Use of separate insulin infusions with total parenteral nutrition

The efficacy, safety, and cost effectiveness of treating total parenteral nutrition (TPN)-induced hyperglycemia with a continuous insulin infusion, separate from the actual TPN bottle, was evaluated. A patient was included in the study if his serum glucose was greater than 200 mg/dl at a TPN infusion rate of less than 75% of the calculated caloric goal. The insulin infusion was run into the central line with the TPN via a Y-connector. At the patient's caloric goal, the infusion was stopped and the insulin was added to the TPN bottle, after the glucose was in the 100-200 mg/dl range for 24 hr. Sixteen patients including five known diabetics were studied, with data gathered retrospectively through chart review. It was estimated that 7.3 liters of TPN per patient were saved, compared to the amount used when insulin was added to newly prepared bottles of TPN each time a dosage change was required. In our institution, this amounts to a savings of $395.00 per patient (including charges for materials and an infusion pump for the insulin infusion). We conclude that separate insulin infusion is a reasonable and cost-effective alternative when treating glucose intolerance in patients receiving TPN.