Delivery of tobramycin by three infusion systems

The delivery of tobramycin was studied at the flow rates of 2, 4 and 6 ml/h after injection into the various sites of IVAC, IMED and Auto Syringe infusion systems. The actual times were markedly longer than the predicted times of delivery, especially for all sites of IVAC system and Buretrol site of IMED system. About 20% of tobramycin was never delivered by the Buretrol sites of IVAC and IMED during a 12-hour period at the flow rate of 2 ml/h. If tobramycin delivery is to be assured within 30 min after the start of infusion, at 2-6 ml/h, proximal y-site of IMED or Auto Syringe systems must be utilized. These data suggest the need for considering the method of tobramycin infusion when monitoring and interpreting its serum concentrations.