Hyperglycemia during critical illness

Clinical nutrition in patients with Acute Kidney Injury: Traditional approaches and emerging perspectives

Acute kidney injury (AKI) is a complex clinical syndrome characterized by a rapid decline in kidney function, often resulting in complex metabolic and hormonal derangements. A major concern in managing AKI patients is the development of protein energy wasting (PEW), a condition marked by loss of lean body mass and negative impact on overall health outcomes. Additionally, the need of Kidney Replacement Therapy (KRT) for the most severe forms of AKI may further increase the risk of PEW, with a substantial impact on fluid and metabolic balance. Adequate nutritional support is crucial in the management of AKI, as it plays a pivotal role in muscle mass preservation, morbidity reduction and recovery of renal function. This paper aims to evaluate the current evidence regarding nutritional strategies in AKI patients, focusing on energy and protein requirements, timing and route of nutritional intervention, and impact of individualized nutrition plans on PEW prevention and management.

The association between hemoglobin A1c and all-cause mortality in the ICU: A cross-section study based on MIMIC-IV 2.0

BACKGROUND

Hyperglycemia has been reported to be associated with the outcomes of patients in the intensive care unit (ICU). However, the relationship between hemoglobin A1c (HbA1c) and long-term or short-term mortality in the ICU is still unknown. This study used the Medical Information Mart for Intensive Care (MIMIC)-IV database to investigate the relationship between HbA1c and long-term or short-term mortality among ICU patients without a diabetes diagnosis.

METHODS

A total of 3,154 critically ill patients without a diabetes diagnosis who had HbA1c measurements were extracted and analyzed from the MIMIC-IV. The primary outcome was 1-year mortality, while the secondary outcomes were 30-day mortality and 90-day mortality after ICU discharge. HbA1c levels were classified into four levels according to three HbA1c values (5.0%, 5.7%, and 6.5%). The Cox regression model was used to investigate the relationship between the highest HbA1c measurement and mortality. Finally, this correlation was validated using the XGBoost machine learning model and Cox regression after propensity score matching (PSM).

RESULTS

The study eventually included 3,154 critically ill patients without diabetes who had HbA1c measurements in the database. HbA1c levels of below 5.0% or above 6.5% were significantly associated with 1-year mortality after adjusting for covariates in Cox regression (HR: 1.37; 95% CI: 1.02-1.84 or HR: 1.62; 95% CI: 1.20-2.18). In addition, HbA1c 6.5% was linked to 30-day mortality (HR: 1.81; 95% CI: 1.21-2.71) and 90-day mortality (HR: 1.62; 95% CI: 1.14-2.29). The restricted cubic spline demonstrated a U-shaped relationship between HbA1c levels and 1-year mortality. The AUCs of the training and testing datasets in the XGBoost model were 0.928 and 0.826, respectively, while the SHAP plot revealed that HbA1c was somewhat important for the 1-year mortality. Higher HbA1c levels in Cox regression were still significantly associated with 1-year mortality after PSM for other factors.

CONCLUSIONS

The 1-year mortality, 30-day mortality, and 90-day mortality rates for critically ill patients after discharge from ICU are significantly associated with HbA1c. HbA1c < 5.0% and ≥6.5% would increase 30-day, 90-day, and 1-year mortality, while levels between 5.0% and 6.5% of HbA1c did not significantly affect these outcomes.

Inpatient hyperglycaemia, and impact on morbidity, mortality and re-hospitalisation rates

INTRODUCTION

Hyperglycaemia is related to poorer outcomes among hospital inpatients. We investigated the impact of hyperglycaemia at admission on length of hospital stay, readmission rate and mortality rate.

METHOD

We retrospectively analysed the records of 1,132 patients admitted to hospital in January 2019, April 2019, August 2019 and April 2020.

RESULTS

Hyperglycaemia was present in 14.1% of patients. New-onset hyperglycaemia on admission (in 3.9% of patients) was related to a higher mortality rate than in patients known to have diabetes admitted with hyperglycaemia (43.3% vs 17.9%; p=0.006). Mortality at 90 days and 1 year increased with higher admission glucose levels (p=0.03 and p=0.005, respectively), severe hyperglycaemia (>20 mmol/L) having a 1-year mortality of 34.3%. After accounting for confounding variables, admission glucose and length of stay remained significant predictors of 1-year mortality (p=0.034 and p=0.003, respectively).

CONCLUSION

Hyperglycaemia is an important prognostic marker and may indicate a more severe illness. These patients should be highlighted for a greater level of care.

The goldilocks problem: Nutrition and its impact on glycaemic control

BACKGROUND

Glucose intolerance and insulin resistance manifest as hyperglycaemia in intensive care, which is associated with mortality and morbidities. Glycaemic control (GC) may improve outcomes, though safe and effective control has proven elusive. Nutritional glucose intake affects blood glucose (BG) outcomes, but few protocols actively control it. This study aims to examine BG outcomes in the context of nutritional management during GC.

METHODS

Retrospective cohort analysis of 5 glycaemic control cohorts spanning 4 years (n = 273) from Christchurch Hospital Intensive Care Unit (ICU). GC is delivered using a single model-based protocol (STAR), with default 4.4-8.0 mmol/L target range via. modulation of insulin and nutrition. Clinical adaptations/cohorts include variations on upper target (UL-9 with 9.0 mmol/L, reducing workload and nutrition responsiveness), and insulin only (IO) with clinically set nutrition at 3 glucose concentrations (71 g/L vs. 120 and 180 g/L in the TARGET study).

RESULTS

Percent of BG hours in the 4.4-8.0 mmol/L range highest under standard STAR conditions (78%), and was lower at 64% under UL-9, likely due to reduced time-responsiveness of nutrition-insulin changes. By comparison, IO only resulted in 64-69% BG in range across different nutrition types. A subset of patients receiving high glucose nutrition under IO were persistently hyperglycaemic, indicating patient-specific glucose tolerance.

CONCLUSION

STAR GC is most effective when nutrition and insulin are modulated together with timely responsiveness to persistent hyperglycaemia. Results imply modulation of nutrition alongside insulin improves GC, particularly in patients with persistent hyperglycaemia/low glucose tolerance.

Pathophysiology and management of critical illness polyneuropathy and myopathy

Critical illness-associated weakness (CIAW) is an umbrella term used to describe a group of neuromuscular disorders caused by severe illness. It can be subdivided into three major classifications based on the component of the neuromuscular system (i.e. peripheral nerves or skeletal muscle or both) that are affected. This includes critical illness polyneuropathy (CIP), critical illness myopathy (CIM), and an overlap syndrome, critical illness polyneuromyopathy (CIPNM). It is a common complication observed in people with critical illness requiring intensive care unit (ICU) admission. Given CIAW is found in individuals experiencing grave illness, it can be challenging to study from a practical standpoint. However, over the past 2 decades, many insights into the pathophysiology of this condition have been made. Results from studies in both humans and animal models have found that a profound systemic inflammatory response and factors related to bioenergetic failure as well as microvascular, metabolic, and electrophysiological alterations underlie the development of CIAW. Current management strategies focus on early mobilization, achieving euglycemia, and nutritional optimization. Other interventions lack sufficient evidence, mainly due to a dearth of large trials. The goal of this Physiology in Medicine article is to highlight important aspects of the pathophysiology of these enigmatic conditions. It is hoped that improved understanding of the mechanisms underlying these disorders will lead to further study and new investigations for novel pharmacologic, nutritional, and exercise-based interventions to optimize patient outcomes.

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.

Diabetes and elevated preoperative HbA1c level as risk factors for postoperative delirium after cardiac surgery: an observational cohort study

INTRODUCTION

Postoperative delirium (POD) is a common complication of cardiac surgery associated with increased mortality, morbidity, and long-term cognitive dysfunction. Diabetic patients, especially those with poor diabetes control and long-standing hyperglycemia, may be at risk of developing delirium. The aim of this study was to analyze whether the occurrence of POD in cardiac surgery is associated with diabetes or elevated preoperative glycated hemoglobin (HbA1c) level.

MATERIALS AND METHODS

We performed a cohort analysis of prospectively collected data from a register of cardiac surgery department of a university hospital. Delirium assessment was performed twice a day during the first 5 days after the operation based on Diagnostic Statistical Manual of Mental Disorders, fifth edition criteria.

RESULTS

We analyzed a cohort of 3,178 consecutive patients, out of which 1,010 (31.8%) were diabetic and 502 (15.8%) were diagnosed with POD. Patients with delirium were more often diabetic (42.03% vs 29.86%, P<0.001) and on oral diabetic medications (34.66% vs 24.07%, P<0.001), no difference was found in patients with insulin treatment. Preoperative HbA1c was elevated above normal (≥6%) in more delirious than nondelirious patients (44.54% vs 33.04%, P<0.001), but significance was reached only in nondiabetic patients (20.44% vs 14.86%, P=0.018). In univariate analysis, the diagnosis of diabetes was associated with an increased risk of developing POD (OR: 1.703, 95% CI: 1.401-2.071, P<0.001), but only for patients on oral diabetic medications (OR: 1.617, 95% CI: 1.319-1.983, P<0.001) and an association was noted between HbA1c and POD (OR: 1.269, 95% CI: 1.161-1.387, P<0.001). Multivariate analysis controlled for diabetes showed that POD was associated with age, heart failure, preoperative creatinine, extracardiac arteriopathy, and preoperative HbA1c level.

CONCLUSION

More diabetic patients develop POD after cardiac surgery than nondiabetic patients. Elevated preoperative HbA1c level is a risk factor for postcardiac surgery delirium regardless of the diagnosis of diabetes.

Sepsis: A Review of Advances in Management

Infections represent a common health problem in people of all ages. Usually, the response given to them is appropriate and so little treatment is needed. Sometimes, however, the response to the infection is inadequate and may lead to organ dysfunction; this is the condition known as sepsis. Sepsis can be caused by bacteria, fungi or viruses and at present there is no specific treatment; its management basically focuses on containing the infection through source control and antibiotics plus organ function support. This article reviews key elements of sepsis management, focusing on diagnosis, biomarkers and therapy. The main recent advance in therapy is the strategy of personalized medicine, based on a precise approach using biomarkers to identify specific individuals who are likely to benefit from more personalized attention.

Neural network approach for non-invasive detection of hyperglycemia using electrocardiographic signals

Hyperglycemia or high blood glucose (sugar) level is a common dangerous complication among patients with Type 1 diabetes mellitus (T1DM). Hyperglycemia can cause serious health problems if left untreated such as heart disease, stroke, vision and nerve problems. Based on the electrocardiographic (ECG) parameters, we have identified hyperglycemic and normoglycemic states in T1DM patients. In this study, a classification unit is introduced with the approach of feed forward multi-layer neural network to detect the presences of hyperglycemic/normoglycemic episodes using ECG parameters as inputs. A practical experiment using the real T1DM patients' data sets collected from Department of Health, Government of Western Australia is studied. Experimental results show that proposed ECG parameters contributed significantly to the good performance of hyperglycemia detections in term of sensitivity, specificity and geometric mean (70.59%, 65.38%, and 67.94%, respectively). From these results, it is proved that hyperglycemic events in T1DM can be detected non-invasively and effectively by using ECG signals and ANN approach.

Candida Score as a Predictor of Worse Outcomes and Mortality in Severely Injured Trauma Patients with Positive Candida Cultures

Invasive candidiasis is associated with worse outcomes and increased mortality in critically ill patients. The Candida score (CS) provides a clinical tool for identifying patients at risk for invasive candidiasis. Outcomes of severely injured trauma patients with positive Candida cultures stratified by their CS have not been well described. In this retrospective observational study, all severely injured trauma patients (Injury Severity Score ≥16) admitted to the Los Angeles County and University of Southern California Medical Center from April 2008 to April 2014 with positive Candida cultures were included. Outcomes of patients with a low risk for invasive candidiasis (CS < 3) were compared with those with a high risk (CS ≥ 3). A CS ≥ 3 was significantly associated with higher mortality (35.9% vs 5.0%, P = 0.001), longer length of stay (LOS) (median 49.0 vs 28.0, P = 0.002), longer intensive care unit LOS (35.0 vs 20.0, P < 0.001), requirement for renal replacement therapy (38.5% vs 4.9%, P < 0.001), and increased ventilator days (22.0 vs 12.0, P < 0.001). Multi-variable regression analysis revealed a CS ≥ 3 as a significant predictor for increased mortality [OR 6.983], longer LOS [regression coefficient (RC) 1.572] and intensive care unit LOS (RC 1.698), more frequent need for renal replacement therapy (OR 13.268), and increased ventilator days (RC 1.836). In conclusion, a CS ≥ 3 is significantly associated with increased mortality and worse outcomes in severely injured trauma patients with positive Candida cultures. The CS thus may serve as a clinical tool to predict outcomes in this patient population.

Effect of blood-sugar limitation on intensive care mortality: Intragroup evaluation

OBJECTIVE

To evaluate the safety profile of blood sugar limits in intensive care unit (ICU) patients.

METHODS

Adult patients with ICU stay >36 h, more than two blood sugar measurements and antibiotic therapy concordant with locally adapted guidelines were included. For analyses, one study cohort was defined in two ways: as a narrow group, euglycaemic patients' blood sugar levels 80-150 mg/dl; as a moderate group, euglycaemic patients' blood sugar levels 80-180 mg/dl. Dysglycaemia was defined as blood sugar levels <80 mg/dl for >5% of measurements, and >150 mg/dl or >180 mg/dl (narrow or moderate groups, respectively) for >10% of measurements. The primary endpoint was ICU mortality (euglycaemia versus dysglycaemia).

RESULTS

The study comprised 668 patients. When defined as a narrow group, ICU mortality was 3% (four of 135) euglycaemic versus 10% (54/533) dysglycaemic patients (odds ratio [OR] 3.692, 95% confidence interval [CI] 1.313, 10.382). When defined as a moderate group, ICU mortality was 6% (21/351) euglycaemic versus 12% (37/317) dysglycaemic patients (OR 2.077, 95% CI 1.188, 3.630). Frequency of severe hypoglycaemia (blood sugar <40 mg/dl) was not different between the narrow and moderate euglycaemic ranges.

CONCLUSIONS

Euglycaemia was associated with lower ICU mortality than dysglycaemia, and incidence of hypoglycaemia was low overall in this study. Based on current published evidence, therapeutic targets should be defined according to individual patient characteristics.

Software-guided insulin dosing: tight glycemic control and decreased glycemic derangements in critically ill patients

OBJECTIVE

To determine whether glycemic derangements are more effectively controlled using software-guided insulin dosing compared with paper-based protocols.

PATIENTS AND METHODS

We prospectively evaluated consecutive critically ill patients treated in a tertiary hospital surgical intensive care unit (ICU) between January 1 and June 30, 2008, and between January 1 and September 30, 2009. Paper-based protocol insulin dosing was evaluated as a baseline during the first period, followed by software-guided insulin dosing in the second period. We compared glycemic metrics related to hyperglycemia, hypoglycemia, and glycemic variability during the 2 periods.

RESULTS

We treated 110 patients by the paper-based protocol and 87 by the software-guided protocol during the before and after periods, respectively. The mean ICU admission blood glucose (BG) level was higher in patients receiving software-guided intensive insulin than for those receiving paper-based intensive insulin (181 vs 156 mg/dL; P=.003, mean of the per-patient mean). Patients treated with software-guided intensive insulin had lower mean BG levels (117 vs 135 mg/dL; P=.0008), sustained greater time in the desired BG target range (95-135 mg/dL; 68% vs 52%; P=.0001), had less frequent hypoglycemia (percentage of time BG level was <70 mg/dL: 0.51% vs 1.44%; P=.04), and showed decreased glycemic variability (BG level per-patient standard deviation from the mean: ±29 vs ±42 mg/dL; P=.01).

CONCLUSION

Surgical ICU patients whose intensive insulin infusions were managed using the software-guided program achieved tighter glycemic control and fewer glycemic derangements than those managed with the paper-based insulin dosing regimen.

Obesity and burns

The population of overweight patients presenting to burn facilities is expected to increase significantly over the next decades due to the global epidemic of obesity. Excess adiposity mediates alterations to key physiological responses and poses challenges to the optimal management of burns. The purpose of this study is to document the general epidemiological aspects of thermal injuries in the obese population, outline relevant physiological aspects associated with obesity, and draw attention to topics relating to the management, rehabilitation, and prognosis of burns in this emerging subpopulation of patients.

Duration of time on intensive insulin therapy predicts severe hypoglycemia in the surgically critically ill population

BACKGROUND

Hypoglycemia has emerged as a barrier to the practice of intensive insulin therapy. Current literature suggests that hypoglycemia occurs at variable rates and has different effects on outcomes in surgical and medical populations. We sought to determine the incidence, independent predictors, and effect on outcome of severe hypoglycemia (≤ 40 mg/dl) in a surgical population.

METHODS

A retrospective analysis was performed on all critically ill surgical patients treated with IIT from October 2004 to February 2007. Euglycemia (goal 80-110 mg/dl) was maintained using automated computerized titration of an insulin infusion. The primary outcome of interest was any episode of severe hypoglycemia (≤ 40 mg/dl). Multivariate logistic regression was used to determine the independent predictors of developing severe hypoglycemia.

RESULTS

A total of 60,298 data entries (1,118 patients) for glucose were analyzed. There were 64 severe hypoglycemic episodes in 52 patients (4.6% of the patients). There was a significant increase in deaths among patients who experienced at least one episode of hypoglycemia when compared with those who did not (26.9% vs. 15.3%, P = 0.03). Logistic regression revealed that the time spent on the protocol was the best predictor of developing a hypoglycemic event when controlling for other known risk factors of hypoglycemia.

CONCLUSIONS

Intensive insulin therapy can be implemented with a low percentage of patients (4.6%) experiencing severe hypoglycemia. Mortality rate was higher for patients experiencing hypoglycemia. The duration of the time spent on the protocol was the best predictor of hypoglycemia, suggesting that hypoglycemia is a mathematic probability of prolonged illness, not a reflection of illness severity or demographic features.

Effect of glycemic state on hospital mortality in critically ill surgical patients

Intensive insulin therapy can reduce mortality. Hypoglycemia related to intensive therapy may worsen outcomes. This study compared risk adjusted mortality for different glycemic states. A retrospective review of patients admitted to a surgical intensive care unit over 4 years was performed. Patients were divided into glycemic groups: HYPER (≥1 episode > 180 mg/dL, any <60), HYPO (≥1 episode < 60 mg/dL, any >180), BOTH (≥1 episode < 60 and ≥1 episode > 180 mg/dL), NORMO (all episodes 60-180 mg/dL), HYPER-Only (≥1 episode > 180, none <60 mg/dL), and HYPO-Only (≥1 episode < 60, none >180 mg/dL). Observed to expected Acute Physiology and Chronic Health Evaluation (APACHE) III mortality ratios (O/E) were studied. Number of adverse glycemic events was compared with mortality. Hypoglycemia and hyperglycemia occurred in 18 per cent and 50 per cent of patients. Mortality was 12.4 per cent (O/E = 0.88). BOTH had the highest O/E ratio (1.43) with HYPO the second highest (1.30). Groups excluding hypoglycemia (NORMO and HYPER-only) had the lowest O/E ratios: 0.56 and 0.88. Increasing number of hypoglycemic events were associated with increasing O/E ratio: 0.69 O/E for no events, 1.19 for 1-3 events, 1.35 for 4-6 events, 1.9 for 7-9 events, and 3.13 for ≥ 10 events. Ten or more hyperglycemic events were needed to significantly associate with worse mortality (O/E 1.53). Hyper- and hypoglycemia increase mortality compared with APACHE III expected mortality, with highest mortality risk if both are present. Hypoglycemia is associated with worse risk. Glucose control may need to be loosened to prevent hypoglycemia and reduce glucose variability.

Near-target caloric intake in critically ill medical-surgical patients is associated with adverse outcomes

BACKGROUND

The objective of this study was to determine whether caloric intake independently influences mortality and morbidity of critically ill patients.

METHODS

The study was conducted as a nested cohort study within a randomized controlled trial in a tertiary care intensive care unit (ICU). The main exposure in the study was average caloric intake/target for the first 7 ICU days. The primary outcomes were ICU and hospital mortality. Secondary outcomes included ICU-acquired infections, ventilator-associated pneumonia (VAP), duration of mechanical ventilation days, and ICU and hospital length of stay (LOS). The authors divided patients (n = 523) into 3 tertiles according to the percentage of caloric intake/target: tertile I <33.4%, tertile II 33.4%-64.6%, and tertile III >64.6%. To adjust for potentially confounding variables, the authors assessed the association between caloric intake/target and the different outcomes using multivariate logistic regression for categorical outcomes (tertile I was used as reference) and multiple linear regression for continuous outcomes.

RESULTS

Tertile III was associated with higher adjusted hospital mortality, higher risk of ICU-acquired infections, and a trend toward higher VAP rate. Increasing caloric intake was independently associated with a significant increase in duration of mechanical ventilation, ICU LOS, and hospital LOS.

CONCLUSIONS

The data demonstrate that near-target caloric intake is associated with significantly increased hospital mortality, ICU-acquired infections, mechanical ventilation duration, and ICU and hospital LOS. Further studies are needed to explore whether reducing caloric intake would improve the outcomes in critically ill patients.

Recognition and prevention of nosocomial pneumonia in the intensive care unit and infection control in mechanical ventilation

Nosocomial pneumonia (NP) is a difficult diagnosis to establish in the critically ill patient due to the presence of underlying cardiopulmonary disorders (e.g., pulmonary contusion, acute respiratory distress syndrome, atelectasis) and the nonspecific radiographic and clinical signs associated with this infection. Additionally, the classification of NP in the intensive care unit setting has become increasingly complex, as the types of patients who develop NP become more diverse. The occurrence of NP is especially problematic as it is associated with a greater risk of hospital mortality, longer lengths of stay on mechanical ventilation and in the intensive care unit, a greater need for tracheostomy, and significantly increased medical care costs. The adverse effects of NP on healthcare outcomes has increased pressure on clinicians and healthcare systems to prevent this infection, as well as other nosocomial infections that complicate the hospital course of patients with respiratory failure. This manuscript will provide a brief overview of the current approaches for the diagnosis of NP and focus on strategies for prevention. Finally, we will provide some guidance on how standardized or protocolized care of mechanically ventilated patients can reduce the occurrence of and morbidity associated with complications like NP.

Prognostic value of admission serum lactate concentrations in intensive care unit patients

BACKGROUND

Although blood lactate concentrations have an established prognostic value in circulatory shock or after cardiac arrest, their relationship with morbidity and length of stay in general intensive care unit (ICU) populations has not been well defined.

METHODS

This study included all 433 patients (246 surgical and 187 medical) consecutively admitted to the Department of medico-surgical intensive care. Hyperlactataemia was defined as a serum lactate concentration > or = 2 mEq/l.

RESULTS

On admission, 195 patients (45%) had hyperlactataemia. Hyperlactataemic patients had higher Acute Physiology and Chronic Health Evaluation (APACHE) II (13.3 +/- 6.9 vs 10.0 +/- 5.2) and Sequential Organ Failure Assessment (SOFA) (5.3 +/- 3.3 vs 3.3 +/- 2.3) scores than patients with normal lactate concentrations (both p < 0.01). There was no overall difference in length of ICU stay (LOS) between the two groups but survivors in the hyperlactataemic group had a longer LOS than survivors in the normal lactate group, whereas hyperlactataemic non-survivors had a shorter LOS than normal lactate non-survivors. Mortality was 9% in patients with normal lactate concentrations and 23% in hyperlactataemic patients. The mortality rate increased with increasing lactate concentrations, from 17% in patients with lactate concentrations from 2-4 mEq/l to 64% in those with concentrations more than 8 mEq/l. Non-survivors had higher lactate concentrations than survivors on admission, and after 24 and 48 hours. Risk factors for developing hyperlactataemia that were present on admission were SOFA score > 5, mean arterial blood pressure less than 70 mmHg, blood sugar greater than 110 mg/dl, and current use of vasopressors.

CONCLUSIONS

Our study documents a direct relationship between the serum lactate level on ICU admission and not only the risk of death in ICU but also the length of ICU stay. Hyperlactataemic survivors have a longer LOS and non-survivors a shorter LOS than normal lactate survivors and non-survivors, respectively.

Acute insulin resistance following injury

Hyperglycemia and insulin resistance often occur following injury and/or critical illness. Whereas intensive insulin treatment reduces hyperglycemia, mortality and morbidity in certain patients, little is known regarding the pathophysiology of acute insulin resistance following injury and infection. Studies suggest that acute insulin resistance is complex and might differ in a tissue-specific manner, involving multiple causative factors and intracellular signaling pathways. Therefore, the advantages of intensive insulin therapy might not be uniform to all injuries or critical illnesses. Clearly, the increased incidence of hypoglycemic incidents following intensive insulin therapy indicates a need for understanding the underlying molecular mechanisms of the acute development of insulin resistance, which will allow a more targeted approach to treat altered glucose metabolism of critically ill patients.

Sympathetic overstimulation during critical illness: adverse effects of adrenergic stress

The term ''adrenergic'' originates from ''adrenaline'' and describes hormones or drugs whose effects are similar to those of epinephrine. Adrenergic stress is mediated by stimulation of adrenergic receptors and activation of post-receptor pathways. Critical illness is a potent stimulus of the sympathetic nervous system. It is undisputable that the adrenergic-driven ''fight-flight response'' is a physiologically meaningful reaction allowing humans to survive during evolution. However, in critical illness an overshooting stimulation of the sympathetic nervous system may well exceed in time and scope its beneficial effects. Comparable to the overwhelming immune response during sepsis, adrenergic stress in critical illness may get out of control and cause adverse effects. Several organ systems may be affected. The heart seems to be most susceptible to sympathetic overstimulation. Detrimental effects include impaired diastolic function, tachycardia and tachyarrhythmia, myocardial ischemia, stunning, apoptosis and necrosis. Adverse catecholamine effects have been observed in other organs such as the lungs (pulmonary edema, elevated pulmonary arterial pressures), the coagulation (hypercoagulability, thrombus formation), gastrointestinal (hypoperfusion, inhibition of peristalsis), endocrinologic (decreased prolactin, thyroid and growth hormone secretion) and immune systems (immunomodulation, stimulation of bacterial growth), and metabolism (increase in cell energy expenditure, hyperglycemia, catabolism, lipolysis, hyperlactatemia, electrolyte changes), bone marrow (anemia), and skeletal muscles (apoptosis). Potential therapeutic options to reduce excessive adrenergic stress comprise temperature and heart rate control, adequate use of sedative/analgesic drugs, and aiming for reasonable cardiovascular targets, adequate fluid therapy, use of levosimendan, hydrocortisone or supplementary arginine vasopressin.

[Glycemic control in sepsis and septic shock: friend or foe?]

INTRODUCTION

Intensive care patients commonly suffer from hyperglycemia. Evidence is growing that strictly maintaining normoglycemia by intensive insulin therapy (IIT) ameliorates outcome in these patients. Whether or not this also holds true for patients with sepsis and septic shock is the issue of this post-hoc analysis of the database (2,748 patients) of 2 recent prospective clinical trials.

MATERIAL AND METHODS

A total of 950 patients suffering from sepsis were identified and of these 462 fulfilled the diagnostic criteria of septic shock upon admission to the intensive care unit (ICU). Patients were treated by either IIT [mean glycemia 5.88 mmol/l (106 mg/dl)] or conventional glucose management [mean glycemia 8.44 mmol/l (152 mg/dl)].

RESULTS

Under IIT the mortality of patients treated for more than 3 days in the ICU was lowered by 7.6% (p=0.03) in septic patients and by 8.7% (p=0.08) in septic shock patients. Polyneuropathy occurred less frequently under IIT compared to conventional glucose management (sepsis -9.8%, septic shock -14%; p<0.001). The incidence of acute renal failure was not affected by either treatment regimen (sepsis -3.3%, septic shock -3.1%; p<0.25). Intensive insulin therapy was associated with an increased risk of hypoglycemia (sepsis +16.7%, septic shock +18.8; p<0.0001) which did not, however, directly affect morbidity nor mortality.

CONCLUSIONS

These data suggest that IIT improves outcome of patients with sepsis or septic shock. Hypoglycemia is a frequent complication, but its clinical relevance remains to be defined.

Hyperglycemia is associated with morbidity in critically ill children with meningococcal sepsis

OBJECTIVE

To determine the association between hyperglycemia and outcome in children ventilated for meningococcal sepsis.

DESIGN

Retrospective case notes review.

SETTING

Eight bedded pediatric intensive care unit in London.

PATIENTS

Consecutive children ventilated for meningococcal sepsis 2001-2004.

INTERVENTIONS

None.

MEASUREMENTS

Peak glucose for the entire admission was determined and mean glucose was calculated for the following three epochs: 1) first 24 hrs, 2) second 24 hrs, and 3) the entire pediatric intensive care unit admission. Patients were also grouped according to whether their blood glucose rose to >7 mmol/L (126 mg/dL), >10 mmol/L (180 mg/dL), or remained below these levels during the pediatric intensive care unit admission. Outcome measures were predicted mortality (based on pediatric risk of mortality score), ventilator free days at 30 days, nosocomial infection, use of renal replacement therapy, use of inotropes, and skin necrosis.

MAIN RESULTS

Ninety-seven patients were identified with a median age of 2.1 yrs and a median length of stay of 4 days. Four patients died. Peak glucose significantly correlated with predicted mortality and negatively correlated with ventilator free days at 30 days (p < 0.001 and p < 0.001, respectively). Patients who received renal replacement therapy or inotropic support, or developed a nosocomial infection or skin necrosis had significantly higher peak glucose than those who did not (p = 0.006, p < 0.0001, p = 0.022, and p < 0.0001, respectively). Patients who received renal replacement therapy or who developed skin necrosis had significantly higher mean blood glucose in the second 24 hrs of admission (p = 0.017 and p = 0.004, respectively). However, mean blood glucose in the first 24 hrs and over the entire admission did not correlate with outcome. Patients defined as hyperglycemic with blood glucose either >7 mmol/L or >10 mmol/L also had a significantly worse outcome than those who maintained blood glucose below these levels.

CONCLUSIONS

There was a significant association between hyperglycemia and outcome. Our results support a trial of tight glycemic control in this group of critically ill children.

Glycemic control modulates arginine and asymmetrical-dimethylarginine levels during critical illness by preserving dimethylarginine-dimethylaminohydrolase activity

In the context of the hypercatabolic response to stress, critically ill patients reveal hyperglycemia and elevated levels of asymmetrical-dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthases. Both hyperglycemia and elevated ADMA levels predict increased morbidity and mortality. Tight glycemic control by intensive insulin therapy lowers circulating ADMA levels, and improves morbidity and mortality. Methylarginines are released from proteins during catabolism. ADMA is predominantly cleared by the enzyme dimethylarginine-dimethylaminohydrolase (DDAH) in different tissues, whereas its symmetrical isoform (SDMA) is cleared via the kidneys. Therefore, glycemic control or glycemia-independent actions of insulin on protein breakdown and/or on DDAH activity resulting in augmented ADMA levels may explain part of the clinical benefit of intensive insulin therapy. Therefore, we investigated in our animal model of prolonged critical illness the relative impact of maintaining normoglycemia and of glycemia-independent action of insulin over 7 d in a four-arm design on plasma and tissue levels of ADMA and SDMA, on proteolysis as revealed by surrogate parameters as changes of body weight, plasma urea to creatinine ratio, and plasma levels of SDMA, and on tissue DDAH activity. We found that ADMA levels remained normal in the two normoglycemic groups and increased in hyperglycemic groups. SDMA levels in the investigated tissues remained largely unaffected. The urea to creatinine ratio indicated reduced proteolysis in all but normoglycemic/normal insulin animals. DDAH activity deteriorated in hyperglycemic compared with normoglycemic groups. Insulin did not affect this finding independent of glycemic control action. Conclusively, maintenance of normoglycemia and not glycemia-independent actions of insulin maintained physiological ADMA plasma and tissue levels by preserving physiological DDAH activity.

Inpatient insulin therapy

PURPOSE OF REVIEW

In a 2001 report from a surgical intensive care unit in Leuven, Belgium, intravenous insulin infusion targeting blood glucose 80-110 mg/dl reduced patient mortality and morbidities. Subsequent research has failed to define glycemic targets necessary or sufficient for attainment of desired health outcomes in other inpatient settings, but a large body of evidence suggests hospital outcomes are related to hyperglycemia.

RECENT FINDINGS

Recent literature describes observational evidence for hypoglycemia as an independent predictor of mortality in a general medical intensive care unit; superiority of performance of computerized intravenous insulin algorithms in comparison to earlier manual algorithms; acceptability of early transition to scheduled basal prandial correction subcutaneous insulin analog therapy for maintenance of glycemic targets after induction of euglycemia by intravenous insulin infusion, among cardiothoracic surgery patients; inferiority of sliding scale insulin compared to basal prandial correction therapy; and feasibility of diabetes patient self-management in the hospital setting.

SUMMARY

With development of improved insulin administration strategies problems of hypoglycemia and variability of glycemic control are reduced. Investigators and care providers need to achieve glycemic targets to optimize patient outcomes.

Computerized clinical decision support: a technology to implement and validate evidence based guidelines

Faced with a documented crisis of patients not receiving appropriate care, there is a need to implement and refine evidence-based guidelines (EBGs) to ensure that patients receive the best care available. Although valuable in content, among their deficiencies, EBGs do not provide explicit methods to bring proven therapies to the bedside. Computerized information technology, now an integral part of the US healthcare system at all levels, presents clinicians with information from laboratory, imaging, physiologic monitoring systems, and many other sources. It is imperative that we clinicians use this information technology to improve medical care and efficacy of its delivery. If we do not do this, nonclinicians will use this technology to tell us how to practice medicine. Computerized clinical decision support (CCDS) offers a powerful method to use this information and implement a broad range of EBGs. CCDS is a technology that can be used to develop, implement, and refine computerized protocols for specific processes of care derived from EBGs, including complex care provided in intensive care units. We describe this technology as a desirable option for the trauma community to use information technology and maintain the trauma surgeon/intensivist's essential role in specifying and implementing best care for patients. We describe a process of logical protocol development based on standardized clinical decision making to enable EBGs. The resulting logical process is readily computerized, and, when properly implemented, provides a stable platform for systematic review and study of the process and interventions.

CONCLUSION

: CCDS to implement and refine EBG derived computerized protocols offers a method to decrease variability, test interventions, and validate improved quality of care.

Severe hypoglycemia in critically ill patients: risk factors and outcomes

OBJECTIVE

To determine the risk factors for development of severe hypoglycemia (defined as glucose <40 mg/dL) in critically ill patients and define the outcomes of this complication.

DESIGN

Retrospective database review, including a case-control analysis that matched each patient with severe hypoglycemia with three controls.

SETTING

Adult intensive care unit of a university-affiliated community hospital.

PATIENTS

A total of 102 patients with at least one episode of severe hypoglycemia extracted from a series of 5,365 medical, surgical, and cardiac patients admitted consecutively between October 1, 1999, and June 15, 2006.

INTERVENTIONS

A program of intensive glycemic monitoring and management, or tight glycemic control, was implemented on February 1, 2003; 2,666 patients were treated before and 2,699 after this date.

MEASUREMENTS AND MAIN RESULTS

Multivariable logistic regression analysis identified diabetes, septic shock, renal insufficiency, mechanical ventilation, severity of illness, reflected by Acute Physiology and Chronic Health Evaluation II score with the age component deleted, and treatment in the tight glycemic control period as independent risk factors for the development of severe hypoglycemia. Mortality was 55.9% among the 102 patients with severe hypoglycemia and 39.5% among the 306 controls (p = .0057). Multivariable logistic regression analysis identified severe hypoglycemia as an independent predictor of mortality for the entire cohort (odds ratio, 2.28; 95% confidence interval, 1.41-3.70; p = .0008). Among patients with severe hypoglycemia, only modified Acute Physiology and Chronic Health Evaluation II score and mechanical ventilation were identified as independent predictors of mortality. A sensitivity analysis was constructed that suggested that quadrupling the rate of severe hypoglycemia and doubling the mortality attributable to severe hypoglycemia would negate the survival benefit of tight glycemic control in this series.

CONCLUSIONS

Case-control methodology and multivariable logistic regression analysis concurred that even a single episode of severe hypoglycemia was independently associated with increased risk of mortality. Safe implementation of tight glycemic control requires appropriate monitoring to reduce the risk of this complication.

Hyperactive delirium and blood glucose control in critically ill patients

Delirium is a common complication of critically ill patients and is often associated with metabolic disorders. One of the most frequent metabolic disorders in intensive care unit (ICU) patients is hyperglycaemia. The aim of this retrospective study of 196 adult ICU patients was to determine if there is an association between hyperactive delirium and blood glucose levels in ICU patients. Hyperactive delirium was diagnosed using the delirium detection score. Blood glucose levels were monitored by blood gas analysis every 4 h. Hyperactive delirium was detected in 55 (28%) patients. Delirious patients showed significantly higher blood glucose levels than non-delirious patients Higher overall complication rates, length of ventilation, ICU stay and mortality rates were seen in the delirium group. In a multivariate analysis, glucose level, alcohol abuse, APACHE II score, complication by hospital-acquired pneumonia and a diagnosis of polytrauma on-admission all significantly influenced the appearance of delirium.

Structure-based design of robust glucose biosensors using a Thermotoga maritima periplasmic glucose-binding protein

We report the design and engineering of a robust, reagentless fluorescent glucose biosensor based on the periplasmic glucose-binding protein obtained from Thermotoga maritima (tmGBP). The gene for this protein was cloned from genomic DNA and overexpressed in Escherichia coli, the identity of its cognate sugar was confirmed, ligand binding was studied, and the structure of its glucose complex was solved to 1.7 Angstrom resolution by X-ray crystallography. TmGBP is specific for glucose and exhibits high thermostability (midpoint of thermal denaturation is 119 +/- 1 degrees C and 144 +/- 2 degrees C in the absence and presence of 1 mM glucose, respectively). A series of fluorescent conjugates was constructed by coupling single, environmentally sensitive fluorophores to unique cysteines introduced by site-specific mutagenesis at positions predicted to be responsive to ligand-induced conformational changes based on the structure. These conjugates were screened to identify engineered tmGBPs that function as reagentless fluorescent glucose biosensors. The Y13C*Cy5 conjugate is bright, gives a large response to glucose over concentration ranges appropriate for in vivo monitoring of blood glucose levels (1-30 mM), and can be immobilized in an orientation-specific manner in microtiter plates to give a reversible response to glucose. The immobilized protein retains its response after long-term storage at room temperature.

Practical aspects of intensive insulinization in the intensive care unit

PURPOSE OF REVIEW

Strategies used for intensive insulin therapy of critically ill patients and differences of approach according to medical condition are reviewed.

RECENT FINDINGS

Acceptance of proposed glycemic targets for critically ill patients has been tempered by uncertainties about benefit of strict glycemic control for specific target subpopulations, differences between treatment centers, optimal timing and duration of intervention, and safety. Present-day intravenous insulin infusion protocols may perform well only for restricted populations. Assessment of protocol performance requires knowledge of algorithm behavior on or near the narrow target range and, using the patient as unit of observation, examination of glycemic variability. Systems of the future will permit adjustment of algorithm parameters to meet individual- or population-specific targets and match carbohydrate exposure.

SUMMARY

Attainment and preservation of glycemic control among critically ill patients are best attempted with intravenous insulin infusion. Advances in the design of decision support and insulin delivery systems, and progress in the technology of continuous blood glucose monitoring, are likely to reduce the risk of hypoglycemia, without compromise of target range control, such that the patient outcomes enjoyed by experienced centers in the future will prove generalizable to others through the extension of new technologies.

Glycemic control, diabetic status, and mortality in a heterogeneous population of critically ill patients before and during the era of intensive glycemic management: six and one-half years experience at a university-affiliated community hospital

Hyperglycemia occurs commonly in acutely and critically ill patients and has been associated with adverse clinical consequences. An emerging body of literature describes the beneficial effects of intensive glycemic monitoring and treatment (tight glycemic control, or "TGC"). This manuscript reviews the experience of a cohort of 5365 non-cardiac surgery patients admitted to the adult intensive care unit of a university-affiliated community hospital before and after implementation of TGC. Significant decreases in mortality occurred among medical and surgical patients during the TGC era, but not among trauma patients. Non-diabetics who sustained hyperglycemia had an especially high risk of mortality, and benefited greatly from treatment. Further investigations will be needed to identify the most appropriate glycemic targets for different populations of patients.