Epidural Anesthesia and Analgesia Decrease the Postoperative Incidence of Insulin Resistance in Preoperative Insulin-Resistant Subjects Only

The Quality of Preoperative Glycemic Control Predicts Insulin Sensitivity During Major Upper Abdominal Surgery: A Case-Control Study

Objective

To examine the association of the quality of preoperative glycemic control and insulin sensitivity during major upper abdominal surgery.

Background

In cardiac surgery, glycated hemoglobin A1c (HbA1c), an indicator of glycemic control during the preceding 3 months, correlated with intraoperative insulin sensitivity. Furthermore, insulin resistance showed a significant association with adverse clinical outcomes.

Methods

This study is a post hoc exploratory analysis of a randomized controlled trial in patients undergoing elective hepatectomy and receiving the hyperinsulinemic-normoglycemic clamp (HNC) as a potential intervention to reduce surgical site infections (ClinicalTrials.gov NCT01528189). Immediately before skin incision, the HNC was initiated by infusing insulin at the rate of 2 mU/kg/min. Dextrose was administered at rates titrated to maintain normoglycemia (4.0-6.0 mmol/L). The average of 3 consecutive dextrose infusion rates during steady state was used as a measure of insulin sensitivity. Primary outcome was the relationship between preoperative HbA1c and insulin sensitivity during surgery. Secondary outcomes were the associations of insulin sensitivity with the patient's body mass index (BMI) and postoperative morbidity.

Results

Thirty-four patients were studied. HbA1c (Y = -0.52X + 4.8, P < 0.001, R2 = 0.29), BMI (Y = -0.12X + 5.0, P < 0.001, R2 = 0.43) showed negative correlations with insulin sensitivity. The odds ratio of postoperative complications within 30 days of surgery for every increase in insulin sensitivity by 1 mg/kg/min was 0.22 (95% confidential interval, 0.06-0.59; P = 0.009).

Conclusions

We demonstrate significant associations of the quality of preoperative glycemic control and body mass index with insulin sensitivity during hepatectomy. The degree of insulin resistance correlated with postoperative morbidity.

Effect of Intraoperative Magnesium Sulfate Administration on Blood Glucose Control following Total Joint Arthroplasty in Patients with Diabetes

Magnesium deficiency, which is known to be highly prevalent among patients with diabetes, has been associated with insulin resistance and poor glucose control. Here, we aimed to investigate the effects of intraoperative magnesium administration on postoperative glucose control in patients with diabetes. We retrospectively reviewed the medical records of patients with type 2 diabetes who had undergone total joint arthroplasty at a tertiary hospital, where intraoperative magnesium sulfate injections were frequently performed for postoperative analgesia. The patients were grouped based on whether treated with magnesium or not (magnesium vs. control groups). We investigated postoperative blood glucose levels and sliding scale insulin requirements. After propensity matching, 170 patients were allotted to each group. Both the mean glucose level and the incidence of a mean glucose level of >200mg/dL were significantly lower in the magnesium group than in the control group (p = 0.040 and 0.013, respectively). There was also a lower insulin requirement in the magnesium group (p = 0.043). Multivariate logistic regression revealed that magnesium treatment was significantly related to a less frequent incidence of a mean blood glucose level of >200 mg/dL (p = 0.047). This study demonstrated that magnesium sulfate infusion was associated with an improved postoperative blood glucose profile in patients with diabetes.

The effects of body mass index on insulin resistance in patients undergoing total hip arthroplasty: a pilot study

PURPOSE

We aimed to examine the effects of body mass index (BMI) on insulin resistance (IR), glycaemic control and adverse events in patients undergoing total hip arthroplasty (THA).

METHODS

A total of 118 patients undergoing THA were enrolled in this prospective cohort study and divided into two groups based on their BMI: Group A (n = 50, 18.5 ≤ BMI < 24 kg/m²) and Group B (n = 68, BMI ≥ 24 kg/m²). IR was calculated using Homeostasis Model Assessment 2 (HOMA2). Insulin resistance indicators, fasting plasma glucose (FPG), inflammatory markers, blood loss, length of stay and complications were compared between the two groups.

RESULTS

Multivariate analysis using generalized estimating equations revealed that BMI and surgery stress were risk factors for IR (P < 0.001). These two factors exhibited significant interactions for HOMA2-IR on post-operative day one (Exp (B) = 1.880, P = 0.003), accompanied by a higher level of FPG (Group B versus Group A, P = 0.004). Furthermore, subgroup analysis based on the IR value demonstrated that patients in Group B with a HOMA2-IR greater than 2.25 after surgery were at increased risk of wound complications (P = 0.045). Similarly, our results showed that the rate of post-operative hyperglycaemia was notably higher in Group B than in Group A (P = 0.013).

CONCLUSION

Patients with high BMI may experience significantly elevated IR and increased risk of hyperglycaemia and wound complications after THA. Therefore, routine glycaemia monitoring should be suggested for those patients during peri-operative period to optimize surgical stress management.

Effect of multimodal analgesia on perioperative insulin resistance in patients with colon cancer

Background

High risk of post-surgery complications have always been related with uncontrolled blood glucose, while the relationship between blood glucose and analgesia has not been compared on radical resection of colon cancer. The aim of this study is to investigate the effects of multimodal analgesia on perioperative insulin resistance in patients undergoing radical resection of colon cancer.

Methods

Sixty patients with colon cancer scheduled for radical resection surgery were equally divided into two groups randomly, the control group (TAP group) received general anesthesia and the transversus abdominis plane block analgesia, and the experimental group (GEA group) received extra epidural anesthesia. The analgesic efficacy was evaluated with visual analog scale (VAS). Insulin resistance indicators like fasting plasma glucose (FPG), resistin (RESIS), fasting insulin (FINS), homeostasis model assessment (HOMA) levels, and inflammation indicator interleukin-6 (IL-6) were evaluated during the surgery.

Results

IL-6 increase was significant in the TAP group than that in GEA group (P < 0.01). The insulin resistance increased significantly in TAP group than that in GEA group including HOMA (P < 0.05) and FPG (P < 0.05). There was no significant difference in RESIS levels and VAS scores in the two groups.

Conclusion

Epidural anesthesia leads to less inflammation in radical resection of colon cancer and the insulin level and insulin resistance increased after the surgeries based on FINS and HOMA..

Association Between Intercostal Nerve Block and Postoperative Glycemic Control in Patients With Diabetes Undergoing Video-Assisted Thoracoscopic Pulmonary Resection: A Retrospective Study

OBJECTIVES

The present study was performed to investigate the possible association between intercostal nerve block (INB) and postoperative glycemic control in patients with diabetes undergoing video-assisted thoracoscopic pulmonary resection.

DESIGN

A retrospective study.

SETTING

Single-center tertiary academic hospital.

PARTICIPANTS

Patients with diabetes, ages 18 to 79 years, who had undergone elective video-assisted thoracoscopic pulmonary resection (segmentectomy or lobectomy) from January 1, 2015, to December 31, 2018.

INTERVENTIONS

Postoperative blood glucose levels and insulin dosage were extracted from the record.

MEASUREMENTS AND MAIN RESULTS

Patients with diabetes who received INB before closure of surgical incisions were compared with those who did not receive INB. The primary outcome was the daily blood glucose (BG) level. Univariate analyses and multivariate regression analysis were performed to explore risk factors of hyperglycemia within 48 hours after the surgery. Baseline characteristics were comparable between the two groups. Patients who received INB had a lower maximum BG level and amplitude of glycemic excursion from zero-to-24 hours after surgery (p = 0.007 and p = 0.041, respectively) and lower maximum and minimum BG levels from 24-to-48 hours after surgery (p = 0.023 and p = 0.006, respectively). Meanwhile, the daily insulin dose increment during zero-to-24 hours and 24-to-48 hours after surgery decreased (p = 0.010 and p = 0.003, respectively), the white blood cell counts within 48 hours after surgery were lower (p = 0.021), and the length of postoperative stay decreased in the INB group (p = 0.044). Multivariate regression analysis further confirmed that INB was an independent protective factor of postoperative hyperglycemia (Nagelkerke R² value 0.229; odds ratio 0.298; 95% confidence interval 0.099-0.901; p = 0.032).

CONCLUSION

INB, performed before closure of surgical incisions, was associated with improved glycemic control in patients with diabetes within 48 hours after video-assisted thoracoscopic pulmonary resection.

Postoperative adverse events in patients with diabetes undergoing orthopedic and general surgery

Factors that may result in the occurrence of adverse clinical events in diabetic patients during the postoperative period are not entirely clear. This study evaluated factors that may cause adverse events following elective orthopedic or general surgery.Patients with diabetes who underwent orthopedic or general surgery between January 2010 and October 2015 were retrospectively selected from the General Hospital of People's Liberation Army database. Factors associated with postoperative adverse events were analyzed using multivariable logistic regression.Among 1525 patients included, mean age was 63.5 ± 10.8 years and mean duration of diabetes was 8.8 ± 6.6 years. Among them, 49.9% underwent orthopedic surgery and 50.1% underwent general surgery. Postoperatively, 118 (7.7%) patients had adverse events, including delayed extubation (n = 43, 36.4%), circulatory disorder (n = 15, 12.7%), respiratory and circulatory abnormalities (n = 23, 19.5%), nonhealing of the incision (n = 11, 9.3%), infections at other sites (n = 15, 12.7%), other complications (n = 8, 6.8%), and death (n = 3, 2.5%). Multivariable regression analysis showed that age >65 years old [odds ratio (OR) = 2.23, 95% confidence interval (CI): 1.25-3.98], male sex (OR = 2.14, 95% CI: 1.24-3.38), postoperative peripheral blood glucose (OR = 1.13, 95% CI: 1.13-1.82), diabetic complications (OR = 2.41, 95% CI: 1.36-4.28), abnormal kidney function (OR = 2.73, 95% CI: 1.13-6.58) and general surgery (OR = 1.48, 95% CI: 1.11-5.26) were associated with the occurrence of postoperative adverse events.In patients with diabetes undergoing intermediate or major elective surgery, older age, male sex, high postoperative peripheral blood glucose, diabetic complications, abnormal kidney function, and general surgery type were associated with the occurrence of postoperative adverse events.

Perioperative insulin therapy

Surgical patients commonly develop hyperglycemia secondary to the neuroendocrine stress response. Insulin treatment of hyperglycemia is required to overcome the perioperative catabolic state and acute insulin resistance. Besides its metabolic actions on glucose metabolism, insulin also displays nonmetabolic physiological effects. Preoperative glycemic assessment, maintenance of normoglycemia, and avoidance of glucose variability are paramount to optimize surgical outcomes. This review discusses the basic physiology and effects of insulin as well as practical issues pertaining to its management during the perioperative period.

[Evaluation and perioperative management of patients with diabetes mellitus. A challenge for the anesthesiologist]

Diabetes mellitus (DM) is characterized by alteration in carbohydrate metabolism, leading to hyperglycemia and increased perioperative morbidity and mortality. It evolves with diverse and progressive physiological changes, and the anesthetic management requires attention regarding this disease interference in multiple organ systems and their respective complications. Patient's history, physical examination, and complementary exams are important in the preoperative management, particularly glycosylated hemoglobin (HbA1c), which has a strong predictive value for complications associated with diabetes. The goal of surgical planning is to reduce the fasting time and maintain the patient's routine. Patients with Type 1 DM must receive insulin (even during the preoperative fast) to meet the basal physiological demands and avoid ketoacidosis. Whereas patients with Type 2 DM treated with multiple injectable and/or oral drugs are susceptible to develop a hyperglycemic hyperosmolar state (HHS). Therefore, the management of hypoglycemic agents and different types of insulin is fundamental, as well as determining the surgical schedule and, consequently, the number of lost meals for dose adjustment and drug suspension. Current evidence suggests the safe target to maintain glycemic control in surgical patients, but does not conclude whether it should be obtained with either moderate or severe glycemic control.

Evaluation and perioperative management of patients with diabetes mellitus. A challenge for the anesthesiologist

Diabetes mellitus (DM) is characterized by alteration in carbohydrate metabolism, leading to hyperglycemia and increased perioperative morbidity and mortality. It evolves with diverse and progressive physiological changes, and the anesthetic management requires attention regarding this disease interference in multiple organ systems and their respective complications. Patient's history, physical examination, and complementary exams are important in the preoperative management, particularly glycosylated hemoglobin (HbA1c), which has a strong predictive value for complications associated with diabetes. The goal of surgical planning is to reduce the fasting time and maintain the patient's routine. Patients with Type 1 DM must receive insulin (even during the preoperative fast) to meet the basal physiological demands and avoid ketoacidosis. Whereas patients with Type 2 DM treated with multiple injectable and/or oral drugs are susceptible to develop a hyperglycemic hyperosmolar state (HHS). Therefore, the management of hypoglycemic agents and different types of insulin is fundamental, as well as determining the surgical schedule and, consequently, the number of lost meals for dose adjustment and drug suspension. Current evidence suggests the safe target to maintain glycemic control in surgical patients, but does not conclude whether it should be obtained with either moderate or severe glycemic control.

Stress Hyperglycemia During Surgery and Anesthesia: Pathogenesis and Clinical Implications

Numerous studies have demonstrated an association between hyperglycemia in the perioperative period and adverse clinical outcomes. Many patients who experience hyperglycemia while hospitalized do not have a known history of diabetes and experience a transient phenomenon often described as "stress hyperglycemia" (SH). We discuss the epidemiology and pathogenesis of SH as well as evidence to date regarding predisposing factors and outcomes. Further research is needed to identify the long-term sequelae of SH as well as perioperative measures that may modulate glucose elevations and optimal treatment strategies.

Promoting Perioperative Metabolic and Nutritional Care

Surgery represents a major stressor that disrupts homeostasis and can lead to loss of body cell mass. Integrated, multidisciplinary medical strategies, including enhanced recovery programs and perioperative nutrition support, can mitigate the surgically induced metabolic response, promoting optimal patient recovery following major surgery. Clinical therapies should identify those who are poorly nourished before surgery and aim to attenuate catabolism while preserving the processes that promote recovery and immunoprotection after surgery. This review will address the impact of surgery on intermediary metabolism and describe the clinical consequences that ensue. It will also focus on the role of perioperative nutrition, including preoperative nutrition risk, carbohydrate loading, and early initiation of oral feeding (centered on macronutrients) in modulating surgical stress, as well as highlight the contribution of the anesthesiologist to nutritional care. Emerging therapeutic concepts such as preoperative glycemic control and prehabilitation will be discussed.

Twenty-four hour hyperinsulinemic-euglycemic clamp improves postoperative nitrogen balance only in low insulin sensitivity patients following cardiac surgery

BACKGROUND

Critically ill patients often suffer from a protein catabolic state. The aim of this study was to demonstrate that nitrogen balance (NB) in cardiac patients admitted to the intensive care unit (ICU) is related to their insulin sensitivity level and that supraphysiologic doses of insulin can restore anabolism.

MATERIALS AND METHODS

Twenty-eight patients that were admitted to ICU in enteral and/or parenteral nutrition have been enrolled in this study. All patients received a standard nutrition protocol for at least 3 days before starting the study. These patients received either enteral or parenteral nutrition based on 1.4 kcal/kg/h and 1.1 g/kg/24 h of proteins. Participants were studied for three 24 h periods (P1 , P2 , and P3 ). Twenty-four hour NB was calculated from urinary urea nitrogen excretion, fixed protein and energy intake during each of the three periods (P1 , P2 , and P3 ). Simultaneous to P2, a 24 h hyperinsulinemic-euglycemic clamp (HEC) was performed to determine patients' insulin sensitivity (IS) or insulin resistance (IR), as well as the impact of high doses of insulin on NB.

RESULTS

Nitrogen balance remained consistently positive in the IS group regardless of the clamp. In IR patients, NB was negative before the clamp and became positive during P2 and P3 . Insulin sensitivity improved during the HEC in IR patients (P < 0.001).

CONCLUSIONS

A negative NB was found only in insulin resistant patients admitted to the ICU for more than 7 days. A 24-h period HEC improved NB in these patients.

Risk factors for perioperative hyperglycemia in primary hip and knee replacements

BACKGROUND AND PURPOSE

Perioperative hyperglycemia has been associated with adverse outcomes in several fields of surgery. In this observational study, we identified factors associated with an increased risk of hyperglycemia following hip and knee replacement.

PATIENTS AND METHODS

We prospectively monitored changes in glucose following primary hip and knee replacements in 191 patients with osteoarthritis. Possible associations of patient characteristics and operation-related factors with hyperglycemia (defined as glucose > 7.8 mmol/L in 2 consecutive measurements) and severe hyperglycemia (glucose > 10 mmol/L) were analyzed using binary logistic regression with adjustment for age, sex, operated joint, and anesthesiological risk score.

RESULTS

76 patients (40%) developed hyperglycemia, and 48 of them (25% of the whole cohort) had severe hyperglycemia. Glycemic responses were similar following hip replacement and knee replacement. Previously diagnosed diabetes was associated with an increased risk of hyperglycemia and severe hyperglycemia, compared to patients with normal glucose metabolism, whereas newly diagnosed diabetes and milder glucose metabolism disorders had no effect. In patients without previously diagnosed diabetes, increased values of preoperative glycosylated hemoglobin (HbA1c) and fasting glucose on the day of operation were associated with hyperglycemia. Higher anesthesiological risk score-but none of the operation-related factors analyzed-was associated with an increased risk of hyperglycemia.

INTERPRETATION

Perioperative hyperglycemia is common in primary hip and knee replacements. Previously diagnosed diabetes is the strongest risk factor for hyperglycemia. In patients with no history of diabetes, preoperative HbA1c and fasting glucose on the day of operation can be used to stratify the risk of hyperglycemia.

Investigation of Effects of Epidural Anaesthesia Combined with General Anaesthesia on the Stress Response in Patients Undergoing Hip and Knee Arthroplasty

OBJECTIVE

To investigate the effects of general anaesthesia and general+epidural anaesthesia on the stress response which was evaluated with the adrenocorticotrophic hormone (ACTH), cortisol, insulin, and glucose levels and the haemodynamic parameters.

METHODS

Forty two, American Society of Anesthesiologists physiologic status I-II, patients undergoing hip and knee arthroplasty were randomized into two groups; general anaesthesia (Group G) and general anaesthesia+epidural anaesthesia (Group E). Epidural anaesthesia: patients in Group E received epidural anaesthesia with 0.5% bupivacaine, a lumbar epidural catheter was placed and after achieving sensorial block at T10 dermatome, general anaesthesia was commenced. General anaesthesia was standardized in both groups. Further, plasma ACTH, cortisol, insulin and glucose levels were determined at preoperative=t1, after the surgical incision=t2, postoperative 2(nd) hour=t3 and postoperative 24(th) hour=t4. Perioperative heart rate, blood pressures, pain scores and morphine consumption were also determined.

RESULTS

ACTH levels were higher in Group G than Group E [Group G, t2: 71.4±39.9 pg mL(-1), t3: 578.6±566.1 pg mL(-1), Group E, t2: 20.2±16.2 pg mL(-1), t3: 56.3±73.6 pg mL(-1) (p<0.001)]. Cortisol, was higher in Group G compared with Group E [Group G, t3: 33.4±13.1 μg dL(-1), t4: 34.1±22.5 μg dL(-1), Group E, t3: 19.1±10.3 μg dL(-1), t4: 21.3±8.1 μg dL(-1) (p=0.001 and p=0.002)]. The insulin levels were higher compared with the baseline values at t3, and glucose was higher at t3 and t4 in both groups. Haemodynamic parameters were stable in Group E, and pain scores and morphine consumption were higher in Group G than in Group E.

CONCLUSION

Our results suggest that epidural anaesthesia combined with general anaesthesia suppressed the stress response, which was evaluated with ACTH, cortisol levels and haemodynamic parameters; however, this method was ineffective to attenuate the increase in glucose and insulin levels.

Perioperative catabolism

PURPOSE

This article reviews the pathophysiology, clinical relevance, and therapy of the catabolic response to surgical stress.

PRINCIPLE FINDINGS

The key clinical features of perioperative catabolism are hyperglycemia and loss of body protein, both metabolic consequences of impaired insulin function. Muscle weakness and (even moderate) increases in perioperative blood glucose are associated with morbidity after major surgery. Although the optimal glucose concentration for improving clinical outcomes is unknown, most medical associations recommend treatment of random blood glucose > 10 mmol·L(-1). Neuraxial anesthesia blunts the neuroendocrine stress response and enhances the anabolic effects of nutrition. There is evidence to suggest that the avoidance of preoperative fasting prevents insulin resistance and accelerates recovery after major abdominal surgery.

CONCLUSIONS

Current anticatabolic therapeutic strategies include glycemic control and perioperative nutrition in combination with optimal pain control and the avoidance of preoperative starvation. All these elements are part of Enhanced Recovery After Surgery (ERAS) programs.

[Aspects of perioperative care in patients with diabetes]

Diabetes is a common disease in Germany. Due to diabetes-associated end-organ disease, such as large and small vessel disease and neuropathy, diabetic patients require more intense anesthesia care during the perioperative phase. An in-depth and comprehensive medical history focusing on hemodynamic alterations, gastroparesis, neuropathy and stiff joint syndrome is a cornerstone of perioperative care and may affect outcome of diabetes patients more than specific anesthetic medications or the anesthetic procedure. Intraoperative anesthetic care needs to focus on preservation of hemodynamic stability, perioperative infection control and maintenance of glucose homeostasis. Whereas some years ago strict glucose control by aggressive insulin therapy was adamantly advocated, the results of recent studies have put the risk of such therapeutic algorithms into perspective. Therefore, optimized perioperative care of diabetic patients consists of setting a predefined targeted blood glucose level, evidence-based therapeutic approaches to reach that goal and finally adequate and continuous monitoring and amendment of the therapeutic approach if required.

Effects of regional analgesia on stress responses to pediatric surgery

Invasive surgery induces a combination of local response to tissue injury and generalized activation of systemic metabolic and hormonal pathways via afferent nerve pathways and the central nervous system. The local inflammatory responses and the parallel neurohumoral responses are not isolated but linked through complex signaling networks, some of which remain poorly understood. The magnitude of the response is broadly related to the site of injury (greater in regions with visceral pain afferents such as abdomen and thorax) and the extent of the trauma. The changes include alterations in metabolic, hormonal, inflammatory, and immune systems that can be collectively termed the stress response. Integral to the stress responses are the effects of nociceptive afferent stimuli on systemic and pulmonary vascular resistance, heart rate, and blood pressure, which are a combination of efferent autonomic response and catecholamine release via the adrenal medulla. Therefore, pain responses, cardiovascular responses, and stress responses need to be considered as different aspects of a combined bodily reaction to surgery and trauma. It is important at the outset to understand that not all components of the stress response are suppressed together and that this is important when discussing different analgesic modalities (i.e. opioids vs regional anesthesia). For example, in terms of the use of fentanyl in the infant, the dose required to provide analgesia (1-5 mcg·kg(-1)) is less than that required for hemodynamic stability in response to stimuli (5-10 mcg·kg(-1)) (1) and that this in turn is less than that required to suppress most aspects of the stress response (25-50 mcg·kg(-1)) (2). In contrast to this considerable dose dependency, central local anesthetic blocks allow blockade of the afferent and efferent sympathetic pathways at relatively low doses resulting in profound suppression of hemodynamic and stress responses to surgery.

Anesthetic considerations in diabetic patients. Part I: preoperative considerations of patients with diabetes mellitus

Diabetes mellitus is an increasingly common disease that affects people of all ages, resulting in significant morbidity and mortality. Diabetic patients require perioperative care more frequently than their nondiabetic counterparts. The major risk factors for diabetics undergoing surgery are the associated end-organ diseases: cardiovascular disease, autonomic neuropathy, joint collagen tissue, and immune deficiency. Physicians need to pay extra attention to preoperative and preprocedure evaluation and treatment of these diseases to ensure optimal perioperative management.

Randomized clinical trial to compare the effects of preoperative oral carbohydrate versus placebo on insulin resistance after colorectal surgery

Background

Preoperative oral carbohydrate (OCH) reduces postoperative insulin resistance (PIR). This randomized trial investigated whether this effect is related to insulin-induced activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB) signalling pathway.

Methods

Patients with colorectal cancer scheduled for elective open resection were randomly assigned to preoperative OCH, fasting or placebo. Preoperative general well-being, insulin resistance before and immediately after surgery, and postoperative expression of PI3K, PKB, protein tyrosine kinase (PTK) and glucose transporter 4 (GLUT4) in rectus abdominis muscle were evaluated.

Results

Patient and operative characteristics did not differ between groups. Subjective well-being was significantly better in OCH and placebo groups than in the fasting group, primarily because of reduced thirst (P = 0·005) and hunger (P = 0·041). PIR was significantly greater in fasting and placebo groups (P &lt; 0·010). By the end of surgery, muscle PTK activity as well as PI3K and PKB levels were significantly increased in the OCH group compared with values in fasting and placebo groups (P &lt; 0·050), but GLUT4 expression was unaffected.

Conclusion

PIR involves the PI3K/PKB signalling pathway. Preoperative OCH intake improves preoperative subjective feelings of hunger and thirst compared with fasting, while attenuating PIR by stimulation of the PI3K/PKB pathway. Registration number: NCT00755729 (http://www.clinicaltrials.gov).

A comparison of regional and general anaesthesia for total replacement of the hip or knee: a meta-analysis

We performed a meta-analysis to evaluate the relative efficacy of regional and general anaesthesia in patients undergoing total hip or knee replacement. A comprehensive search for relevant studies was performed in PubMed (1966 to April 2008), EMBASE (1969 to April 2008) and the Cochrane Library. Only randomised studies comparing regional and general anaesthesia for total hip or knee replacement were included. We identified 21 independent, randomised clinical trials. A random-effects model was used to calculate all effect sizes. Pooled results from these trials showed that regional anaesthesia reduces the operating time (odds ratio (OR) -0.19; 95% confidence interval (CI) -0.33 to -0.05), the need for transfusion (OR 0.45; 95% CI 0.22 to 0.94) and the incidence of thromboembolic disease (deep-vein thrombosis OR 0.45, 95% CI 0.24 to 0.84; pulmonary embolism OR 0.46, 95% CI 0.29 to 0.80). Regional anaesthesia therefore seems to improve the outcome of patients undergoing total hip or knee replacement.

Correlation between pre-operative metabolic syndrome and persistent blood glucose elevation during cardiac surgery in non-diabetic patients

BACKGROUND

Cardiopulmonary-bypass (CPB) induces hyperglycemia. There is growing evidence that perioperative maintenance of blood glucose within the physiological range improves patients' outcome. Nevertheless, perioperative normoglycemia is often difficult to achieve during surgery with CPB and the response to insulin infusion is characterized by a considerable variability. The aim of this study was to determine to what extent the presence of pre-operative metabolic syndrome (MS) influences the blood glucose and insulin response during cardiac surgery.

METHODS

Forty-five patients scheduled for elective cardiac surgery were screened for the presence of MS according to the International Diabetes Federation definition. Patients were then assigned to two groups: those with metabolic syndrome (MSP) and those without (control). During surgery, blood glucose levels were measured in all patients and hyperglycemia was treated with a standard protocol of continuous insulin infusion.

RESULTS

The mean blood glucose levels during CPB increased only in the MSP group (P<0.001). Mean blood glucose in control patients did not increase during CPB (P=0.4). Patients with MS received 13.3+/-8.4 IU of insulin during CPB, while the control group did not require insulin treatment (P<0.001). Forty percent of patients in the control group and 100% of those in the MSP group developed post-operative insulin resistance. C-reactive protein was higher in the MSP group before, during and at 48 h after surgery.

CONCLUSIONS

The mean blood glucose levels during CPB increased only in patients with MS, while they remained unchanged in patients in the control group.

Postburn trauma insulin resistance and fat metabolism

Hyperglycemia and insulin resistance have long been recognized in severe burn patients. More recently, it has been observed that controlling hyperglycemia, or alleviating insulin resistance, is associated with improved outcomes. This has led to a renewed interest in the etiology of insulin resistance in this population. The postinjury hyperglycemic response appears to be associated with multiple metabolic abnormalities, such as elevated basal energy expenditure, increased protein catabolism, and, notably, significant alterations in fat metabolism. The synergy of all of the responses is not understood, although many studies have been conducted. In this article we will review the present understanding of the relationship between fat metabolism and insulin resistance posttrauma, and discuss some of the recent discoveries and potential therapeutic measures. We propose that the insulin resistance is likely related to the development of "ectopic" fat stores, i.e., triglyceride (TG) storage in sites such as the liver and muscle cells. Deposition of TG in ectopic sites is due to an increase in free fatty acid delivery secondary to catecholamine-induced lipolysis, in conjunction with decreased beta-oxidation within muscle and decreased hepatic secretion of fats. The resultant increases in intracellular TG or related lipid products may in turn contribute to alterations in insulin signaling.