycemic control may improve transplant outcome. In this prospective study we evaluated the feasibility of using Glucommander (a Computer-Guided Glucose Management System; CGGM) in order to achieve improved glucose control in hospitalized HCT patients. Nineteen adult patients contributed 21 separate instances on CGGM. Patients were on CGGM for a median of 43 h. Median initial blood glucose (BG) on CGGM was 244 mg/dL, and patients on 20 study instances reached the study BG target of 100-140 mg/dL after a median of 6 h. After BG reached the target range, the median average BG level per patient was 124 mg/dL. Six patients had a total of 10 events of BG <70 mg/dL (0.9% of BG measurements), and no patients experienced BG level <40 mg/dL. The total estimated duration of BG <70 mg/dL was 3 h (0.2% of the total CGGM time). In conclusion, our study demonstrates that stringent BG control in HCT patients using CGGM is feasible.

Incidence and predisposing factors for the development of disturbed glucose metabolism and DIabetes mellitus AFter Intensive Care admission: the DIAFIC study

Introduction

Elevated blood glucose levels during intensive care unit (ICU) stay, so-called stress hyperglycaemia (SH), is a common finding. Its relation with a future diabetes risk is unclear. Our objective was to determine the incidence of disturbed glucose metabolism (DGM) post ICU admission and to identify predictors for future diabetes risk with a focus on stress hyperglycaemia.

Methods

This single center prospective cohort trial (DIAFIC trial) had a study period between September 2011 and March 2013, with follow-up until December 2013. The setting was a mixed medical/surgical ICU in a tertiary teaching hospital in Belgium. 338 patients without known diabetes mellitus were included for analysis. We assessed the level of glucose metabolism disturbance (as diagnosed with a 75 g oral glucose tolerance test (OGTT) and/or HbA1c level) eight months after ICU admission, and investigated possible predictors including stress hyperglycaemia.

Results

In total 246 patients (73 %) experienced stress hyperglycaemia during the ICU stay. Eight months post-ICU admission, 119 (35 %) subjects had a disturbed glucose metabolism, including 24 (7 %) patients who were diagnosed with diabetes mellitus. A disturbed glucose metabolism tended to be more prevalent in subjects who experienced stress hyperglycaemia during ICU stay as compared to those without stress hyperglycaemia (38 % vs. 28 %, P = 0.065). HbA1c on admission correlated with the degree of stress hyperglycaemia. A diabetes risk score (FINDRISC) (11.0 versus 9.5, P = 0.001), the SAPS3 score (median of 42 in both groups, P = 0.003) and daily caloric intake during ICU stay (197 vs. 222, P = 0.011) were independently associated with a disturbed glucose metabolism.

Conclusions

Stress hyperglycaemia is frequent in non-diabetic patients and predicts a tendency towards disturbances in glucose metabolism and diabetes mellitus. Clinically relevant predictors of elevated risk included a high FINDRISC score and a high SAPS3 score. These predictors can provide an efficient, quick and inexpensive way to identify patients at risk for a disturbed glucose metabolism or diabetes, and could facilitate prevention and early treatment.

Trial registration

At ClinicalTrials.gov NCT02180555. Registered 1 July, 2014.

U-shaped relationship between early blood glucose and mortality in critically ill children

BACKGROUND

The aims of this study are to evaluate the relationship between early blood glucose concentrations and mortality and to define a 'safe range' of blood glucose concentrations during the first 24 h after pediatric intensive care unit (PICU) admission with the lowest risk of mortality. We further determine whether associations exist between PICU mortality and early hyperglycemia and hypoglycemia occurring within 24 h of PICU admission, even after adjusting for illness severity assessed by the pediatric risk of mortality III (PRISM III) score.

METHODS

This retrospective cohort study included patients admitted to PICU between July 2008 and June 2011 in a tertiary teaching hospital. Both the initial admission glucose values and the mean glucose values over the first 24 h after PICU admission were analyzed.

RESULTS

Of the 1349 children with at least one blood glucose value taken during the first 24 h after admission, 129 died during PICU stay. When analyzing both the initial admission and mean glucose values during the first 24 h after admission, the mortality rate was compared among children with glucose concentrations ≤ 65, 65-90, 90-110, 110-140, 140-200, and >200 mg/dL (≤ 3.6, 3.6-5.0, 5.0-6.1, 6.1-7.8, 7.8-11.1, and >11.1 mmol/L). Children with glucose concentrations ≤ 65 mg/dL (3.6 mmol/L) and >200 mg/dL (11.1 mmol/L) had significantly higher mortality rates, indicating a U-shaped relationship between glucose concentrations and mortality. Blood glucose concentrations of 110-140 mg/dL (6.1-7.8 mmol/L), followed by 90-110 mg/dL (5.0-6.1 mmol/L), were associated with the lowest risk of mortality, suggesting that a 'safe range' for blood glucose concentrations during the first 24 h after admission in critically ill children exists between 90 and 140 mg/dL (5.0 and 7.8 mmol/L). The odds ratios of early hyperglycemia (>140 mg/dL [7.8 mmol/L]) and hypoglycemia (≤ 65 mg/dL [3.6 mmol/L]) being associated with increased risk of mortality were 4.13 and 15.13, respectively, compared to those with mean glucose concentrations of 110-140 mg/dL (6.1-7.8 mmol/L) (p <0.001). The association remained significant after adjusting for PRISM III scores (p <0.001).

CONCLUSIONS

There was a U-shaped relationship between early blood glucose concentrations and PICU mortality in critically ill children. Both early hyperglycemia and hypoglycemia were associated with mortality, even after adjusting for illness severity.

Role of protein farnesylation in burn-induced metabolic derangements and insulin resistance in mouse skeletal muscle

Objective

Metabolic derangements, including insulin resistance and hyperlactatemia, are a major complication of major trauma (e.g., burn injury) and affect the prognosis of burn patients. Protein farnesylation, a posttranslational lipid modification of cysteine residues, has been emerging as a potential component of inflammatory response in sepsis. However, farnesylation has not yet been studied in major trauma. To study a role of farnesylation in burn-induced metabolic aberration, we examined the effects of farnesyltransferase (FTase) inhibitor, FTI-277, on burn-induced insulin resistance and metabolic alterations in mouse skeletal muscle.

Methods

A full thickness burn (30% total body surface area) was produced under anesthesia in male C57BL/6 mice at 8 weeks of age. After the mice were treated with FTI-277 (5 mg/kg/day, IP) or vehicle for 3 days, muscle insulin signaling, metabolic alterations and inflammatory gene expression were evaluated.

Results

Burn increased FTase expression and farnesylated proteins in mouse muscle compared with sham-burn at 3 days after burn. Simultaneously, insulin-stimulated phosphorylation of insulin receptor (IR), insulin receptor substrate (IRS)-1, Akt and GSK-3β was decreased. Protein expression of PTP-1B (a negative regulator of IR-IRS-1 signaling), PTEN (a negative regulator of Akt-mediated signaling), protein degradation and lactate release by muscle, and plasma lactate levels were increased by burn. Burn-induced impaired insulin signaling and metabolic dysfunction were associated with increased inflammatory gene expression. These burn-induced alterations were reversed or ameliorated by FTI-277.

Conclusions

Our data demonstrate that burn increased FTase expression and protein farnesylation along with insulin resistance, metabolic alterations and inflammatory response in mouse skeletal muscle, all of which were prevented by FTI-277 treatment. These results indicate that increased protein farnesylation plays a pivotal role in burn-induced metabolic dysfunction and inflammatory response. Our study identifies FTase as a novel potential molecular target to reverse or ameliorate metabolic derangements in burn patients.

Endocrine disorders and the neurologic manifestations

The nervous system and the endocrine system are closely interrelated and both involved intimately in maintaining homeostasis. Endocrine dysfunctions may lead to various neurologic manifestations such as headache, myopathy, and acute encephalopathy including coma. It is important to recognize the neurologic signs and symptoms caused by the endocrine disorders while managing endocrine disorders. This article provides an overview of the neurologic manifestations found in various endocrine disorders that affect pediatric patients. It is valuable to think about 'endocrine disorder' as a cause of the neurologic manifestations. Early diagnosis and treatment of hormonal imbalance can rapidly relieve the neurologic symptoms. Better understanding of the interaction between the endocrine system and the nervous system, combined with the knowledge about the pathophysiology of the neurologic manifestations presented in the endocrine disorders might allow earlier diagnosis and better treatment of the endocrine disorders.

Insulin infusion therapy in critical care patients: regular insulin vs short-acting insulin. A prospective, crossover, randomized, multicenter blind study

INTRODUCTION

The aim of this multicenter, prospective, randomized, crossover trial is to compare, in critical care patients receiving insulin infusion therapy (IIT), the pharmacodynamic of Humulin insulin (Hlin), currently used as "standard of care," and Humalog insulin (Hlog), a shorter acting insulin formulation. This was measured as extent and duration of the carryover effect of insulin treatment, with the latter calculated as ratio between blood glucose concentration (BGC) reduction during and after IIT.

MATERIALS AND METHODS

Twenty-eight patients treated in an intensive care unit and receiving full nutritional support were randomly assigned to Hlin or Hlog as first treatment. Insulin was infused at a constant rate in patients presenting with BGC greater than or equal to 180 mg/dL (0.04 U/kg per hour) and was discontinued when BGC was less than or equal to 140 mg/dL (therapeutic BGC drop). Further reductions in BGC after discontinuation of insulin infusion were recorded (postinfusional BGC drop). During the study period, whole blood BGC was measured every 30 minutes. A minimal 6-hour washout interval was maintained between treatments with the 2 types of insulin. The primary end point was the extent (calculated as ratio between the therapeutic BGC drop and the postinfusional BGC drop) and duration of the carryover effect.

RESULTS

Treatment with Hlog, as compared with Hlin, was associated with a less profound carryover effect as well as a briefer duration of carryover (median, 0.40 vs 0.62; P < .001; median, 1 vs 1.5 hours; P < .001).

CONCLUSIONS

The use of constant Hlog infusion for IIT, when compared with Hlin at the same dose, is associated with a less profound carryover effect on BGC after discontinuation of IIT, a briefer duration of carryover, a faster BGC drop during infusion, and a quicker BGC rise after discontinuation. These characteristics suggest that Hlog IIT may be preferable for use in critically ill patients.

Review of insulin treatment in stress-related hyperglycaemia in children without preexisting diabetes

A systematic review was undertaken to assess the effect of using insulin therapy in the treatment for stress hyperglycaemia in children without preexisting diabetes in: achieving normoglycaemia, improving symptoms associated with hyperglycaemia and survival, and to determine if any adverse effects were associated with the use of insulin therapy.

CONCLUSION

There is currently insufficient evidence for the routine use of insulin therapy in stress hyperglycaemia compared with conventional care in children without preexisting diabetes.

Continuous Glucose Monitoring Systems: A Review

There have been continuous advances in the field of glucose monitoring during the last four decades, which have led to the development of highly evolved blood glucose meters, non-invasive glucose monitoring (NGM) devices and continuous glucose monitoring systems (CGMS). Glucose monitoring is an integral part of diabetes management, and the maintenance of physiological blood glucose concentration is the only way for a diabetic to avoid life-threatening diabetic complications. CGMS have led to tremendous improvements in diabetic management, as shown by the significant lowering of glycated hemoglobin (HbA1c) in adults with type I diabetes. Most of the CGMS have been minimally-invasive, although the more recent ones are based on NGM techniques. This manuscript reviews the advances in CGMS for diabetes management along with the future prospects and the challenges involved.

In search of the perfect glucose concentration for hospitalized patients: a brief review of the meta-analyses

In hospitalized patients, the optimal target blood glucose concentration is controversial. Numerous studies have examined clinical use of glucose control in various patient populations. In the present review, we briefly discuss corresponding meta-analyses. We electronically searched MEDLINE, EMBASE and CINAHL for meta-analyses relevant to the subject. Fifteen meta-analyses were identified that analyzed effects of a targeted glucose control. Twelve meta-analyses examined studies performed in critically ill patients. Included studies in this review varied in terms of the type of nutritional support, the efficacy of glucose control, the kind of glucose measurement, clinical end points (hospital or intensive care unit mortality, or 28-, 90- or 180-d mortality, or mortality 30 d after discharge), and the intensity of glucose control (moderate, tight, very tight). Four meta-analyses also including studies with a less stringent glucose control (glucose target <200 mg/dL) showed a beneficial effect on mortality. This effect disappeared when analyzing studies with a tighter glucose control (glucose target <150 mg/dL or <110/120 mg/dL, n = 5), with a very tight glucose control (glucose target <110/120 mg/dL, n = 2), or with a more precise definition of clinical endpoints (28-d mortality, n = 2). Eight meta-analyses showed that, despite the intensity of glucose control, the frequency of hypoglycemic episodes increased. The residual heterogeneity of individual studies incorporated into the various meta-analyses prevents a valid conclusion regarding potential benefits of a specific glucose target. A glucose concentration <200 mg/dL appears preferable.

Continuous glucose monitoring by intravenous microdialysis: influence of membrane length and dialysis flow rate

BACKGROUND

The benefit of tight glucose control in the intensive care unit is controversial. Part of the debate is around the frequency of glucose measurements, and therefore, a continuous glucose monitoring system is needed. Previously, we have shown that intravenous microdialysis has the potential for this purpose but that the accuracy must be improved. The aim of this study was to investigate the effects of the microdialysis membrane length and the perfusion rate on improving the accuracy.

METHODS

Two volunteer studies were performed, one comparing intravenous microdialysis catheters with different lengths (10 and 20 mm) and one comparing different perfusion rates (0.5, 1 and 2 μl/min) with plasma glucose reference levels. Median values of seven samples taken over 70-min periods were compared using Bland-Altman plots.

RESULTS

When microdialysis membranes of 10 and 20 mm perfused at a rate of 1 μl/min were used, the differences with measured plasma glucose levels were 30% ± 21% and 14% ± 13%. In comparison, plasma glucose measured in two different veins gave a difference of 3% ± 3%. In the second study, the differences between measured plasma glucose and that estimated with a microdialysis membrane of 30 mm perfused at 0.5, 1 and 2 μl/min were 8% ± 7%, 25% ± 19% and 39% ± 28%. Bland-Altman analyses gave the best line of equality (-0.11 mM) and the lowest limits of agreement (1.13 and -1.35 mM) when using the 30-mm membrane perfused with 0.5 μl/min.

CONCLUSION

The agreement of the intravenous microdialysis with plasma glucose levels improved significantly when increasing the microdialysis membrane length, and thereby the membrane area, and decreasing the perfusion rate.

Abnormalities in glucose homeostasis in critically ill children

OBJECTIVES

To study the prevalence of hyperglycemia (blood glucose >126 mg/dL [>7 mmol/L]) in critically ill children older than 1 month in the first week of PICU stay and to determine its effect on mortality, organ dysfunction, and the length of PICU stay. We also determined the prevalence of glucose variability and hypoglycemia and studied their effect on mortality and morbidity.

DESIGN

Prospective, observational cohort study.

SETTING

PICU of a tertiary care hospital.

PATIENTS

Children admitted to the PICU older than 1 month of age (January 2009 to June 2010).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Blood glucose values, clinical and laboratory data to calculate Pediatric Index of Mortality-2 and Pediatric Logistic Organ Dysfunction scores, caloric and carbohydrate intake, vasoactive drugs, and steroid and insulin usage for upto 7 days were recorded. Out of 170 critically ill children admitted to the PICU, hyperglycemia (blood glucose >126 mg/dL [7 mmol/L]) was observed in 78.24% children (95% confidence interval 72-84.4). On adjusted analysis, blood glucose level >180 mg/dL (10 mmol/L) was associated with increased mortality. Blood glucose >126 mg/dL (7 mmol/L) was not associated with mortality or PICU length of stay but was associated with multiple organ dysfunction. Hypoglycemia and glucose variability also occurred frequently in critically ill children; these were associated with occurrence of multiple organ failure.

CONCLUSIONS

Hyperglycemia (blood glucose >126 mg/dL [7 mmol/L]) is common in critically ill children, and values >180 mg/dL (10 mmol/L) are associated with mortality. We also noted that hyperglycemia, hypoglycemia (blood glucose <40 mg/dL [2.2 mmol/L]), and glucose variability were associated with multiple organ dysfunction.

Management of hyperglycemia in the intensive care unit: when glucose reaches critical levels

Hyperglycemia among hospitalized critically ill patients has been shown to be an independent predictor of poorer outcomes. Appropriate treatment of hyperglycemia among these patients has been associated with reduced mortality and morbidity. There are risk and benefits associated with management of hyperglycemia in the critically ill patient. The ultimate goal of treatment is to obtain glycemic control without causing undue hypoglycemia. This article discusses issues related to glycemic control among critically ill patients, glucose targets in this population, and best practices in the management of hyperglycemia in patients in the intensive care unit.

Elderly patients may benefit from tight glucose control

BACKGROUND

While minimizing hyperglycemia in critically injured patients improves outcomes, it is debatable whether postinjury glucose control should aim for conventional glucose control levels (≤180 mg/dL) or tight glucose control levels (81-108 mg/dL). We queried our 17-year prospective database of patients at risk for postinjury multiple organ failure to examine the association between glucose levels and adverse outcomes.

METHODS

Acutely injured patients admitted to a Level I trauma center intensive care unit from 1992 to 2008 who were more than 15 years of age, had Injury Severity Scores >15, and who survived >48 hours were eligible for the study. Multiple logistic regression was used to determine the independent association of glucose control with adverse outcomes (death, ventilator-free days, intensive care unit-free days, and major infections), adjusted for Injury Severity Score, age, and red blood cell transfusion in the first 12 hours.

RESULTS

Overall, 2,231 patients were eligible, of whom 153 (6.9%) died. The mean age was 37.8 ± 0.4 years, and the median Injury Severity Score was 27 (interquartile range, 21-35). The majority (77%) of these patients maintained mean glucose within conventional glucose control levels and only 10% achieved mean glucose levels within tight glucose control levels. Nonsurvivors required greater doses of insulin to control glucose levels and had greater mean insulin to glucose ratios (t test; P = .025). After adjusting for confounders, mean glucose remained significantly associated with the studied adverse outcomes. Age significantly modified all these associations with older patients seeming to benefit more from tight glucose control levels than their younger counterparts.

CONCLUSION

Age is an effect modifier of the association between glucose levels and adverse outcomes. Future studies including larger samples of elderly trauma patients are needed to determine the ideal levels for glucose control in this growing population.

Identification of dihydropyrimidine dehydrogenase as a virulence factor essential for the survival of Entamoeba histolytica in glucose-poor environments

Adaptation to nutritional changes is a key feature for successful survival of a pathogen within its host. The protozoan parasite Entamoeba histolytica normally colonizes the human colon and in rare occasions, this parasite spread to distant organs, such as the liver. E. histolytica obtains most of its energy from the fermentation of glucose into ethanol. In this study, we were intrigued to know how this parasite reacts to changes in glucose availability and we addressed this issue by performing a DNA microarray analysis of gene expression. Results show that parasites that were adapted to growth in absence of glucose increased their virulence and altered the transcription of several genes. One of these genes is the dihydropyrimidine dehydrogenase (DPD), which is involved in degradation of pyrimidines. We showed that this gene is crucial for the parasite's growth when the availability of glucose is limited. These data contribute to our understanding of the parasite's ability to survive in glucose-poor environments and reveal a new role for the DPD enzyme.

Intensive insulin therapy in brain injury: a meta-analysis

Many studies have addressed the question of whether intensive insulin therapy (IIT) provides better outcomes for brain-injured patients than does conventional insulin therapy (CIT), with conflicting results. We performed a systematic review and meta-analysis of the literature to estimate the effect of IIT on patients with brain injury. We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and citations of key articles and selected "all randomized controlled trials" (RCTs) comparing the effect of IIT to CIT among adult patients with acute brain injury (traumatic brain injury, stroke, subarachnoid hemorrhage, and encephalitis). Of the 2807 studies, we identified 9 RCTs with a total of 1160 patients for analysis. IIT did not appear to decrease the risk of in-hospital or late mortality (RR=1.04, 95% CI=0.75, 1.43 and RR=1.07, 95%CI=0.91, 1.27 respectively). No significant heterogeneity was found (I(2)=0.0%). IIT also did not have a protective effect on long-term neurological outcomes (LTNO) (RR=1.10, 95% CI=0.96, 1.27). IIT, however, did decrease the rate of infections (RR=0.76, 95% CI=0.58, 0.98). Heterogeneity was present (I(2)=64%), which was eliminated upon sensitivity analysis bringing the RR to 0.66 (95% CI=0.55, 0.80, I(2)=0%). IIT increased the rate of hypoglycemic episodes (RR=1.72, 95% CI=1.20, 2.46) however there was intractable heterogeneity present (I(2)=89%), which did not resolve upon sensitivity analysis. We found no evidence of publication bias by Egger's test (p=0.50). To conclude, IIT has no mortality or LTNO benefit to patients with brain injury, but is beneficial at decreasing infection rates.

Predictive value of admission blood glucose level on short-term mortality in acute cerebral ischemia

BACKGROUND

Admission hyperglycemia increases the risk of death in patients with acute stroke. However, the most appropriate cut-off of glucose level indicating an increased risk of short-term mortality remains unknown.

PURPOSE AND METHODS

We aimed at establishing the optimum cut-offs of several variables (including admission blood glucose levels) predicting case-fatality (72hours, 7days) and unfavorable outcome [modified Rankin Scale (mRS) score 5-6 at 7 days] in consecutive first-ever acute ischemic stroke. Receiver operating characteristic (ROC) curves were constructed.

RESULTS

Eight hundred eleven consecutive patients were included [median age of 77 (69-83) years; 418 (52%) male; 239 (30%) diabetics; median admission National Institutes of Health Stroke Scale (NIHSS) 7 (4-12), 32 (4%) dead within 72hours; 64 (8%) dead within day 7; 155 (19%) with unfavorable outcome]. Median admission glucose levels were 113 (97-155)mg/dL. Diabetics had significantly higher median glucose levels than non-diabetics [163 (133-214) vs. 107 (92-123) mg/dL, p<0.001]. According to ROC analysis, the only significant predictive value of glycemia was ≥143mg/dL for 72-hour fatality (sensitivity 88% and specificity 70%) especially in non-diabetics (sensitivity 88% and sensitivity 62%). This cut-off point was an independent predictor for 72-hour fatality (overall: OR=4.0, CI=1.6-9.9, p=0.003; non-diabetics: OR=4.9, CI=1.7-14.5, p=0.004). The cut-offs of fasting total cholesterol levels and admission leukocytes had poor predictive values for each outcome, while those of admission NIHSS had good discrimination in predicting short-term outcome measures.

CONCLUSIONS

Admission hyperglycemia (≥143mg/dL) is a strong and an independent predictor for 72-hour fatality, especially in patients with no prior history of diabetes mellitus.

The effects of precision, haematocrit, pH and oxygen tension on point-of-care glucose measurement in critically ill patients: a prospective study

BACKGROUND

Critical care glycaemic control protocols commonly have treatment adjustment (target) ranges spanning ≤2 mmol/L. These require precise point-of-care glucose measurement, unaffected by other variables, to avoid measurement errors increasing glycaemic variability and hypoglycaemic episodes (both strongly associated with mortality in critically ill patients).

METHODS

A prospective 206 intensive care patient study was carried out. Arterial glucose concentrations were measured in duplicate using three point-of-care instruments (MediSense Precision PCχ, HemoCue DM and Radiometer 700), a central laboratory instrument (Siemens ADVIA), and in whole blood and plasma using the Yellow Springs Instruments 2300 instrument.

RESULTS

Coefficients of variation for the MediSense, HemoCue, Radiometer and Siemens instruments were 5.1%, 2.5%, 2.1% and 2.3%, respectively. Compared with the Siemens instrument, the bias (95% limits of agreement) for the MediSense, HemoCue and Radiometer instruments were 0.0 (-1.4 to 1.4), 0.0 (-1.2 to 1.1) and -0.2 (-0.9 to 0.6) mmol/L, respectively. The whole blood-plasma glucose concentration difference was significantly affected by the haematocrit. MediSense and HemoCue instrument performances were substantially affected by haematocrit. MediSense instrument performance was also affected by pH and PaO(2). Radiometer instrument performance was not affected by haematocrit, pH or PaO(2).

CONCLUSIONS

The MediSense instrument was too imprecise for use in critically ill patients. The haematocrit range seen is too great to allow fixed-factor conversion between whole blood and plasma values, substantially affecting the accuracy of both glucose meters. However, the Radiometer instrument was unaffected by the haematocrit, pH or pO(2), resulting in a performance equivalent to the laboratory method. Instrument performance differences may therefore partially explain the differing results of tight glycaemic control therapy trials.

Hypoglycemia in critically ill children

BACKGROUND

The practice of glycemic control with intravenous insulin in critically ill patients has brought clinical focus on understanding the effects of hypoglycemia, especially in children. Very little is published on the impact of hypoglycemia in this population. We aimed to review the existing literature on hypoglycemia in critically ill neonates and children.

METHODS

We performed a systematic review of the literature up to August 2011 using PubMed, Ovid MEDLINE and ISI Web of Science using the search terms "hypoglycemia or hypoglyc*" and "critical care or intensive care or critical illness". Articles were limited to "all child (0-18 years old)" and "English".

RESULTS

A total of 513 articles were identified and 132 were included for review. Hypoglycemia is a significant concern among pediatric and neonatal intensivists. Its definition is complicated by the use of a biochemical measure (i.e., blood glucose) for a pathophysiologic problem (i.e., neuroglycopenia). Based on associated outcomes, we suggest defining hypoglycemia as <40-45 mg/dl in neonates and <60-65 mg/dl in children. Below the suggested threshold values, hypoglycemia is associated with worse neurological outcomes, increased intensive care unit stay, and increased mortality. Disruptions in carbohydrate metabolism increase the risk of hypoglycemia incritically ill children. Prevention of hypoglycemia, especially in the setting of intravenous insulin use, will be best accomplished by the combination of accurate measuring techniques, frequent or continuous glucose monitoring, and computerized insulin titration protocols.

CONCLUSION

Studies on hypoglycemia in critically ill children have focused on spontaneous hypoglycemia. With the current practice of maintaining blood glucose within a narrow range with intravenous insulin, the risk factors and outcomes associated with insulin-induced hypoglycemia should be rigorously studied to prevent hypoglycemia and potentially improve outcomes of critically ill children.

Association of hyperglycemia, glucocorticoids, and insulin use with morbidity and mortality in the pediatric intensive care unit

BACKGROUND

Studies of pediatric intensive care unit (PICU) patients have shown a significant association of morbidity and mortality with hyperglycemia. We retrospectively evaluated the degree of hyperglycemia as well as its correlation with glucocorticoid and insulin use and assessed its association with hospital length of stay (LOS) and mortality. This study preceded the initiation of a standard glycemic control protocol.

METHODS

We examined medical records at Kosair Children's Hospital for all PICU admissions from 2008 of patients without diabetes mellitus. Critical illness hyperglycemia (CIH) was defined by having three or more peak glucose values greater than thresholds of 110, 140, 180, and 200 mg/dl. These patients were evaluated for glucocorticoid, insulin use, and outcome measures.

RESULTS

We evaluated the eligible 1173 admissions, where 10.5% of these patients reached the highest threshold (200 mg/dl) of CIH. Glucocorticoids were used in 43% of these patients, with dexamethasone being the most common (58%). There was a significant correlation between glucocorticoids and higher peak glucose values, where 81% of the patients who were above the 200 mg/dl cutoff level were treated with glucocorticoids. Only 36.8% in that group were also treated with insulin. Patients at the 200 mg/dl cutoff had the highest median PICU and total hospital length of stays (4 and 10 days, respectfully). Mortality was associated with increasing glucose levels, reaching 18.7% among patients above the 200 mg/dl cutoff.

CONCLUSION

Hyperglycemia was prevalent in the PICU and was associated with increased morbidity, as characterized by increased LOS and increased mortality. Glucocorticoid use was prevalent among patients exhibiting hyperglycemia. Insulin use was uncommon.

Glycemic control in the pediatric intensive care unit of Leuven: two years of experience

Stress hyperglycemia and hypoglycemia are associated with increased mortality and morbidity in critically ill patients. Three randomized controlled trials, in the surgical, medical, and pediatric intensive care unit (PICU) of the Leuven University in Belgium, demonstrated the beneficial response of tightly controlling blood glucose levels within age-adjusted narrow limits by applying intensive insulin therapy. Follow-up studies could not confirm the results obtained in the Leuven studies but revealed the complexity associated with tight glycemic control (TGC). This article gives an overview of the methodological aspects typical of the Leuven TGC concept, with the focus on the PICU. Differences between the adult and the PICU are described. This overview article might help other ICUs by addressing potential differences in clinical practice when implementing TGC.

Glycemic control: how tight in the intensive care unit?

Determining the optimal level of glycemic control in critical illness has proven difficult since the original Leuven study conclusions were published in 2001. Conflicting evidence, scientific methodologies, hospital cultures, and a-priori biases have challenged many clinical practice patterns. Specifically, the prioritization of patient safety has resulted in many practitioners changing from a glycemic control target of 80-110 mg/dL to a more liberal target of 140-180 mg/dL. However, a detailed examination of the evidence can provide a more population-specific glycemic control strategy. This position paper presents an approach for cardiac surgery patients in the intensive care unit (ICU) consistent with extant evidence and real-life variables. We argue that in the cardiac surgery ICU, glycemic targets may be as low as 80-110 mg/dL when formal intensive insulin therapy and nutrition support protocols are used with low rates of hypoglycemia, patient safety mechanisms, properly trained staff, and a supportive hospital administration all in force. Cardiac surgery ICUs that already follow this model may continue with 80-110 mg/dL blood glucose targets, whereas others may advance their blood glucose targets in a stepwise fashion: from 140 to 180 mg/dL to 110-140 mg/dL to 80-110 mg/dL, on the basis of their performance.

Intensive insulin therapy in critically ill hospitalized patients: making it safe and effective

Intensive insulin therapy (IIT) for hyperglycemia in critically ill patients has become a standard practice. Target levels for glycemia have fluctuated since 2000, as evidence initially indicated that tight glycemic control to so-called normoglycemia (80-110 mg/dl) leads to the lowest morbidity and mortality without hypoglycemic complications. Subsequent studies have demonstrated minimal clinical benefit combined with greater hypoglycemic morbidity and mortality with tight glycemic control in this population. The consensus glycemic targets were then liberalized to the mid 100s (mg/dl). Handheld POC blood glucose (BG) monitors have migrated from the outpatient setting to the hospital environment because they save time and money for managing critically ill patients who require IIT. These devices are less accurate than hospital-grade POC blood analyzers or central laboratory analyzers. Three questions must be answered to understand the role of IIT for defined populations of critically ill patients: (1) How safe is IIT, with various glycemic targets, from the risk of hypoglycemia? (2) How tightly must BG be controlled for this approach to be effective? (3) What role does the accuracy of BG measurements play in affecting the safety of this method? For each state of impaired glucose regulation seen in the hospital, such as hyperglycemia, hypoglycemia, or glucose variability, the benefits, risks, and goals of treatment, including IIT, might differ. With improved accuracy of BG monitors, IIT might be rendered even more intensive than at present, because patients will be less likely to receive inadvertent overdosages of insulin. Greater doses of insulin, but with dosing based on more accurate glucose levels, might result in less hypoglycemia, less hyperglycemia, and less glycemic variability.