No Patient Left Behind: Evaluation and Design of Intravenous Insulin Infusion Algorithms

Perioperative Management of the Diabetic Patient Referred to Cardiac Surgery

Currently there is a progressive increase in the prevalence of diabetes in a referred for cardiovascular surgery. Benefits of glycemic management (< 180 mg/dL) in diabetic patients compared to patients without diabetes in perioperative cardiac surgery. The purpose of this study is to present recommendations based on international evidence and adapted to our clinical practice for the perioperative management of hyperglycemia in adult patients with and without diabetes undergoing cardiovascular surgery. This update is based on the latest current literature derived from articles and guidelines regarding perioperative management of diabetic patients to cardiovascular surgery.

Managing hyperglycemia in hospitalized patients

Insulin infusion is used in the critical care setting for prevention of hyperglycemia and is administered most safely under a structured, dynamic, dose-defining algorithm. The ordering of basal-prandial-correction SC insulin therapy, appropriate for most hospitalized patients who are eating, is simplified and standardized to excellence by the development of institutional order sets or computerized order entry templates. Basal insulin therapy is prescribed as intermediate-acting insulin or long-acting insulin analogue. Prandial insulin therapy is delivered with meals to prevent excessive glycemic excursions from occurring after ingestion of meals and is prescribed as rapid-acting insulin analogue. Correction-dose insulin therapy is ordered as small doses of rapid-acting insulin analogue delivered to correct hyperglycemia and is prescribed with appropriate timing so as to avoid stacking with previously administered doses of rapid-acting insulin analogue. Patients knowledgeable in diabetes self-management will experience satisfaction under an institutional policy that allows self-management to continue under appropriate conditions during hospitalization. To craft appropriate institutional tools for patient care, the input and consensus of a multidisciplinary group of health care professionals, including primary care providers and hospitalists, as well as specialists in diabetes with backgrounds in endocrinology, nutrition and dietetics, nursing, pharmacy, laboratory sciences, and quality assurance, is required.

Pharmacotherapies for diabetes management: an update for the practicing clinician

Over the past several years, the pharmacologic options for the management of glycemic control have tremendously expanded. Whereas prior to the introduction of metformin therapy in 1995 the only alternatives were human insulin therapies and sulfonylurea drugs, we now have the option of using several different classes of oral antidiabetic drugs, injectable non-insulin therapies, and insulin analogs. In this article we present a functional classification of glycemic therapies available for the treatment of diabetes in an attempt to provide the clinician with a practical framework which optimize blood glucose management. Patients with diabetes, especially type 2 diabetes, are often managed with a wide variety of injectable and non-injectable options in the attempt to improve glycemic control and glycemic variability, minimize hypoglycemia (as well as weight gain) and prevent both micro- and macrovascular complications. We specifically focus on novel therapies and present macrovascular complications. We specifically focus on novel therapies and present information about their efficacy and safety, as well as potential contraindications. The last section of this paper will present some suggestions for how to manage glycemia in the in-patient setting, including the use of rapid and long-acting insulin preparations to cover fasting and nutritional needs, as well as the proper use of insulin scales.

Intensive insulin therapy in critical care: a review of 12 protocols

OBJECTIVE

To review performance characteristics of 12 insulin infusion protocols.

RESEARCH DESIGN AND METHODS

We systematically identify and compare 12 protocols and then apply the protocols to generate insulin recommendations in the management of a patient with hyperglycemia. The main focus involves a comparison of insulin doses and patterns of insulin administration.

RESULTS

There is great variability in protocols. Areas of variation include differences in initiation and titration of insulin, use of bolus dosing, requirements for calculation in adjustment of the insulin infusion, and method of insulin protocol adjustments. Insulin recommendations for a sample patient are calculated to highlight differences between protocols, including the patterns and ranges of insulin dose recommended (range 27-115 units [mean +/- SD 66.7 +/- 27.9]), amount recommended for glucose readings >200 mg/dl, and adjustments nearing target glucose.

CONCLUSIONS

The lack of consensus in the delivery of intravenous insulin infusions is reflected in the wide variability of practice noted in this survey. This mandates close attention to the choice of a protocol. One protocol may not suffice for all patients.

Practical aspects of intensive insulinization in the intensive care unit

PURPOSE OF REVIEW

Strategies used for intensive insulin therapy of critically ill patients and differences of approach according to medical condition are reviewed.

RECENT FINDINGS

Acceptance of proposed glycemic targets for critically ill patients has been tempered by uncertainties about benefit of strict glycemic control for specific target subpopulations, differences between treatment centers, optimal timing and duration of intervention, and safety. Present-day intravenous insulin infusion protocols may perform well only for restricted populations. Assessment of protocol performance requires knowledge of algorithm behavior on or near the narrow target range and, using the patient as unit of observation, examination of glycemic variability. Systems of the future will permit adjustment of algorithm parameters to meet individual- or population-specific targets and match carbohydrate exposure.

SUMMARY

Attainment and preservation of glycemic control among critically ill patients are best attempted with intravenous insulin infusion. Advances in the design of decision support and insulin delivery systems, and progress in the technology of continuous blood glucose monitoring, are likely to reduce the risk of hypoglycemia, without compromise of target range control, such that the patient outcomes enjoyed by experienced centers in the future will prove generalizable to others through the extension of new technologies.

Performance of a dose-defining insulin infusion protocol among trauma service intensive care unit admissions

BACKGROUND

Among critically ill patients, glycemic control reduces mortality and morbidities, but the use of intravenous insulin infusion is complicated by hypoglycemia. Having a standardized algorithm increases the likelihood of effective and safe utilization of intravenous insulin therapy. A tabular dose-defining protocol for intravenous insulin infusion is described, containing design elements intended to minimize risk for hypoglycemia while seeking control in a narrow target range, and performance is evaluated among critically ill trauma service patients.

METHODS

The protocol assigns insulin infusion rate (IR) for ranges of blood glucose (BG). The columns are arranged in order of increasing maintenance rate (MR) for insulin infusion. Patient column assignment is determined according to rate of change of BG. During stable column assignment, the IR is a function of column MR and BG. Within-column, the protocol formula provides that (a) for BG between 70 mg/dL and target BG, the IR increases exponentially to the column MR; and (b) for BG above upper target BG range, the IR increases linearly as an adaptation of the rule of 1800, with slope determined by the column MR. Values for IR calculated by formula are rounded to correspond to BG ranges of the table. Performance was assessed in 27 sequential runs among 24 trauma service patients admitted to a surgical intensive care unit (2004-2005).

RESULTS

Using point-of-care measurements, mean preinfusion BG was 230.0 +/- 67.9 mg/dL. BG < 140 mg/dL was reached during all 27 runs (median time 5.0 h), and target BG was < 110 mg/dL during 25 runs (median time 11.0 h). For the group of runs attaining target before interruption of insulin infusion, the average +/- SD of the principal measure of glycemic control, the within-run mean BG, was 113.7 +/- 14.8 mg/dL (coefficient of variation 13%, n = 25 runs). After attaining target, the average within-run SD for BG was 22.9 mg/dL. The within-run frequency of hypoglycemic measurements (BG < 70 mg/dL) as a percentage of BG determinations was 2.4%. In this series, no instance of BG <50 mg/dL was seen.

CONCLUSIONS

This report describes a nurse-implemented tabular protocol for intravenous insulin infusion having the advantages of efficacy, safety, and simplicity of use. Wide variability of IR in the neighborhood of BG 110 mg/dL is associated with stable BG response, and protection against hypoglycemia is achieved by rapid decline of IR at BGs in or below the target range.