An overview of hypoglycemia in the critically ill

Between blood glucose and mortality in critically ill patients: Retrospective analysis of the MIMIC-IV database

AIMS/INTRODUCTION

Mean blood glucose (MBG) level is associated with mortality among critically ill patients. We undertook a cohort study to investigate the relationship between MBG and mortality in critically ill patients.

MATERIALS AND METHODS

Critically ill patients were enrolled from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. MBG was calculated to represent the overall glycemic status during intensive care unit (ICU) hospitalization, and a multivariate logistic regression determined the relationship between MBG and ICU mortality in different subgroups of critically ill patients.

RESULTS

A total of 8,973 patients were included in the study, 1,244 of whom died within 28 days, including 5,402 men and 3,571 women. Multivariate adjusted restricted cubic spline analyses suggested that the relationship between MBG and ICU mortality was a "J" shape. Logistic regression showed 28 day mortality in group 3 (glucose ≥10 mmol/L): the adjusted odds ratio was 2.06 (95% confidence interval 1.65-2.57). The results of subgroup analysis showed that hyperglycemia had a more significant impact on ICU mortality in patients without diabetes, hypoglycemia and liver disease, and the ICU mortality risk of non-diabetes patients was always higher than that of diabetes patients with the same hyperglycemia level.

CONCLUSIONS

Current evidence suggested a J-shaped relationship between MBG and mortality in critically ill patients.

Workup and Management of Recurrent Attacks of Post-bariatric Hypoglycemia in a Patient With Non-alcoholic Steatohepatitis

Bariatric surgery is an established treatment option for patients with non-alcoholic fatty liver disease (NAFLD) as well as non-alcoholic steatohepatitis (NASH) and is said to effectively reduce hepatic inflammation as well as steatosis in these patients. However, bariatric surgery is associated with multiple complications, including nutritional deficiencies, malnutrition, post-bariatric hypoglycemia (PBH), anastomotic leaks, and bowel strictures. This case report describes a rare but significant complication of post-bariatric surgery hypoglycemia in a patient with NASH, which started almost six months after Roux-en-Y gastric bypass (RYGB) surgery. This 55-year-old male patient presented with recurrent episodes of severe hypoglycemia, which, on further work-up, were found to be predominantly nocturnal as well as occurring two to three hours after meals. We report the successful treatment of the patient with an unconventional approach using nifedipine and acarbose. Our findings emphasize the importance of careful evaluation of patients who have undergone bariatric surgery, as this complication can occur as early as six months following the bariatric surgery as well as several years after the surgery. Our case report highlights the need for early recognition, relevant workup, and appropriate management of resistant hypoglycemic events using calcium channel blockers and acarbose, thus adding to the existing literature on this topic.

Clinical challenges of glycemic control in the intensive care unit: A narrative review

Glucose control in patient admitted to the intensive care unit has been a topic of much debate over the past 20 years. The harmful effects of uncontrolled hyperglycemia and hypoglycemia in critically ill patients is well established. Although a large clinical trial in 2001 demonstrated significant mortality and morbidity benefits with tight glucose control in this patient population, the results could not be replicated by other investigators. The “Normoglycemia in Intensive Care Evaluation-Survival Using Glucose Algorithm Regulation” trial in 2009 established that tight glucose control was not only of no benefit, but in fact harmful due to the significant risk of hypoglycemia. The current guidelines suggest a moderate approach with the initiation of intravenous insulin therapy in critically ill patients when the blood glucose level is above 180 mg/dL. The most important factor that underpins glycemic management in intensive care unit patients is the consequent prevention of hypoglycemia. Robust glucose monitoring strategies and insulin protocols need to be implemented in order to achieve this goal.

Predicting hypoglycemia in critically Ill patients using machine learning and electronic health records

Hypoglycemia is a common occurrence in critically ill patients and is associated with significant mortality and morbidity. We developed a machine learning model to predict hypoglycemia by using a multicenter intensive care unit (ICU) electronic health record dataset. Machine learning algorithms were trained and tested on patient data from the publicly available eICU Collaborative Research Database. Forty-four features including patient demographics, laboratory test results, medications, and vitals sign recordings were considered. The outcome of interest was the occurrence of a hypoglycemic event (blood glucose < 72 mg/dL) during a patient's ICU stay. Machine learning models used data prior to the second hour of the ICU stay to predict hypoglycemic outcome. Data from 61,575 patients who underwent 82,479 admissions at 199 hospitals were considered in the study. The best-performing predictive model was the eXtreme gradient boosting model (XGBoost), which achieved an area under the received operating curve (AUROC) of 0.85, a sensitivity of 0.76, and a specificity of 0.76. The machine learning model developed has strong discrimination and calibration for the prediction of hypoglycemia in ICU patients. Prospective trials of these models are required to evaluate their clinical utility in averting hypoglycemia within critically ill patient populations.

Hyperglycemia and Hypoglycemia Are Associated with In-Hospital Mortality among Patients with Coronavirus Disease 2019 Supported with Extracorporeal Membrane Oxygenation

Metabolic abnormalities, such as preexisting diabetes or hyperglycemia or hypoglycemia during hospitalization aggravated the severity of COVID-19. We evaluated whether diabetes history, hyperglycemia before and during extracorporeal membrane oxygenation (ECMO) support, and hypoglycemia were risk factors for mortality in patients with COVID-19. This study included data on 195 patients with COVID-19, who were aged ≥19 years and were treated with ECMO. The proportion of patients with diabetes history among nonsurvivors was higher than that among survivors. Univariate Cox regression analysis showed that in-hospital mortality after ECMO support was associated with diabetes history, renal replacement therapy (RRT), and body mass index (BMI) < 18.5 kg/m2. Glucose at admission >200 mg/dL and glucose levels before ventilator >200 mg/dL were not associated with in-hospital mortality. However, glucose levels before ECMO >200 mg/dL and minimal glucose levels during hospitalization <70 mg/dL were associated with in-hospital mortality. Multivariable Cox regression analysis showed that glucose >200 mg/dL before ECMO and minimal glucose <70 mg/dL during hospitalization remained risk factors for in-hospital mortality after adjustment for age, BMI, and RRT. In conclusion, glucose >200 mg/dL before ECMO and minimal glucose level <70 mg/dL during hospitalization were risk factors for in-hospital mortality among COVID-19 patients who underwent ECMO.

Left Hemiplegia Possibly Due to Glucose Reperfusion Injury after Recovery of Severe Hypoglycemia in a Woman with Type 2 Diabetes Mellitus

A 79-year-old woman with type 2 diabetes receiving insulin was rushed to our hospital due to severe hypoglycemia. Glucose was administered, and the consciousness disturbance was promptly improved. A few hours later, conjugate deviation of the eyes to the right and left hemiplegia occurred at a normal glucose level. Cerebral magnetic resonance imaging (MRI) showed hyperintensities of the right posterior limb of the internal capsule and the medial thalamus on diffusion-weighted imaging sequences. However, the changes observed using MRI disappeared completely on the third day, and her symptoms subsequently improved. This may have been a case of glucose reperfusion injury.

Hypoglycemia in a Surgical Intensive Care Unit

BACKGROUND

Glycemic control is an important aspect of critical care because derangements are associated with morbidity and mortality. Patients at highest risk for hypoglycemia in the surgical intensive care unit (SICU) are incompletely described by existing literature. Our objective was to delineate this high-risk patient population in our SICU.

STUDY DESIGN

In this single-center, retrospective, observational study, SICU patients admitted from June 1, 2019 to July 31, 2020 with ≥1 episode of hypoglycemia (blood glucose <60 mg/dL) were included.

RESULTS

There were 41 hypoglycemic events in 27 patients, comprising an incidence of 1.5% among SICU patients. The most common admission diagnoses were cirrhosis (n = 13, 48%), polytrauma (n = 12, 44%), multisystem organ failure (n = 11, 41%), diabetes mellitus (n = 9, 33%), and soft tissue infection (n = 8, 30%). Four high-risk populations were identified: patients in multisystem organ failure (MSOF) (n = 11, 41%); those who were nil per os (NPO) (n = 10, 37%); patients receiving long acting subcutaneous insulin, for example, Lantus (n = 3, 11%); and those on continuous intravenous insulin infusions (n = 3, 11%). After multi-disciplinary peer review, most hypoglycemic events (n = 16, 59%) were deemed iatrogenic.

CONCLUSIONS

Hypoglycemia is rare in surgical critical care. When it does occur, patients are typically in MSOF, NPO, on long acting subcutaneous insulin or continuous insulin infusions, have soft tissue infections, or have acute or chronic liver failure. Increased vigilance with frequent blood glucose monitoring in these high-risk patients may reduce the risk of hypoglycemia in the SICU.

A Multicenter Evaluation of a Point-of-Care Blood Glucose Meter System in Critically Ill Patients

BACKGROUND

Our purpose was to evaluate the performance of the ACCU-CHEK® Inform II blood glucose monitoring system (Roche Diagnostics GmbH) compared with the perchloric acid hexokinase (PCA-HK) comparator method on the cobas® 6000 analyzer (Roche Diagnostics International Ltd) in critically ill patients.

METHODS

Overall, 476 arterial (376 pediatric/adult, 100 neonate), 375 venous, and 100 neonatal heel-stick whole-blood samples were collected and evaluated from critical care settings at 10 US hospitals, including the emergency department, medical and surgical intensive care units (ICUs), and neonatal and pediatric ICUs. The ACCU-CHEK Inform II system was evaluated at 2 cutoff boundaries: boundary 1 was ≥95% of results within ±12 mg/dL of the reference (samples with blood glucose <75 mg/dL) or ±12% of the reference (glucose ≥75 mg/dL), and boundary 2 was ≥98% of results within ±15 mg/dL or ±15% of the reference. Clinical performance was assessed by evaluating sample data using Parkes error grid, Monte Carlo simulation, and sensitivity and specificity analyses to estimate clinical accuracy and implications for insulin dosing when using the ACCU-CHEK Inform II system.

RESULTS

Proportions of results within evaluation boundaries 1 and 2, respectively, were 96% and 98% for venous samples, 94% and 97% for pediatric and adult arterial samples, 84% and 98% for neonatal arterial samples, and 96% and 100% for neonatal heel-stick samples. Clinical evaluation demonstrated high specificity and sensitivity, with low risk of potential insulin-dosing errors.

CONCLUSIONS

The ACCU-CHEK Inform II system demonstrated clinically acceptable performance against the PCA-HK reference method for blood glucose monitoring in a diverse population of critically ill patients in US care settings.

Feeding practices and association of fasting and low or hypo glycaemia in severe paediatric illnesses in Malawi - a mixed method study

BACKGROUND

The presence of low or hypo glycaemia in children upon admission to hospital in low income countries is a marker for poor outcome. Fasting during illness may contribute to low blood glucose and caretakers' feeding practices during childhood illnesses may thus play a role in the development of low or hypo glycaemia. This study aims to describe the caretaker's feeding practices and association of fasting with low or hypo glycaemia in sick children in Malawi.

METHODS

A mixed method approach was used combining quantitative cross-sectional data for children aged 0-17 years admitted to Queen Elizabeth Central Hospital (QECH), a tertiary hospital in Malawi, with qualitative focus group discussions conducted with caretakers of young children who were previously referred to QECH from the five health centres around QECH. Logistic regression was used to analyse the quantitative data and thematic content analysis was conducted for qualitative data analysis.

RESULTS

Data for 5131 children who were admitted through the hospital's Paediatric Accident and Emergency Department (A&E) were analysed whereof 2.1% presented with hypoglycaemia (< 2.5 mmol/l) and 6.6% with low glycaemia (≥2.5mmoll/l - < 5 mmol/l). Fasting for more than eight hours was associated with low glycaemia as well as hypoglycaemia with Adjusted Odds Ratios (AOR) of 2.9 (95% Confidence Interval (CI) of 2.3-3.7) and 4.6, (95% CI 3.0-7.0), respectively. Caretakers demonstrated awareness of the importance of feeding during childhood illness and reported intensified feeding attention to sick children but face feeding challenges when illness becomes severe causing them to seek care at a health facility.

CONCLUSION

Results suggests that caretakers understand the importance of feeding during illness and make efforts to intensify feeding a sick child but challenges occur when illness is severe leading to fasting. Fasting among children admitted to hospitals may serve as a marker of severe illness and determine those at risk of low and hypoglycaemia.

Degree of hyperglycemia independently associates with hospital mortality and length of stay in critically ill, nondiabetic patients: Results from the ANZICS CORE binational registry

PURPOSE

Hyperglycemia (HG) in critically ill patients influences clinical outcomes and hospitalization costs. We aimed to describe association of HG with hospital mortality and length of stay in large scale, real-world scenario.

MATERIALS

From The Australian and New Zealand Intensive Care Society (ANZICS) Adult Patient Database (APD) we included 739,152 intensive care unit (ICU) patients admitted during 2007-2016. Hyperglycemia was quatified using midpoint blood glucose level (MBGL). Association with outcomes (hospital mortality and length of stay (LOS)) was tested using multivariable, mixed effects, 2-level hierarchical regression.

RESULTS

Degree of HG (defined using MBGL as a continuous variable) was significantly associated with hospital mortality and longer hospital stay in a dose-dependent fashion. The fourth, third and second MBGL (compared to the first) quartiles were associated with hospital mortality (odds ratio 1.34, 1.05 and 0.97, respectively) and longer hospital stay (1.56, 1.38 and 0.93 days, respectively). These associations were stronger associations in trauma (especially head injury), neurological disease and coma patients. Significant variation across ICUs was observed for all associations.

CONCLUSIONS

In this largest study of nondiabetic ICU patients, HG was associated with both study outcomes. This association was differential across ICUs and diagnostic categories.

Hypoglycemia but Not Hyperglycemia Is Associated with Mortality in Critically Ill Patients with Diabetes

BACKGROUND

Both severe hyperglycemia (> 200 mg/dL) and hypoglycemia (≤70 mg/dL) are known to be associated with increased mortality in critically ill patients. Therefore, we investigated associations of a single episode of blood glucose deviation (concentration either ≤70 mg/dL and/or > 200 mg/dL) during an intensive care unit (ICU) stay with mortality in these patients.

METHODS

A total of 4,986 patients (age 65 ± 15 years; 39% female; 14% type 2 diabetes [T2DM] based on medical records) admitted to a German ICU in a tertiary care hospital were investigated retrospectively. The intra-ICU and long-term mortality of patients between 4 and 7 years after their ICU submission were assessed.

RESULTS

A total 62,659 glucose measurements were analyzed. A single glucose deviation was associated with adverse outcomes compared to patients without a glucose deviation, represented by both intra-ICU mortality (22 vs. 10%; OR 2.62; 95% CI 2.23-3.09; p < 0.001) and long-term mortality (HR 2.01; 95% CI 1.81-2.24; p < 0.001). In patients suffering from T2DM hypoglycemia (30 vs. 13%; OR 2.94; 95% CI 2.28-3.80; p < 0.001) but not hyperglycemia (16 vs. 14%; OR 1.05; 95% CI 0.68-1.62; p = 0.84) was associated with mortality.

CONCLUSION

In patients with dia-betes, hypo- but not hyperglycemia was associated with increased mortality, whereas in patients without diabetes, both hyper- and hypoglycemia were associated with adverse outcome. Blood glucose concentration might need differential approaches depending on concomitant diseases.

Update on glucose in critical care

The aim of this review is to summarize recent developments on the mechanisms involved in stress hyperglycemia associated with critical illness. Different aspects of the consequences of stress hyperglycemia as well as the therapeutic approaches tested so far are discussed: the physiological regulations of blood glucose, the mechanisms underlying stress hyperglycemia, the clinical associations, and the results of the prospective trials and meta-analyses to be taken into consideration when interpreting the available data. Current recommendations, challenges, and technological hopes for the future are be discussed.

Decreased blood glucose at admission has a prognostic impact in patients with severely decompensated acute heart failure complicated with diabetes mellitus

The prognostic impact of a decreased blood glucose level in acute heart failure (AHF) has not been sufficiently clarified. The data from 1234 AHF patients were examined in the present study. The blood glucose (BG) levels were evaluated at admission. The patients were divided into groups based on the following: with or without diabetes mellitus (DM), and BG level ≥ 200 mg/dl (elevated BG) or < 200 mg/dl (decreased BG). The elevated and decreased BG patients were further divided into another three groups: 200 mg/ml ≤ BG < 300 mg/dl (mild-elevated), 300 mg/ml ≤ BG < 400 mg/dl (moderate-elevated) and BG ≥ 400 mg/ml (severe-elevated); and 150 mg/ml ≤ BG < 200 mg/dl (mild-decreased), 100 mg/ml ≤ BG < 150 mg/dl (moderate-decreased) and BG < 100 mg/ml (severe-decreased), respectively. The DM patients had a significantly poorer mortality than the non-DM patients. The prognosis was different between patients with elevated or decreased BG. In DM patients with elevated BG, the severe-elevated patients had a significantly poorer prognosis than moderate- and mild-elevated patients. In the DM patients with decreased BG, the severe-decreased patients had a significantly poorer prognosis than those moderate- and mild-decreased patients. The multivariate Cox regression model showed that a severe-decreased [hazard ratio (HR) 3.245, 95% confidence interval (CI) 1.271-8.282] and severe-elevated (HR 2.300, 95% CI 1.143-4.628) status were independent predictors of 365-day mortality in AHF patients with DM. The mortality was high among AHF patients with DM. Furthermore, both severe hyperglycemia and hypoglycemia were independent predictors of the mortality in patients with AHF complicated with DM.

Nrf2 as a target for prevention of age-related and diabetic cataracts by against oxidative stress

Cataract is one of the most important causes of blindness worldwide, with age-related cataract being the most common one. Agents preventing cataract formation are urgently required. Substantial evidences point out aggravated oxidative stress as a vital factor for cataract formation. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/Kelch-like erythroid-cell-derived protein with CNC homology (ECH)-associated protein 1 (Keap1) system is considered as one of the main cellular defense mechanisms against oxidative stresses. This review discusses the role of Nrf2 pathway in the prevention of cataracts and highlights that Nrf2 suppressors may augment oxidative stress of the lens, and Nrf2 inducers may decrease the oxidative stress and prevent the cataract formation. Thus, Nrf2 may serve as a promising therapeutic target for cataract treatment.

Energy, Protein, Carbohydrate, and Lipid Intakes and Their Effects on Morbidity and Mortality in Critically Ill Adult Patients: A Systematic Review

The guidelines for nutritional support in critically ill adult patients differ in various aspects. The optimal amount of energy and nutritional substrates supplied is important for reducing morbidity and mortality, but unfortunately this is not well known, because the topic is complex and every patient is individual. The aim of this review was to gather recent pertinent information concerning the nutritional support of critically ill patients in the intensive care unit (ICU) with respect to the energy, protein, carbohydrate, and lipid intakes and the effect of their specific utilization on morbidity and mortality. Enteral nutrition (EN) is generally recommended over parenteral nutrition (PN) and is beneficial when administered within 24-48 h after ICU admission. In contrast, early PN does not provide substantial advantages in terms of morbidity and mortality, and the time when it is safe and beneficial remains unclear. The most advantageous recommendation seems to be administration of a hypocaloric (<20 kcal · kg^-1 · d^-1), high-protein diet (amino acids at doses of ≥2 g · kg^-1 · d^-1), at least during the first week of critical illness. Another important factor for reducing morbidity is the maintenance of blood glucose concentrations at 120-150 mg/dL, which is accomplished with the use of insulin and lower doses of glucose of 1-2 g · kg^-1 · d^-1, because this prevents the risk of hypoglycemia and is associated with a better prognosis according to recent studies. A fat emulsion is used as a source of required calories because of insulin resistance in the majority of patients. In addition, lipid oxidation in these patients is ∼25% higher than in healthy subjects.

Targets and probes for non-invasive imaging of β-cells

β-cells, located in the islets of the pancreas, are responsible for production and secretion of insulin and play a crucial role in blood sugar regulation. Pathologic β-cells often cause serious medical conditions affecting blood glucose level, which severely impact life quality and are life-threatening if untreated. With 347 million patients, diabetes is one of the most prevalent diseases, and will continue to be one of the largest socioeconomic challenges in the future. The diagnosis still relies mainly on indirect methods like blood sugar measurements. A non-invasive diagnostic imaging modality would allow direct evaluation of β-cell mass and would be a huge step towards personalized medicine. Hyperinsulinism is another serious condition caused by β-cells that excessively secrete insulin, like for instance β-cell hyperplasia and insulinomas. Treatment options with drugs are normally not curative, whereas curative procedures usually consist of the resection of affected regions for which, however, an exact localization of the foci is necessary. In this review, we describe potential tracers under development for targeting β-cells with focus on radiotracers for PET and SPECT imaging, which allow the non-invasive visualization of β-cells. We discuss either the advantages or limitations for the various tracers and modalities. This article concludes with an outlook on future developments and discuss the potential of new imaging probes including dual probes that utilize functionalities for both a radioactive and optical moiety as well as for theranostic applications.

Point-of-Care Glucose Critical Values: A Q-Probes Study Involving 50 Health Care Facilities and 2349 Critical Results

CONTEXT

Accuracy of blood glucose measurements in the critical value range is important for properly treating patients with severe hypoglycemia and hyperglycemia.

OBJECTIVE

To evaluate the performance and reliability of point-of-care glucose (POCG) results in the critical value range among multiple facilities.

DESIGN

Q-Probes participants retrospectively collected data from up to 50 POCG results in their critical value range including patient location, type of testing operator, repeat glucose results, and caregiver notification. A repeat measurement at 10 minutes or less that was within 15 mg/dL of initial critical low or 20% of initial critical high value was considered a confirmed result.

RESULTS

Fifty facilities submitted data. Of 2349 critical POCG measurements, 1386 (59.0%) were retested. The median institutional retest rate was 56%. The retest rate was significantly higher when initial results were in the critical low range, P < .001. Although 30 of 50 facilities (60%) had written procedures for retesting, this was not associated with higher retest rates (P = .34). Among 35 facilities that routinely retested critical POCG results, 23 (65.7%) had criteria defined for interpreting results. The median institutional confirmation rate for retested specimens was 81.7%. The median institutional rate for caregiver notification of critical POCG results was 85.7%. Five hundred eighty-six of 1488 critical POCG notifications (39.4%) were done on patients in whom specimens were not retested.

CONCLUSIONS

This study shows that POCG results in the critical range may be unreliable because of testing errors that are not recognized from lack of confirmatory testing. In addition, notification of critical POCG results is not consistently performed.

Association between hypoglycemia and dementia in patients with type 2 diabetes

In addition to increased risks of macrovascular and microvascular complications, patients with type 2 diabetes mellitus (T2DM) usually also are at increased risk for cognitive impairment and dementia. Hypoglycemia, a common consequence of diabetes treatment, is considered an independent risk factor for dementia in patients with T2DM. Hypoglycemia and dementia are clinically underestimated and are related to poor outcomes; thus, they may compromise the life expectancy of patients with T2DM. Epidemiological evidence of hypoglycemia-associated cognitive decline and dementia is highly varied. Acute, severe hypoglycemic episodes induce chronic subclinical brain damage, cognitive decline, and subsequent dementia. However, the effects of recurrent moderate hypoglycemia on cognitive decline and dementia remain largely uninvestigated. Poor glycemic control (including fluctuation of hemoglobin A1C [HbA1c] and glucose values) and the viscous circle of bidirectional associations between dementia and hypoglycemia may be clinically relevant. The possible pathophysiological hypotheses include post-hypoglycemic neuronal damage, inflammatory processes, coagulation defects, endothelial abnormalities, and synaptic dysfunction of hippocampal neurons during hypoglycemia episodes. This article reviews previous findings, provides insight into the detection of groups at high risk of hypoglycemia-associated dementia, and proposes specific strategies to minimize the potential burdens associated with hypoglycemia-related neurocognitive disorders in patients with T2DM.

Cost and co-morbidities associated with hypoglycemic inpatients in Belgium

BACKGROUND AND OBJECTIVES

Little is known about the economic burden of hypoglycemia in Belgium, or its related co-morbidities. This study aimed at estimating the cost and length of stay associated with hypoglycemia-related hospitalizations in diabetic patients in Belgium and the association between hypoglycemia and in-hospital all-cause mortality, incidence of traumatic fractures, depression, and cardiovascular diseases (myocardial infarction or unstable angina), using retrospective data from 2011.

METHODS

Patient data were retrieved from the IMS Hospital Disease Database, including longitudinal (per calendar year) information on diagnoses, procedures, and drugs prescribed in ∼20% of all Belgian hospital beds. The eligible population included all adult (<19 year) diabetic (both types) patients, further split between those with/without a history of hypoglycemia-related hospitalizations. Diabetes, hypoglycemia, and co-morbidities of interest were identified based on International Classification of Diseases and Related Health Problems Version 9 (ICD-9) diagnosis codes. All costs were extrapolated to 2014 using progression in hospitalization costs since 2001.

RESULTS

A total of 43,410 diabetes-related hospitalizations were retrieved, corresponding to 30,710 distinct patients. The average hospitalization cost was €10,258 when hypoglycemia was documented (n = 2625), vs €7173 in other diabetic hospitalized patients (n = 40,785). When controlling for age and sex, a higher mortality risk (OR = 1.59; p-value <0.001), a higher incidence of traumatic fractures (OR = 1.25; p-value = 0.009), and a higher probability of depression-related hospitalizations (OR = 1.90; p-value <0.001) were observed in hypoglycemic patients. A similar risk of cardiovascular event was observed in both groups, but hypoglycemic patients were more at risk of experiencing multiple events.

CONCLUSION

Hospitalizations for hypoglycemia are expensive and associated with an increased risk of depression and traumatic fractures as well as increased in-hospital mortality. Interventions that can help reduce the risk of hypoglycemia, and consequently the burden on hospitals and society, without compromising glycemic control, will help to further improve diabetes management.

A Cytotoxic, Co-operative Interaction Between Energy Deprivation and Glutamate Release From System xc- Mediates Aglycemic Neuronal Cell Death

The astrocyte cystine/glutamate antiporter (system xc(-)) contributes substantially to the excitotoxic neuronal cell death facilitated by glucose deprivation. The purpose of this study was to determine the mechanism by which this occurred. Using pure astrocyte cultures, as well as, mixed cortical cell cultures containing both neurons and astrocytes, we found that neither an enhancement in system xc(-) expression nor activity underlies the excitotoxic effects of aglycemia. In addition, using three separate bioassays, we demonstrate no change in the ability of glucose-deprived astrocytes--either cultured alone or with neurons--to remove glutamate from the extracellular space. Instead, we demonstrate that glucose-deprived cultures are 2 to 3 times more sensitive to the killing effects of glutamate or N-methyl-D-aspartate when compared with their glucose-containing controls. Hence, our results are consistent with the weak excitotoxic hypothesis such that a bioenergetic deficiency, which is measureable in our mixed but not astrocyte cultures, allows normally innocuous concentrations of glutamate to become excitotoxic. Adding to the burgeoning literature detailing the contribution of astrocytes to neuronal injury, we conclude that under our experimental paradigm, a cytotoxic, co-operative interaction between energy deprivation and glutamate release from astrocyte system xc(-) mediates aglycemic neuronal cell death.

Reporting on Glucose Control Metrics in the Intensive Care Unit

The 'diabetes of injury' typically associated with critical illness has recently been thoroughly revisited and much better characterised following major therapeutic advances. The occurrence of severe hyperglycaemia, moderate hypoglycaemia or high glycaemic variability has been associated with an increased mortality and rate of complications in large independent cohorts of acutely ill patients. Hence, current guidelines advocate the prevention and avoidance of each of these three dysglycaemic domains, and the use of a common metrics for a quantitative description of dysglycaemic events, such as the proportion of time spent in the target glycaemic range as a unifying variable. Using a common language will help to face the future challenges, including the definition of the most appropriate blood glucose (BG) target according to the category of admission, the time interval from the initial injury and the medical history. The clinical testing of technological improvements in the monitoring systems and the therapeutic algorithms should be assessed using the same metrics.

Hypoglycemia-induced alterations in hippocampal intrinsic rhythms: Decreased inhibition, increased excitation, seizures and spreading depression

Seizures are the most common clinical presentation of severe hypoglycemia, usually as a side effect of insulin treatment for juvenile onset type 1 diabetes mellitus and advanced type 2 diabetes. We used the mouse thick hippocampal slice preparation to study the pathophysiology of hypoglycemia-induced seizures and the effects of severe glucose depletion on the isolated hippocampal rhythms from the CA3 circuitry.

METHODS AND RESULTS

Dropping the glucose perfusate concentration from the standard 10 mM to 1 mM produced epileptiform activity in 14/16 of the slices. Seizure-like events (SLEs) originated in the CA3 region and then spread into the CA1 region. Following the SLE, a spreading-depression (SD)-like event occurred (12/16 slices) with irreversible synaptic failure in the CA1 region (8/12 slices). CA3 SD-like events followed ~30 s after the SD-like event in the CA1 region. Less commonly, SD-like events originated in the CA3 region (4/12). Additionally, prior to the onset of the SLE in the CA3 area, there was decreased GABA correlated baseline SPW activity (bSPW), while there was increased large-amplitude sharp wave (LASW) activity, thought to originate from synchronous pyramidal cell firing. CA3 pyramidal cells displayed progressive tonic depolarization prior to the seizure which was resistant to synaptic transmission blockade. The initiation of hypoglycemic seizures and SD was prevented by AMPA/kainate or NMDA receptor blockade.

CONCLUSIONS

Severe glucose depletion induces rapid changes initiated in the intrinsic CA3 rhythms of the hippocampus including depressed inhibition and enhanced excitation, which may underlie the mechanisms of seizure generation and delayed spreading depression.

Hyper/hypoglycemia and acute kidney injury in critically ill patients

BACKGROUND & AIMS

Abnormalities of blood glucose (BG) concentration (hyper- and hypoglycemia), now referred to with the cumulative term of dysglycemia, are frequently observed in critically ill patients, and significantly affect their clinical outcome. Acute kidney injury (AKI) may further complicate glycemic control in the same clinical setting. This narrative review was aimed at describing the pathogenesis of hyper- and hypoglycemia in the intensive care unit (ICU), with special regard to patients with AKI. Moreover, the complex relationship between AKI, glycemic control, hypoglycemic risk, and outcomes was analyzed.

METHODS

An extensive literature search was performed, in order to identify the relevant studies describing the epidemiology, pathogenesis, treatment and outcome of hypo- and hyperglycemia in critically ill patients with AKI.

RESULTS AND CONCLUSION

Patients with AKI are at increased risk of both hyper-and hypoglycemia. The available evidence does not support a protective effect on the kidney by glycemic control protocols employing Intensive Insulin Treatment (IIT), i.e. those aimed at maintaining normal BG concentrations (80-110 mg/dl). Recent guidelines taking into account the high risk for hypoglycemia associated with IIT protocols in critically ill patients, now suggest higher BG concentration targets (<180 mg/dl or 140-180 mg/dl) than those previously recommended (80-110 mg/dl). Notwithstanding the limited evidence available, it seems reasonable to extend these indications also to ICU patients with AKI.

Application of a glycaemic control optimization programme in patients with stress hyperglycaemia

BACKGROUND

Stress-induced hyperglycaemia (SHG) can be observed in as high as 75% of critically ill patients, which can induce severe complications or adverse events. However, conventional intensive insulin therapy (CIIT) tends to induce hypoglycaemia and glucose variability.

AIMS

This study investigated the clinical effects of a blood glycaemic control optimization programme (BGCOP) in patients with stress hyperglycaemia post hepatobiliary or pancreatic surgery.

DESIGN

This study is a randomized, controlled, prospective clinical observation.

METHODS

Eighty-six patients with postoperative SHG were randomly divided into a control and experimental groups. Participants in the control group underwent CIIT, while participants in the experimental group underwent blood glycaemic control optimization programme (BGCOP). A range of 7·8-10·0 mmol/L was designated as the target range for effective control of blood sugar. The validity index, adverse events and complications were compared between two groups.

RESULTS

Compared to participants treated with CIIT, participants treated with BGCOP reached the target range of blood sugar levels more quickly (p = 0·000). The high glycaemic index (p = 0·000), incidence of hypoglycaemia (p = 0·011), and other adverse events as well as the incidence of abdominal infection (p = 0·026), incision infection (p = 0·044), and lung infection (p = 0·047) were significantly lower in participants who underwent the BGCOP than in patients treated with CIIT.

CONCLUSION

BGCOP can more effectively control blood sugar levels compared with CIIT in patients with SHG after hepatobiliary or pancreatic surgery.

RELEVANCE TO CLINICAL PRACTICE

This study provides a direction for blood glycaemic control in patients with stress hyperglycaemia post hepatobiliary or pancreatic surgery.

Reliability of point-of-care capillary blood glucose measurements in the critical value range

CONTEXT

Point-of-care glucose (POCG) testing on capillary blood specimens is central to maintaining glycemic control in patients with diabetes. Although there are known performance issues with POCG methods, especially for maintaining tight glucose control, there is little information about the accuracy of results in the critical ranges that may involve life-threatening conditions.

OBJECTIVES

To evaluate the reliability of POCG measurements in critical, high (>600 mg/dL) and low (<40 mg/dL) ranges.

DESIGN

One-year retrospective analysis of POCG (ACCU-CHEK glucose meter, Roche Diagnostics Corporation, Indianapolis, Indiana) results for routine patient care were obtained. The frequency and accuracy of repeat testing after critical POCG results was analyzed. A convenience sample of noncritical capillary POCG measurements retested on venous blood specimens by another point-of-care device (RAPIDPoint 405 analyzer, Siemens Medical Solutions USA, Malvern, Pennsylvania) was also evaluated.

RESULTS

Critical values were observed in 2.4 per 1000 POCG tests (256 of 105,928; 0.24%), with the highest rate (76 of 2289; 3.32%) from the emergency department. Twice as many critical high values as critical low values were seen. Nearly 80% of critical POCG tests (204 of 256) were repeated within 10 minutes. Of these 204 repeat measurements, 112 (54.9%) met accuracy criteria (±15 mg/dL of low and ±20% of high initial values). Accuracy was significantly higher when retesting was performed on the same meter or by the same operator (P ≤ .05). Comparison of capillary and venous POCG testing of noncritical results showed no significant difference (P = .95), with 89.8% (125 of 139) meeting accuracy criteria.

CONCLUSIONS

POCG measurements in the critical range are frequently erroneous, which is likely caused by preanalytic factors associated with sampling capillary blood. POCG testing practices should include retesting to confirm critical results.

Incidence of hypoglycaemia associated with transient loss of consciousness. A retrospective cohort study

OBJECTIVE

To define the incidence of hypoglycaemia associated with transient loss of consciousness (TLoC).

DESIGN

Retrospective cohort study using a nested case-control analysis.

SETTING

Presentations to the emergency departments (EDs) of four general metropolitan hospitals in Azienda Sanitaria 10, Florence, Italy during 2012.

PARTICIPANTS

The cohort consisted of 133,285 patients extracted from the database of ED presentations. All patients with TLoC were identified by nurse triage, and their levels of glycaemia were recorded. Clinical investigations were undertaken using patients' charts and witness statements. Patients were matched with controls according to year of birth, year of cohort entry and gender.

RESULTS

Of the 133,285 patients, 3964 (2.9%) presented with TLoC, and 39 (1%) of the patients with TLoC had transient hypoglycaemia. Mean glycaemia in these 39 patients was 52 mg/dl (a level of 112 mg/dl was in controls). Symptoms associated with TLoC during hypoglycaemia differed from those characteristic of syncope. TLoC during hypoglycaemia mainly occurred in elderly patients with diabetes, who had relatively long disease duration, were receiving treatment, often also had renal failure and were experiencing symptoms as a result of lack of food intake. Together, these factors make it easier to diagnose hypoglycaemia associated with TLoC, and our results may prompt modification in medical practice.

CONCLUSION

Correct diagnosis of hypoglycaemia associated with TLoC has economic benefits if a protracted and costly series of clinical investigations can be avoided. A diagnosis of hypoglycaemia might also facilitate the resolution of patients' symptoms through lifestyle changes and adjustment of therapy.

Hypoglycemia: The neglected complication

Hypoglycemia is an important complication of glucose-lowering therapy in patients with diabetes mellitus. Attempts made at intensive glycemic control invariably increases the risk of hypoglycemia. A six-fold increase in deaths due to diabetes has been attributed to patients experiencing severe hypoglycemia in comparison to those not experiencing severe hypoglycemia Repeated episodes of hypoglycemia can lead to impairment of the counter-regulatory system with the potential for development of hypoglycemia unawareness. The short- and long-term complications of diabetes related hypoglycemia include precipitation of acute cerebrovascular disease, myocardial infarction, neurocognitive dysfunction, retinal cell death and loss of vision in addition to health-related quality of life issues pertaining to sleep, driving, employment, recreational activities involving exercise and travel. There is an urgent need to examine the clinical spectrum and burden of hypoglycemia so that adequate control measures can be implemented against this neglected life-threatening complication. Early recognition of hypoglycemia risk factors, self-monitoring of blood glucose, selection of appropriate treatment regimens with minimal or no risk of hypoglycemia and appropriate educational programs for healthcare professionals and patients with diabetes are the major ways forward to maintain good glycemic control, minimize the risk of hypoglycemia and thereby prevent long-term complications.

Mild hypoglycemia is independently associated with increased risk of mortality in patients with sepsis: a 3-year retrospective observational study

INTRODUCTION

Mild hypoglycemia is associated with increased mortality in critically ill patients. However, data regarding the association between mild hypoglycemia and patient outcomes among patients with sepsis are limited.

METHODS

Patients admitted to a medical ICU for sepsis, as defined by the Surviving Sepsis Campaign guidelines, during a 3-year period were enrolled retrospectively. Data on blood glucose (BG) control parameters and patient outcomes were collected. The primary outcome was the relationship of mild hypoglycemia (defined as minimum BG of 40 to 69 mg/dl during ICU stay) to hospital mortality, and the secondary outcomes were ICU-acquired complication rates, ICU and 1-year mortality rates. A relationship between glucose variability and hypoglycemic events was also investigated.

RESULTS

Three-hundred and thirteen consecutive patients with sepsis were enrolled (mean age, 71.8 ± 11.3 years; male, n = 166; diabetics, n = 102). A total of 14,249 (5.6/day/patient) BG tests were performed, and 175 hypoglycemic events (spontaneous, n = 71; iatrogenic, n = 104) occurred in 80 (25.6%) patients during the ICU stay; severe hypoglycemia (minimum BG level < 40 mg/dl) occurred in 24 (7.7%) patients, and mild hypoglycemia (minimum BG level 40 to 69 mg/dl) was found in 56 (17.9%) patients. The frequency of hypoglycemic events increased with higher glucose variability, and patients with mild hypoglycemia had higher rates of ICU-acquired complications than did those with no hypoglycemia (renal, 36.2% vs. 15.6%, P = 0.003; cardiac, 31.9% vs. 14.3%, P = 0.008; hepatic, 34.0% vs. 18.2%, P = 0.024; bacteremia, 14.9% vs. 4.5%, P = 0.021). Multivariate analysis revealed that mild hypoglycemia was independently associated with increased hospital mortality (odds ratio, 3.43; 95% confidence interval, 1.51 to 7.82), and even a single event was an independent risk factor (odds ratio, 2.98; 95% confidence interval, 1.10 to 8.09). Kaplan-Meier analysis demonstrated that mild hypoglycemia was significantly associated with a lower 1-year cumulative survival rate among patients with sepsis (P < 0.001).

CONCLUSION

Mild hypoglycemia was associated with increased risk of hospital and 1-year mortality, as well as the occurrence of ICU-acquired complications. Physicians thus need to recognize the importance of mild hypoglycemia in patients with sepsis.

Glucose Control in Critical Care Oncology

The optimal strategy for glucose control in critically ill patients remains controversial and may vary depending on their diagnostic groups. This retrospective study addresses this question in a cohort of critically ill oncology patients. Serial blood glucose levels were measured in a specialist oncology intensive care unit (ICU) in England between January 2009 and May 2010. Intravenous sliding scale insulin was started when blood glucose levels were greater than 8.3 mmol/L, aiming for a target glucose level below 10 mmol/L. There were 565 patients admitted to the ICU, of whom 181 (32%) were medical and 384 (68%) surgical. The mean blood glucose was 7.8 mmol/L. Mortality rates relative to mean glucose levels followed a U-shaped curve. There was a statistically significant increase in mortality among patients who spent longer periods with blood glucose levels less than 6 mmol/L, and those whose glucose was greater than 10 mmol/L (20% vs 7.3%; p <0.001). Fluctuations in blood glucose levels measured by the coefficient of variation against mean glucose levels demonstrated a significant increase in mortality in patients with higher variability (p<0.01). Higher coefficients of variation were also associated with an increased length of ICU stay and increased readmission rates to ICU. In this study, hypoglycaemia, hyperglycaemia and increased variability in glucose levels were each independently associated with worse outcomes in critically ill patients.

Intensive versus conventional glucose control in critically ill patients: a meta-analysis of randomized controlled trials

BACKGROUND

Critically ill patients commonly develop hyperglycemia. It remains unclear, however, to what extent correcting hyperglycemia will benefit these patients. We performed this meta-analysis to evaluate the benefits and risks of intensive glucose control versus conventional glucose control in critically ill adult patients.

METHODS

A systematic literature search of MEDLINE, PubMed, and Cochrane databases (until June 2011) was conducted using specific search terms. Randomized controlled trials that compared intensive glucose control with a target glucose goal <6.1 mmol/l (110 mg/dl) to conventional glucose control in adult intensive care patients were included. The random-effect model was used to estimate the pooled risk ratio of the two treatment arms.

RESULTS

Twenty two studies that randomized 13,978 participants were included in the meta-analysis. Overall, intensive glucose control did not reduce the short-term mortality (RR=1.02, 95% CI: 0.95-1.10, p=0.51), 90 day or 180 day mortality (RR=1.06, 95% CI: 0.99-1.13, p=0.08), sepsis (RR=0.96, 95% CI: 0.83-1.12, p=0.59) or new need for dialysis (RR=0.96, 95% CI: 0.83-1.11, p=0.57). The incidence of hypoglycemia was significantly higher in intensive glucose control group compared with conventional glucose control group (RR=5.01, 95% CI: 3.45-7.28, p<0.00001).

CONCLUSIONS

This meta-analysis found that intensive glucose control in critically ill adults did not reduce mortality but is associated with a significantly increased risk of hypoglycemia.

Low glucose under hypoxic conditions induces unfolded protein response and produces reactive oxygen species in lens epithelial cells

Aging is enhanced by hypoxia and oxidative stress. As the lens is located in the hypoglycemic environment under hypoxia, aging lens with diabetes might aggravate these stresses. This study was designed to examine whether low glucose under hypoxic conditions induces the unfolded protein response (UPR), and also if the UPR then generates the reactive oxygen species (ROS) in lens epithelial cells (LECs). The UPR was activated within 1 h by culturing the human LECs (HLECs) and rat LECs in <1.5 mM glucose under hypoxic conditions. These conditions also induced the Nrf2-dependent antioxidant-protective UPR, production of ROS, and apoptosis. The rat LECs located in the anterior center region were the least susceptible to the UPR, whereas the proliferating LECs in the germinative zone were the most susceptible. Because the cortical lens fiber cells are differentiated from the LECs after the onset of diabetes, we suggest that these newly formed cortical fibers have lower levels of Nrf2, and are then oxidized resulting in cortical cataracts. Thus, low glucose and oxygen conditions induce the UPR, generation of ROS, and expressed the Nrf2 and Nrf2-dependent antioxidant enzymes at normal levels. But these cells eventually lose reduced glutathione (GSH) and induce apoptosis. The results indicate a new link between hypoglycemia under hypoxia and impairment of HLEC functions.

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.

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.

Mild hypoglycemia is strongly associated with increased intensive care unit length of stay

Background

Hypoglycemia is associated with increased mortality in critically ill patients. The impact of hypoglycemia on resource utilization has not been investigated. The objective of this investigation was to evaluate the association of hypoglycemia, defined as a blood glucose concentration (BG) < 70 mg/dL, and intensive care unit (ICU) length of stay (LOS) in three different cohorts of critically ill patients.

Methods

This is a retrospective investigation of prospectively collected data, including patients from two large observational cohorts: 3,263 patients admitted to Stamford Hospital (ST) and 2,063 patients admitted to three institutions in The Netherlands (NL) as well as 914 patients from the GLUCONTROL trial (GL), a multicenter prospective randomized controlled trial of intensive insulin therapy.

Results

Patients with hypoglycemia were more likely to be diabetic, had higher APACHE II scores, and higher mortality than did patients without hypoglycemia. Patients with hypoglycemia had longer ICU LOS (median [interquartile range]) in ST (3.0 [1.4-7.1] vs. 1.2 [0.8-2.3] days, P < 0.0001), NL (5.2 [2.6-10.3] vs. 2.0 [1.3-3.2] days, P < 0.0001), and GL (9 [5-17] vs. 5 [3-9] days, P < 0.0001). For the entire cohort of 6,240 patients ICU LOS was 1.8 (1.0-3.3) days for those without hypoglycemia and 3.0 (1.5-6.7) days for those with a single episode of hypoglycemia (P < 0.0001). This was a consistent finding even when patients were stratified by severity of illness or survivor status. There was a strong positive correlation between the number of episodes of hypoglycemia and ICU LOS among all three cohorts.

Conclusions

This multicenter international investigation demonstrated that hypoglycemia was consistently associated with significantly higher ICU LOS in heterogeneous cohorts of critically ill patients, independently of severity of illness and survivor status. More effective methods to prevent hypoglycemia in these patients may positively impact their cost of care.

Glycemic control during critical illness

Tight glucose control in the intensive care unit was associated with an improved survival in one pioneering study, but this finding was not confirmed in seven other trials. The reasons underlying this discrepancy are not fully elucidated, indicating that an improved understanding of the physiology and pathophysiology of blood glucose (BG) regulation is needed. Potential reasons for the discrepancies between the studies also include: case-mix, with different optimal BG in different types of patients; hypoglycemia, which is associated with a poor outcome; and the magnitude of glucose variability. Safe and effective glucose control will require progress in the definition of optimal BG, and in the measurement techniques including continuous monitoring insulin algorithms and closed-loop systems.

Understanding glycemic control in the critically ill: 2011 update

Intensive monitoring of blood glucose concentrations in critically ill patients has become a standard of care in intensive care units over the past 10 years, following the publication of a single-center randomized trial targeting euglycemia in postoperative patients. This article summarizes the literature describing the relationship between hyperglycemia and mortality in the critically ill, the main findings of the major interventional trials of intensive insulin therapy, the association between hypoglycemia and increased glycemic variability with adverse outcomes, and the impact of a preexisting diagnosis of diabetes. A framework for understanding dysglycemia in the critically ill, an approach that recognizes disturbances in the "3 domains" of glycemic control--hyperglycemia, hypoglycemia, and increased glycemic variability--is presented. Finally, practical considerations relating to the implementation of glycemic management protocols are discussed.

Mild hypoglycemia is independently associated with increased mortality in the critically ill

Introduction

Severe hypoglycemia (blood glucose concentration (BG) < 40 mg/dL) is independently associated with an increased risk of mortality in critically ill patients. The association of milder hypoglycemia (BG < 70 mg/dL) with mortality is less clear.

Methods

Prospectively collected data from two observational cohorts in the USA and in The Netherlands, and from the prospective GLUCONTROL trial were analyzed. Hospital mortality was the primary endpoint.

Results

We analyzed data from 6,240 patients: 3,263 admitted to Stamford Hospital (ST), 2,063 admitted to three institutions in The Netherlands (NL) and 914 who participated in the GLUCONTROL trial (GL). The percentage of patients with hypoglycemia varied from 18% to 65% among the different cohorts. Patients with hypoglycemia experienced higher mortality than did those without hypoglycemia even after stratification by severity of illness, diagnostic category, diabetic status, mean BG during intensive care unit (ICU) admission and coefficient of variation (CV) as a reflection of glycemic variability. The relative risk (RR, 95% confidence interval) of mortality associated with minimum BG < 40, 40 to 54 and 55 to 69 mg/dL compared to patients with minimum BG 80 to 109 mg/dL was 3.55 (3.02 to 4.17), 2.70 (2.31 to 3.14) and 2.18 (1.87 to 2.53), respectively (all P < 0.0001). The RR of mortality associated with any hypoglycemia < 70 mg/dL was 3.28 (2.78 to 3.87) (P < 0.0001), 1.30 (1.12 to 1.50) (P = 0.0005) and 2.11 (1.62 to 2.74) (P < 0.0001) for the ST, NL and GL cohorts, respectively. Multivariate regression analysis demonstrated that minimum BG < 70 mg/dL, 40 to 69 mg/dL and < 40 mg/dL were independently associated with increased risk of mortality for the entire cohort of 6,240 patients (odds ratio (OR) (95% confidence interval (CI)) 1.78 (1.39 to 2.27) P < 0.0001), 1.29 (1.11 to 1.51) P = 0.0011 and 1.87 (1.46 to 2.40) P < 0.0001) respectively.

Conclusions

Mild hypoglycemia was associated with a significantly increased risk of mortality in an international cohort of critically ill patients. Efforts to reduce the occurrence of hypoglycemia in critically ill patients may reduce mortality

Provision of balanced nutrition protects against hypoglycemia in the critically ill surgical patient

BACKGROUND

Intensive insulin therapy lowers blood glucose and improves outcomes but increases the risk of hypoglycemia. Typically, insulin protocols require a dextrose solution to prevent hypoglycemia. The authors hypothesized that the provision of balanced nutrition (enteral nutrition [EN] or parenteral nutrition [PN]) would be more protective against hypoglycemia (≤50 mg/dL) than carbohydrate alone.

METHODS

A retrospective analysis was performed of patients treated with intensive insulin therapy and surviving ≥24 hours. The computer-based insulin protocol requires infusion of D10W at 30 mL/h if EN or PN is not provided. Nutrition provision was assessed in 2-hour increments, comparing periods of blood glucose control with and without balanced nutrition. The risk of hypoglycemia for each blood glucose measurement was estimated by multivariable regression.

RESULTS

In total, 66,592 glucose measurements were collected on 1392 patients. Hypoglycemic events occurred in 5.8/1000 glucose tests after 2 hours without balanced nutrition compared to 2.2/1000 tests when balanced nutrition was given in the preceding 2 hours. In multivariable regression models, balanced nutrition was the strongest protective factor against hypoglycemia. Patients who did not receive balanced nutrition in the preceding 2 hours had a 3 times increase in the odds of a hypoglycemic event at their next glucose check (odds ratio = 3.6, P < .001). Providing carbohydrate alone was not protective.

CONCLUSIONS

Balanced nutrition is associated with reduced risk of hypoglycemia. These results suggest that balanced nutrition should be given when insulin therapy is initiated. Future studies should evaluate the efficacy of EN vs PN in preventing hypoglycemia.

Tight glycemic control in critical care--the leading role of insulin sensitivity and patient variability: a review and model-based analysis

Tight glycemic control (TGC) has emerged as a major research focus in critical care due to its potential to simultaneously reduce both mortality and costs. However, repeating initial successful TGC trials that reduced mortality and other outcomes has proven difficult with more failures than successes. Hence, there has been growing debate over the necessity of TGC, its goals, the risk of severe hypoglycemia, and target cohorts. This paper provides a review of TGC via new analyses of data from several clinical trials, including SPRINT, Glucontrol and a recent NICU study. It thus provides both a review of the problem and major background factors driving it, as well as a novel model-based analysis designed to examine these dynamics from a new perspective. Using these clinical results and analysis, the goal is to develop new insights that shed greater light on the leading factors that make TGC difficult and inconsistent, as well as the requirements they thus impose on the design and implementation of TGC protocols. A model-based analysis of insulin sensitivity using data from three different critical care units, comprising over 75,000h of clinical data, is used to analyse variability in metabolic dynamics using a clinically validated model-based insulin sensitivity metric (S(I)). Variation in S(I) provides a new interpretation and explanation for the variable results seen (across cohorts and studies) in applying TGC. In particular, significant intra- and inter-patient variability in insulin resistance (1/S(I)) is seen be a major confounder that makes TGC difficult over diverse cohorts, yielding variable results over many published studies and protocols. Further factors that exacerbate this variability in glycemic outcome are found to include measurement frequency and whether a protocol is blind to carbohydrate administration.

Safety and effectiveness of intensive insulin protocol use in post-operative liver transplant recipients

There is a paucity of data regarding the safety and utility of strict glycemic control in patients undergoing orthotopic liver transplantation (OLT). Although control of hyperglycemia may theoretically be beneficial, concerns exist regarding the effect of iatrogenic hypoglycemia on graft function. We performed a retrospective observational study evaluating the impact of the introduction of a nurse-initiated glycemic control protocol on OLT recipients cared for in a single intensive care unit (ICU). The medical records of 84 OLT recipients in 2003 (Preprotocol group) and 77 recipients in 2007 (Protocol group) were reviewed. Data regarding demographics, medical history, physiology, perioperative anesthesia and surgical events, ICU stay, graft function, and mortality were abstracted. Glucose values on admission to ICU, at 2, 6, 12, 18, and 24 hours after surgery, and at 4 am on the morning after OLT were recorded. Patients in the Protocol group achieved better and faster glycemic control. The odds ratio for severe hyperglycemia (glucose >250 mg/dL) in the Protocol group was 0.16 (95% confidence interval, 0.09-0.28). Hypoglycemia was not observed. The 1-year mortality was 5.3% in the Preprotocol and 6.0% in the Protocol group (P = .86). The rate of graft loss was low, and there was no difference in the incidence of graft failure between the Preprotocol and Protocol groups. We conclude that nurse-initiated and -directed glycemic control protocols can be safely and effectively used in the early period after OLT, though we did not identify a beneficial effect on graft function.

Intensive insulin therapy to control hyperglycemia in the critically ill: a look back at the evidence shapes the challenges ahead

The major interventional trials of intensive insulin therapy in critically ill patients have reached divergent results. The present viewpoint article explores some of the potential reasons, including differences in monitoring technology and protocol design and performance, the occurrence of severe hypoglycemia and changes in the standard of care since publication of the landmark single-center trial. Recently published data detailing the deleterious effect of hypoglycemia are discussed, as is the emerging body of literature describing the important impact of glycemic variability on the risk of mortality in heterogeneous populations of acutely ill and severely ill patients. These new findings have important implications for the design of future interventional trials of intensive insulin therapy in the intensive care unit setting.

Year in review 2009: Critical Care--metabolism

Novel insights into the metabolic alterations of critical illness were published in Critical Care in 2009. The association between early hypoglycaemia/high glycemic variability and poor outcome was confirmed. Improvements in the understanding of the pathophysiological mechanisms of stress hyperglycemia and potential progress in the bedside management of glucose control were presented. With regard to enteral nutrition, some alterations of gastrointestinal physiology were better delineated. The relationship between the achievement of nutritional goals and outcomes was further investigated. Finally, understanding of some critical-illness-related endocrine and neuromuscular disorders improved through new experimental and clinical findings.

International recommendations for glucose control in adult non diabetic critically ill patients

INTRODUCTION

The purpose of this research is to provide recommendations for the management of glycemic control in critically ill patients.

METHODS

Twenty-one experts issued recommendations related to one of the five pre-defined categories (glucose target, hypoglycemia, carbohydrate intake, monitoring of glycemia, algorithms and protocols), that were scored on a scale to obtain a strong or weak agreement. The GRADE (Grade of Recommendation, Assessment, Development and Evaluation) system was used, with a strong recommendation indicating a clear advantage for an intervention and a weak recommendation indicating that the balance between desirable and undesirable effects of an intervention is not clearly defined.

RESULTS

A glucose target of less than 10 mmol/L is strongly suggested, using intravenous insulin following a standard protocol, when spontaneous food intake is not possible. Definition of the severe hypoglycemia threshold of 2.2 mmol/L is recommended, regardless of the clinical signs. A general, unique amount of glucose (enteral/parenteral) to administer for any patient cannot be suggested. Glucose measurements should be performed on arterial rather than venous or capillary samples, using central lab or blood gas analysers rather than point-of-care glucose readers.

CONCLUSIONS

Thirty recommendations were obtained with a strong (21) and a weak (9) agreement. Among them, only 15 were graded with a high level of quality of evidence, underlying the necessity to continue clinical studies in order to improve the risk-to-benefit ratio of glucose control.