Addition of Insulin to Parenteral Nutrition for Control of Hyperglycemia

Administration of parenteral nutrition (PN) may result in hyperglycemia in patients with preexisting diabetes or disease-related insulin resistance, and it can be associated with increased rates of complications. Treatment requires insulin therapy. Insulin can be administered subcutaneously, intravenously via a variable rate sliding scale, or by adding it directly to the PN. The last method is a potentially attractive technique for a number of reasons-it could deliver the insulin intravenously at a steady rate alongside carbohydrates, and in malnourished patients with little subcutaneous tissue, it may prevent the need for frequent insulin injections. Despite such potential advantages, the addition of insulin to PN remains controversial, largely with respect to the bioavailability of insulin in PN and resultant concerns of the risk of hypoglycemia. There is a paucity of long-term quality controlled studies to address this question. The available literature suggests that, at least in the short term, insulin addition to PN can achieve reasonable glycemic control with low rates of hypoglycemia, and the technique compares favorably with the use of long-acting insulin preparations. This literature review finds a wide range of values reported for insulin availability via PN, ranging from 44% to 95% depending on the type of PN container material used and the presence of added vitamins and trace elements. Few studies looking at glycemic control among patients receiving home PN were found, and larger prospective trials are needed to assess the efficacy and safety of this technique in this patient group.