Start-up delays of infusion syringe pumps

Background: We performed a bench experiment to investigate the extent of start-up delays in fluid delivery for four different syringe pumps after initially placing the infusion syringe in the syringe pump. Methods: Pump performance was determined at an infusion rate of 1 ml.h(-1) with and without a fluid bolus delivered by the infusion pump prior to connecting the infusion line to the simulated patient. Results: The time (mean +/- SD) from starting the pump up to first fluid delivery (t(1)) differed considerably between pumps (from 6.75 +/-4.4 to 57.2 +/- 28.6 min) as did the time to steady state fluid delivery (t(2)) (from 19.6 +/-9.3 to 76.3 +/- 29.0 min). Applying an initial bolus of 2 ml before connecting the line to the simulated patient practically eliminated the delay in fluid delivery (t(1) ranging from 0.3 +/-0.1 to 1.1 +/-0.8 min). This manoeuvre also reduced the time to steady flow delivery (t(2) from 6.0 +/-3.1 to 11.1 +/-4.3 min, P<0.001) and minimized the differences between syringe pumps. Conclusions: Syringe pump design affects start-up delay times because of free play of the syringe. These delays can be eliminated by a start-up bolus of 2 ml prior to connecting the infusion line to the patient.