Glucose metabolism and insulin therapy

Vitamin B12, folate, and homocysteine in metabolic syndrome: a systematic review and meta-analysis

Background & aims

Metabolic syndrome (MetS) is associated with life-threatening conditions. Several studies have reported an association of vitamin B12, folic acid, or homocysteine (Hcy) levels with MetS. This systematic review and meta-analysis assessed the association of vitamin B12, folic acid, and Hcy levels with MetS.

Methods

PubMed, Scopus, Embase, Ovid/Medline, and Web of Science were searched up to February 13, 2023. Cross-sectional, case-control, or cohort studies were included. A random-effects model was performed using the DerSimonian and Laird method to estimate the between-study variance. Effect measures were expressed as odds ratios (OR) with their corresponding 95% confidence intervals (95% CI). Between-study heterogeneity was evaluated using Cochran's Q test and the I2 statistic.

Results

Sixty-six articles (n = 87,988 patients) were included. Higher vitamin B12 levels were inversely associated with MetS (OR = 0.87; 95% CI: 0.81-0.93; p < 0.01; I2 = 90%). Higher Hcy levels were associated with MetS (OR = 1.19; 95% CI: 1.14-1.24; p < 0.01; I2 = 90%). Folate levels were not associated with MetS (OR = 0.83; 95% CI: 0.66-1.03; p = 0.09; I2 = 90%).

Conclusion

Higher vitamin B12 levels were inversely associated with MetS, whereas higher Hcy levels were associated with MetS. Studies assessing the pathways underlying this association are required.

Development of synthetic lipoxin-A4 mimetics (sLXms): New avenues in the treatment of cardio-metabolic diseases

Resolution of inflammation is a complex, dynamic process consisting of several distinct processes, including inhibition of endothelial activation and leukocyte trafficking; promotion of inflammatory cell apoptosis and subsequent non-phlogistic scavenging and degradation; augmentation of pathogen phagocytosis; modulation of stromal cell phenotype coupled to the promotion of tissue regeneration and repair. Among these tightly regulated processes, the clearance and degradation of apoptotic cells without eliciting an inflammatory response is a crucial allostatic mechanism vital to developmental processes, host defence, and the effective resolution of inflammation. These efferocytic and subsequent effero-metabolism processes can be carried out by professional and non-professional phagocytes. Defective removal or inadequate processing of apoptotic cells leads to persistent unresolved inflammation, which may promote insidious pathologies including scarring, fibrosis, and eventual organ failure. In this manuscript, the well-established role of endothelial activation and leukocyte extravasation, as classical vascular targets of the 'inflammation pharmacology', will be briefly reviewed. The main focus of this work is to bring attention to a less explored aspect of the 'resolution pharmacology', aimed at tackling defective efferocytosis and inefficient effero-metabolism, as key targeted mechanisms to prevent or pre-empt vascular complications in cardio-metabolic diseases. Despite the use of gold standard lipid-lowering drugs or glucose-lowering drugs, none of them are able to tackle the so called residual inflammatory risk and/or the metabolic memory. In this review, the development of synthetic mimetics of endogenous mediators of inflammation is highlighted. Such molecules finely tune key components across the whole inflammatory process, amongst various other novel therapeutic paradigms that have emerged over the past decade, including anti-inflammatory therapy. More specifically, FPR2-agonists in general, and Lipoxin analogues in particular, greatly enhance the reprogramming and cross-talk between classical and non-classical innate immune cells, thus inducing both termination of the pro-inflammatory state as well as promoting the subsequent resolving phase, which represent pivotal mechanisms in inflammatory cardio-metabolic diseases.

The clinical prediction factors for non-culprit lesion progression in patients with acute ST elevation myocardial infarction after primary percutaneous coronary intervention

BACKGROUND

To investigate the relationship between the clinical features and progression of non-culprit lesions in patients with ST-elevation myocardial infarction (STEMI) after primary percutaneous coronary intervention (PPCI).

METHODS

A total of 480 patients (57.1 ± 9.2 y) with STEMI who underwent PPCI between January 2016 and December 2017 in Beijing Anzhen Hospital were enrolled in this study. All patients underwent PPCI as a treatment for culprit lesions. Clinical and angiographic follow-up were performed for 12 months. All patients were divided into a non-culprit lesions (NCL) progression group (205 cases) and a control group (275 cases) based on angiographic follow-up outcomes at 12 months. The clinical and angiographic features were analyzed.

RESULTS

Body mass index (BMI), serum creatinine (Scr), fasting blood glucose (FBG), glycated serum albumin, glycated hemoglobin and homocysteine levels in the NCL progression group were significantly higher than those in the control group (P < 0.05). A logistic regression analysis showed that FBG (odds ratio 1.274, 95% confidence interval 1.077-1.505, P = 0.005) and Scr (odds ratio 1.020, 95% confidence interval 1.002-1.038, P = 0.027) were independent predictors of NCL progression. A partial correlation analysis showed that FBG was positively correlated with NCL progression (r = 0.231, P = 0.001). A receiver operating characteristic curve showed that the boundary point of FBG to predict NCL progression was 5.715 mmol/L, and the sensitivity was 74.4% and the specificity was 46.4%.

CONCLUSION

FBG is a valuable predictor for NCL progression in patients with STEMI after PPCI.

An Update on Postoperative Cognitive Dysfunction Following Cardiac Surgery

Postoperative cognitive dysfunction is extremely prevalent following cardiac surgery. The increasing patient age and comorbidity profile increases their susceptibility to cognitive impairment. The underlying pathophysiological mechanisms leading to cognitive impairment are not clearly elucidated. Using the contemporary literature (2015-present), this narrative review has three aims. Firstly, to provide an overview of postoperative cognitive impairment. Secondly, to analyse the predominant pathophysiological mechanisms leading to cognitive dysfunction following cardiac surgery such as inflammation, cerebral hypoperfusion, cerebral microemboli, glycaemic control and anaesthesia induced neurotoxicity. Lastly, to assess the current therapeutic strategies of interest to address these pathophysiological mechanisms, including the administration of dexamethasone, the prevention of prolonged cerebral desaturations and the monitoring of cerebral perfusion using near-infrared spectroscopy, surgical management strategies to reduce the neurological effects of microemboli, intraoperative glycaemic control strategies, the effect of volatile vs. intravenous anaesthesia, and the efficacy of dexmedetomidine.

Role of Vitamin B12 and Folate in Metabolic Syndrome

Metabolic syndrome (MS) is a collection of pathological metabolic conditions that includes insulin resistance, central or abdominal obesity, dyslipidemia, and hypertension. It affects large populations worldwide, and its prevalence is rising exponentially. There is no specific mechanism that leads to the development of MS. Proposed hypotheses range from visceral adiposity being a key factor to an increase in very-low-density lipoprotein and fatty acid synthesis as the primary cause of MS. Numerous pharmaceutical therapies are widely available in the market for the treatment of the individual components of MS. The relationship between MS and vitamin B complex supplementation, specifically folic acid and vitamin B12, has been a subject of investigation worldwide, with several trials reporting a positive impact with vitamin supplementation on MS.

In this study, an all-language literature search was conducted on Medline, Cochrane, Embase, and Google Scholar till September 2021. The following search strings and Medical Subject Headings (MeSH) terms were used: “Vitamin B12,” “Folate,” “Metabolic Syndrome,” and “Insulin Resistance.” We explored the literature on MS for its epidemiology, pathophysiology, newer treatment options, with a special focus on the effectiveness of supplementation with vitamins B9 and B12.

According to the literature, vitamin B12 and folate supplementation, along with a host of novel therapies, has a considerable positive impact on MS. These findings must be kept in mind while designing newer treatment protocols in the future.

Hyperglycemia, Insulin, and Insulin Resistance in Sepsis

Critically ill patients frequently have hyperglycemia. This event may reflect severe stress with an imbalance between anabolic hormones and catabolic hormones. Alternatively, it may reflect alterations in either insulin levels or insulin function. Insulin is a pleiotropic hormone with multiple important metabolic effects. In patients with sepsis, insulin levels are increased but insulin sensitivity is decreased. However, there is variability in insulin sensitivity, and this creates variability in glucose levels and insulin requirements and increases the frequency of hypo- and hyperglycemia. The factors that influence insulin sensitivity are complex and include inhibition of tyrosine kinase activity of the beta subunit, increased proteolytic activity resulting in loss of receptors from the plasma membrane, and possibly the transfer of insulin receptors into the nucleus where they bind to gene promoters. Better understanding of the role of insulin in critically ill patients requires prospective studies measuring insulin levels in various patient groups and the development of a simple measure of insulin sensitivity.

Hospital outcomes and cumulative burden from complications in type 2 diabetic sepsis patients: a cohort study using administrative and hospital-based databases

BACKGROUND

The association between type 2 diabetes and hospital outcomes of sepsis remains controversial when severity of diabetes is not taken into consideration. We examined this association using nationwide and hospital-based databases.

METHODS

The first part of this study was mainly conducted using a nationwide database, which included 1.6 million type 2 diabetic patients. The diabetic complication burden was evaluated using the adapted Diabetes Complications Severity Index score (aDCSI score). In the second part, we used laboratory data from a distinct hospital-based database to make comparisons using regression analyses.

RESULTS

The nationwide study included 19,719 type 2 diabetic sepsis patients and an equal number of nondiabetic sepsis patients. The diabetic sepsis patients had an increased odds ratio (OR) of 1.14 (95% confidence interval 1.1-1.19) for hospital mortality. The OR for mortality increased as the complication burden increased [aDCSI scores of 0, 1, 2, 3, 4, and ⩾5 with ORs of 0.91, 0.87, 1.14, 1.25, 1.56, and 1.77 for mortality, respectively (all p < 0.001)].The hospital-based database included 1054 diabetic sepsis patients. Initial blood glucose levels did not differ significantly between the surviving and deceased diabetic sepsis patients: 273.9 ± 180.3 versus 266.1 ± 200.2 mg/dl (p = 0.095). Moreover, the surviving diabetic sepsis patients did not have lower glycated hemoglobin (HbA1c; %) values than the deceased patients: 8.4 ± 2.6 versus 8.0 ± 2.5 (p = 0.078).

CONCLUSIONS

For type 2 diabetic sepsis patients, the diabetes-related complication burden was the major determinant of hospital mortality rather than diabetes per se, HbA1c level, or initial blood glucose level.

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.

Anabolic and anticatabolic agents in critical care

PURPOSE OF REVIEW

A complex network of hormones and other effectors characterize the hypermetabolic response in critical illness; these mediators work together to induce numerous pathophysiologic alterations. Increased incidence of infection, multiorgan failure, long-term debilitation, delays in rehabilitation, and death result from an inability to meet the prohibitively elevated protein and energy requirements, which occur during illness and can persist for several years. Pharmacologic interventions have been successfully utilized to attenuate particular aspects of the hypermetabolic response; these modalities are a component of managing critically ill patients - including those patients with severe burns. Here, we review recent advances in pharmacologically attenuating the hypermetabolic and catabolic responses.

RECENT FINDINGS

Propranolol, a nonspecific β-adrenergic receptor antagonist, is one of the most widely used anticatabolic therapies. Oxandrolone, testosterone, and intensive insulin therapy represent anabolic pharmacological strategies. Promising therapies, such as metformin, glucagon-like peptide 1, peroxisome proliferator-activated receptor agonists, are currently being investigated.

SUMMARY

Profound metabolic derangements occur in critically ill patients; this hypermetabolic response is a major contributor to adverse outcomes. Despite the pharmacological therapies currently available to counteract this devastating cascade, future studies are warranted to explore new multimodality agents that will counteract these effects while maintaining glycemic control and preventing unfavorable complications.

Blood glucose is unlikely to be a prognostic biomarker in acute colitis with systemic inflammatory response syndrome in Thoroughbred racehorses

Although hyperglycemia at admission with colic has been reported to have a poor prognosis, there is no report specifically about acute colitis with systemic inflammatory response syndrome (SIRS) in horses. In this study, we measured blood glucose (Glu), insulin (Ins), and cortisol (Cor) levels in 17 Thoroughbred racehorses diagnosed as having acute colitis with SIRS, and examined the relationship between time-dependent changes in Glu, Ins, and Cor and prognosis. Glu levels were high in 3 horses at admission, but thereafter no horses had persistently high Glu levels. There was no significant difference in Glu, Ins, and Cor levels within 72 hr between surviving and non-surviving horses. In conclusion, the Glu level is unlikely to be a useful prognostic biomarker in acute colitis with SIRS.

Computerised insulin dosing calculators for the management of continuous insulin infusions after cardiac surgery: A systematic review and meta-analysis

OBJECTIVES

To investigate the effectiveness of computerised insulin dosing calculators for the management of continuous insulin infusions in adult patients who underwent cardiac surgery.

METHOD

A systematic review was conducted. The CINAHL, MEDLINE and Cochrane databases were searched for primary studies that compared a computerised insulin dosing calculator to a paper protocol. The main outcome measures were mean Blood Glucose Level (BGL), time to achieve BGL target range, time spent within BGL target range, the incidence of hyperglycaemia and the incidence of hypoglycaemia.

RESULTS

Five studies were included in the final review. Pooled data demonstrated significant improvements in mean BGL (MD -14.24, 95% CI -26.93 to -1.55), p=0.03 and significantly lower rates of hypoglycaemia (OR 0.038, 95% CI: 0.16-0.90), p=0.03 amongst the computer calculator groups in comparison to the paper protocol groups. No significant difference in the incidence of severe hypoglycaemia was demonstrated (OR 0.21, 95% CI 0.02-1.79), p=0.15. No difference was found in time (hours) to reach target blood glucose range (MD -1.47, 95% CI -3.75 to 0.81), p=0.21.

CONCLUSION

There is some evidence to support the use of computerised insulin dosing calculators for insulin infusion management within critical care environments.

Impact of early mobilization on glycemic control and ICU-acquired weakness in critically ill patients who are mechanically ventilated

BACKGROUND

ICU-acquired weakness (ICU-AW) has immediate and long-term consequences for critically ill patients. Strategies for the prevention of weakness include modification of known risk factors, such as hyperglycemia and immobility. Intensive insulin therapy (IIT) has been proposed to prevent critical illness polyneuropathy. However, the effect of insulin and early mobilization on clinically apparent weakness is not well known.

METHODS

This is a secondary analysis of all patients with mechanical ventilation (N = 104) previously enrolled in a randomized controlled trial of early occupational and physical therapy vs conventional therapy, which evaluated the end point of functional independence. Every patient had IIT and blinded muscle strength testing on hospital discharge to determine the incidence of clinically apparent weakness. The effects of insulin dose and early mobilization on the incidence of ICU-AW were assessed.

RESULTS

On logistic regression analyses, early mobilization and increasing insulin dose prevented the incidence of ICU-AW (OR, 0.18, P = .001; OR, 0.001, P = .011; respectively) independent of known risk factors for weakness. Early mobilization also significantly reduced insulin requirements to achieve similar glycemic goals as compared with control patients (0.07 units/kg/d vs 0.2 units/kg/d, P < .001).

CONCLUSIONS

The duel effect of early mobilization in reducing clinically relevant ICU-AW and promoting euglycemia suggests its potential usefulness as an alternative to IIT.

Cardiac arrhythmias and electrolyte disturbances in colic horses

BACKGROUND

Despite increased focus on cardiac arrhythmias in horses, the nature and prevalence is still poorly described. Case reports suggest that arrhythmias occurring secondary to systemic disease are seen more commonly in the clinic than arrhythmias caused by cardiac disease. The aim of this study was to investigate the prevalence of arrhythmias in colic horses referred for hospital treatment. Associations between electrolyte disturbances and arrhythmias were also investigated.

RESULTS

Heart rate was 37.4 ± 3.7 bpm in the control group, and 51.6 ± 11.8 bpm, in the colic group, which was significantly different (P < 0.0001). AV blocks and SVPCs were found in both groups, however only colic horses showed VPCs. No significant difference between the two groups was found for AV blocks, SVPCs, and VPCs (P = 0.08 - 0.76). The mean levels of potassium, sodium, ionized calcium, and chloride were significantly lower in the colic group compared to the control group at admission. Mean levels of glucose and L-lactate were significantly elevated in the colic group (P < 0.05).

CONCLUSIONS

This study describes prevalence of cardiac arrhythmias and electrolytes concentrations in colic horses compared to healthy controls. Although we only observed VPCs in the colic horses, no significant differences between colic horses and controls were found. Despite the colic horses having electrolyte changes at admission no correlation was found between the electrolyte disturbances and cardiac arrhythmias. Although no clear conclusions can be drawn from the present study, the results indicate that relatively mild colic per se is not pro-arrhythmogenic, whereas severe colic probably are more likely to result in ventricular arrhythmia.

Determination of burn patient outcome by large-scale quantitative discovery proteomics

OBJECTIVES

Emerging proteomics techniques can be used to establish proteomic outcome signatures and to identify candidate biomarkers for survival following traumatic injury. We applied high-resolution liquid chromatography-mass spectrometry and multiplex cytokine analysis to profile the plasma proteome of survivors and nonsurvivors of massive burn injury to determine the proteomic survival signature following a major burn injury.

DESIGN

Proteomic discovery study.

SETTING

Five burn hospitals across the United States.

PATIENTS

Thirty-two burn patients (16 nonsurvivors and 16 survivors), 19-89 years old, were admitted within 96 hours of injury to the participating hospitals with burns covering more than 20% of the total body surface area and required at least one surgical intervention.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We found differences in circulating levels of 43 proteins involved in the acute-phase response, hepatic signaling, the complement cascade, inflammation, and insulin resistance. Thirty-two of the proteins identified were not previously known to play a role in the response to burn. Interleukin-4, interleukin-8, granulocyte macrophage colony-stimulating factor, monocyte chemotactic protein-1, and β2-microglobulin correlated well with survival and may serve as clinical biomarkers.

CONCLUSIONS

These results demonstrate the utility of these techniques for establishing proteomic survival signatures and for use as a discovery tool to identify candidate biomarkers for survival. This is the first clinical application of a high-throughput, large-scale liquid chromatography-mass spectrometry-based quantitative plasma proteomic approach for biomarker discovery for the prediction of patient outcome following burn, trauma, or critical illness.

Trauma and aggressive homeostasis management

Homeostasis refers to the capacity of the human body to maintain a stable constant state by means of continuous dynamic equilibrium adjustments controlled by a medley of interconnected regulatory mechanisms. Patients who sustain tissue injury, such as trauma or surgery, undergo a well-understood reproducible metabolic and neuroendocrine stress response. This review discusses 3 issues that concern homeostasis in the acute care of trauma patients directly related to the stress response: hyperglycemia, lactic acidosis, and hypothermia. There is significant reason to question the "conventional wisdom" relating to current approaches to restoring homeostasis in critically ill and trauma patients.

What, how, and how much should patients with burns be fed?

The hypermetabolic response to severe burn injury is characterized by hyperdynamic circulation and profound metabolic, physiologic, catabolic, and immune system derangements. Failure to satisfy overwhelming energy and protein requirements after, and during, severe burn injury results in multiorgan dysfunction, increased susceptibility to infection, and death. Attenuation of the hypermetabolic response by various pharmacologic modalities is emerging as an essential component of the management of patients with severe burn injury. This review focuses on the more recent advances in therapeutic strategies to attenuate the hypermetabolic response and its postburn-associated insulin resistance.

Adrenocortical insufficiency in horses and foals

The adrenal cortices produce various steroid hormones that play vital roles in several physiologic processes. Although permanent adrenocortical insufficiency is rare in all species, emerging evidence in both human and equine medicine suggests that transient reversible adrenocortical dysfunction resulting in cortisol insufficiency frequently develops during critical illness. This syndrome is termed relative adrenal insufficiency (RAI) or critical illness-related corticosteroid insufficiency (CIRCI) and can contribute substantially to morbidity and mortality associated with the primary disease. This review discusses the mechanisms, diagnosis, and clinical consequences of adrenocortical insufficiency, with particular focus on the current understanding of RAI/CIRCI in horses and foals.

Burns: where are we standing with propranolol, oxandrolone, recombinant human growth hormone, and the new incretin analogs?

PURPOSE OF REVIEW

The hypermetabolic response in critically ill patients is characterized by hyperdynamic circulatory, physiologic, catabolic and immune system responses. Failure to satisfy overwhelming energy and protein requirements after, and during critical illness, results in multiorgan dysfunction, increased susceptibility to infection, and death. Attenuation of the hypermetabolic response by various pharmacologic modalities is emerging as an essential component of the management of severe burn patients. This review focuses on the more recent advances in therapeutic strategies to attenuate the hypermetabolic response and its associated insulin resistance postburn.

RECENT FINDINGS

At present, beta-adrenergic blockade with propranolol represents probably the most efficacious anticatabolic therapy in the treatment of burns. Other pharmacological strategies include growth hormone, insulin-like growth factor, oxandrolone and intensive insulin therapy.

SUMMARY

Novel approaches to the management of critical illness by judicious glucose control and the use of pharmacologic modulators to the hypercatabolic response to critical illness have emerged. Investigation of alternative strategies, including the use of metformin, glucagon-like-peptide-1 and the PPAR-γ agonists are under current investigation.

Acute glucose dysmetabolism in the elderly with ST elevation myocardial infarction submitted to mechanical revascularization

Though age is a predictor of adverse events after acute coronary syndrome, including in-hospital and post-hospital mortality rates, elderly patients are under-represented in randomized trials evaluating strategies of early coronary revascularization in acute myocardial infarction. Several factors can account for the unfavorable outcome of the elderly, comprising increased glucose values. Diabetes is more common in the elderly patients with acute myocardial infarction in respect to younger patients and elevated glucose, though common, are rarely treated and associated with increased mortality, particularly in those without recognized diabetes. Age itself is thought to affect the acute glucose response to stress. Human aging is associated with impaired β-cell sensitivity to glucose and impaired β-cell compensation to insulin resistance and older people exhibit an impaired glucose response after injury characterized by a more marked increases in endogenous glucose production. In the early phase of ST elevation myocardial infarction (STEMI), the acute glucose response to stress comprises not only hyperglycemia but also insulin-resistance (assessed by the Homeostatic Model Assessment). Recently it has been documented in 346 STEMI patients submitted to mechanical revascularization that the acute glucose response to myocardial injury differs in respect to age, since older patients showed the highest glucose levels and the poorest glycemic control during ICCU stay in the lack of differences in insulin resistance incidence. Taking into account that aging impairs the acute glucose response to stress in elderly STEMI patients, further studies are needed to establish whether a different (more aggressive) therapeutic regime is needed in this subgroup of patients at higher risk.

Association of adiponectin levels and insulin demand in critically ill patients

PURPOSE

Intensive care unit patients usually have a deregulated glucose homeostasis and present with hyperglycemia and hyperinsulinemia, suggesting overall insulin resistance. Adiponectin has significant anti-inflammatory and insulin-sensitizing effects and is diminished in morbidly obese and in critically ill patients. Reduced adiponectin could contribute to insulin resistance in these patients. We examined how far insulin demand in critically ill patients is correlated with patient adiponectin levels.

PATIENTS AND METHODS

Adiponectin, resistin, leptin, insulin demand, minimal and maximal blood sugar levels, epinephrine, and hydrocortisone demand were measured 1 day after diagnosis of severe sepsis or septic shock in 25 patients (8 female, 17 male; median age 65 years; range: 31 to 87 years).

RESULTS

INSULIN DEMAND (RANGE: 0-8 IU/h; median 3.5 IU) was positively correlated with serum adiponectin levels (median: 10.1 μg/mL; range: 2.9-47.6 μg/mL; r = +0.56, P < 0.01). There was no significant correlation between insulin demand and leptin serum levels (median: 18.1 ng/mL; range: 0.3-80.7 ng/mL; r = +0.29, P = 0.08) or resistin serum levels (median: 103.9 ng/mL; range: 14.7-352.3 ng/mL; r = +0.13, P = 0.27). Epinephrine demand (median: 0.08 μg/kg*min; range: 0.02-0.63 μg/kg*min) was negatively correlated with male adiponectin levels (r = -0.58; P < 0.01; females: r = -0.36; P = 0.19) and positively correlated with resistin levels (r = 0.43; P = 0.02). Patient body mass index (median 26 kg/m(2); range: 18-37) was positively correlated with serum leptin (r = 0.60; P < 0.01) but was not correlated with insulin demand (r = 0.19; P = 0.19), or adiponectin (females: r = -0.37, P = 0.18; males: r = -0.16, P = 0.27), or resistin levels (r = +0.17; P = 0.21).

CONCLUSION

Adiponectin levels and insulin demand were positively correlated during sepsis. Adiponectin levels were negatively correlated with epinephrine demand in male patients and epinephrine demand was positively correlated with resistin levels, which might have increased insulin resistance. The relationship between adiponectin and insulin action in humans is more complex than often suggested.

Beta-cell dysfunction and insulin resistance after subarachnoid haemorrhage

BACKGROUND

Hyperglycaemia is a common finding and an independent risk factor for increased morbidity and mortality in aneurysmal subarachnoid haemorrhage (SAH). Although in these patients hyperglycaemia is commonly ascribed to insulin resistance, there is little understanding of underlying mechanisms.

AIMS

To prospectively study temporal disturbances of glucose metabolism after aneurysmal SAH in patients without known abnormalities of glucose metabolism and to explore possible correlations with markers of stress.

METHODS

In consecutive aneurysmal SAH patients not subjected to insulin therapy, in-hospital and follow-up oral glucose tolerance tests (OGTTs) and assessments of insulin resistance, pancreatic β-cell function, free fatty acids (FFA) and cortisol were performed and compared with reference values.

RESULTS

We included 13 patients. In the first 2 weeks of admission, median fasting glucose and FFA levels were elevated while insulin levels were not. OGTTs were indicative of glucose intolerance in all patients at days 3 and 7, while on follow-up 1 patient had glucose intolerance and all patients had normal fasting glucose levels. Pancreatic β-cell function was impaired throughout the first week and insulin resistance from day 4 to 10. Levels of cortisol correlated with higher fasting glucose and increased FFA. FFA in turn correlated with pancreatic β-cell dysfunction.

CONCLUSIONS

Aneurysmal SAH patients have transient abnormalities of glucose metabolism. During the first week, it appears to result predominantly from transient pancreatic β-cell dysfunction, in combination with insulin resistance.

Alterations in adipose tissue during critical illness: An adaptive and protective response?

RATIONALE

Critical illness is characterized by lean tissue wasting, whereas adipose tissue is preserved. Overweight and obese critically ill patients may have a lower risk of death than lean patients, suggestive of a protective role for adipose tissue during illness.

OBJECTIVES

To investigate whether adipose tissue could protectively respond to critical illness by storing potentially toxic metabolites, such as excess circulating glucose and triglycerides.

METHODS

We studied adipose tissue morphology and metabolic activity markers in postmortem biopsies of 61 critically ill patients and 20 matched control subjects. Adipose morphology was also studied in in vivo biopsies of 27 patients and in a rabbit model of critical illness (n = 22).

MEASUREMENTS AND MAIN RESULTS

Adipose tissue from critically ill patients revealed a higher number and a smaller size of adipocytes and increased preadipocyte marker levels as compared with control subjects. Virtually all adipose biopsies from critically ill patients displayed positive macrophage staining. The animal model demonstrated similar changes. Glucose transporter levels and glucose content were increased. Glucokinase expression was up-regulated, whereas glycogen and glucose-6-phosphate levels were low. Acetyl CoA carboxylase protein and fatty acid synthase activity were increased. Hormone-sensitive lipase activity was not altered, whereas lipoprotein lipase activity was increased. A substantially increased AMP-activated protein kinase activity may play a crucial role.

CONCLUSIONS

Postmortem adipose tissue biopsies from critically ill patients displayed a larger number of small adipocytes in response to critical illness, revealing an increased ability to take up circulating glucose and triglycerides. Similar morphologic changes were present in vivo. Such changes may render adipose tissue biologically active as a functional storage depot for potentially toxic metabolites, thereby contributing to survival.

Implementation of tight glucose control for critically ill surgical patients: a process improvement analysis

BACKGROUND

Tight glucose control has been advocated as a method to improve outcomes of surgical critical care. However, continuous infusion of insulin has potential morbidity (e.g., neurologic consequences of hypoglycemia), and it remains unclear to what degree the glucose concentration must be controlled. We examined our performance in instituting a protocol for tight glucose control in our surgical intensive care unit (ICU).

METHODS

Prospective study of 220 consecutive patients (February, 2003-March, 2006) who received an infusion of insulin for glucose control for >24 h by protocol. Data collected included age, acuity (Acute Physiology and Chronic Health Evaluation [APACHE] III) score, sex, history of diabetes mellitus, organ dysfunction (Marshall), and death or survival. Infusion-related data included initial glucose concentration, time to glucose <120 mg/dL, h/day of glucose <110 mg/dL and <140 mg/dL, duration of infusion (days), insulin units/day, year of therapy, and complications. Analysis was performed by chi(2), analysis of variance, and logistic regression, with p < 0.05 considered significant.

RESULTS

Insulin drips were required by 10.2% of patients (287/2,804); 29 of these (10.1%) had diabetes mellitus. The mean APACHE III score for the treated patients was 77 +/- 2 (standard deviation), and the mortality rate was 24%. Hypoglycemia (<60 mg/dL) occurred in 4.2% of patients. The trigger insulin concentration decreased over time (2003 vs. 2005) from 249 +/- 14 to 160 +/- 5 mg/dL, and the h/day of glucose <140 increased from 11 +/- 1 to 16 +/- 1. However, age, acuity, APACHE III, days of insulin, time to achieve glucose <120, h/day of glucose <110, and mortality rate were unchanged. By logistic regression, only the year of treatment (odds ratio [OR] 1.871; 95% confidence interval [CI] 1.177, 2.972; p = 0.008] predicted success in controlling the blood glucose concentration to <140 mg/dL; age, illness severity, diabetes history, and trigger glucose concentration [OR 0.996; 95% CI 0.992, 1.001; p = 0.11] did not.

CONCLUSIONS

Success in implementing tight glucose control was modest, albeit improving, despite a specific protocol for administration. No medical reason could be identified for inability to achieve tight glucose control; therefore, successful implementation must be volitional. Education, particularly regarding hypoglycemia, and possible refinement of our protocol may improve our ability to control blood glucose in our ICU.

Tight glycemic control and point-of-care testing

Until recently, inpatient glycemic management focused solely on the diabetic patient with few reported studies that discussed hyperglycemic management of the nondiabetic patient. For the last 35 years, the prevailing notion was that hyperglycemia in the acutely ill nondiabetic inpatient was a consequence of illnesses as well as a marker of its severity. It was also thought to be an adaptive response to injury necessary for survival and not necessarily a prognostic indicator of morbidity or mortality. In this article, we discuss the current school of thought regarding prognostic implications of nondiabetic inpatient hyperglycemia, its management (tight glycemic control), and the relationship of point-of-care testing to tight glycemic control.

Glucose dysmetabolism and prognosis in critical illness

Acute hyperglycemia frequently present in stress conditions, has long been generally accepted as normal, and not thought to be a cause for concern since a moderate hyperglycemia in critically ill adult patients has been thought to be beneficial during the "fight or flight" response to ensure a supply of glucose as a source of energy to organs that do not require insulin for glucose uptake (i.e., the brain and the immune system). However, an increasing body of evidence associates the upon-admission degree and duration of hyperglycemia during critical illness with an adverse outcome. Hyperglycemia should be regarded as a part of the systemic and complex metabolic derangements observed in critical illness in response to stress and inflammation, which can lead, independent of initial disease, to multiorgan dysfunction and death. A tight glycemic control should be constantly pursued and achieved by insulin infusion bearing in mind that the therapeutic target is fighting the systemic inflammatory response and not merely the glucose plasma levels.

Clinical review: Critical care management of spontaneous intracerebral hemorrhage

Intracerebral hemorrhage is by far the most destructive form of stroke. The clinical presentation is characterized by a rapidly deteriorating neurological exam coupled with signs and symptoms of elevated intracranial pressure. The diagnosis is easily established by the use of computed tomography or magnetic resonance imaging. Ventilatory support, blood pressure control, reversal of any preexisting coagulopathy, intracranial pressure monitoring, osmotherapy, fever control, seizure prophylaxis, treatment of hyerglycemia, and nutritional supplementation are the cornerstones of supportive care in the intensive care unit. Dexamethasone and other glucocorticoids should be avoided. Ventricular drainage should be performed urgently in all stuporous or comatose patients with intraventricular blood and acute hydrocephalus. Emergent surgical evacuation or hemicraniectomy should be considered for patients with large (>3 cm) cerebellar hemorrhages, and in those with large lobar hemorrhages, significant mass effect, and a deteriorating neurological exam. Apart from management in a specialized stroke or neurological intensive care unit, no specific medical therapies have been shown to consistently improve outcome after intracerebral hemorrhage.

Blood glucose concentrations in critically ill neonatal foals

REASONS FOR PERFORMING STUDY

Critical illness is associated with hyperglycemia in humans, and a greater degree and duration of hyperglycemia is associated with nonsurvival. Hypoglycemia is also seen in critically ill humans, and is associated with nonsurvival. This might also be true in the critically ill foal.

OBJECTIVES

To investigate the association of blood glucose concentrations with survival, sepsis, and the systemic inflammatory response syndrome (SIRS).

METHODS

Blood glucose concentrations at admission (515 foals) and 24 hours (159 foals), 36 hours (95), 48 hours (82), and 60 hours (45) after admission were analyzed. Logistic regression analyses were performed to investigate the association of glucose concentrations with survival, sepsis, a positive blood culture, or SIRS.

RESULTS

29.1% of foals had blood glucose concentrations within the reference range (76-131 mg/dL) at admission, 36.5% were hyperglycemic, and 34.4% were hypoglycaemic. Foals that did not survive to hospital discharge had lower mean blood glucose concentrations at admission, as well as higher maximum and lower minimum blood glucose concentrations in the 1st 24 hours of hospitalization, and higher blood glucose at 24 and 36 hours. Foals with blood glucose concentrations <2.8 mmol/L (50 mg/dL) or >10 mmol/L (180 mg/dL) at admission were less likely to survive. Hypoglycemia at admission was associated with sepsis, a positive blood culture, and SIRS.

CONCLUSIONS AND POTENTIAL RELEVANCE

Derangements of blood glucose concentration are common in critically ill foals. Controlling blood glucose concentrations may therefore be beneficial in the critically ill neonatal foal, and this warrants further investigation.

Comparison of the Accu-Chek Aviva point-of-care glucometer with blood gas and laboratory methods of analysis of glucose measurement in equine emergency patients

BACKGROUND

More information is needed regarding accuracy of commonly used methods of glucose measurement in the critically ill horse.

HYPOTHESIS

Glucometry will have good agreement with a laboratory standard. Glucometry with plasma will have better agreement than when performed with whole blood.

ANIMALS

Fifty sequentially admitted equine emergency patients, aged >1year.

METHODS

Venous blood was collected at admission and immediately analyzed by point-of-care glucometry on both whole blood (POC/WB) and plasma (POC/PL), a multielectrode blood gas analyzer with whole blood (BLG), and a standard laboratory method with plasma (CHEM). Paired data were compared using Lin's concordance correlation, Pearson's correlation, and robust regression. Bias and limits of agreement were tested by the Bland-Altman technique. Bivariate regression analysis was used to explore confounding factors.

RESULTS

Concordance was significant for all comparisons, and was strongest for CHEM-POC/PL (0.977) and weakest for POC/WB-POC/PL (0.668). Pearson's correlation was excellent for all comparisons except those with POC/WB. All comparisons had excellent robust regression coefficients except those with POC/WB.

CONCLUSIONS AND CLINICAL IMPORTANCE

POC glucometry with plasma had excellent agreement with a laboratory standard, as did blood gas analysis. POC glucometry with whole blood correlated poorly with a laboratory standard. These differences may be clinically important, and could affect decisions based on glucose concentrations.

Insulin resistance following cardiothoracic surgery in patients with and without a preoperative diagnosis of type 2 diabetes during treatment with intravenous insulin therapy for postoperative hyperglycemia

OBJECTIVE

To assess insulin resistance postoperatively in patients with (DM) and without (nonDM) a prior diagnosis of diabetes.

RESEARCH DESIGN AND METHODS

Following cardiac surgery, 122 nonDM and 33 DM were treated with insulin infusions to obtain glucose levels <110 mg dl(-1). Glucose levels, insulin infusion rates, and insulin infusion rate/glucose ratios were calculated to assess insulin resistance.

RESULTS

The average blood glucose at insulin drip initiation (209 vs. 173 mg dl(-1); P<.001) and during the first 12 h (146 vs. 135 mg dl(-1); P<.05) was higher in DM, but during Hours 12-24 glucose levels were not different. The peak (5.7 vs. 4.1 U h(-1); P<.001) and average insulin drip rates (3.7 vs. 2.9 U h(-1); P<.01) were higher in DM. Insulin resistance (insulin drip rate/glucose ratio) was higher in DM during Hours 1-12 (0.029 vs. 0.022 U h(-1) mg(-1) dl(-1); P<.001), but not during Hours 12-24 (P=.57). To eliminate glucotoxicity as a cause of the insulin resistance, 23 DM patients were pair matched with 23 nonDM patients based first on glucose levels at drip initiation then by body mass index (BMI) and then catecholamine use to maintain blood pressure. The average blood glucose levels, insulin drip rates, and insulin resistance ratios were not significantly different between the pair-matched groups at all time points.

CONCLUSIONS

When matched for initial glucose levels, insulin resistance is not different between DM and nonDM following cardiac surgery, likely due to the overwhelming stress response. Insulin drip protocols used postoperatively do not have to be modified for those with a prior diagnosis of diabetes.

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.

[Severe accidental hypothermia with cardiac arrest and extracorporeal rewarming. A case report of a 2-year-old child]

In patients with severe hypothermia and cardiac arrest, active rewarming is recommended by extracorporeal circulation with cardiopulmonary bypass. The current guidelines for resuscitation of the European Resuscitation Council now include the recommendation regarding patients with hypothermia remaining comatose after initial resuscitation to accomplish an active rewarming only up to a temperature of 32-34 degrees C and to maintain a mild hypothermia for 12-24 h. We report the case of a 2-year-old boy who suffered from severe hypothermia after falling into ice-cold water. On discovery cardiac arrest with asystole was present and the first measured temperature was 23.8 degrees C. Resuscitation led to restoration of spontaneous circulation. The patient was rewarmed by extracorporeal circulation with cardiopulmonary bypass to 33 degrees C then mild hypothermia was maintained for a further 12 h. On the third day after the accident the patient was extubated and after a further 9 days was discharged without any sequelae.

Trauma and aggressive homeostasis management

Three important issues concerning homeostasis in the acute care of trauma patients that are related directly to the stress response are hyperglycemia, lactic acidosis, and hypothermia. Recently, there has been a resurgence of interest in investigating the effects of aggressive thermal and glucose concentration and volume resuscitation on outcomes in critically ill and trauma patients. Significant reason exists to question the "conventional wisdom" relating to current approaches to restoring homeostasis in this patient population.

Nutrition support and the chronic critical illness syndrome

Critical illness can be viewed as consisting of 4 distinct stages: (1) acute critical illness (ACI), (2) prolonged acute critical illness, (3) chronic critical illness, and (4) recovery. ACI represents the evolutionarily programmed response to a stressor. In ACI, substrate is shunted away from anabolism and toward vital organ support and inflammatory proteins. Nutrition support in this stage is unproven and may ultimately prove detrimental. As critical illness progresses, there is no evolutionary precedent, and man owes his life to modern critical care medicine. It is at this point that nutrition and metabolic support become integral to the care of the patient. This paper (1) delineates and develops the 4 stages of critical illness using current evidence, clinical experience, and new hypotheses; (2) defines the chronic critical illness syndrome (CCIS); and (3) details an approach to the metabolic and nutrition support of the chronically critically ill patient using the metabolic model of critical illness as a guide. It is our hope that this clinical model can generate testable hypotheses that can improve the outcome of this unique population of patients.

The dynamic neuroendocrine response to critical illness

The severity of striking alterations in the hypothalamic-anterior pituitary-peripheral hormone axes, which are the hallmark of severity of critical illness, is associated with a high risk for morbidity and mortality. Most attempts to correct the hormone balance are ineffective or harmful because of lack of pathophysiologic understanding. Extensive research has provided more insight in the biphasic neuroendocrine response to critical illness: the acute phase is characterized by an actively secreting pituitary but low peripheral effector hormone levels. In contrast, in prolonged critical illness, uniform suppression of the neuroendocrine axes, predominantly of hypothalamic origin, contributes to low serum levels of the respective target-organ hormones.

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.