Intravenous Bolus-infusion Versus Sliding Scale of Insulin for Intra-operative Glycemic Control

Pre-operative blood glucose (BG) concentrations in type 2 diabetic patients undergoing elective non-cardiac surgery; have an increased incidence of in-hospital morbidity for cardiopulmonary and infectious complications. Also, hyperglycemia is associated with increased production and impaired scavenging of oxygen reactive species, polymorph nuclear neutrophil dysfunction and decreased intracellular killing, resulting in poor wound healing and increased risk of infection. Thus, perioperative optimal glucose management contributes to reduced morbidity and mortality. Recommendations favor moderate levels of capillary blood glucose (CBG); maintaining it in the range of 140-180 mg/dl.

Peri-operative doses of rapidly acting insulin for glycemic control could be done by the sliding scale or the bolus-infusion approaches. The sliding scale of insulin is commonly used to manage peri-operative hyper-glycaemia. It involves administering prescribed doses of insulin when the CBG is within determined ranges and withholding insulin when the CBG is within normal range. When used as a sole therapy; it results in under-insulinisation and thus hyper-glycaemia. The use of a dynamic insulin regimen like the intravenous bolus-infusion approach; allows adjusting the blood glucose level according to the insulin sensitivity of each patient, thus, better glucose control and less variations than the intermittent intravenous bolus of short-acting insulin in the sliding scale despite the same blood glucose target.