The Impact of Insulin Adsorption onto the Infusion Sets in the Adult Intensive Care Unit

The difficulty in achieving tight glycemic control (TGC)1,2 in the adult intensive care unit (ICU) is well documented.3,4 We aimed to explore the impact of insulin adsorption onto infusion sets in the laboratory and to assess retrospectively if higher insulin doses are required after syringe changes in practice in the ICU. �dsorption is reported to occur predominantly during the first hour of infusion, after which binding sites are saturated.5 There is greater insulin recovery with faster flow rates and higher insulin concentration.6 The clinical significance of such adsorption in the ICU setting is uncertain.5 In our study—approved by the local ethics committee—adsorption of insulin onto the giving sets used in our adult ICU was analyzed. The infusion set used was a 5� � ml polypropylene syringe (BD Plastipak ®) and 1.6 ml/2��� � cm polyethylene (PE) tubing (Cardinal Health, extension set). In the laboratory, the concentration investigated was 1 U/ml of neutral insulin in sodium chloride ��.9%. The concentrations were determined using a high�performance liquid chromatography method with a Jupitor 3����, 5 μm C18, 25� � mm x 4.6 mm column (Phenomenex), a mobile phase of 30 % acetonitrile and 0.1 % TFA in water, and ultraviolet detection at �10 nm. �ignificant insulin adsorption of 10% occurred during the first hour of an infusion when the infusion rate was 1 ml�h ( / Figure 1). Our experience suggests that this is a common infusion rate used in intensive insulin therapy. �o significant adsorption occurred when the infusio