Clinical review: Strict or loose glycemic control in critically ill patients--implementing best available evidence from randomized controlled trials

Clinical practice guidelines for nutritional assessment and monitoring of adult ICU patients in China

The Chinese Society of Critical Care Medicine (CSCCM) has developed clinical practice guidelines for nutrition assessment and monitoring for patients in adult intensive care units (ICUs) in China. This guideline focuses on nutrition evaluation and metabolic monitoring to achieve optimal and personalized nutrition therapy for critically ill patients. This guideline was developed by experts in critical care medicine and evidence-based medicine methodology and was developed after a thorough review of the system and a summary of relevant trials or studies published from 2000 to July 2023. A total of 18 recommendations were formed and consensus was reached through discussions and reviews by expert groups in critical care medicine, parenteral and enteral nutrition, and surgery. The recommendations are based on currently available evidence and cover several key fields, including screening and assessment, evaluation and assessment of enteral feeding intolerance, metabolic and nutritional measurement and monitoring during nutrition therapy, and organ function evaluation related to nutrition supply. Each question was analyzed according to the Population, Intervention, Comparison, and Outcome (PICO) principle. In addition, interpretations were provided for four questions that did not reach a consensus but may have potential clinical and research value. The plan is to update this nutrition assessment and monitoring guideline using the international guideline update method within 3-5 years.

Nutritional support and prevention of post-intensive care syndrome: the Italian SIAARTI survey

BACKGROUND

Malnutrition and muscle wasting are common in ICU patients and predict adverse patient-centered outcomes. The Italian Society of Anesthesia Analgesia Resuscitation and Intensive Care (SIAARTI) conducted a nationwide survey to identify the nutritional practices in the Italian ICUs and to plan future, training interventions to improve the national clinical practice.

METHODS

Nationwide online survey, involving Italian ICUs, developed by experts affiliated with SIAARTI. Invitations to participate were distributed through emails and social networks. Data were collected over a period of three months (October 1 to December 31, 2022) during 2022.

RESULTS

One hundred full responses from participating ICUs were collected. The number of beds is < 10 in most ICUs and > 20 in 11 ICUs. Most ICUs (87%) are mixed, cardiac (5%), neurosurgical (4%), or pediatric ICUs (1%). Although the nutritional program is widely prescribed based on the patients' general evaluation, 52 ICUs (52%) do not perform nutritional risk evaluation at admission in case of > 24-h stay. Daily caloric intake is mainly based on the 25 kcal/kg equation; otherwise, the Harris-Benedict formula is mostly used, whereas indirect calorimetry is less used. Most clinicians apply a personalized nutritional approach to organ failure. Most ICUs have a nutritional management protocol, and enteral nutrition (EN) is frequently started within 2 days from admission, while supplemental parenteral nutrition is used when EN is insufficient by most clinicians. The EN administered seems to correspond to that prescribed, but it is stopped if the gastric residual gastric is > 300-500 ml in most ICUs.

CONCLUSION

Prescription, route, and mode of administration of nutritional support seem to be in line with international recommendations, while suggestions on the tools for assessing the nutritional risk and monitoring efficacy and complications seem far less followed. Future national clinical studies are necessary to investigate the optimal nutritional and metabolic management of critically ill patients and the correspondence with the results of this survey on actual practices.

ESPEN practical and partially revised guideline: Clinical nutrition in the intensive care unit

Following the new ESPEN Standard Operating Procedures, the previous 2019 guideline to provide best medical nutritional therapy to critically ill patients has been shortened and partially revised. Following this update, we propose this publication as a practical guideline based on the published scientific guideline, but shortened and illustrated by flow charts. The main goal of this practical guideline is to increase understanding and allow the practitioner to implement the Nutrition in the ICU guidelines. All the items discussed in the previous guidelines are included as well as special conditions.

Advances in safe insulin infusions

Hyperglycaemia is recognized as a marker of adverse clinical outcomes for hospitalized patients with and without diabetes, including mortality, morbidity, increased length of stay, infections and overall complications. In some cases, intravenous (IV) insulin infusions are the optimal intervention and, to date, these have been compounded in hospital pharmacy departments or, alternatively, at the point of care, when timeliness is a concern or the pharmacy is closed. However, in-house compounding of high-risk medications such as IV insulin poses risks both for patients and institutions. The critical nature of certain high-risk therapies has led to the development of ready-to-administer products to improve the safety, timeliness, efficacy and efficiency of critical infusions. Recently, IV insulin, a high-alert therapy, has been added to the ready-to-use armamentarium. This narrative review explores the expanding indications, risks and opportunities associated with insulin infusions and potential options for improved safety.

Increased insulin resistance in intensive care: longitudinal retrospective analysis of glycaemic control patients in a New Zealand ICU

BACKGROUND

Critical care populations experience demographic shifts in response to trends in population and healthcare, with increasing severity and/or complexity of illness a common observation worldwide. Inflammation in critical illness impacts glucose-insulin metabolism, and hyperglycaemia is associated with mortality and morbidity. This study examines longitudinal trends in insulin sensitivity across almost a decade of glycaemic control in a single unit.

METHODS

A clinically validated model of glucose-insulin dynamics is used to assess hour-hour insulin sensitivity over the first 72 h of insulin therapy. Insulin sensitivity and its hour-hour percent variability are examined over 8 calendar years alongside severity scores and diagnostics.

RESULTS

Insulin sensitivity was found to decrease by 50-55% from 2011 to 2015, and remain low from 2015 to 2018, with no concomitant trends in age, severity scores or risk of death, or diagnostic category. Insulin sensitivity variability was found to remain largely unchanged year to year and was clinically equivalent (95% confidence interval) at the median and interquartile range. Insulin resistance was associated with greater incidence of high insulin doses in the effect saturation range (6-8 U/h), with the 75th percentile of hourly insulin doses rising from 4-4.5 U/h in 2011-2014 to 6 U/h in 2015-2018.

CONCLUSIONS

Increasing insulin resistance was observed alongside no change in insulin sensitivity variability, implying greater insulin needs but equivalent (variability) challenge to glycaemic control. Increasing insulin resistance may imply greater inflammation and severity of illness not captured by existing severity scores. Insulin resistance reduces glucose tolerance, and can cause greater incidence of insulin saturation and resultant hyperglycaemia. Overall, these results have significant clinical implications for glycaemic control and nutrition management.

Near-Continuous Glucose Monitoring Makes Glycemic Control Safer in ICU Patients

OBJECTIVES

Tight glycemic control using intermittent blood glucose measurements is associated with a risk of hypoglycemia. Glucose concentrations can now be measured near continuously (every 5-15 min). We assessed the quality and safety of glycemic control guided by a near-continuous glucose monitoring system in ICU patients.

DESIGN

Prospective, cluster-randomized, crossover study.

SETTING

Thirty-five-bed medico-surgical department of intensive care with four separate ICUs.

PATIENTS

Adult patients admitted to the department and expected to stay for at least 3 days were considered for inclusion if they had persistent hyperglycemia (blood glucose > 150 mg/dL) up to 6 hours after admission and/or were receiving insulin therapy.

INTERVENTIONS

A peripheral venous catheter was inserted in all patients and connected to a continuous glucose monitoring sensor (GlucoClear; Edwards Lifesciences, Irvine, CA). The four ICUs were randomized in pairs in a crossover design to glycemic control using unblinded or blinded continuous glucose monitoring monitors. The insulin infusion rate was adjusted to keep blood glucose between 90 and 150 mg/dL using the blood glucose values displayed on the continuous glucose monitor (continuous glucose monitoring group-unblinded units) or according to intermittent blood glucose readings (intermittent glucose monitoring group-blinded units).

MEASUREMENTS AND MAIN RESULTS

The quality and safety of glycemic control were assessed using the proportion of time in range, the frequency of blood glucose less than 70 mg/dL, and the time spent with blood glucose less than 70 mg/dL (TB70), using blood glucose values measured by the continuous glucose monitoring device. Seventy-seven patients were enrolled: 39 in the continuous glucose monitoring group and 38 in the intermittent glucose monitoring group. A total of 43,107 blood glucose values were recorded. The time in range was similar in the two groups. The incidence of hypoglycemia (8/39 [20.5%] vs 15/38 [39.5%]) and the TB70 (0.4% ± 0.9% vs 1.6% ± 3.4%; p < 0.05) was lower in the continuous glucose monitoring than in the intermittent glucose monitoring group.

CONCLUSIONS

Use of a continuous glucose monitoring-based strategy decreased the incidence and severity of hypoglycemia, thus improving the safety of glycemic control.

ESPEN guideline on clinical nutrition in the intensive care unit

Following the new ESPEN Standard Operating Procedures, the previous guidelines to provide best medical nutritional therapy to critically ill patients have been updated. These guidelines define who are the patients at risk, how to assess nutritional status of an ICU patient, how to define the amount of energy to provide, the route to choose and how to adapt according to various clinical conditions. When to start and how to progress in the administration of adequate provision of nutrients is also described. The best determination of amount and nature of carbohydrates, fat and protein are suggested. Special attention is given to glutamine and omega-3 fatty acids. Particular conditions frequently observed in intensive care such as patients with dysphagia, frail patients, multiple trauma patients, abdominal surgery, sepsis, and obesity are discussed to guide the practitioner toward the best evidence based therapy. Monitoring of this nutritional therapy is discussed in a separate document.

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.

Continuous glucose monitoring in the ICU: clinical considerations and consensus

Glucose management in intensive care unit (ICU) patients has been a matter of debate for almost two decades. Compared to intermittent monitoring systems, continuous glucose monitoring (CGM) can offer benefit in the prevention of severe hyperglycemia and hypoglycemia by enabling insulin infusions to be adjusted more rapidly and potentially more accurately because trends in glucose concentrations can be more readily identified. Increasingly, it is apparent that a single glucose target/range may not be optimal for all patients at all times and, as with many other aspects of critical care patient management, a personalized approach to glucose control may be more appropriate. Here we consider some of the evidence supporting different glucose targets in various groups of patients, focusing on those with and without diabetes and neurological ICU patients. We also discuss some of the reasons why, despite evidence of benefit, CGM devices are still not widely employed in the ICU and propose areas of research needed to help move CGM from the research arena to routine clinical use.

Untangling glycaemia and mortality in critical care

Background

Hyperglycaemia is associated with adverse outcomes in the intensive care unit, and initial studies suggested outcome benefits of glycaemic control (GC). However, subsequent studies often failed to replicate these results, and they were often unable to achieve consistent, safe control, raising questions about the benefit or harm of GC as well as the nature of the association of glycaemia with mortality and clinical outcomes. In this study, we evaluated if non-survivors are harder to control than survivors and determined if glycaemic outcome is a function of patient condition and eventual outcome or of the glycaemic control provided.

Methods

Clinically validated, model-based, hour-to-hour insulin sensitivity (SI) and its hour-to-hour variability (%ΔSI) were identified over the first 72 h of therapy in 145 patients (119 survivors, 26 non-survivors). In hypothesis testing, we compared distributions of SI and %ΔSI in 6-hourly blocks for survivors and non-survivors. In equivalence testing, we assessed if differences in these distributions, based on blood glucose measurement error, were clinically significant.

Results

SI level was never equivalent between survivors and non-survivors (95% CI of percentage difference in medians outside ±12%). Non-survivors had higher SI, ranging from 9% to 47% higher overall in 6-h blocks, and this difference became statistically significant as glycaemic control progressed. %ΔSI was equivalent between survivors and non-survivors for all 6-hourly blocks (95% CI of difference in medians within ±12%) and decreased in general over time as glycaemic control progressed.

Conclusions

Whereas non-survivors had higher SI levels, variability was equivalent to that of survivors over the first 72 h. These results indicate survivors and non-survivors are equally controllable, given an effective glycaemic control protocol, suggesting that glycaemia level and variability, and thus the association between glycaemia and outcome, are essentially determined by the control provided rather than by underlying patient or metabolic condition.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1725-y) contains supplementary material, which is available to authorized users.

Non-invasive breath monitoring with eNose does not improve glucose diagnostics in critically ill patients in comparison to continuous glucose monitoring in blood

Continuous glucose monitoring (CGM) can be beneficial in critically ill patients. Current CGM devices rely on subcutaneous or blood plasma glucose measurements and consequently there is an increased risk of infections and the possibility of loss of blood with each measurement. A potential method to continuously and non-invasively measure blood glucose levels is using exhaled breath. A correlation between blood glucose levels and volatile organic compounds (VOCs) in the exhaled breath was already reported. VOCs can be analyzed continuously using a so-called electronic nose (eNose). We hypothesize that continuous exhaled breath analysis using an eNose can be used to accurately predict blood glucose levels in intubated, mechanically ventilated ICU-patients. Mechanically ventilated patients whose blood glucose concentration was monitored with a CGM device were eligible. An eNose with four metal oxide sensors was used to continuously measure changes in exhaled breath. After pre-processing the data, several regression models were trained, consisting of: (1) only eNose sensor values; (2) only the 1st and 2nd principal components (PC) of eNose values; (3) eNose sensor values and last known blood glucose value as random effect; (4) 1st and 2nd PC of eNose sensor values and CGM value of one minute ago as fixed effect; (5) CGM value of one minute ago as fixed effect. Model performance was measured using the R ² value, the akaike information criterion and the Clarke error grid. Twenty-three patients were included in the study and 1165 hours of measurements were collected. Performance was low in models 1, 2 and 3 with a mean R ² of 0.07 [95%-CI: 0.00-0.28], 0.10 [95%-CI: 0.00-0.40] and 0.30 [0.02-0.79], respectively. Performance in models 4 and 5 was better with a mean R ² of 0.77 [0.02-1.00]. Subsequently, eNose data in model 4 had no added value over using CGM only in model 5. Continuous exhaled breath analysis using this eNose cannot be used to accurately predict blood glucose levels in intubated, mechanically ventilated ICU-patients.

[Metabolic control in the critically ill patient an update: hyperglycemia, glucose variability hypoglycemia and relative hypoglycemia]

BACKGROUND

Metabolic changes of glucose in critically ill patients increase morbidity and mortality. The appropriate level of blood glucose has not been established so far and should be adjusted for different populations. However concepts such as glucose variability and relative hypoglycemia of critically ill patients are concepts that are changing management methods and achieving closer monitoring.

OBJECTIVES

The purpose of this review is to present new data about the management and metabolic control of patients in critical areas.

CONCLUSIONS

Currently glucose can no longer be regarded as an innocent element in critical patients; both hyperglycemia and hypoglycemia increase morbidity and mortality of patients. Protocols and better instruments for continuous measurement are necessary to achieve the metabolic control of our patients.

Manual versus Automated moNitoring Accuracy of GlucosE II (MANAGE II)

BACKGROUND

Intravascular continuous glucose monitoring (CGM) may facilitate glycemic control in the intensive care unit (ICU). We compared the accuracy of a CGM device (OptiScanner®) with a standard reference method.

METHODS

Adult patients who had blood glucose (BG) levels >150 mg/dl and required insertion of an arterial and central venous catheter were included. The OptiScanner® was inserted into a multiple-lumen central venous catheter. Patients were treated using a dynamic-scale insulin algorithm to achieve BG values between 80 and 150 mg/dl. The BG values measured by the OptiScanner® were plotted against BG values measured using a reference analyzer. The correlation between the BG values measured using the two methods and the clinical relevance of any differences were assessed using the coefficient of determination (r 2) and the Clarke error grid, respectively; bias was assessed by the mean absolute relative difference (MARD). Three different standards of glucose monitoring were used to assess accuracy. Glycemic control was assessed using the time in range (TIR). Six indices of glycemic variability were calculated.

RESULTS

The analysis included 929 paired samples from 88 patients, monitored for a total of 2584 hours. Reference BG values ranged between 60 and 484 mg/dl. The r 2 value was 0.89. The percentage of BG values within zones A and B of the Clarke error grid was 99.9%; the MARD was 7.7%. Using the ISO 15197 standard and Food and Drug Administration and consensus standards, respectively, 80.4% of measurements were within 15 mg/dl and 88.2% within 15% of reference values, 40% of measurements were within 7 mg/dl and 72.5% within 10% of reference values, and 65.2% of measurements were within 10 mg/dl and 82.7% within 12.5% of reference values. The TIR was slightly lower with the OptiScanner® than with the reference method. The J-index, standard deviation and maximal glucose change were the indices of glycemic variability least affected by the measurement device.

CONCLUSIONS

Based on the MARD, the performance of the OptiScanner® is adequate for use in ICU patients. Because recent standards for accuracy were not met, the OptiScanner® should not be used as a sole monitor. The assessment of glycemic variability is influenced by the time interval between BG determinations.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01720381 . Registered 31 October 2012.

Diabetes and the Association of Postoperative Hyperglycemia With Clinical and Economic Outcomes in Cardiac Surgery

OBJECTIVE

The management of postoperative hyperglycemia is controversial and generally does not take into account pre-existing diabetes. We analyzed clinical and economic outcomes associated with postoperative hyperglycemia in cardiac surgery patients, stratifying by diabetes status.

RESEARCH DESIGN AND METHODS

Multicenter cohort study in 4,316 cardiac surgery patients operated on in 2010. Glucose was measured at 6-h intervals for 48 h postoperatively. Outcomes included cost, hospital length of stay (LOS), cardiac and respiratory complications, major infections, and death. Associations between maximum glucose levels and outcomes were assessed with multivariable regression and recycled prediction analyses.

RESULTS

In patients without diabetes, increasing glucose levels were associated with a gradual worsening of outcomes. In these patients, hyperglycemia (≥180 mg/dL) was associated with an additional cost of $3,192 (95% CI 1,972 to 4,456), an additional hospital LOS of 0.8 days (0.4 to 1.3), an increase in infections of 1.6% (0.5 to 2.8), and an increase in respiratory complications of 2.6% (0.0 to 5.3). However, among patients with insulin-treated diabetes, optimal outcomes were associated with glucose levels considered to be hyperglycemic (180 to 240 mg/dL). This level of hyperglycemia was associated with cost reductions of $6,225 (-12,886 to -222), hospital LOS reductions of 1.6 days (-3.7 to 0.4), infection reductions of 4.1% (-9.1 to 0.0), and reductions in respiratory complication of 12.5% (-22.4 to -3.0). In patients with non-insulin-treated diabetes, outcomes did not differ significantly when hyperglycemia was present.

CONCLUSIONS

Glucose levels <180 mg/dL are associated with better outcomes in most patients, but worse outcomes in patients with diabetes with a history of prior insulin use. These findings support further investigation of a stratified approach to the management of patients with stress-induced postoperative hyperglycemia based on prior diabetes status.

Associations between bolus infusion of hydrocortisone, glycemic variability and insulin infusion rate variability in critically Ill patients under moderate glycemic control

Background

We retrospectively studied associations between bolus infusion of hydrocortisone and variability of the blood glucose level and changes in insulin rates in intensive care unit (ICU) patients.

Methods

‘Glycemic variability’ and ‘insulin infusion rate variability’ were calculated from and expressed as the standard deviation (SD) of all blood glucose levels and insulin infusion rates during stay in the ICU, respectively. Glycemic and insulin infusion rate variability in patients who received bolus infusion of hydrocortisone were compared to those in patients who never received bolus infusion of hydrocortisone. Multivariate analysis was performed to correct for potential covariates including disease severity.

Results

We included 6409 patients over 6 years; of them 962 received bolus infusion of hydrocortisone. Compared to patients who never received bolus infusion of hydrocortisone, patients who received hydrocortisone had their blood glucose level measured more frequently, had higher glycemic variability; were more frequently treated with intravenous insulin and had higher insulin infusion rate variability. The association between hydrocortisone treatment and glycemic variability was independent of disease severity, but the effect of hydrocortisone treatment on blood glucose variability was less strong in the more severely ill patients. The association between hydrocortisone and insulin infusion rate variability was also independent of disease severity, and independent of glycemic variability.

Conclusions

Bolus infusion of hydrocortisone is independently associated with higher glycemic variability and higher insulin infusion rate variability in ICU patients. Studies are needed to see if continuous infusion of hydrocortisone prevents higher glycemic variability and higher insulin infusion rate variability.

Electronic supplementary material

The online version of this article (doi:10.1186/s13613-015-0077-5) contains supplementary material, which is available to authorized users.

Health Economic Evaluation of a Strict Glucose Control Guideline Implemented Using Point-of-Care Testing in Three Intensive Care Units in The Netherlands

BACKGROUND

Point-of-care testing of blood glucose (BG-POCT) is essential for safe and effective insulin titrations in critically ill patients under glucose control with insulin. The costs associated with this practice are considered substantial, especially when more frequent blood glucose (BG) testing is needed, as with more strict glucose control (SGC) aiming for lower BG levels.

OBJECTIVE

The objective of this study was to estimate, from a hospital perspective, the incremental cost effectiveness of an SGC guideline, aiming for BG levels of 4.4-6.1 mmol/L, compared to the situation before implementation of that guideline (aiming for BG levels <8.3 mmol/L), both using BG-POCT.

METHODS

This is a secondary analysis of a guideline implementation project aiming for implementation of a guideline of SGC in three intensive care units in The Netherlands. A Markov model including the four health states 'target glucose', 'hyperglycaemia' (defined as BG levels >6.1 mmol/L), 'hypoglycaemia' (defined as BG levels <4.4 mmol/L) and 'in-hospital death' was developed to compare expected costs, number of patients within target and number of life-years saved before and after implementation of the SGC guideline. The effectiveness estimates are based on empirical data from 3195 patients 12 and 24 months before and after implementation of the guideline, respectively. All costs have been converted to price year 2013, and are estimated based on hospital data, the literature and available price lists.

RESULTS

The number of BG-POCT increased from 4.8 [interquartile range (IQR) 2.6-6.7] to 8.0 [IQR 4.1-11.2] per patient per day, accruing 58% higher costs for BG-POCT (€13.56 vs. €8.57 per patient) in the SGC protocol versus the situation before implementation. When taking total hospital costs and clinical effects into account, implementation of the SGC guideline increased total hospital costs per patient by 1.8%, i.e., €355 (from €20,617 to €20,972) during the inpatient stay, while the number of patients in target glucose levels increased by 1.4% (i.e., from 881 to 895 per 1000 patients). This translates to an incremental cost-effectiveness ratio of €25 per additional patient within the target glucose level. The model outcomes are most sensitive to changes in ICU length of stay.

CONCLUSION

The increase in the number of patients and time within target glucose levels is achieved with a small increase in total direct hospital costs.

Hypocaloric enteral nutrition protects against hypoglycemia associated with intensive insulin therapy better than intravenous dextrose

Intensive insulin therapy treats hyperglycemia but increases the risk of hypoglycemia. Typically, intravenous dextrose is given to prevent hypoglycemia; however, enteral nutrition is preferred. We hypothesized that the provision of hypocaloric enteral nutrition would protect against hypoglycemia. A retrospective analysis was performed evaluating patients treated with intensive insulin therapy comparing the use of enteral nutrition versus a dextrose-only intravenous solution. Nutrition in the 2 hours before each blood glucose test was assessed, and the association with hypoglycemia (50 mg/dL or less) evaluated. Risk of hypoglycemia as a function of nutrition type and rate was estimated by multivariable regression. A total of 26,140 blood glucose tests were collected on 1289 patients. Hypoglycemia occurred in 6.4 per cent of patients. In regression models, enteral nutrition was the strongest protective factor against hypoglycemia (P < 0.001) with the largest risk reduction (steepest portion of the curve) occurring at 60 per cent goal. Hypocaloric enteral nutrition showed a greater risk reduction than a peripheral dextrose-only intravenous solution alone. In the setting of intensive insulin therapy, the provision of enteral nutrition, even if hypocaloric, is sufficient to protect against hypoglycemia. Future prospective studies should evaluate the efficacy of enteral nutrition in reducing the risk of hypoglycemia and whether lower rates of hypoglycemia correspond to improved outcomes.

Hypocaloric Enteral Nutrition Protects against Hypoglycemia Associated with Intensive Insulin Therapy Better than Intravenous Dextrose

Intensive insulin therapy treats hyperglycemia but increases the risk of hypoglycemia. Typically, intravenous dextrose is given to prevent hypoglycemia; however, enteral nutrition is preferred. We hypothesized that the provision of hypocaloric enteral nutrition would protect against hypoglycemia. A retrospective analysis was performed evaluating patients treated with intensive insulin therapy comparing the use of enteral nutrition versus a dextrose-only intravenous solution. Nutrition in the 2 hours before each blood glucose test was assessed, and the association with hypoglycemia (50 mg/dL or less) evaluated. Risk of hypoglycemia as a function of nutrition type and rate was estimated by multivariable regression. A total of 26,140 blood glucose tests were collected on 1289 patients. Hypoglycemia occurred in 6.4 per cent of patients. In regression models, enteral nutrition was the strongest protective factor against hypoglycemia ( P < 0.001) with the largest risk reduction (steepest portion of the curve) occurring at 60 per cent goal. Hypocaloric enteral nutrition showed a greater risk reduction than a peripheral dextrose-only intravenous solution alone. In the setting of intensive insulin therapy, the provision of enteral nutrition, even if hypocaloric, is sufficient to protect against hypoglycemia. Future prospective studies should evaluate the efficacy of enteral nutrition in reducing the risk of hypoglycemia and whether lower rates of hypoglycemia correspond to improved outcomes.

Influence of smart real-time electronic alerting on glucose control in critically ill patients

PURPOSE

Hyperglycemia and hypoglycemia are frequently encountered in critically ill patients and associated with adverse outcomes. We configured a smart glycemia alert (S-GLY alert) with our Intensive Care Information System to decrease the number of hyperglycemic values and increase the proportion of time within the glucose interval of 80 to 150 mg/dL.

MATERIALS AND METHODS

Prospective intervention study in surgical intensive care unit in a tertiary care hospital. An 11-week prealert phase was followed by a 15-week intervention phase where the S-GLY alert was alerting the nurses through the Clinical Notification System of the Intensive Care Information System.

RESULTS

Overall, 2335 S-GLY alerts were recorded. There were less hyperglycemic values and less persistent hyperglycemic episodes in the alert phase (19.5% vs 26.5% [P < .001] and 9.9% vs 15.4% [P < .001], respectively). More time was spent within target glucose interval (82.3% vs 75.0%, P = .009). A lower proportion of patients experienced a new-onset hypoglycemic event (<70 mg/dL) in the alert phase (9.2% vs 15.2%, P = .016). The Sequential Organ Failure Assessment score was significantly reduced (5.2 vs 4.2, P < .001).

CONCLUSIONS

The implementation of a real-time smart electronic glycemia alert resulted in significantly less episodes of persistent hyperglycemia and a higher proportion of time with normoglycemia, while decreasing the number of hypoglycemic events.

Glucose prediction by analysis of exhaled metabolites - a systematic review

Background

In critically ill patients, glucose control with insulin mandates time– and blood–consuming glucose monitoring. Blood glucose level fluctuations are accompanied by metabolomic changes that alter the composition of volatile organic compounds (VOC), which are detectable in exhaled breath. This review systematically summarizes the available data on the ability of changes in VOC composition to predict blood glucose levels and changes in blood glucose levels.

Methods

A systematic search was performed in PubMed. Studies were included when an association between blood glucose levels and VOCs in exhaled air was investigated, using a technique that allows for separation, quantification and identification of individual VOCs. Only studies on humans were included.

Results

Nine studies were included out of 1041 identified in the search. Authors of seven studies observed a significant correlation between blood glucose levels and selected VOCs in exhaled air. Authors of two studies did not observe a strong correlation. Blood glucose levels were associated with the following VOCs: ketone bodies (e.g., acetone), VOCs produced by gut flora (e.g., ethanol, methanol, and propane), exogenous compounds (e.g., ethyl benzene, o–xylene, and m/p–xylene) and markers of oxidative stress (e.g., methyl nitrate, 2–pentyl nitrate, and CO).

Conclusion

There is a relation between blood glucose levels and VOC composition in exhaled air. These results warrant clinical validation of exhaled breath analysis to monitor blood glucose levels.

Hyperglycemia and survival rate in Asian patients with acute coronary syndrome

Current studies are debating on the association of higher admission blood glucose (BG) and increased mortality of acute coronary syndrome (ACS). This study evaluated association of mortality between admission BG and BG control in 222 patients with ACS who received coronary intervention in the intensive care unit. This study observed medical records through electronic medical record retrospectively and evaluated all patients who were admitted for the first attack of ST-segment elevation MI (STEMI), non-STEMI, and unstable angina pectoris. Admission BG higher than 220 mg/dl was statistically significantly associated with lower survival in patients; the association was stronger than in patients with admission BG higher than 140 mg/dl to less than 220 mg/dl and patients with admission BG less than 140 mg/dl (Wilcoxon test, p = 0.002). Survival time after admission was also associated with the history of diabetes mellitus (DM). Patients with diabetes had significantly lower survival than those without diabetes (Wilcoxon test, p = 0.028). Survival after ACS was not consistent with each insulin intervention of on admission to 6, 24, and 48 h after admission. There is a statistically significant association between admission BG higher than 220 mg/dl and low survival but each intervention of post admission BG levels were not consistently associated with the mortality. Additionally, history of DM is associated with lower survival in patients with ACS on admission.

Accuracy and limitations of continuous glucose monitoring using spectroscopy in critically ill patients

BACKGROUND

OptiScanner devices, continuous glucose monitoring devices that perform automated blood draws via a central venous catheter and create plasma through centrifugation, measure plasma glucose levels through mid-infrared spectroscopy at the bedside. The objective of this study was to determine accuracy and practicality of the devices in critically ill patients attempting glycemic control.

METHODS

The plasma glucose level was measured by the devices and in comparative plasma samples using Yellow Springs Instrument (YSI) plasma analyzers. After adding several previously unrecognized interferences in the interference library, we reanalyzed the mid-infrared signals and compared the resulting plasma glucose level with the reference value. Results are presented in Clarke error grids, glucose prediction errors and Bland-Altman plots and expressed as correlation coefficients.

RESULTS

We analyzed 463 comparative samples from 71 patients (median 6 (4 to 9) samples per patient). After calibrating the system, a Clarke error grid showed 100% of the values in zones A or B. The glucose predictor error demonstrated that 86% of the glucose values < 75 mg/dL were within ± 15 mg/dL of the YSI results and 95% ≥ 75 mg/dL were within 20% of the comparative YSI results. Bland-Altman plot showed a bias of -0.6 with limit of agreement of -24.6 to 23.3. The Pearson correlation coefficient was 0.93 and R2 was 0.87. In one third of the patients the devices had to be disconnected prematurely (that is before planned disconnection) because of repeated occlusion alarms suggesting blood draw errors.

CONCLUSION

The devices needed calibration for several previously unrecognized interferences. Thereafter, accuracy of the device to measure plasma glucose levels in 'our cohort' of critically ill patients improved, but external validation is highly recommended. The automated blood draw system of the devices needs further improvement to make this device of value for clinical use (trial registration (Netherlands Trial Register): NTR2864).

Glycemic Control in Pediatric Patients on Extracorporeal Membrane Oxygenation

OBJECTIVES To determine whether glycemic control has an effect on outcomes for pediatric patients on extracorporeal membrane oxygenation (ECMO) therapy, while controlling for multiple factors.

METHODS A single-center retrospective chart review was performed on 82 patients who required ECMO from January 1, 2008, to December 31, 2010. All glucose concentrations collected while patients were on ECMO were analyzed; multiple other factors that may have affected mortality were also recorded. Primary outcome was mortality, and secondary outcomes were length of time on ECMO and length of time until death or discharge from the hospital.

RESULTS Of 82 patients, 53 patients survived ECMO (64.6%). Glucose control had no effect on survival of patients on ECMO (p=0.56), even when controlling for multiple factors (p=0.48). Similarly, statistical evaluation showed no differences for hospital mortality in relationship to controlled serum glucose (p=0.50). Patients with controlled glucose spent an average of 31.5% more time on ECMO than non-controlled patients (p=0.048).

CONCLUSIONS In this study, glycemic control, defined as serum glucose concentration between 60 mg/dL and 250 mg/dL for &gt;95% of the time on ECMO, had no statistically significant effect on mortality for patients on ECMO. Future studies could focus on tighter glucose control or specific dextrose/glucose protocols to evaluate whether improved glucose control would have an effect on morbidity and mortality.

[The optimal blood glucose target in critically ill patient: comparison of two intensive insulin therapy protocols]

BACKGROUND AND OBJECTIVE

Recent studies in critically ill patients receiving insulin intravenous therapy (IIT) have shown an increased incidence of severe hypoglycemia, while intermittent subcutaneous insulin «sliding scales» (conventional insulin therapy [CIT]) is associated with hyperglycemia. The objective of this study is to assess whether glycemic control range IIT can affect glucose levels and their variability and to compare it with CIT.

PATIENTS AND METHOD

Prospective comparative cohort study in intensive care unit, with 2 study periods: Period 1, IIT with glycemic target range 110-140 mg/dL, and Period 2, IIT of 140-180 mg/dL. In both periods CIT glycemic target was 110-180 mg/dL. We assessed severe hypoglycemia (< 50 mg/dL), moderate hypoglycemia (51-79 mg/dL), hyperglycemia (> 216 mg/L) and the variability of blood glucose.

RESULTS

We studied 221 patients with 12.825 blood glucose determinations. Twenty-six and 17% of patients required IIT for glycemic control in Period 1 and 2, respectively. Hypoglycemia was associated with a discontinuous nutritional intake, glycemic target 110-140 mg/dL and low body mass index (BMI) (P = .002). Hyperglycemia was exclusively associated with a history of diabetes mellitus (OR 2.6 [95% CI 1.6 to 4.5]). Glycemic variability was associated with a discontinuous nutritional intake, low BMI, CIT insulinization, diabetes mellitus, elderly and high APACHE II (P < .001).

CONCLUSIONS

The use of IIT is useful to reduce the variability of blood glucose. Although the 140-180 mg/dL range would be more secure as to presenting greater variability and hyperglycemia, the 110-140 mg/dL range is most suitable.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Guidelines for the use of an insulin infusion for the management of hyperglycemia in critically ill patients

OBJECTIVE

To evaluate the literature and identify important aspects of insulin therapy that facilitate safe and effective infusion therapy for a defined glycemic end point.

METHODS

Where available, the literature was evaluated using Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) methodology to assess the impact of insulin infusions on outcome for general intensive care unit patients and those in specific subsets of neurologic injury, traumatic injury, and cardiovascular surgery. Elements that contribute to safe and effective insulin infusion therapy were determined through literature review and expert opinion. The majority of the literature supporting the use of insulin infusion therapy for critically ill patients lacks adequate strength to support more than weak recommendations, termed suggestions, such that the difference between desirable and undesirable effect of a given intervention is not always clear.

RECOMMENDATIONS

The article is focused on a suggested glycemic control end point such that a blood glucose ≥ 150 mg/dL triggers interventions to maintain blood glucose below that level and absolutely <180 mg/dL. There is a slight reduction in mortality with this treatment end point for general intensive care unit patients and reductions in morbidity for perioperative patients, postoperative cardiac surgery patients, post-traumatic injury patients, and neurologic injury patients. We suggest that the insulin regimen and monitoring system be designed to avoid and detect hypoglycemia (blood glucose ≤ 70 mg/dL) and to minimize glycemic variability.Important processes of care for insulin therapy include use of a reliable insulin infusion protocol, frequent blood glucose monitoring, and avoidance of finger-stick glucose testing through the use of arterial or venous glucose samples. The essential components of an insulin infusion system include use of a validated insulin titration program, availability of appropriate staffing resources, accurate monitoring technology, and standardized approaches to infusion preparation, provision of consistent carbohydrate calories and nutritional support, and dextrose replacement for hypoglycemia prevention and treatment. Quality improvement of glycemic management programs should include analysis of hypoglycemia rates, run charts of glucose values <150 and 180 mg/dL. The literature is inadequate to support recommendations regarding glycemic control in pediatric patients.

CONCLUSIONS

While the benefits of tight glycemic control have not been definitive, there are patients who will receive insulin infusion therapy, and the suggestions in this article provide the structure for safe and effective use of this therapy.

Discrepancies between capillary glucose measurements and traditional laboratory assessments in both shock and non-shock states after trauma

INTRODUCTION

The purpose of this study was to analyze the accuracy of capillary blood glucose (CBG) against laboratory blood glucose (LBG) in critically ill trauma patients during the shock state.

METHODS

All critically ill trauma patients admitted to the Surgical Intensive Care Unit at the Los Angeles County + University of Southern California Medical Center requiring blood glucose monitoring from January 2007 to December 2008 were included. Accuracy of CBG was compared against LBG during shock and non-shock states. Shock was defined as either systolic blood pressure <90 mm Hg or mean arterial pressure <70 mm Hg and the need for vasopressor therapy. The Bland-Altman method was used to determine the agreement between CBG and LBG during shock and non-shock states. CBG values were considered to disagree significantly with LBG values when the difference exceeded 15%.

RESULTS

During the 2-y study period, a total of 1215 patients were admitted to the Surgical Intensive Care Unit. Overall, the mean age was 38.4 ± 20.9 y, 79.6% (967) were male, and 75.0% (911) sustained blunt trauma. A total of 1935 paired samples of CBG and LBG were included in this analysis (367 during shock and 1568 during non-shock). During shock, the mean difference between CBG and LBG levels was 13.4 mg/dL (95% CI, -15.4 to 42.2 mg/dL), and the limits of agreement were -27.1 and 53.9 mg/dL. A total of 136 CBG values (37.1%) differed from the LBG values by more than 15%. During non-shock, the mean difference between CBG and LBG levels was 12.6 mg/dL (95% CI, -19.9 to 32.5 mg/dL), and the limits of agreement were -20.6 and 45.8 mg/dL. A total of 639 CGB values (40.8%) differed from the LBG values by more than 15%. Agreement was lowest among hypoglycemic readings in both shock and non-shock states.

CONCLUSION

There is poor correlation between the capillary and laboratory glucose values in both shock and non-shock states.

Finding the sweet spot: identification of optimal glucose levels in critically injured patients

BACKGROUND

Conflicting data exist regarding optimal glycemic control in critically ill trauma patients. We therefore compared glucose parameters and outcomes among three different glycemic control regimens in a single trauma intensive care unit (ICU), hypothesizing that a moderate regimen would yield optimal avoidance of hyper- and hypoglycemia with equivalent outcomes when compared with a more aggressive approach.

METHODS

We retrospectively reviewed 1,422 trauma patients with at least 3-day ICU stay and five glucose measurements from May 2001 to January 2010, spanning three nonoverlapping, sequential glucose control protocols: "relaxed," "aggressive," and "moderate." For each, we extracted mean blood glucose, hypoglycemic and hyperglycemic event frequency, and glucose variability and investigated their association with outcomes.

RESULTS

Mortality was associated with elevated mean glucose (135.6 mg/dL vs. 126.2 mg/dL), more frequent hypoglycemic (2.67 ± 7 vs. 1.28 ± 5) and hyperglycemic (30.6 ± 28 vs. 16.0 ± 22 per 100 patient-ICU days) events, and higher glucose variability (37.1 ± 20 vs. 29.4 ± 20; all p < 0.001). Regression identified hyperglycemic episodes (p < 0.05) as an independent predictor of mortality. The "moderate" regimen had rare hyperglycemia, low glucose variability, and intermediate mean blood glucose range and frequency of hypoglycemia. Multiorgan failure and mortality did not differ between groups.

CONCLUSIONS

Hyperglycemic events (glucose >180 mg/dL) most strongly predicted mortality. Of glucose control protocols analyzed, the "moderate" protocol had fewest hyperglycemic events. As outcomes were otherwise equivalent between "moderate" and "aggressive" protocols, we conclude that hyperglycemia can be safely avoided using a moderate glycemic control protocol without inducing hypoglycemia.

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.

Is critical illness neuromyopathy and duration of mechanical ventilation decreased by strict glucose control?

Strict glycemic control (SGC) is reported to have a beneficial effect on critical illness polyneuropathy/myopathy (CINM) and the duration of mechanical ventilation. The methodology used to diagnose CINM differs substantially in studies on this topic. This may influence the reported treatment effect. We reviewed literature on the effect of SGC on CINM and duration of ventilation by conducting a OVID Medline systematic electronic search of literature describing effects of SGC on occurrence of CINM and the effect of SGC on the duration of mechanical ventilation. A beneficial effect of SGC on CINM, diagnosed by needle myography, was reported in three studies. One of these studies showed that the incidence of weakness or failure to wean did not decrease by SGC, as the number of electrophysiological studies (EMG) ordered for these problems remained the same. Another study reported no improvement of muscle strength due to SGC. SGC reduced the duration of mechanical ventilation in three studies while six other studies did not report this beneficial effect. SGC seems to have a beneficial effect on CINM, but the reported risk reduction is likely to be an overestimation of the treatment effect due to the diagnostic methods used. Duration of mechanical ventilation may not be a reliable surrogate marker for CINM and a beneficial effect of SGC on this parameter has not been proven. We propose to use the recently developed diagnostic criteria for ICU-acquired weakness and critical illness neuromyopathy in future studies.

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.

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.

Which variables are associated with blood glucose levels outside the target range in surgical critically ill patients? A retrospective observational study

BACKGROUND

The aim of the present study is to determine the variables affecting blood glucose concentrations outside the target range of 80 and 150 mg/dl in critically ill surgical patients.

METHODS

All critically ill surgical patients admitted to a university ICU, from 01/2007 to 12/2008, were surveyed daily using computer assistance with respect to minimal and maximal daily blood glucose concentrations, application of insulin and demographic/clinical variables. Multiple logistic regression for clustered data with backward elimination was performed to identify variables strongly associated with blood glucose concentrations < 80 mg/dl or ≥ 150 mg/dl in 804 patients with an ICU stay > 72 hours.

RESULTS

Application of insulin (odds ratio (OR) 2.1, with corresponding 95% confidence interval (CI) 1.7; 2.6), noradrenaline (OR 1.4, 95% CI 1.2 - 1.8) or steroids (1.3, 1.003 - 1.7), and age (per year) (1.02, 1.01 - 1.03) were associated with an increased risk of blood glucose concentrations < 80 mg/dl. In analogy, application of insulin (OR 2.4, 95% CI 2.0 - 2.7), noradrenaline (1.4, 1.2 - 1.6) or steroids (1.4, 1.2 - 1.7), severe sepsis (1.2, 1.1 - 1.4), neurosurgery (OR 1.0) compared to abdominal, vascular and trauma surgery, and age (per year) (1.01, 1.01 - 1.02), were associated with an increased risk of blood glucose concentrations ≥ 150 mg/dl.

CONCLUSIONS

Critically ill surgical patients are at an increased risk for fluctuating blood glucose concentrations ranging < 80 mg/dl or ≥ 150 mg/dl in particular if they are of advanced age and require administration of insulin, noradrenaline, and/or steroids. Patients who underwent neurosurgery and/or presented with severe sepsis/shock are those in particular at risk for blood glucose concentrations ≥ 150 mg/dl.

Increasing blood glucose variability heralds hypoglycemia in the critically ill

BACKGROUND

Control of hyperglycemia improves outcomes, but increases the risk of hypoglycemia. Recent evidence suggests that blood glucose variability (BGV) is more closely associated with mortality than either isolated or mean BG. We hypothesized that differences in BGV over time are associated with hypoglycemia and can be utilized to estimate risk of hypoglycemia (<50 mg/dL).

MATERIALS AND METHODS

Patients treated with intravenous insulin in the Surgical Intensive Care Unit of a tertiary care center formed the retrospective cohort. Exclusion criteria included death within 24 h of admission. We describe BGV in patients over time and its temporal relationship to hypoglycemic events. The risk of hypoglycemia for each BG measurement was estimated in a multivariable regression model. Predictors were measures of BGV, infusions of dextrose and vasopressors, patient demographics, illness severity, and BG measurements.

RESULTS

A total of 66,592 BG measurements were collected on 1392 patients. Hypoglycemia occurred in 154 patients (11.1%). Patient BGV fluctuated over time, and increased in the 24 h preceding a hypoglycemic event. In crude and adjusted analyses, higher BGV was positively associated with a hypoglycemia (OR 1.41, P < 0.001). Previous hypoglycemic events and time since previous BG measurement were also positively associated with hypoglycemic events. Severity of illness, vasopressor use, and diabetes were not independently associated with hypoglycemia.

CONCLUSIONS

BGV increases in the 24 h preceding hypoglycemia, and patients are at increased risk during periods of elevated BG variability. Prospective measurement of variability may identify periods of increased risk for hypoglycemia, and provide an opportunity to mitigate this risk.

Glucose elevations and outcome in critically injured trauma patients

Tight glucose control is associated with improved outcome among critically ill trauma patients. Further research is necessary, however, to better elucidate the etiology of this beneficial therapy. Additionally, future randomized trials on this important topic are warranted, as are investigations of emerging technologies that better facilitate tight glucose control in the ICU after trauma.

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.