A comparison of two intravenous insulin regimens among surgical patients with insulin-dependent diabetes mellitus

Clinical recommendations in the management of the patient with type 1 diabetes on insulin pump therapy in the perioperative period: a primer for the anaesthetist

Insulin pump therapy is increasingly common in patients with type 1 diabetes. Many of these patients will require surgery at some point in their lifetime. Few doctors will have experience of managing these patients, and little evidence exists to assist in the development of guidelines for patients with insulin pump therapy, undergoing surgery.It is clear that during emergency surgery insulin pump therapy is not appropriate and should be discontinued, but patients undergoing some elective surgery can and should continue insulin pump therapy, without any adverse effect on their blood sugar control, or on the outcome of their surgery. Individual hospitals need to formalize guidance on the management of patients receiving continuous subcutaneous insulin therapy, to allow patients the choice to continue their therapy during surgery. This expert opinion presents anaesthetists with a suggested clinical framework to help facilitate continued insulin pump therapy, during elective surgery and into the postoperative period.

A novel glucose-insulin infusion maintains perioperative glycaemic control through multiple transitions of care

To measure the efficacy of the Glucose-Insulin Infusion--Parkland Protocol (GIPPr) compared to subcutaneous (SC) insulin, blood glucose readings were reviewed in diabetic adults admitted for surgical intervention of a soft tissue or bone infection in Dallas, Texas. Hypoglycaemia occurred in 0.69% of readings in GIPPr-treated patients compared to 4.52% in SC-treated patients. The GIPPr maintained a higher proportion of blood glucose readings between 3.89-10 mmol/L compared to SC insulin (85.40% versus 50.68%).

Perioperative glycaemic control for diabetic patients undergoing surgery

BACKGROUND

Patients with diabetes mellitus are at increased risk of postoperative complications. Data from randomised clinical trials and meta-analyses point to a potential benefit of intensive glycaemic control, targeting near-normal blood glucose, in patients with hyperglycaemia (with and without diabetes mellitus) being submitted to surgical procedures. However, there is limited evidence concerning this question in patients with diabetes mellitus undergoing surgery.

OBJECTIVES

To assess the effects of perioperative glycaemic control for diabetic patients undergoing surgery.

SEARCH METHODS

Trials were obtained from searches of The Cochrane Library, MEDLINE, EMBASE, LILACS, CINAHL and ISIS (all up to February 2012).

SELECTION CRITERIA

We included randomised controlled clinical trials that prespecified different targets of perioperative glycaemic control (intensive versus conventional or standard care)

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias. We summarised studies using meta-analysis or descriptive methods.

MAIN RESULTS

Twelve trials randomised 694 diabetic participants to intensive control and 709 diabetic participants to conventional glycaemic control. The duration of the intervention ranged from just the duration of the surgical procedure up to 90 days. The number of participants ranged from 13 to 421, and the mean age was 64 years. Comparison of intensive with conventional glycaemic control demonstrated the following results for our predefined primary outcomes: analysis restricted to studies with low or unclear detection or attrition bias for infectious complications showed a risk ratio (RR) of 0.46 (95% confidence interval (CI) 0.18 to 1.18), P = 0.11, 627 participants, eight trials, moderate quality of the evidence (grading of recommendations assessment, development and evaluation - (GRADE)). Evaluation of death from any cause revealed a RR of 1.19 (95% CI 0.89 to 1.59), P = 0.24, 1365 participants, 11 trials, high quality of the evidence (GRADE).On the basis of a posthoc analysis, there is the hypothesis that intensive glycaemic control may increase the risk of hypoglycaemic episodes if longer-term outcome measures are analysed (RR 6.92, 95% CI 2.04 to 23.41), P = 0.002, 724 patients, three trials, low quality of the evidence (GRADE). Analysis of our predefined secondary outcomes revealed the following findings: cardiovascular events had a RR of 1.03 (95% CI 0.21 to 5.13), P = 0.97, 682 participants, six trials, moderate quality of the evidence (GRADE) when comparing the two treatment modalities; and renal failure also did not show significant differences between intensive and regular glucose control (RR 0.61, 95% CI 0.34 to 1.08), P = 0.09, 434 participants, two trials, moderate quality of the evidence (GRADE). We did not meta-analyse length of hospital stay and intensive care unit (ICU) stay due to substantial unexplained heterogeneity. Mean differences between intensive and regular glucose control groups ranged from -1.7 days to 2.1 days for ICU stay and between -8 days to 3.7 days for hospital stay (moderate quality of the evidence (GRADE)). One trial assessed health-related quality of life in 12/37 (32.4%) of participants in the intervention group and 13/44 (29.5%) of participants in the control group, and did not show an important difference (low quality of the evidence (GRADE)) in the measured physical health composite score of the short-form 12-item health survey (SF-12). None of the trials examined the effects of the interventions in terms of costs.

AUTHORS' CONCLUSIONS

The included trials did not demonstrate significant differences for most of the outcomes when targeting intensive perioperative glycaemic control compared with conventional glycaemic control in patients with diabetes mellitus. However, posthoc analysis indicated that intensive glycaemic control was associated with an increased number of patients experiencing hypoglycaemic episodes. Intensive glycaemic control protocols with near-normal blood glucose targets for patients with diabetes mellitus undergoing surgical procedures are currently not supported by an adequate scientific basis. We suggest that insulin treatment regimens, patient- and health-system relevant outcomes, and time points for outcome measures should be defined in a thorough and uniform way in future studies.

Perioperative blood glucose monitoring in the general surgical population

Several studies have shown a relationship between poor outcome and uncontrolled blood glucose (BG) in cardiac, neurosurgical, critical care, and general surgical patients. A major study showed that tight glycemic control (80-110mg/dl) was related to increased mortality. Based on evidence from controlled studies, the American Diabetes Association, and the Society of Thoracic Surgeons, maintaining intraoperative BG levels in the 140-180 mg/dl range seems appropriate. Optimization of the patient's preoperative medications and the use of insulin infusions, as well as surgical and anesthetic technique, are important factors for achieving desirable perioperative BG control. Minimizing BG variability during surgery should be part of the glycemic control strategy. Advances in real-time glucose monitoring may soon benefit hospitalized diabetes and nondiabetes patients.

Strategies for managing the diabetic patient

Diabetes mellitus is now classified as either 'type 1' (failure of endogenous insulin production) or 'type 2' ('insulin resistance') and can be diagnosed if fasting blood glucose is >6.1 mmol/l (110mg/dl) on two separate occasions or there is unequivocal hyperglycaemia with acute metabolic decompensation or obvious symptoms. The prevalence of the disease is rising and may be as great as 12-14% in western populations aged over 40 years. Diabetes is complicated by micro- and macrovascular consequences of chronically elevated blood glucose concentrations, and diabetic patients are over-represented in hospital populations, particularly among patients requiring surgical interventions. It is associated with increased perioperative mortality and morbidity. Evidence is now accumulating that intensive glycaemic monitoring and the administration of insulin infusions to achieve tight glycaemic control are associated with an improvement of both perioperative mortality and morbidity.

Inpatient management of diabetes

Hyperglycemia is common in hospitalized patients with diabetes and contributes to poor outcomes in this population. Use of intravenous insulin protocols for patients who are unable to eat, continuation of usual insulin regimens for those who are eating, pre-meal insulin supplements for hyperglycemia, and avoidance of sliding-scale insulin can help the clinician improve glycemic control. Careful attention to management of diabetes in the hospitalized patient decreases the risk of ketoacidosis, fluid and electrolyte abnormalities, and infection; in critically ill postoperative patients, tight glucose control with insulin administration decreases the risk of death.

Perioperative management of type 1 diabetes mellitus

Clearly, perioperative management of diabetic patients requires thorough preoperative evaluation and planning whenever possible. A firm understanding of the pathophysiology of type 1 diabetes mellitus, the metabolic stress response, and the interactions between various forms of insulin and other variables such as supplemental nutrition and glucocorticoids can greatly assist in achieving a positive outcome. Consultation with an endocrinologist, internist, or other primary care provider comfortable with managing type 1 diabetes patients is strongly recommended to assist in the details of in-patient care and overseeing of proper ancillary support. It may also be helpful to allow the patient to function as an active decision-maker in the coordination of care, especially because a large percentage of type 1 diabetes patients (particularly those who are on insulin pumps) are well-educated about their disease process and their own physiologic idiosyncrasies. This knowledge can save valuable time and effort toward achieving the ultimate united goal of avoiding perioperative morbidity and mortality by maximizing glycemic control.

Preparing the azotemic diabetic patient for surgery

Azotemic diabetic patients have more risk of complications during or after surgery than those without diabetes and azotemia. These complications include infection, excessive bleeding, cardiovascular events, and electrolyte imbalance. The appropriate preoperative evaluation, measures to be taken to avoid the complications, and how to adequately manage blood sugar during surgery is discussed.