Do antisiphon valves reduce flow irregularities during vertical displacement of infusion pump systems?
Vertical displacement of syringe pumps may cause irregular drug delivery due to hydrostatic pressure changes in the infusion line. The extent of flow fluctuations depends on the internal compliance of infusion lines, syringes and syringe pumps. We evaluated whether pressure regulation by antisiphon valves (ASV) reduces the flow variation during vertical displacement of 50 ml standard syringes and infusion pumps. An infusion assembly comprising a standard 50 ml BD Plastipak or a 50 ml Fresenius syringe, with syringe pump and 2 m low compliance infusion line was used for in vitro measurement of fluid delivery. The assembly was tested without ASV, and with two ASVs of differing operating pressure (ASV:75: valve opening pressure = 75 mmHg; ASV:155, 155 mmHg). Retrograde aspiration volume, zero-drug delivery time and valve opening bolus were determined after lowering the syringe pump by 50 cm. After elevating the syringe pump to its initial position the ensuing infusion bolus was recorded.
