Downward movement of syringe pumps reduces syringe output

We studied how lowering a syringe pump and changing the outflow pressure co uld affect syringe pump output. We experimentally reduced the height of thr ee different syringe pump systems by 80 cm (adult setting) or 130 cm (neona tal setting), as can happen clinically, using five flow rates. We measured the rime of backward flow, no flow and the total time without flow. An expo nential negative correlation was present between infusion rate and time wit hout flow (r(2)=0.809 to 0.972, P <0.01). Minimum flow rates of 4.4 and 2.6 mi h(-1) respectively were calculated to give 60 and 120 s without infusio n. The compliance of the different syringe pumps and their infusion systems was linearly correlated with the effective time without infusion (r(2)=0.8 63, P <0.05). We conclude that the height of the syringe pumps should not b e changed during transportation. If vertical movement of the syringe pump i s necessary, the drugs should be diluted so that the flow rate is at least 5 mi h(-1).