Cleveland Clinic Cardiovascular Intensive Care Unit Insulin Conversion Protocol

Abstract

Background: The importance of near-normal blood glucose in the immediate postoperative period is generally accepted and is best achieved in the perioperative period with a constant intravenous (IV) infusion of insulin. This requires intensive nursing only achievable in an intensive care unit (ICU) setting. Glucose management after transfer to a regular nursing floor (RNF) has not been studied systematically. In August 2006, the Cleveland Clinic began using long-acting insulin glargine as the insulin infusion was terminated in the ICU. Methods: This prospective analysis examined all patients receiving IV insulin infusion after cardiothoracic surgery in a 1 month period. The analyses evaluated the safety and efficacy of a protocol using a transition to subcutaneous insulin glargine of 50% of the calculated 24 h requirement at the end of the ICU insulin infusion protocol in preparation for transfer to the RNF. Results: Only 1 patient in 99 developed hypoglycemia, and no patient suffered severe hypoglycemia (glucose < 40 mg/dl), while the majority (70%) had euglycemia (glucose between 70 and 150 mg/dl). Conclusions: This approach was both safe—as there was very little hypoglycemia (1 patient in 99)—and effective, as blood sugar was well controlled in most subjects. Efficacy for achieving euglycemia was 70%. Efficacy was likely reduced because of the upper limit of insulin glargine dosage imposed by some providers as a safety consideration. Although there was a physician option to override, the maximum protocol dose of 30 U was rarely exceeded, leading to inadequate dosing in some subjects who required high insulin infusion rates in the ICU.

Evaluation of Glycemic Control with a Pharmacist-Managed Post-Cardiothoracic Surgery Insulin Protocol

“…However, it should be noted that the rates of post-operative hyperglycemia in this current study were much lower than that in Olanksy's study [7]. One possible explanation for this discrepancy may be related to the advancement of perioperative care and development of less invasive surgical techniques since Olanksy's study was conducted in 2007 [7]. As surgeries have evolved to become less invasive, it would be expected that less stress would be induced on the body which in turn could result in less post-operative hyperglycemia.…”

“…This estimate was based off of results from a previous study evaluating glycemic control with a post-cardiothoracic insulin protocol [7].…”

Comparison of 3 Algorithms for Basal Insulin in Transitioning from Intravenous to Subcutaneous Insulin in Stable Patients after Cardiothoracic Surgery

“…Firstly, there was a difference in hypoglycemia between the 50% group and the other 2 groups, suggesting that the 50% dose is safer for most patients. An observational study of cardiac surgery patients also reported a low incidence of hypoglycemia (1%) over an unspecified time period using the 50% conversion factor (8). Secondly, the small, albeit nonsignificant difference in the initial dose of detemir and initial AM glucose is completely lost by day 2, suggesting that the initial dose will have little impact on overall glycemia.…”

Management of Hyperglycemia During the Perioperative Period

“…Similar to previously published recommendations [76][77][78] we suggest using 60-80% of the total daily calculated insulin requirement based on the final 6 h of the infusion rate. Other institutions have attained modest and safe control using a transition from IV to SQ insulin of 50% of the daily calculated dose [79]. • Determine level of glycemic control • Discontinue metformin prior to surgery in patients with renal dysfunction and who will receive IV contrast • Avoid oral agents and noninsulin injectables the day of surgery • Base perioperative use of insulin on safety concerns and maintenance of adequate glucose control • Use basal (long-, intermediate-acting, or continuous SQ rapid-acting)-prandial/supplemental (short-or rapid-acting) insulin • Avoid alterations of long-acting basal insulin (glargine or detemir) the day before surgery unless there is report of hypoglycemia and in patients on diet restriction preoperatively.…”