Intraoperative hyperglycemia and perioperative outcomes in cardiac surgery patients

Comparison of blood glucose management strategies to achieve control following cardiac surgery (computerized versus paper)

INTRODUCTION

Blood glucose control can be time-consuming and difficult to achieve. We hypothesized that a computerized system to obtain glucose control would enable faster "time to target" and produce less variability in blood glucose levels.

METHODS

Patients who underwent cardiac surgery at a community hospital between January and December 2007 (n = 1131) with glucose control obtained under a paper protocol were compared with similar patients operated on between January and December 2008 (n = 769) whose glucose control was obtained with a computer-driven protocol.

RESULTS

Glucose control was achieved in both groups. The computer group had less variability in glucose levels than the paper group. The mean time to target for the computer group was 3.5 (+/-1.3) hours. The time to target for the paper group was quite skewed; therefore, the median time to target was 6 hours.

CONCLUSIONS

The computer-driven protocol achieved excellent glycemic control.

Design and Organization of the Dexamethasone, Light Anesthesia and Tight Glucose Control (DeLiT) Trial: a factorial trial evaluating the effects of corticosteroids, glucose control, and depth-of-anesthesia on perioperative inflammation and morbidity from major non-cardiac surgery

BACKGROUND

The perioperative period is characterized by an intense inflammatory response. Perioperative inflammation promotes postoperative morbidity and increases mortality. Blunting the inflammatory response to surgical trauma might thus improve perioperative outcomes. We are studying three interventions that potentially modulate perioperative inflammation: corticosteroids, tight glucose control, and light anesthesia.

METHODS/DESIGN

The DeLiT Trial is a factorial randomized single-center trial of dexamethasone vs placebo, intraoperative tight vs. conventional glucose control, and light vs deep anesthesia in patients undergoing major non-cardiac surgery. Anesthetic depth will be estimated with Bispectral Index (BIS) monitoring (Aspect medical, Newton, MA). The primary outcome is a composite of major postoperative morbidity including myocardial infarction, stroke, sepsis, and 30-day mortality. C-reactive protein, a measure of the inflammatory response, will be evaluated as a secondary outcome. One-year all-cause mortality as well as post-operative delirium will be additional secondary outcomes. We will enroll up to 970 patients which will provide 90% power to detect a 40% reduction in the primary outcome, including interim analyses for efficacy and futility at 25%, 50% and 75% enrollment.

DISCUSSION

The DeLiT trial started in February 2007. We expect to reach our second interim analysis point in 2010. This large randomized controlled trial will provide a reliable assessment of the effects of corticosteroids, glucose control, and depth-of-anesthesia on perioperative inflammation and morbidity from major non-cardiac surgery. The factorial design will enable us to simultaneously study the effects of the three interventions in the same population, both individually and in different combinations. Such a design is an economically efficient way to study the three interventions in one clinical trial vs three.

TRIAL REGISTRATION

This trial is registered at Clinicaltrials.gov #: NTC00433251.

Article Commentary: Optimizing Surgical Care: A Contemporary Assessment of Temperature, Oxygen, and Glucose

Factors such as temperature, oxygen, and glucose have recently been implicated in the development of surgical sepsis by either promoting or attenuating protective components of the innate immune response. Reducing infective sequelae and the improvement of the quality of care of surgical patients is a top practice priority today. These factors and their associated effects are discussed through the examination of recent clinical and scientific studies to provide an up-to-date evidence-based review.

Pre-procedural glucose levels and the risk for contrast-induced acute kidney injury in patients undergoing coronary angiography

OBJECTIVES

We sought to evaluate whether pre-procedural glucose levels are associated with contrast-induced acute kidney injury (CI-AKI) after coronary angiography.

BACKGROUND

Although diabetes is a known risk factor for CI-AKI in patients undergoing coronary angiography, whether elevated pre-procedural glucose levels (regardless of pre-existing diabetes) are associated with higher risk for CI-AKI is unknown.

METHODS

We evaluated 6,358 patients with acute myocardial infarctions undergoing coronary angiography. Patients were stratified into 5 pre-procedural glucose groups: <110 mg/dl, 110 to <140 mg/dl, 140 to <170 mg/dl, 170 to <200 mg/dl, and >or=200 mg/dl. Logistic regression models were used to evaluate the relationship between glucose levels and risk for CI-AKI, first in the entire cohort and then in patients with and without established diabetes. The primary outcome was CI-AKI (>or=0.3 mg/dl absolute or >or=50% relative serum creatinine increase during 48 h after the procedure).

RESULTS

The relationship between pre-procedural glucose and CI-AKI varied markedly in patients with and without diabetes. There was a strong association between glucose and CI-AKI risk in patients without diabetes (CI-AKI rates across the 5 glucose groups from lowest to highest: 8.2%, 9.9%, 12.4%, 14.9%, and 24.3%; p<0.001), but not in patients with diabetes (20.9%, 16.1%, 16.3%, 14.8%, and 19.2%, respectively; p=0.24; p for glucose x diabetes interaction<0.001). After adjusting for confounders (including baseline glomerular filtration rate), the relationship between higher glucose and greater CI-AKI risk persisted in patients without diabetes (odds ratios [95% confidence intervals] for glucose groups of 110 to <140 mg/dl, 140 to <170, mg/dl 170 to <200 mg/dl, and >or=200 mg/dl: 1.31 [1.00 to 1.71], 1.51 [1.11 to 2.10], 1.58 [1.03 to 2.43], and 2.14 [1.46 to 3.14] vs. glucose<110 mg/dl, respectively), but this relationship was not seen in patients with established diabetes.

CONCLUSIONS

Elevated pre-procedural glucose is associated with greater risk for CI-AKI in patients without known diabetes who undergo coronary angiography in the setting of acute myocardial infarction. Measures used to prevent CI-AKI should be considered in these patients.

Impact of admission serum glucose level on in-hospital outcomes following coronary artery bypass grafting surgery

OBJECTIVE

The impact of admission serum glucose (SG) level on outcomes in coronary artery bypass grafting (CABG) surgery is unknown. The present study sought to determine whether elevated admission SG level is associated with adverse outcomes following CABG surgery.

METHODS

Patients undergoing CABG surgery between January 2000 and December 2005 at a single centre were identified (n=2856). Admission SG levels of less than 9.2 mmol/L and 9.2 mmol/L or greater were chosen to divide patients into two groups based on the 75th percentile of SG distribution. A logistic regression model was generated to determine the impact of admission SG level on a composite outcome of any one or more of in-hospital mortality, stroke, perioperative myocardial infarction, sepsis, deep sternal wound infection, renal failure, requirement for postoperative inotropes and prolonged ventilation.

RESULTS

In total, 76.3% of patients had an admission SG level of less than 9.2 mmol/L (group A) and 23.7% had an admission SG level of 9.2 mmol/L or greater (group B). Group B patients were more likely to be female, have diabetes, have preoperative renal failure, have an ejection fraction of less than 40%, experience myocardial infarction within 21 days before surgery, and have triple vessel or left main disease (P<0.05). Univariate analysis revealed no difference in in-hospital mortality between group A (2.2%) and group B (3.2%) (P=0.12); however, the composite outcome was more likely to occur in group B (40.8%) versus group A (27.9%) (P=0.0001). After multivariable adjustment, admission SG level of 9.2 mmol/L or greater remained an independent predictor of composite outcome (OR=1.3, 95% CI 1.0 to 1.7, P=0.02, receiver operating characteristic = 78%).

CONCLUSION

Admission SG level of 9.2 mmol/L or greater is associated with significant morbidity in patients undergoing CABG surgery.

How to manage perioperative endocrine insufficiency

Patients with endocrinopathies frequently present to the operating room. Although many of these disorders are managed on a chronic basis, patients may have acute changes in the perioperative period that, if left unrecognized, can have a negative effect on perioperative morbidity and mortality. It is imperative that anesthesiologists understand the implications of the surgical stress response on hormonal flux. This article focuses on the 4 most commonly encountered endocrinopathies: diabetes mellitus, hyperthyroidism, hypothyroidism, and adrenal insufficiency. Specific challenges pertaining to patients with pheochromocytoma are also discussed.

Clinical benefits of tight glycaemic control: effect on the kidney

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

Intraoperative hyperglycemia and postoperative bacteremia in the pediatric cardiac surgery patient

BACKGROUND

Intraoperative hyperglycemia has been found to be associated with a higher incidence of postoperative infections in the adult cardiac surgery population. The goal of this study was to determine the association of intraoperative hyperglycemia and postoperative bacteremia in the pediatric population.

METHODS

A retrospective chart review of all cardiac surgical cases for patients 18 years of age or younger requiring cardiopulmonary bypass support between June 2002 and July 2007 yielded 1,132 total cases representing 992 unique patients. Patient demographic and clinical data of interest were collected. Descriptive statistics and regression analyses were performed to investigate the hypothesized relationship between glucose levels and infection rates.

RESULTS

From the 992 patient records examined, 15 patients exhibited a bacteremia within 14 days of surgery (1.5%). The association between the highest glucose during cardiopulmonary bypass and bacteremia reached statistical significance when the glucose level reached 175 mg/dL (chi(2) = 4.59, 1 degree of freedom; p = 0.032). A patient was more than three times as likely to have a postoperative bacteremia when the glucose level reached this amount or exceeded it (odds ratio, 3.3, 95% confidence interval, 1.04 to 10.39). Ten of the 15 (66.7%) postoperative infections occurred in patients with peak bypass glucose levels of at least 175 mg/dL.

CONCLUSIONS

Intraoperative hyperglycemia was found to be associated with a higher risk of postoperative bacteremia in the pediatric cardiac surgery population.

Scientific principles and clinical implications of perioperative glucose regulation and control

Development of hyperglycemia after major operations is very common and is modulated by many factors. These factors include perioperative metabolic state, intraoperative management of the patient, and neuroendocrine stress response to surgery. Acute insulin resistance also develops perioperatively and contributes significantly to hyperglycemia. Hyperglycemia is associated with poor outcomes in critically ill and postsurgical patients. A majority of the investigations use the term "hyperglycemia" very loosely and use varying thresholds for initiating treatment. Initial studies demonstrated improved outcomes in critically ill, postsurgical patients who received intensive glycemic control (IGC) (target serum glucose <110 mg/dL). These results were quickly extrapolated to other clinical areas, and IGC was enthusiastically recommended in the perioperative period. However, there are few studies investigating the value of intraoperative glycemic control. Moreover, recent prospective trials have not been able to show the benefit of IGC; neither an appropriate therapeutic glycemic target nor the true efficacy of perioperative glycemic control has been fully determined. Practitioners should also appreciate technical nuances of various glucose measurement techniques. IGC increases the risk of hypoglycemia significantly, which is not inconsequential in critically ill patients. Until further specific data are accumulated, it is prudent to maintain glucose levels <180 mg/dL in the perioperative period, and glycemic control should always be accompanied by close glucose monitoring.

Review article: glucose measurement in the operating room: more complicated than it seems

Abnormalities of blood glucose are common in patients undergoing surgery, and in recent years there has been considerable interest in tight control of glucose in the perioperative period. Implementation of any regime of close glycemic control requires more frequent measurement of blood glucose, a function for which small, inexpensive, and rapidly responding point-of-care devices might seem highly suitable. However, what is not well understood by many anesthesiologists and other staff caring for patients in the perioperative period is the lack of accuracy of home glucose meters that were designed for self-monitoring of blood glucose by patients. These devices have been remarketed to hospitals without appropriate additional testing and without an appropriate regulatory framework. Clinicians who are accustomed to the high level of accuracy of glucose measurement by a central laboratory device or by an automated blood gas analyzer may be unaware of the potential for harmful clinical errors that are caused by the inaccuracy exhibited by many self-monitoring of blood glucose devices, especially in the hypoglycemic range. Knowledge of the limitations of these meters is essential for the perioperative physician to minimize the possibility of a harmful measurement error. In this article, we will highlight these areas of interest and review the indications, technology, accuracy, and regulation of glucose measurement devices used in the perioperative setting.

The relationship between glycosylated hemoglobin and perioperative glucose control in patients with diabetes

PURPOSE

Hyperglycemia and elevated glycosylated hemoglobin (HbA(1c)) are associated with perioperative morbidity in patients with diabetes, but the relationship between long-term glycemic control and perioperative glucose control is unknown. The purpose of this study was to determine the relationship between glycosylated hemoglobin (HbA(1c)) and perioperative glucose in fasting patients with type 2 diabetes undergoing elective non-cardiac surgery.

METHODS

This was a prospective observational study of 244 adult patients with type 2 diabetes who were evaluated before elective non-cardiac surgery at a preoperative medicine clinic in a tertiary care medical centre during the period September 2004 to May 2005. Preoperative HbA(1c) levels were determined, and preoperative and postoperative glucose values were measured on the day of surgery. The primary outcome variables were preoperative and postoperative blood glucose values.

RESULTS

Half of all study patients had an HbA(1c) > or = 7%, including 23% of patients with HbA(1c) >/= 8%. HbA(1c) levels predict preoperative glucose levels, and preoperative glucose levels and duration of surgery predict postoperative glucose levels. Glucose levels in one-third of the patients with type 2 diabetes decreased during surgery without administration of insulin or glucose-regulating medications.

CONCLUSION

HbA(1c) values may serve as biomarkers for glucose control during the immediate perioperative period in patients with type 2 diabetes undergoing elective surgery.

Automated control of blood glucose in the OR and surgical ICU

A device which integrates existing intravenous continuous glucose monitors and infusion pumps into a central hub for automated intravenous intensive insulin therapy, targeting non-diabetic critically-ill patients is presented. Additionally, a fuzzy logic based controller that is capable of automatically making closed-loop decisions to achieve tight glycemic control between a euglycemic range of 90 to 120 mg/dl is presented. Initial bench top testing shows a significant improvement in glycemic control with fuzzy logic control when compared to manual infusion protocols currently used in hospitals; future animal testing will be performed to verify these results in vivo.

Surgery in the patient with endocrine dysfunction

Patients with preoperative endocrinopathies represent a particular challenge not only to anesthesiologists but also to surgeons and perioperative clinicians. The "endocrine axis" is complex and has multiple feedback loops, some of which are endocrine and paracrine related, and others that are strongly influenced by the surgical stress response. Familiarity with several of the common endocrinopathies facilitates management in the perioperative period. This article focuses on 4 of the most common endocrinopathies: diabetes mellitus, hyperthyroidism, hypothyroidism, and adrenal insufficiency. Perioperative challenges in patients presenting with pheochromocytoma are also discussed.

Emergency and urgent surgery

Patients presenting with general surgical emergencies are hypovolemic, and require early aggressive resuscitative efforts. Although these efforts may safely be accomplished preoperatively in a select subset of patients, it is often the combined task of surgeons, anesthesiologists, and internists to optimize these critically ill patients in the intraoperative and postoperative period. Early surgical consultation and intervention can be lifesaving. This article presents the current state of emergency surgical care in the United States and the approach to the patient with an emergency surgical illness. The aggressiveness of the surgical intervention is patient- and disease-specific and requires frequent and open communication between all health care providers, the patient, and his or her family. In addition to aggressive resuscitation, life-threatening general surgical conditions often require specific diagnostic and therapeutic interventions.

Morbidity and mortality caused by cardiac adverse events after revascularization for critical limb ischemia

BACKGROUND

We assessed cardiac adverse events (AEs) after primary lower extremity arterial revascularization (LEAR) for critical lower limb ischemia (CLI) in order to evaluate the impact of cardiac AEs on the clinical outcome. We created an optimized care protocol concerning CLI patients' preoperative work-up as well as intra- and postoperative surveillance according to recent important literature and guidelines.

METHODS

We conducted a prospective analysis of clinical outcome after LEAR using patient-related risk factors, comorbidity, surgical therapy, and AEs. This cohort was divided into patients with and without AEs. AEs were categorized according to predefined standards: minor, surgical, failed revascularization, and systemic. The consequences of AEs were reoperation, additional medication, irreversible physical damage, and early death.

RESULTS

There were 106 patients (Fontaine III n=49, 46%, and Fontaine IV n=57, 56%) who underwent primary revascularization by bypass graft procedure (n=67, 63%) or balloon angioplasty (n=39, 37%). No difference in comorbidity was registered between the two groups. Eighty-four AEs were registered in 34 patients (32%). Patients experiencing AEs had significantly less antiplatelet agents (without AEs n=63, 88%, vs. with AEs n=18, 53%; p=0.000) and/or beta-blockers (without AEs n=66, 92%, vs. with AEs n=16, 47%; p=0.000) compared to patients without AEs. The two most harmful consequences of AEs were irreversible physical damage (n=3) and early death (n=8). Sixty percent (n=9) of systemic AEs were heart-related. The postprocedural mortality rate was 7.5%, with a 75% (n=6) heart-related cause of death.

CONCLUSION

AEs occur in >30% of CLI patients after LEAR. The most harmful AEs on the clinical outcome of CLI patients were heart-related, causing increased morbidity and death. Significant correlations between prescription of beta-blockers and antiplatelet agents and prevention of AEs were observed. A persistent focus on the prevention of systemic AEs in order to ameliorate the outcome after LEAR for limb salvage remains of utmost importance. Therefore, we advise the implementation of an optimized care protocol by discussing patients in a strict manner according to a predetermined protocol, to optimize and standardize the preoperative work-up as well as intra- and postoperative patient surveillance.

Prevention of sternal wound infections after coronary artery bypass graft surgery with use of insulin drug therapy: a review of the literature

Diabetes is a disease that can increase the risks of developing cardiac problems, which can include coronary artery bypass graft surgery. These patients are at an increased risk of developing serious complications after this surgery, including deep sternal wound infections. In addition, nondiabetic patients may also develop this complication. Therefore, it is essential to monitor and maintain glucose levels after open heart surgery. This literature review discusses some of the studies in this area.

A cost-effective screening method for preoperative hyperglycemia

INTRODUCTION

The preoperative encounter may offer a cost-effective opportunity for diabetes screening.

METHODS

Three hundred forty-seven fasting patients had a preoperative glucose measurement determined from blood residue left on the IV needle, measured with an Accu-Chek glucometer (Roche Diagnostics, Indianapolis, IN).

RESULTS

After excluding patients with a diabetes history, 4.0% had a glucose measurement between 100 and 125 mg/dL, at a cost of $14.22 per identification, and 1.2% had a glucose measurement more than 125 mg/dL, at a cost of $32.00 per identification.

CONCLUSIONS

This preoperative blood glucose screening test was implemented at a cost of approximately one-tenth of current methods.

An overview of preoperative glucose evaluation, management, and perioperative impact

Perioperative hyperglycemia is a common phenomenon affecting patients both with and without a known prior history of diabetes. Despite an exponential rise in publications and studies of inpatient hyperglycemia over the last decade, many questions still exist as to what defines optimal care of these patients. Initial enthusiasm for tight glycemic control has waned as the unanticipated reality of hypoglycemia and mortality has been realized in some prospective studies. The recent dramatic modification of national practice guidelines to endorse more modest inpatient glycemic targets highlights the dynamic nature of current knowledge as the next decade approaches. This review discusses perioperative hyperglycemia and the categories of patients affected by it. It reviews current recommendations for ambulatory diabetes screening and its importance in preoperative patient care. Finally, it concludes with a review of current practice guidelines, as well as a discussion of future direction and goals for inpatient perioperative glycemic control.

Hyperglycemia in critical illness: a review

Hyperglycemia is commonplace in the critically ill patient and is associated with worse outcomes. It occurs after severe stress (e.g., infection or injury) and results from a combination of increased secretion of catabolic hormones, increased hepatic gluconeogenesis, and resistance to the peripheral and hepatic actions of insulin. The use of carbohydrate-based feeds, glucose containing solutions, and drugs such as epinephrine may exacerbate the hyperglycemia. Mechanisms by which hyperglycemia cause harm are uncertain. Deranged osmolality and blood flow, intracellular acidosis, and enhanced superoxide production have all been implicated. The net result is derangement of endothelial, immune and coagulation function and an association with neuropathy and myopathy. These changes can be prevented, at least in part, by the use of insulin to maintain normoglycemia.

Challenges to glycemic measurement in the perioperative and critically ill patient: a review

Accurate monitoring of glucose in the perioperative environment has become increasingly important over the last few years. Because of increased cost, turnaround time, and sample volume, the use of central laboratory devices for glucose measurement has been somewhat supplanted by point-of-care (POC) glucose devices. The trade-off in moving to these POC systems has been a reduction in accuracy, especially in the hypoglycemic range. Furthermore, many of these POC devices were originally developed, marketed, and received Food and Drug Administration regulatory clearance as home use devices for patients with diabetes. Without further review, many of these POC glucose measurement devices have found their way into the hospital environment and are used frequently for measurement during intense insulin therapy, where accurate measurements are critical. This review covers the technology behind glucose measurement and the evidence questioning the use of many POC devices for perioperative glucose management.

Amiodarone for the prevention of reperfusion ventricular fibrillation

OBJECTIVE

The purpose of this study was to evaluate the efficacy of prophylactic single-dose amiodarone administered through the pump circuit before releasing the aortic cross-clamp (ACC) in preventing the occurrence of reperfusion ventricular fibrillation (RVF).

DESIGN

A prospective, randomized double-blind, placebo-controlled efficacy study.

SETTING

A tertiary level teaching hospital.

INTERVENTION

Seventeen patients received 150 mg of amiodarone in 10 mL of normal saline by way of the pump 3 minutes before releasing the ACC, and a control group of 17 patients received 10 mL of normal saline.

MEASUREMENT AND MAIN RESULTS

The primary outcome of the study was the incidence of ventricular fibrillation requiring defibrillation during the 30-minute period after myocardial reperfusion. A large decrease in RVF (65% to 18%) was observed in the amiodarone-treated group with the number needed to treat only 2.1.The myocardial performance in terms of cardiac output was better in the amiodarone group; this could be attributed to the lower incidence of RVF and subsequent direct current shock therapy.

CONCLUSIONS

The observations showed that single-dose prophylactic amiodarone administered through the pump circuit 3 minutes before ACC release was an effective therapy to reduce the incidence of post-ACC release ventricular arrhythmias.

Emergency and urgent surgery

Patients presenting with general surgical emergencies are hypovolemic, and require early aggressive resuscitative efforts. Although these efforts may safely be accomplished preoperatively in a select subset of patients, it is often the combined task of surgeons, anesthesiologists, and internists to optimize these critically ill patients in the intraoperative and postoperative period. Early surgical consultation and intervention can be lifesaving. This article presents the current state of emergency surgical care in the United States and the approach to the patient with an emergency surgical illness. The aggressiveness of the surgical intervention is patient- and disease-specific and requires frequent and open communication between all health care providers, the patient, and his or her family. In addition to aggressive resuscitation, life-threatening general surgical conditions often require specific diagnostic and therapeutic interventions.

Surgery in the patient with endocrine dysfunction

Patients with preoperative endocrinopathies represent a particular challenge not only to anesthesiologists but also to surgeons and perioperative clinicians. The "endocrine axis" is complex and has multiple feedback loops, some of which are endocrine and paracrine related, and others that are strongly influenced by the surgical stress response. Familiarity with several of the common endocrinopathies facilitates management in the perioperative period. This article focuses on 4 of the most common endocrinopathies: diabetes mellitus, hyperthyroidism, hypothyroidism, and adrenal insufficiency. Perioperative challenges in patients presenting with pheochromocytoma are also discussed.

Cardiopulmonary bypass increases postoperative glycemia and insulin consumption after coronary surgery

BACKGROUND

Perioperative hyperglycemia should be avoided in patients undergoing coronary surgery. The aim of our study was to find out what the influence of cardiopulmonary bypass is on postoperative glycemia and insulin consumption in patients with and without diabetes mellitus undergoing coronary artery surgery and whether a marked hyperglycemia in the early postoperative period is among the factors associated with early mortality and morbidity.

METHODS

We retrospectively reviewed all patients who underwent first-time coronary artery surgery in our institution during the 11-month period. Among 814 patients, 239 patients (29.4%) had diabetes and 575 patients (70.6%) were nondiabetic. Blood glucose levels were registered every 2 hours in all patients during the first 24 postoperative hours. Outcomes were difficult glycemic control (postoperative blood glucose levels >11.0 mmol/L despite aggressive insulin treatment), hospital mortality, and morbidity (defined as any postoperative complication such as stroke, renal failure, wound infection, perioperative myocardial infarction, ventilation > 24 hours, sepsis, and multiorgan failure).

RESULTS

Glycemic control was significantly worse in patients who underwent coronary artery bypass grafting, in comparison with off-pump coronary artery bypass grafting surgery, particularly in nondiabetic patients. Patients with difficult glycemic control had more serious postoperative complications resulting in higher mortality (2.5% versus 0.4%; p = 0.02). In the multivariate analysis, difficult glycemic control was significantly associated with a female sex (odds ratio [OR], 2.36), presence of diabetes (OR, 2.22), and the usage of cardiopulmonary bypass (OR, 1.81). Mortality was significantly associated with the left ventricular ejection fraction less than 0.35 (OR, 7.38), difficult glycemic control (OR, 7.06), and previous stroke (OR, 5.66). Difficult glycemic control was also significantly associated with postoperative morbidity (OR, 1.87).

CONCLUSIONS

Cardiopulmonary bypass increases postoperative glycemia and insulin consumption in both diabetic and nondiabetic patients. The use of cardiopulmonary bypass during coronary artery surgery in diabetic women is associated with a more difficult glycemic control in the early postoperative period. Difficult glycemic control is significantly associated with early mortality and morbidity in patients undergoing coronary artery surgery.

Acute kidney injury in the intensive care unit

Acute kidney injury (AKI) is common among critically ill patients and results in increased mortality in this population. This review focuses on the diagnosis and management of AKI. The authors first explore new aspects of diagnosis, including new criteria that take into account even modest changes in renal function, and the development of novel biomarkers to allow earlier identification and better differential diagnosis of AKI. The authors also explore the available data on choice of dialysis modality and dialysis dose for the treatment of AKI, as well as the breakthrough development of the bioartificial kidney. Last, the authors review co-interventions that may have relevance to prognosis of AKI, such as intensive insulin therapy and the use of erythropoietin.

Severe intraoperative hyperglycemia is independently associated with surgical site infection after liver transplantation

BACKGROUND

Surgical site infection (SSI) is a common postoperative complication associated with increased morbidity and mortality in patients undergoing liver transplantation (LT). Although intraoperative hyperglycemia has been shown to be associated with adverse postoperative outcomes including overall infection rate in LT patients, a relationship between intraoperative hyperglycemia and SSI in LT has not been established. We sought to determine if intraoperative hyperglycemia was associated with SSI after LT.

METHODS

Patients undergoing LT at our medical center between January 2004 and November 2007 were included in the study. Recipient, donor, and intraoperative variables including a variety of glucose indices were retrospectively analyzed. Independent risk factors of SSI were identified using a multivariate logistic regression model.

RESULTS

Of 680 patients, 76 (11.2%) experienced postoperative SSIs. Among all intraoperative glucose indices analyzed, severe hyperglycemia (>or= 200 mg/dL) was independently associated with postoperative SSI (odds ratio [OR] 2.25, 95% confidence interval [CI] 1.26-4.03, P=0.006). Other independent risk factors include repeat surgery (OR 6.58, 95% CI 3.41-12.69, P<0.001), intraoperative administration of vasopressor (OR 3.14, 95% CI 1.65-5.95, P<0.001), preoperative mechanical ventilation (OR 3.01, 95% CI 1.70-5.33, P<0.001), and combined liver and kidney transplantation (OR 2.95, 95% CI 3.41-12.69, P<0.001).

CONCLUSIONS

Severe, but not mild or moderate, intraoperative hyperglycemia is independently associated with postoperative SSI and should be avoided during LT surgery.

[Repercussions and management of perioperative hyperglycemia in cardiac surgery]

Surgery produces a neuroendocrine stress response that affects resistance to insulin, reduces insulin secretion, and increases the release of glucose from the liver. This situation can trigger hyperglycemia in both diabetics and nondiabetics. Hyperglycemia has been linked to an increase in the morbidity and mortality among patients who undergo cardiac surgery, and the benefits of correcting hyperglycemia in this setting by means of intensive insulin therapy are well documented. This review discusses various aspects of hyperglycemia, particularly the evidence supporting stricter control of this condition in patients undergoing cardiac surgery. Furthermore, based on the available data and recommendations, and our clinical experience, we suggest therapeutic strategies to improve the control of hyperglycemia in these patients.

Intensive perioperative glucose control does not improve outcomes of patients submitted to open-heart surgery: a randomized controlled trial

BACKGROUND

The objective of this study was to investigate the relationship between different target levels of glucose and the clinical outcomes of patients undergoing cardiac surgery with cardiopulmonary bypass.

METHODS

We designed a prospective study in a university hospital where 109 consecutive patients were enrolled during a six-month period. All patients were scheduled for open-heart surgery requiring cardiopulmonary bypass. Patients were randomly allocated into two groups. One group consisted of 55 patients and had a target glucose level of 80-130 mg/dl, while the other contained 54 patients and had a target glucose level of 160-200 mg/dl. These parameters were controlled during surgery and for 36 hours after surgery in the intensive care unit. Primary outcomes were clinical outcomes, including time of mechanical ventilation, length of stay in the intensive care unit, infection, hypoglycemia, renal or neurological dysfunction, blood transfusion and length of stay in the hospital. The secondary outcome was a combined end-point (mortality at 30 days, infection or length of stay in the intensive care unit of more than 3 days). A p-value of <0.05 was considered significant.

RESULTS

The anthropometric and clinical characteristics of the patients from each group were similar, except for weight and body mass index. The mean glucose level during the protocol period was 126.69 mg/dl in the treated group and 168.21 mg/dl in the control group (p<0.0016). There were no differences between groups regarding clinical outcomes, including the duration of mechanical ventilation, length of stay in the intensive care unit, blood transfusion, postoperative infection, hypoglycemic event, neurological dysfunction or 30-day mortality (p>0.05).

CONCLUSIONS

In 109 patients undergoing cardiac surgery with cardiopulmonary bypass, both protocols of glycemic control in an intraoperative setting and in the intensive care unit were found to be safe, easily achieved and not to differentially affect clinical outcomes.

Association of stress hyperglycemia and atrial fibrillation in myocardial infarction

BACKGROUND

Stress hyperglycemia has an untoward effect on prognosis in acute myocardial infarction (AMI). Evidence on the interrelationship between stress hyperglycemia and atrial fibrillation (AF) in AMI is sparse. We hypothesized that stress hyperglycemia and AF, both being markers of worse in-hospital prognosis, may be interrelated and we therefore analyzed the relationship between stress hyperglycemia and AF in AMI.

PATIENTS AND METHODS

The study was a retrospective analysis of 543 patients with AMI. The average age was 63.8 +/- 10.6 years and 54.9% were male.

RESULTS

AF was more prevalent in 200 AMI patients with admission glucose >or= 8.0 mmol/l (15.00%) than in 343 patients with admission glucose < 8 mmol/l (7.87%), Pearson's chi-squared P = 0.010, OR 2.07 (95% CI 1.180-3.637). In AMI patients with neither stress hyperglycemia nor AF, in-hospital mortality was 1.67%; in patients with stress hyperglycemia without AF, the mortality was 3.85%. In patients with AF without stress hyperglycemia, mortality was high at 13.04%, and in patients with both stress hyperglycemia and AF it was extremely high at 24.14%. Hyperglycemia (r = 0.1680, P = 0.0472) but not AF correlated with the size of the AMI. Compared with an AF prevalence of 8.28% in the normoglycemic group, AF was found more often (14.65%) in a group with diabetes mellitus (DM), Pearson's chi-squared P = 0.02, OR = 2.04 (95% CI 1.06-3.93). There was no significant difference in the occurrence of AF between patients with previously diagnosed DM and those with new-onset DM (Fisher's exact test P = 0.34).

CONCLUSIONS

Stress hyperglycemia is associated with increased prevalence of AF in AMI. Patients with both stress hyperglycemia at admission (>or= 8.0 mmol/l) and AF had almost 14.5 times higher in-hospital mortality than patients who had neither stress hyperglycemia nor AF. Stress hyperglycemia was an independent predictor of the in-hospital mortality in multivariate regression analysis, but AF was not.

Association between intraoperative and early postoperative glucose levels and adverse outcomes after complex congenital heart surgery

BACKGROUND

This study sought to determine whether associations exist between perioperative glucose exposure, prolonged hospitalization, and morbid events after complex congenital heart surgery.

METHODS AND RESULTS

Metrics of glucose control, including average, peak, minimum, and SD of glucose levels, and duration of hyperglycemia were determined intraoperatively and for 72 hours after surgery for 378 consecutive high-risk cardiac surgical patients. Multivariable regression analyses were used to determine relationships between these metrics of glucose control, hospital length of stay, and a composite morbidity-mortality outcome after controlling for multiple variables known to influence early outcomes after congenital heart surgery. Intraoperatively, a minimum glucose <or=75 mg/dL was associated with greater adjusted odds of reaching the composite morbidity-mortality end point (odds ratio [OR], 3.10; 95% confidence interval [CI], 1.49 to 6.48), but other metrics of glucose control were not associated with the composite end point or length of stay. Greater duration of hyperglycemia (glucose >126 mg/dL) during the 72 postoperative hours was associated with longer duration of hospitalization (P<0.001). In the 72 hours after surgery, average glucose <110 mg/dL (OR, 7.30; 95% CI, 1.95 to 27.25) or >143 mg/dL (OR, 5.21; 95% CI, 1.37 to 19.89), minimum glucose <or=75 mg/dL (OR, 2.85; 95% CI, 1.38 to 5.88), and peak glucose level >or=250 mg/dL (OR, 2.55; 95% CI, 1.20 to 5.43) were all associated with greater adjusted odds of reaching the composite morbidity-mortality end point.

CONCLUSIONS

In children undergoing complex congenital heart surgery, the optimal postoperative glucose range may be 110 to 126 mg/dL. Randomized trials of strict glycemic control achieved with insulin infusions in this patient population are warranted.

Prevalence of abnormal glucose metabolism in atrial fibrillation: a case control study in 75-year old subjects

Background

The prevalence of atrial fibrillation (AF) is increasing world wide and amongst factors that aggravate the risk is diabetes mellitus (DM), also in epidemic development.

However, although DM is a potentially modifiable risk factor for AF, few, if any, studies have explored the prevalence of undiagnosed dysglycaemia among subjects with AF or if duration of AF are related to parameters of glycaemia or dysglycaemia prevalence.

Methods

In this case control study, amongst 75-year old subjects with and without AF, the prevalence of dysglycaemia, i.e., impaired fasting glycaemia, impaired glucose tolerance or DM, according to World Health Organisation criteria was assessed by a 75-g oral glucose tolerance test (OGTT).

Results

Prevalence of undiagnosed DM among the 108 subjects (male/female 73/35, BMI 25.4 ± 3.2) without and the 46 (male/female 34/12, BMI 25.3 ± 3.7) with AF (median AF duration five years) where 3.7% and 13.0%, respectively (p = 0.031, Odds ratio (OR) 3.86 (95% Confidence interval [CI]: 1.01, 16.25)) whereas the overall prevalence of dysglycaemia (prediabetes and DM) where similar (respectively 43.5% and 39.1%, p = 0.46, OR 0.83 [95% CI: 0.41, 1.69]). Patients with AF duration ≥ 5 years had however a higher dysglycaemia prevalence (61.1% [DM 22.2%, prediabetes 38.9%]) as compared to AF duration < 5 years (25% [DM 7.1%, prediabetes 17.9%], p = 0.0014, OR 4.7 [95% CI: 1.30, 16.90]) or no AF (p = 0.17, OR 2.04 [95% CI: 0.73, 5.66]). There was also a significant correlation between the duration of AF and HbA1c (r = 0.408, p = 0.005) and fasting glucose levels (r = 0.353, p = 0.016).

Conclusion

AF is associated with chronic hyperglycaemia amongst 75-year old subjects. Prediabetes and DM should be pro-actively assessed if AF duration ≥ 5 years.