M. Molly McMahon

Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient—2013 update: Cosponsored by american association of clinical endocrinologists, The obesity society, and american society for metabolic & bariatric surgery*

The development of these updated guidelines was commissioned by the AACE, TOS, and ASMBS Board of Directors and adheres to the AACE 2010 protocol for standardized production of clinical practice guidelines (CPG). Each recommendation was re‐evaluated and updated based on the evidence and subjective factors per protocol. Examples of expanded topics in this update include: the roles of sleeve gastrectomy, bariatric surgery in patients with type‐2 diabetes, bariatric surgery for patients with mild obesity, copper deficiency, informed consent, and behavioral issues. There are 74 recommendations (of which 56 are revised and 2 are new) in this 2013 update, compared with 164 original recommendations in 2008. There are 403 citations, of which 33 (8.2%) are EL 1, 131 (32.5%) are EL 2, 170 (42.2%) are EL 3, and 69 (17.1%) are EL 4. There is a relatively high proportion (40.4%) of strong (EL 1 and 2) studies, compared with only 16.5% in the 2008 AACE‐TOS‐ASMBS CPG. These updated guidelines reflect recent additions to the evidence base. Bariatric surgery remains a safe and effective intervention for select patients with obesity. A team approach to perioperative care is mandatory with special attention to nutritional and metabolic issues.

Functioning Insulinoma—Incidence, Recurrence, and Long-Term Survival of Patients: A 60-Year Study

For the 60-year period from 1927 through 1986, we assessed the incidence, recurrence, and long-term survival among all Mayo Clinic patients with histologically confirmed functioning insulinoma. With use of the complete medical record system at Mayo and the comprehensive epidemiologic data base of residents of Olmsted County, Minnesota, we found 224 patients in whom an initial pancreatic exploration at Mayo had confirmed the presence of insulinoma. The median age (and range) of these patients at surgical diagnosis was 47 (8 to 82) years, and 59% were female patients. During the study period, eight cases of insulinoma occurred among residents of Olmsted County; their age and gender distributions were similar to those of the total cohort. The incidence of insulinoma among residents of Olmsted County increased during the study period to a stable level during the last 2 decades of 4 cases per 1 million person-years. For the total cohort, 7.6% had multiple endocrine neoplasia type I (MEN I), and 5.8% had malignant insulinoma. The risk of recurrence was greater among patients with MEN I (21% at 10 and 20 years) than in those without MEN I (5% at 10 years and 7% at 20 years). Although survival of the total cohort was not significantly impaired, it was significantly worse than expected for patients with malignant insulinoma (29% versus 88% expected at 10 years postoperatively). We conclude that insulinoma is less rare than previously suspected. After successful surgical removal, the long-term risk of recurrent insulinoma is relatively high in patients with MEN I; for patients with benign disease, the long-term survival is normal.

Intensive Intraoperative Insulin Therapy versus Conventional Glucose Management during Cardiac Surgery: A Randomized Trial

Context Intensive insulin therapy used to maintain normoglycemia during intensive care after cardiac surgery improves perioperative outcomes. Its effect during cardiac surgery is unknown. Contributions The authors randomly assigned 400 cardiac surgical patients to tight glycemic control (blood glucose level, 4.4 to 5.6 mmol/L [80 to 100 mg/dL]) during surgery or usual intraoperative care. All patients received tight glycemic control in the cardiac intensive care unit. The groups had the same risk for perioperative adverse events (risk ratio, 1.0 [95% CI, 0.8 to 1.2]). The intensive treatment group had more strokes (8 vs. 1) and more deaths (4 vs. 0) than the conventional treatment group. Caution The authors performed the study at a single center. Implications Maintaining normoglycemia during cardiac surgery does not improve outcomes and might worsen them. The Editors Hyperglycemia occurs frequently in patients with and without diabetes during cardiac surgery, especially during cardiopulmonary bypass surgery (1, 2). In a study by Van den Berghe and colleagues (3), intensive insulin therapy after surgery reduced morbidity and death in critically ill patients, most of whom underwent cardiac surgery. As a result, professional organizations have recommended rigorous glycemic control in hospitalized patients (4) and strict glycemic control is now routine practice during the postoperative period in cardiac surgical patients. However, no consensus exists on the optimal management of intraoperative hyperglycemia in cardiac surgical patients because of the lack of evidence from randomized trials. Researchers are increasingly extrapolating evidence from studies that assess the role of strict postoperative glycemic control in critically ill patients to advocate for intravenous insulin therapy for patients in the operating room (3, 57). Evidence, strictly from observational studies, suggests that tight intraoperative glycemic control may reduce postoperative complications (810). We recently reported, in a retrospective, observational study of 409 cardiac surgical patients, that intraoperative hyperglycemia was an independent risk factor for perioperative complications, including death, after adjustment for postoperative glucose concentrations. Each 1.1-mmol/L (20 mg/dL) increase in glucose concentration greater than 5.6 mmol/L (>100 mg/dL) during surgery was associated with a 34% increase in the likelihood of postoperative complications (8). An association between intraoperative hyperglycemia and adverse outcomes based on observational studies does not prove causality. Because hyperglycemia can adversely affect immunity, wound healing, and vascular function, the concept that normoglycemia be maintained during the relatively brief duration of cardiac surgery seems plausible (1116). On the other hand, the degree of intraoperative hyperglycemia may merely reflect the severity of underlying stress. If so, prevention of hyperglycemia might not reduce perioperative complications, and the risks and costs of intensive intraoperative glycemic management may outweigh the benefits. Simple, safe, and effective insulin infusion algorithms that achieve rigorous intraoperative glycemic control are lacking. To address these questions, we conducted a randomized, controlled trial at 1 center to determine whether maintenance of near normoglycemia during cardiac surgery by using intraoperative intravenous insulin infusion reduced perioperative death and morbidity when added to rigorous postoperative glycemic control. Methods Design Overview This was a randomized, open-label, controlled trial with blinded assessment. We randomly assigned patients to receive intensive insulin therapy to maintain intraoperative glucose levels between 4.4 (80 mg/dL) and 5.6 mmol/L (100 mg/dL) or conventional treatment. By design, both groups were postoperatively treated with strict glycemic control to ensure that the observed difference in outcome could be attributed to the effects of intraoperative glycemic control. Setting We performed the study at St. Marys Hospital, Rochester, Minnesota, which is a tertiary care teaching hospital with 1157 beds and an average of more than 41000 admissions per year. Participants Adults undergoing elective cardiac surgery between July 2004 and April 2005 were eligible for enrollment in our study. We excluded patients who had off-pump cardiopulmonary bypass procedures. The Mayo Foundation Institutional Review Board, Rochester, Minnesota, approved the protocol. Randomization and Interventions Before we enrolled patients in our randomized trial, we enrolled 20 patients in a 2-week pilot trial to ensure that the anesthesiologists in the operating room and the nursing staff in the intensive care units (ICUs) had adequate experience with the study insulin infusion algorithm. The 20 patients received intensive insulin therapy during surgery and for 24 hours after surgery. The pilot period data allowed us to modify the graded insulin infusion to achieve desired glucose concentration goals. We built safety features into our infusion protocol to minimize hypoglycemia. We discontinued the infusion when glucose levels were less than 4.4 mmol/L (<80 mg/dL) and initiated dextrose infusion. When glucose levels decreased to less than 3.3 mmol/L (<60 mg/dL), we treated hypoglycemia according to a standardized hypoglycemia protocol. Per protocol, patients treated in the pilot phase were not included in the analyzed cohort. Study coordinators obtained written informed consent from all patients who met eligibility criteria. We randomly assigned patients to receive intensive or conventional intraoperative insulin therapy. Randomization was computer-generated with permuted blocks of 4, with stratification according to surgeon, surgical procedure (coronary artery bypass grafting [CABG] with or without other procedures and no CABG), and diabetes. The randomization assignments were concealed in opaque, sealed, tamper-proof envelopes that were opened sequentially by study personnel after participants signed the patient consent form. We could not possibly know, before obtaining consent, the few patients who would not have intraoperative hyperglycemia (glucose concentration of 5.6 mmol/L or more [100 mg/dL]). Therefore, per protocol, patients who gave consent were randomly assigned, and those whose glucose levels were less than 5.6 mmol/L (<100 mg/dL) during surgery were not included in the final analyses. Intraoperative Period Intensive Treatment Patients in the intensive treatment group received a continuous intravenous insulin infusion, 250 units of NovoLin R (Novo Nordisk, Princeton, New Jersey) in 250 mL of 0.45% sodium chloride, when their blood glucose levels exceeded 5.6 mmol/L (>100 mg/dL). We adjusted the infusions to maintain blood glucose levels between 4.4 (80 mg/dL) and 5.6 mmol/L (100 mg/dL). We adjusted the dose according to a standardized algorithm used by anesthesiologists (Appendix Table 1). Appendix Table 1. Insulin Infusion Protocol* Conventional Treatment Patients in the conventional treatment group did not receive insulin during surgery unless their glucose levels exceeded 11.1 mmol/L (200 mg/dL). If glucose concentration was between 11.1 (200 mg/dL) and 13.9 mmol/L (250 mg/dL), patients received an intravenous bolus of 4 units insulin every hour until the glucose concentration was less than 11.1 mmol/L (<200 mg/dL). If the intraoperative glucose concentration was greater than 13.9 mmol/L (>250 mg/dL), patients received an intravenous infusion of insulin that was continued until the glucose level was less than 8.3 mmol/L (<150 mg/dL). In both study groups, we measured arterial plasma glucose concentration every 30 minutes, starting just before anesthetic induction by using hexokinase method on a Double P Modular System (Roche Diagnostics, Indianapolis, Indiana). Intraoperative procedures, including cardiopulmonary bypass, monitoring, laboratory testing, and treatment, were left to the discretion of anesthesiologists and cardiac surgeons. There was no standard protocol for monitoring and managing intraoperative potassium levels. Postoperative Period Intravenous insulin infusion was started in patients in the conventional treatment group on their arrival in the ICU. Thereafter, both study groups were treated identically, with the intravenous insulin infusion rates adjusted by a nursing staff that was not involved with the study according to a standard protocol. The target blood glucose range was 4.4 (80 mg/dL) to 5.6 mmol/L (100 mg/dL) (Appendix Table 1). Arterial blood glucose levels were measured every 1 to 2 hours by using the Accu-Check Inform blood glucose monitoring system (glucometer) (Roche Diagnostics). During the first 24 hours after surgery, patients were given only clear liquids by mouth; we did not administer subcutaneous insulin or oral diabetic medications during this time. Thereafter, the hospital diabetes consulting service saw all patients and provided individualized recommendations for ongoing care. Outcomes and Measurements The primary outcome variable was a composite of death, sternal wound infections, prolonged pulmonary ventilation, cardiac arrhythmias (new-onset atrial fibrillation, heart block requiring permanent pacemaker, or cardiac arrest), stroke, and acute renal failure within 30 days after surgery. Secondary outcome measures were length of stay in the ICU and hospital. Trained study personnel identified the occurrence of a complication through chart abstraction by using confirmable, objective criteria in accordance with standardized definitions from the Society of Thoracic Surgeons (STS) database committee (17). Personnel who assessed outcomes were not aware of patient treatment assignment or of the study hypothesis. Follow-up Procedures We contacted patients by telephone and used a standardized telephone survey at 30 days after surgery to assess outcomes that occurred after discharge. We considered pat

Intraoperative Hyperglycemia and Perioperative Outcomes in Cardiac Surgery Patients

OBJECTIVE To estimate the magnitude of association between intraoperative hyperglycemia and perioperative outcomes in patients who underwent cardiac surgery. PATIENTS AND METHODS We conducted a retrospective observational study of consecutive adult patients who underwent cardiac surgery between June 10, 2002, and August 30, 2002, at the Mayo Clinic, a tertiary care center in Rochester, Minn. The primary independent variable was the mean intraoperative glucose concentration. The primary end point was a composite of death and infectious (sternal wound, urinary tract, sepsis), neurologic (stroke, coma, delirium), renal (acute renal failure), cardiac (new-onset atrial fibrillation, heart block, cardiac arrest), and pulmonary (prolonged pulmonary ventilation, pneumonia) complications developing within 30 days after cardiac surgery. RESULTS Among 409 patients who underwent cardiac surgery, those experiencing a primary end point were more likely to be male and older, have diabetes mellitus, undergo coronary artery bypass grafting, and receive insulin during surgery (P< or =.05 for all comparisons). Atrial fibrillation (n=105), prolonged pulmonary ventilation (n=53), delirium (n=22), and urinary tract infection (n=16) were the most common complications. The initial, mean, and maximal intraoperative glucose concentrations were significantly higher in patients experiencing the primary end point (P<.01 for all comparisons). In multivariable analyses, mean and maximal glucose levels remained significantly associated with outcomes after adjusting for potentially confounding variables, including postoperative glucose concentration. Logistic regression analyses indicated that a 20-mg/dL increase in the mean intraoperative glucose level was associated with an increase of more than 30% in outcomes (adjusted odds ratio, 1.34; 95% confidence Interval, 1.10-1.62). CONCLUSION Intraoperative hyperglycemia is an independent risk factor for complications, including death, after cardiac surgery.

Effects of Basal Insulin Supplementation on Disposition of Mixed Meal in Obese Patients With NIDDM

Basal insulin supplementation has been used as a therapy for patients with non-insulin-dependent diabetes mellitus (NIDDM) who require insulin. To determine whether basal insulin supplementation in addition to lowering postabsorptive plasma glucose concentration also improves the postprandial pattern of glucose disposition, glucose metabolism after ingestion of a solid mixed meal was assessed in obese patients with NIDDM before and after treatment with ultralente and compared with glucose metabolism observed in nondiabetic subjects. Splanchnic uptake of ingested glucose clearance was assessed by including [2-3H]glucose (a tracer that only minimally cycles through glycogen) in a solid mixed meal. Postprandial gluconeogenesis was estimated by measuring the rate of incorporation of carbon dioxide into glucose. Net glucose and lipid oxidation were measured by indirect calorimetry. Both splanchnic uptake of ingested glucose (27 ± 1 vs. 14 ± 2 g) and postprandial hepatic glucose release (51 ± 5 vs. 24 ± 3 g) were greater (P < .001) in diabetic than in nondiabetic subjects. Although the percentage of postprandial hepatic glucose release accounted for by glucose synthesis from bicarbonate was similar in the two groups (25 ± 2 vs. 35 ± 5%), the absolute rate was greater in the diabetic patients (13 ± 1 vs. 8 ± 1 g; P < .05). Postprandial glucose oxidation and glucose disposal (measured either isotopically or by the forearm-catheterization technique) were similar in both groups. However, total lipid oxidation was increased in the diabetic patients. (P < .05). Two weeks of basal insulin supplementation lowered fasting glucose concentrations (from 219 ± 22 to 144 ± 21 mg/dl; P < .01) and integrated postprandial glycemic response (from 814 ± 68 to 621 ± 72 min · mg· ml−1) but not to normal. Although circulating insulin concentrations were two- to threefold greater (P < .02) after 3 mo of basal insulin supplementation, the postprandial pattern of glucose metabolism remained essentially the same. Basal insulin supplementation decreased (P < .05) both splanchnic uptake of ingested glucose and hepatic glucose release. The addition of a preprandial injection of soluble insulin to basal insulin supplementation further suppressed (P < .05) postprandial hepatic glucose release, thereby further improving postprandial glucose tolerance. These studies indicate that initial splanchnic glucose clearance, hepatic glucose release, and new glucose synthesis, as well as extrahepatic substrate metabolism, are altered in NIDDM after ingestion of a mixed meal. Basal insulin supplementation improves but does not normalize postprandial glucose metabolism.

A.S.P.E.N. Clinical Guidelines: Nutrition Support of Adult Patients With Hyperglycemia

BACKGROUND Hyperglycemia is a frequent occurrence in adult hospitalized patients who receive nutrition support. Both hyperglycemia and hypoglycemia (resulting from attempts to correct hyperglycemia) are associated with adverse outcomes in diabetic as well as nondiabetic patients. This American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) Clinical Guideline summarizes the most current evidence and provides guidelines for the desired blood glucose goal range in hospitalized patients receiving nutrition support, the definition of hypoglycemia, and the rationale for use of diabetes-specific enteral formulas in hospitalized patients. METHOD A systematic review of the best available evidence to answer a series of questions regarding glucose control in adults receiving parenteral or enteral nutrition was undertaken and evaluated using concepts adopted from the Grading of Recommendations, Assessment, Development and Evaluation working group. A consensus process was used to develop the clinical guideline recommendations prior to external and internal review and approval by the A.S.P.E.N. Board of Directors. RESULTS/CONCLUSIONS 1. What is the desired blood glucose goal range in adult hospitalized patients receiving nutrition support? We recommend a target blood glucose goal range of 140-180 mg/dL (7.8-10 mmol/L). (Strong) 2. How is hypoglycemia defined in adult hospitalized patients receiving nutrition support? We recommend that hypoglycemia be defined as a blood glucose concentration of <70 mg/dL (<3.9 mmol/L). (Strong) 3. Should diabetes-specific enteral formulas be used for adult hospitalized patients with hyperglycemia? We cannot make a recommendation at this time.

Accuracy of Roche Accu-Chek Inform Whole Blood Capillary, Arterial, and Venous Glucose Values in Patients Receiving Intensive Intravenous Insulin Therapy After Cardiac Surgery

Intravenous insulin protocols are increasingly common in the intensive care unit to maintain normoglycemia. Little is known about the accuracy of point-of-care glucometers for measuring glucose in this patient population or the impact of sample source (capillary, arterial, or venous whole blood) on the accuracy of glucometer results. We compared capillary, arterial, and venous whole blood glucose values with laboratory plasma glucose values in 20 patients after cardiac surgery. All 4 samples (capillary, arterial, and venous whole blood and laboratory plasma glucose) were analyzed hourly for the first 5 hours during intravenous insulin therapy in the intensive care unit. There were no significant differences between median capillary whole blood (149 mg/dL [8.3 mmol/L]) and laboratory plasma (151 mg/dL [8.4 mmol/L]) glucose levels. The median arterial (161 mg/dL [8.9 mmol/L]) and venous (162 mg/dL [9.0 mmol/L]) whole blood glucose levels were significantly higher than the median laboratory plasma glucose level. Capillary whole blood glucose levels correlate most closely with laboratory plasma glucose levels in patients receiving intensive intravenous insulin therapy after cardiac surgery.

Guidelines for refeeding the marasmic patient

Nutritional support of the malnourished patient can be lifesaving. However, the efficacy of total parenteral nutrition in this setting depends on: a) careful estimation of energy requirements, using the Harris-Benedict equation or indirect calorimetry; b) minimizing the fluid retention which invariably complicates refeeding in marasmus; c) adequate repletion of P, K, and Mg on a daily basis; and d) accurate assessment of the rate of weight regain. (Crit Care Med 1990; 18:1030)

Metabolic acidosis and thiamine deficiency.

We describe a 19-year-old patient who was receiving home parenteral nutrition in whom lactic acidosis developed. A review of her home parenteral nutrition formula revealed the absence of multivitamins, most significantly thiamine. After thiamine administration, the acidosis resolved, and the patient experienced pronounced clinical improvement. Clinicians must be aware that thiamine is essential for normal glucose metabolism and that thiamine deficiency can lead to lactic acidosis. Thiamine deficiency should be included in the differential diagnosis of lactic acidosis. The recent shortage of intravenous multivitamin preparations has led to documented cases of lactic acidosis as a result of thiamine deficiency, and a previous shortage led to several deaths due to lactic acidosis as a consequence of thiamine deficiency. All patients receiving parenteral nutrition must also receive adequate vitamin supplementation.

Nutrition Support in Hospitalized Patients With Diabetes Mellitus

Many physicians will manage the care of hospitalized patients with diabetes mellitus who require parenteral nutrition or enteral tube feeding. The nutritional assessment, indications for nutrition support, estimate of nutritional needs, and biochemical monitoring guidelines for critically ill patients with diabetes are similar to those for nondiabetic patients. In general, a weight loss of up to 10% of body weight is well tolerated and, in the absence of severe stress, the provision of dextrose-containing crystalloid solutions and electrolytes is adequate for as long as 7 to 10 days. Studies that demonstrate a beneficial influence of nutrition support on clinical outcome administered nutrition for a minimum of 1 week. No data have established that support for a briefer duration is of clinical benefit. An important goal in the care of the hospitalized patient with diabetes is to avoid the extremes of hypoglycemia and hyperglycemia. Herein we provide our approach to achieving glucose control in stressed hospitalized patients with diabetes mellitus who are receiving parenteral and enteral nutrition. Although evidence is increasing that hyperglycemia impairs immune function, well-designed prospective randomized trials are needed to determine the risks, costs, and benefits of achieving glucose control and of providing nutrition support to hospitalized patients with diabetes mellitus.