NICE-SUGAR: the end of a sweet dream?

Through the Looking Glass: The Paradoxical Evolution of Targeted Temperature Management for Comatose Survivors of Cardiac Arrest

For the past two decades, targeted temperature management (TTM) has been a staple in the care of comatose survivors following cardiac arrest. However, recent clinical trials have failed to replicate the benefit seen in earlier studies, bringing into question the very existence of such clinical practice. In this review, we explore clinical scenarios within critical care that appeared to share a similar fate, but in actuality changed the landscape of practice in a modern world. Accordingly, clinicians may apply these lessons to the utilization of TTM among comatose survivors following cardiac arrest, potentially paving way for a re-framing of clinical care amidst an environment where current data appears upside down in comparison to past successes.

Intraoperative glycemic control in patients undergoing Orthotopic liver transplant: a single center prospective randomized study

Background

Perioperative hyperglycemia is associated with poor outcomes yet evidence to guide intraoperative goals and treatment modalities during non-cardiac surgery are lacking. End-stage liver disease is associated with altered glucose homeostasis; patients undergoing liver transplantation display huge fluctuations in blood glucose (BG) and represent a population of great interest. Here, we conduct a randomized trial to compare the effects of strict versus conventional glycemic control during orthotopic liver transplant (OLT).

Methods

Following approval by the Institutional Review Board of the University of Michigan Medical School and informed consent, 100 adult patients undergoing OLT were recruited. Patients were randomized to either strict (target BG 80–120 mg/dL) or conventional (target BG 180–200 mg/dL) BG control with block randomization for diabetic and nondiabetic patients. The primary outcomes measured were 1-year patient and graft survival assessed on an intention to treat basis. Graft survival is defined as death or needing re-transplant (www.unos.org). Three and 5-year patient and graft survival, infectious and biliary complications were measured as secondary outcomes. Data were examined using univariate methods and Kaplan-Meir survival analysis. A sensitivity analysis was performed to compare patients with a mean BG of ≤120 mg/dL and those > 120 mg/dL regardless of treatment group.

Results

There was no statistically significant difference in patient survival between conventional and strict control respectively;1 year, 88% vs 88% (p-0.99), 3 years, 86% vs 84% (p- 0.77), 5 years, 82% vs 78. % (p-0.36). Graft survival was not different between conventional and strict control groups at 1 year, 88% vs 84% (p-0.56), 3 years 82% vs 76% (p-0.46), 5 years 78% vs 70% (p-0.362).

Conclusion

There was no difference in patient or graft survival between intraoperative strict and conventional glycemic control during OLT.

Trial registration

Clinical trial number and registry: www.clinicaltrials.gov NCT00780026. This trial was retrospectively registered on 10/22/2008.

Lower Glucose Target Is Associated With Improved 30-Day Mortality in Cardiac and Cardiothoracic Patients

BACKGROUND

Practice guidelines recommend against intensive insulin therapy in patients who are critically ill based on trials that had high rates of severe hypoglycemia. Intermountain Healthcare uses a computerized IV insulin protocol that allows choice of blood glucose (BG) targets (80-110 vs 90-140 mg/dL) and has low rates of severe hypoglycemia. We sought to study the effects of BG target on mortality in adult patients in cardiac ICUs that have very low rates of severe hypoglycemia.

METHODS

Critically ill patients receiving IV insulin were treated with either of two BG targets (80-110 vs 90-140 mg/dL). We created a propensity score for BG target using factors thought to have influenced clinicians' choice, and then we performed a propensity score-adjusted regression analysis for 30-day mortality.

RESULTS

There were 1,809 patients who met inclusion criteria. Baseline patient characteristics were similar. Median glucose was lower in the 80-110 mg/dL group (104 vs 122 mg/dL, P < .001). Severe hypoglycemia occurred at very low rates in both groups (1.16% vs 0.35%, P = .051). Unadjusted 30-day mortality was lower in the 80-110 mg/dL group (4.3% vs 9.2%, P < .001). This remained after propensity score-adjusted regression (OR, 0.65; 95% CI, 0.43-0.98; P = .04).

CONCLUSIONS

Tight glucose control can be achieved with low rates of severe hypoglycemia and is associated with decreased 30-day mortality in a cohort of largely patients in cardiac ICUs. Although such findings should not be used to guide clinical practice at present, the use of tight glucose control should be reexamined using a protocol that has low rates of severe hypoglycemia.

Polytrauma-induced hepatic stress response and the development of liver insulin resistance

Insulin resistance and metabolic dysfunction are common following injury. Polytrauma is defined as combined injuries to more than one body part or organ system, and is common in modern warfare, as well as automobile and industrial accidents. Polytrauma can include any combination of burn injury, fracture, hemorrhage, trauma to the extremities, and blunt or penetrating trauma. Multiple minor injuries are often more deleterious than a more severe single injury. To investigate the mechanisms of development of insulin resistance following injury, we have developed a rat model of polytrauma which combined soft tissue trauma with burn injury and penetrating gastrointestinal (GI) trauma. Male Sprague-Dawley rats were subjected to a laparotomy plus either a 15-18% total body surface area scald burn or a single puncture of the cecum (CLP) with a G30 needle, or the combination of both burn and CLP injuries (polytrauma). We examined the effects of polytrauma which increased markers of hepatic endoplasmic reticulum (ER) stress, and increased hepatic Trib3 mRNA levels coincident with reduced insulin-inducible insulin signaling. Phosphorylation/activation of the insulin receptor (IR) and AKT were decreased at 24, but not 6h following polytrauma. These results demonstrate a complex, time-dependent development of hepatic ER-stress and a diminished response to insulin, which were among the pathological sequelae following polytrauma.

The benefits of tight glycemic control in critical illness: Sweeter than assumed?

Hyperglycemia has long been observed amongst critically ill patients and associated with increased mortality and morbidity. Tight glycemic control (TGC) is the clinical practice of controlling blood glucose (BG) down to the “normal” 4.4–6.1 mmol/L range of a healthy adult, aiming to avoid any potential deleterious effects of hyperglycemia. The ground-breaking Leuven trials reported a mortality benefit of approximately 10% when using this technique, which led many to endorse its benefits. In stark contrast, the multi-center normoglycemia in intensive care evaluation–survival using glucose algorithm regulation (NICE-SUGAR) trial, not only failed to replicate this outcome, but showed TGC appeared to be harmful. This review attempts to re-analyze the current literature and suggests that hope for a benefit from TGC should not be so hastily abandoned. Inconsistencies in study design make a like-for-like comparison of the Leuven and NICE-SUGAR trials challenging. Inadequate measures preventing hypoglycemic events are likely to have contributed to the increased mortality observed in the NICE-SUGAR treatment group. New technologies, including predictive models, are being developed to improve the safety of TGC, primarily by minimizing hypoglycemia. Intensive Care Units which are unequipped in trained staff and monitoring capacity would be unwise to attempt TGC, especially considering its yet undefined benefit and the deleterious nature of hypoglycemia. International recommendations now advise clinicians to ensure critically ill patients maintain a BG of <10 mmol/L. Despite encouraging evidence, currently we can only speculate and remain optimistic that the benefit of TGC in clinical practice is sweeter than assumed.

Tight glucose control in critically ill children--a systematic review and meta-analysis

BACKGROUND

It is unclear if tight glucose control (TGC) with intensive insulin therapy (IIT) can improve outcomes in critically ill children admitted to the intensive care unit (ICU). The objective of this systematic review and meta-analysis is to describe the benefits and risks of TGC with IIT in critically ill children and explore differences between published studies.

METHODS

Prospective randomized controlled trials (RCTs) of TGC with IIT in critically ill children admitted to the ICU were identified through a search of MEDLINE, PubMed, EMBASE, Scopus, ISI Web of Science and Cochrane Database of Systematic Reviews as well as detailed citation review of relevant primary and review articles. RCTs of TGC with IIT in critically ill adults and preterm neonates were excluded. Data on study design and setting, sample size, incidence of hypoglycemia, incidence of acquired infection, and 30-day mortality were abstracted. Meta-analytic techniques were used for analysis of outcomes including 30-day mortality, acquired infection, and incidence of hypoglycemia.

RESULTS

We identified four RCTs of TGC with IIT in critically ill children that included 3288 subjects. Overall, TGC with IIT did not result in a decrease in 30-day mortality [odds ratio (OR): 0.79; 95% confidence interval (CI): 0.55-1.15, p = 0.22]. TGC with IIT was associated with decrease in acquired infection (OR: 0.76; 95% CI: 0.59-0.99, p = 0.04). TGC with IIT was also associated with significant increase in hypoglycemia (OR: 6.14; 95% CI: 2.74-13.78, p < 0.001).

CONCLUSIONS

TGC with IIT does not result in decrease in 30-day mortality, but appears to reduce acquired infection in critically ill children. However, TGC with IIT is associated with higher incidence of hypoglycemia. Large multi-center studies of TGC with IIT using continuous glucose monitoring in critically ill children are needed to determine if this strategy can definitively improve clinical outcomes in this population without increasing hypoglycemia.

Stress hyperglycemia in pediatric critical illness: the intensive care unit adds to the stress!

Stress hyperglycemia (SH) commonly occurs during critical illness in children. The historical view that SH is beneficial has been questioned in light of evidence that demonstrates the association of SH with worse outcomes. In addition to intrinsic changes in glucose metabolism and development of insulin resistance, specific intensive care unit (ICU) practices may influence the development of SH during critical illness. Mechanical ventilation, vasoactive infusions, renal replacement therapies, cardiopulmonary bypass and extracorporeal life support, therapeutic hypothermia, prolonged immobility, nutrition support practices, and the use of medications are all known to mediate development of SH in critical illness. Tight glucose control (TGC) to manage SH has emerged as a promising therapy to improve outcomes in critically ill adults, but results have been inconclusive. Large variations in ICU practices across studies likely resulted in inconsistent results. Future studies of TGC need to take into account the impact of commonly used ICU practices and, ideally, standardize protocols in an attempt to improve the accuracy of conclusions from such studies.

Is there a difference in clinical outcomes, inflammation, and hypermetabolism between scald and flame burn?

OBJECTIVE

Severe thermal injury induces inflammatory and hypermetabolic responses that are associated with morbidity and mortality. However, it is not well-documented whether the causes of burns affect inflammation, hypermetabolism, and morbidity. The aim of the present study was to determine whether there is a difference in degree of inflammation, hypermetabolism, endocrine and acute-phase response, and clinical outcome between pediatric patients with scald and flame burns.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Children with burns requiring surgical intervention were enrolled in this cohort study and divided into two groups, scald or flame burn. In a second assignment, we analyzed the study populations in representative subgroups containing individuals with third-degree burns of 40% to 60% total body surface area. We determined clinical outcomes, resting energy expenditures, cytokine profiles, acute-phase proteins, constitutive proteins, and hormone panels. Statistical analysis was evaluated by analysis of variance, Student's t test corrected with the Bonferroni post hoc test, and the propensity score. Statistical significance was set at p < .05. A total of 912 patients were identified. Six hundred seventy-four had a flame burn and 238 had a scald burn. There was a significant difference (p < .05) in burn size (flame, 48% ± 23%; scald, 40% ± 21%), third-degree burn (flame, 39% ± 27%; scald 22% ± 25%), age (flame, 8 ± 5 yrs; scald, 3 ± 3 yrs), and mortality between groups. Propensity analysis confirmed the type of burn as a significant risk factor for morbidity and mortality. Subanalysis conducted in a representative patient group suffering from 40% to 60% burn total body surface area revealed that flame burns lead to significantly increased hypermetabolic, inflammatory, and acute-phase responses when compared to scald burns (p < .05). The frequency of sepsis was 3% in the scald burn group, while it was 14% in the flame group (p < .001). Multiorgan failure occurred in 14% of the scald patients, while it occurred in 17% of flame patients. The mortality in patients suffering from a scald burn was 3% compared to 6% in the flame-burned group (p < .05).

CONCLUSION

The type of burn affects hypermetabolism, inflammation, acute-phase responses, and mortality postburn.

The place for glycemic control in the surgical patient

BACKGROUND

Hyperglycemia is common in surgical patients and is associated with adverse outcomes. Conflicting data exist regarding the best method and the value of glycemic control in various patient populations. The contributions to hyperglycemia and the components of its control are complex and overlapping and likely contribute to the documented variation in outcomes. We provide an overview of the physiologic contributors to hyperglycemia and its control, review the differences in the major randomized trial results, and summarize the data regarding glycemic control in surgical patients.

METHODS

Major reviews of the pathophysiology of hyperglycemia in surgical patients, large randomized trials in critically ill and peri-operative populations, and meta-analyses were reviewed. Summations are provided for the critically ill population and for the peri-operative group.

RESULTS

A substantial physiologic rationale exists for the control of hyperglycemia in surgical patients during critical illness and in the peri-operative period. Randomized, controlled studies are limited predominately to critically ill populations. The data support controlling hyperglycemia to a serum glucose concentration <200 mg/dL, but the absolute target range remains controversial and studied inadequately. The data indicate the benefit of tight glycemic control using insulin to achieve a target of 80-110 mg/dL (intensive insulin therapy [IIT]) vs. a liberal target of 180-200 mg/dL in critically ill surgical patients, although hypoglycemia is more common with IIT. Inadequate studies are available in the peri-operative period to draw conclusions about non-critically ill surgical patients, but the weight of the data suggests control to < 200 mg/dL likely is beneficial.

CONCLUSIONS

Surgical patients benefit from maintaining serum glucose concentrations <200 mg/dL. Intensive insulin therapy (80-110 mg/dL), which appears beneficial in critically ill surgical patients but requires frequent measurement of glucose to avoid hypoglycemia. Further studies are needed to determine the appropriate target range and the influence of nutritional provision and other factors on outcome.

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.

A physiological Intensive Control Insulin-Nutrition-Glucose (ICING) model validated in critically ill patients

Intensive insulin therapy (IIT) and tight glycaemic control (TGC), particularly in intensive care unit (ICU), are the subjects of increasing and controversial debate in recent years. Model-based TGC has shown potential in delivering safe and tight glycaemic management, all the while limiting hypoglycaemia. A comprehensive, more physiologically relevant Intensive Control Insulin-Nutrition-Glucose (ICING) model is presented and validated using data from critically ill patients. Two existing glucose-insulin models are reviewed and formed the basis for the ICING model. Model limitations are discussed with respect to relevant physiology, pharmacodynamics and TGC practicality. Model identifiability issues are carefully considered for clinical settings. This article also contains significant reference to relevant physiology and clinical literature, as well as some references to the modeling efforts in this field. Identification of critical constant population parameters was performed in two stages, thus addressing model identifiability issues. Model predictive performance is the primary factor for optimizing population parameter values. The use of population values are necessary due to the limited clinical data available at the bedside in the clinical control scenario. Insulin sensitivity, S(I), the only dynamic, time-varying parameter, is identified hourly for each individual. All population parameters are justified physiologically and with respect to values reported in the clinical literature. A parameter sensitivity study confirms the validity of limiting time-varying parameters to S(I) only, as well as the choices for the population parameters. The ICING model achieves median fitting error of <1% over data from 173 patients (N=42,941 h in total) who received insulin while in the ICU and stayed for ≥ 72 h. Most importantly, the median per-patient 1-h ahead prediction error is a very low 2.80% [IQR 1.18, 6.41%]. It is significant that the 75th percentile prediction error is within the lower bound of typical glucometer measurement errors of 7-12%. These results confirm that the ICING model is suitable for developing model-based insulin therapies, and capable of delivering real-time model-based TGC with a very tight prediction error range. Finally, the detailed examination and discussion of issues surrounding model-based TGC and existing glucose-insulin models render this article a mini-review of the state of model-based TGC in critical care.

[Perioperative management of diabetic patient]

The prevalence of diabetes is rising and diabetics may soon represent more than 5% of the world population. The type 2 diabetes is a major independent risk factor for coronary artery disease. The screening for silent myocardial ischemia (IMS) must be systematic. The autonomic dysfunction and the cardiac microcirculatory disorders are at risk of hypotension and hypothermia during anesthesia. After 10 years of diabetes duration the incidence of perioperative complications and of difficult intubation are increased. The neurological deficits related to anesthesia are associated with general anesthesia in 85% of cases. Particular care will be provided during the surgical procedure to avoid skin, muscular and neurologic cuts. In most cases, the regional anesthesia will be preferred to general anesthesia. To avoid hypoglycemia, blood glucose concentration less than 11 mmol.L(-1)(2g.L(-1)) seems a reasonable target during and after surgery.

Changing practice with changing research: results of two UK national surveys of intensive insulin therapy in intensive care patients

We conducted two telephone surveys of all United Kingdom adult intensive care units in 2007/8 and 2010 to assess practice with regard to intensive insulin therapy for glycaemic control in critically ill patients, and to assess the change in practice following publications in 2008 and 2009 that challenged the evidence for this therapy. Of 243 units that had a written policy for intensive insulin therapy in 2007/8, 232 (96%) still had a policy in 2010. One hundred and six (46%) units had updated their policy in response to new evidence, whereas 126 (54%) stated that it had remained the same. Where intensive care units had changed their policy, we found a significant increase in target limits and a wider target range. Regional variations in practice were also seen. Across seven regions, the percentage of units where the glycaemic control policy had been updated since 2007/8 varied from nil to 78.9%.

Hypoglycemia is associated with intensive care unit mortality

OBJECTIVE

The implementation of intensive insulin therapy in the intensive care unit is accompanied by an increase in hypoglycemia. We studied the relation between hypoglycemia on intensive care unit mortality, because the evidence on this subject is conflicting.

DESIGN

Retrospective database cohort study.

SETTING

An 18-bed medical/surgical intensive care unit in a teaching hospital (Onze Lieve Vrouwe Gasthuis Hospital, Amsterdam, The Netherlands).

PATIENTS

A total of 5961 patients admitted to from 2004 to 2007 were analyzed. Readmissions and patients with a withholding care policy or with hypoglycemia on the first glucose measurement were excluded. Patients were treated with a computerized insulin algorithm (target glucose range, 72-126 mg/dL).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

All first episodes of hypoglycemia (glucose < or =45 mg/dL) were derived from 154,015 glucose values. Using Poisson regression, the incidence rates for intensive care unit death and incidence rate ratio comparing exposure and nonexposure to hypoglycemia were calculated. Patients were considered to be exposed to hypoglycemia from the event until the end of intensive care unit admittance. We corrected for severity of disease using the daily Sequential Organ Failure Assessment score. Age, sex, cardiothoracic surgery, sepsis, and diabetes mellitus were also included as possible confounders. Two hundred eighty-eight (4.8%) patients experienced at least one episode of hypoglycemia. Median age was 68 yrs (range, 58-75 yrs), 66% were male, and 6.4% died in the intensive care unit. The incidence rate of death in patients exposed to hypoglycemia was 40 per 1000 intensive care unit days compared with 17 per 1000 intensive care unit days in patients without exposure. The adjusted incidence rate ratio for intensive care unit death was 2.1 (95% confidence interval, 1.6-2.8; p < .001).

CONCLUSIONS

Hypoglycemia is related to intensive care unit mortality, also when adjusted for a daily adjudicated measure of disease severity, indicating the possibility of a causal relationship.

A prospective observational study of the relationship of critical illness associated hyperglycaemia in medical ICU patients and subsequent development of type 2 diabetes

Introduction

Critical illness is commonly complicated by hyperglycaemia caused by mediators of stress and inflammation. Severity of disease is the main risk factor for development of hyperglycaemia, but not all severely ill develop hyperglycemia and some do even in mild disease. We hypothesised that acute disease only exposes a latent disturbance of glucose metabolism which puts those patients at higher risk for developing diabetes.

Methods

Medical patients with no history of impaired glucose metabolism or other endocrine disorder admitted to an intensive care unit between July 1998 and June 2004 were considered for inclusion. Glucose was measured at least two times a day, and patients were divided into the hyperglycaemia group (glucose ≥7.8 mmol/l) and normoglycaemia group. An oral glucose tolerance test was performed within six weeks after discharge to disclose patients with unknown diabetes or pre-diabetes who were excluded. Patients treated with corticosteroids and those terminally ill were also excluded from the follow-up which lasted for a minimum of five years with annual oral glucose tolerance tests.

Results

A five-year follow-up was completed for 398 patients in the normoglycaemia group, of which 14 (3.5%) developed type 2 diabetes. In the hyperglycaemia group 193 patients finished follow-up and 33 (17.1%) developed type 2 diabetes. The relative risk for type 2 diabetes during five years after the acute illness was 5.6 (95% confidence interval (CI) 3.1 to 10.2).

Conclusions

Patients with hyperglycaemia during acute illness who are not diagnosed with diabetes before or during the hospitalization should be considered a population at increased risk for developing diabetes. They should, therefore, be followed-up, in order to be timely diagnosed and treated.

Clinical benefits of tight glycaemic control: effect on the kidney

Acute kidney injury is a frequent and life-threatening complication of critical illness. Prevention of this condition is crucial. Two randomized single center trials in critically ill patients have shown a decrease in acute kidney injury by tight glycaemic control, an effect that appears most pronounced in surgical patients. Subsequent randomized trials did not confirm this renoprotective effect. This apparent contradiction is likely explained by methodological differences between studies, including different patient populations, insufficient patient numbers, comparison with a different control group, use of inaccurate blood glucose analyzers, and differences in the degree of reaching the target blood glucose level. The optimal glycaemic target for renoprotection in critical illness remains to be defined. Possible mechanisms underlying the renoprotective effect of tight glycaemic control are prevention of glucose overload and toxicity and the associated mitochondrial damage, an anti-inflammatory or anti-apoptotic effect, prevention of endothelial dysfunction, and an improvement of the lipid profile.

Year in review 2008: Critical Care--metabolism

In 2008, the interest in metabolic and endocrine issues and their consequences in critically ill patients was high. A large proportion of the research papers related to these issues was related to the metabolism of glucose and its control and to the changes in body composition, including muscular weakness. In Critical Care, original reports from investigations of glucose physiology and clinical data from observational and interventional studies were published. Important reports of the effects of hormone analogues, such as vasopressin and hydrocortisone, and early antioxidants in selected subpopulations were also available in 2008.