Preoperative Glucose Levels Research Articles

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

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

Metabolic consequences of a 50% partial pancreatectomy in humans

Partial pancreatectomy is frequently performed in patients with pancreatic tumours or chronic pancreatitis, but little is known about the metabolic impact of this intervention. We examined the effects of approximately 50% partial pancreatectomy on glucose homeostasis and insulin secretion. Fourteen patients with chronic pancreatitis, ten patients with pancreatic carcinoma and 13 patients with benign pancreatic tumours or extra-pancreatic masses (control group) underwent 240 min oral glucose tolerance tests before and after pancreatic tail-resection (n = 12), duodenopancreatectomy (n = 19) or duodenum-preserving pancreatic-head resection (n = 6). Partial pancreatectomy led to a reduction in post-challenge insulin excursions by 49% in chronic pancreatitis patients, 52% in carcinoma patients and 55% in controls (p < 0.05). Nevertheless, post-challenge glucose concentrations were transiently ameliorated after surgery (p < 0.001). In the control participants, pancreatic-head resection caused a transient reduction of post-challenge glycaemia, whereas pancreatic-tail resection increased both fasting and post-challenge glycaemia (p < 0.05). Insulin sensitivity was highest in chronic pancreatitis patients before surgery (p < 0.01), but remained unchanged by the partial pancreatectomy. High pre-operative body weight and elevated fasting glucose levels were associated with poor glycaemic control after surgery. Insulin secretion is diminished after pancreatic-head and -tail resection, but post-challenge glucose concentrations can be ameliorated after pancreatic-head resection. These data highlight the unequal impact of different surgical procedures on glucose control and suggest that obesity and high pre-operative glucose levels should be considered as risk factors for the development of hyperglycaemia after pancreatic surgery.

Usefulness of Preoperative Oral Glucose Tolerance Testing for Perioperative Risk Stratification in Patients Scheduled for Elective Vascular Surgery

Patients scheduled for major vascular surgery are screened for cardiac risk factors using standardized risk indexes, including diabetes mellitus (DM). Screening in patients without a history of DM includes fasting glucose measurement. However, an oral glucose tolerance test (OGTT) could significantly improve the detection of DM and impaired glucose tolerance (IGT) and the prediction of perioperative cardiac events. In a prospective study, 404 consecutive patients without signs or histories of IGT or DM were included and subjected to OGTT. The primary study end point was the composite of perioperative myocardial ischemia, assessed by 72-hour Holter monitoring using ST-segment analysis and troponin release. The primary end point was noted in 21% of the patients. IGT was diagnosed in 104 patients (25.7%), and new-onset DM was detected in 43 patients (10.6%). The OGTT detected 75% of the patients with IGT and 72% of the patients with DM. Preoperative glucose levels significantly predicted the risk for perioperative cardiac ischemia; odds ratios for DM and IGT were, respectively, 3.2 (95% confidence interval 1.3 to 8.1) and 1.4 (95% confidence interval 0.7 to 3.0). In conclusion, the prevalence of undiagnosed IGT and DM is high in vascular patients and is associated with perioperative myocardial ischemia. Therefore, an OGTT should be considered for all patients who undergo elective vascular surgery.

A novel technique for heterotopic vascularized pancreas transplantation in mice to assess ischemia reperfusion injury and graft pancreatitis

Although various suture techniques for murine pancreas transplantation have been described, severe limitations have limited their widespread use. We therefore designed a surgical model for cervical heterotopic pancreas transplantation using a cuff technique. C57BL6 mice were used as donor and recipient pairs. Recipients were rendered diabetic with streptozotocin and subsequently transplanted. The donor pancreas was isolated using a no-touch technique and then placed in the recipient's cervical region. Vascular anastomoses were completed by pulling the portal vein over the external jugular vein cuff and the donor aortic segment over the carotid cuff and fixed with an 8-0 ligature thereby facilitating a nonsuture technique. To test applicability of this model, graft microcirculation was evaluated by intravital microscopy after prolonged cold ischemia (16 h). The immediate success rate was >90%. Donor operation lasted 40 +/- 5 min; dissection of recipient vessels lasted 20 +/- 4 min. Revascularization time was 4 to 6 min, resulting in a total pancreas ischemia time of 33 +/- 6 min. No thromboembolic complications on the cuff side were observed. Preoperative glucose levels were 518 +/- 59 mg/dl and returned to normal by postoperative day 1 (88 +/- 13 mg/dl). Histology on postoperative days 10 and 30 showed almost normal islet cell and acinar architecture of all grafts. In groups with prolonged cold ischemia, graft microcirculation was significantly reduced and paralleled by increased inflammation, interstitial edema, hemorrhage, acinar vacuolization, and focal areas of necrosis compared with nonischemic controls. This new model may provide an excellent tool to further investigate the pathophysiology as well as novel therapeutic strategies of preservation, ischemia reperfusion injury, and graft pancreatitis.

Increased preoperative glucose levels are associated with perioperative mortality in patients undergoing noncardiac, nonvascular surgery

To determine the relationship between preoperative glucose levels and perioperative mortality in noncardiac, nonvascular surgery. We performed a case-control study in a cohort of 108 593 patients who underwent noncardiac surgery at the Erasmus MC during 1991-2001. Cases were 989 patients who underwent elective noncardiac, nonvascular surgery and died within 30 days during hospital stay. From the remaining patients, 1879 matched controls (age, sex, calendar year, and type of surgery) were selected. Information was obtained regarding the presence of cardiac risk factors, medication, and preoperative laboratory results. Preoperative random glucose levels <5.6 mmol/l (110 mg/dl) were normal. Impaired glucose levels in the range of 5.6-11.1 mmol/l were prediabetes. Glucose levels >or=11.1 mmol/l (200 mg/dl) were diabetes. Preoperative glucose levels were available in 904 cases and 1247 controls. A cardiovascular complication was the primary cause of death in 207 (23%) cases. Prediabetes glucose levels were associated with a 1.7-fold increased mortality risk compared with normoglycemic levels (adjusted odds ratio (OR) 1.7 and 95% confidence interval (CI) 1.4-2.1; P<0.001). Diabetes glucose levels were associated with a 2.1-fold increased risk (adjusted OR 2.1 and 95% CI 1.3-3.5; P<0.001). In cases with cardiovascular death, prediabetes glucose levels had a threefold increased cardiovascular mortality risk (adjusted OR 3.0 and 95% CI 1.7-5.1) and diabetes glucose levels had a fourfold increased cardiovascular mortality risk (OR 4.0 and 95% CI 1.3-12). Preoperative hyperglycemia is associated with increased (cardiovascular) mortality in patients undergoing noncardiac, nonvascular surgery.

Insulin therapy in the diabetic surgical patient: metabolic and hormone response to low dose insulin infusion.

We examined carbohydrate metabolism and endocrine responses during elective abdominal surgery in nondiabetic and in insulin-treated diabetic patients. The diabetic patients were divided into two groups: those receiving preoperative subcutaneous (s.c.) insulin and those receiving continuous, low dose intravenous (i.v.) insulin infusions. Glucose, glucagon, cortisol, growth hormone, and insulin levels were measured preoperatively, intraoperatively, and for up to 6 h postoperatively. In the nondiabetic subjects glucose levels rapidly rose at initiation of surgery and continued to increase slowly, reaching a peak of 269 ± 26 (SEM) mg/dl at 60 min into the recovery period. Insulin levels also slowly increased throughout surgery, peaking at 103 ± 32.6 (SEM) uU/ml at 60 min into the recovery period, which was followed by a prompt decline in glucose levels. Glucagon levels remained relatively stable during surgery, but increased steadily during the recovery period to 300 ± 59 (SEM) pg/ml at the end of the observation period. Both cortisol and growth hormone rose during surgery, with growth hormone reaching a peak at 45 min [31.1 ± 13.8 (SEM) ng/ml], while cortisol continued to increase, plateauing during the recovery period at about 30 μg/dl. In the diabetic patients there were no differences in preoperative glucose, glucagon, cortisol, and growth hormone levels between the two treatment groups, and only the glucose level was different from the nondiabetic group. During surgery, there were trends toward lower plasma glucose levels in the early intraoperative phase in the diabetic patients receiving the continuous, low dose i.v. insulin infusion compared with those who received conventional preoperative s.c. insulin. There was no difference in the timing or magnitude of the rise of the measured hormones between the two groups. We conclude that a continuous, low dose i.v. insulin infusion at the dose used (1 U/h) is as effective in the treatment of the diabetic surgical patient as conventional preoperative s.c. insulin administration. Endocrine and metabolic responses to surgery are not different in the two forms of insulin administration.