Nitroglycerin adsorption to a combination polyvinyl chloride, polyethylene intravenous administration set

Loss of nitroglycerin (NTG) from intravenous solutions to intravenous bags and administration sets has been well documented. This study was designed to examine a commercially available low adsorption administration set that was compatible with a volumetric infusion pump. A solution of NTG 100 micrograms/ml in dextrose 5% in glass bottles was used. Six study administration sets were tested. The infusion sets were connected to the NTG-containing glass bottles, filled as rapidly as possible, placed in the infusion pump, and set at the appropriate rate. Effluent was collected for NTG assay initially, and at 20 and 40 minutes, and 1, 1.5, 2, 3, 6, and 24 hours. The effects of flow rate were studied at 0.2 and 1.0 ml/min. The tubing performed similarly to other polyvinyl chloride (PVC)-containing sets at 0.2 ml/min and similar to non-PVC sets at 1.0 ml/min. The effect of an initial flush with 20-100 ml of 100 micrograms/ml NTG was also examined. An initial flush of 20 ml of 100 micrograms/ml NTG solution was found to enhance delivery of NTG immediately. NTG aliquots were stored frozen in glass vials prior to assay by high performance liquid chromatography.